This work was partially supported by JSPS KAKENHI Grant Number 25871029, the Nippon Sheet Glass Foundation for Materials Science and Engineering, and the Tochigi Industrial Promotion Center. The National Institute of Technology, Oyama College, also assisted with the publication costs of this article.

1. Preparation of Indium-tin-oxide (ITO) Glass for Solar Cell Fabrication
<ol>
	<li>Cut the ITO/glass substrate.
	<ol>
		<li>Using a glass cutter, cut the ITO/glass substrate (10 cm &#215; 10 cm) into pieces measuring approximately 2 cm &#215; 2 cm.</li>
	</ol>
	</li>
	<li>Chemically etch the ITO conductive layer.
	<ol>
		<li>Using a digital multimeter, check that the top of the ITO/glass piece has a conductive side.</li>
		<li>Place masking tape on both sides of the ITO/glass piece, leaving a central area of 2 mm &#215; 2 cm in the middle. Using masking tape, protect the rest of the ITO conductive layer from the etching.</li>
		<li>Pour a few drops of HCl (1 M) onto the ITO conductive layer to remove the ITO conductive layer from the surface of the ITO/glass piece. After approximately 3 min, wipe off the HCl using a cotton swab, and then remove the masking tape.</li>
	</ol>
	</li>
	<li>Pretreat the ITO/glass piece.
	<ol>
		<li>Place the ITO/glass pieces in a glass case and fill the case with water.</li>
		<li>Place the glass case in a water bath that is two-thirds full of water and attach an ultrasonic cleaner. Then, turn on the ultrasonic cleaner for approximately 15 min to remove the few traces of chemical etchant remaining on the ITO/glass piece. Wash these pieces in an ultrasonic bath with water, acetone, and isopropyl alcohol, respectively, for 15 min each, and then dry them in a stream of dry air. Perform ultrasonication at an oscillatory frequency of 42 kHz.</li>
		<li>Place the ITO/glass pieces inside an ultraviolet-ozone (UV-O3) cleaner and run the machine for 30 min.</li>
	</ol>
	</li>
</ol>
2. Preparation of the Precursor Solution for the Photoactive Layer
<ol>
	<li>Dissolve 0.5 mg of poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole] (PFO-DBT) as an electron donor and 1.0 mg of Ti-alkoxide in 1 mL of chlorobenzene. Select the following Ti-alkoxides as electron acceptors: Ti(IV) isopropoxide, ethoxide, butoxide, and butoxide polymer. Then, dissolve 0.5 mg of PFO-DBT and 1.0 mg of [60]PCBM in 1 mL of chlorobenzene as a reference. 
	NOTE: Here, the HOMO-LUMO levels are as follows21. PFO-DBT: 5.4-3.53 eV, Ti(IV) isopropoxide: 7.49-3.86 eV, ethoxide: 7.55-3.90 eV, butoxide: 7.53-3.76 eV, and butoxide polymer: 7.57-3.83 eV.</li>
	<li>On a magnetic hot stirrer, heat the precursor solution to 70 &#176;C while stirring it with a stir bar at a rotational speed of 700 rpm. Do this for 20 min in the absence of light, until the solution is visually clear to the naked eye. Cool the solution to room temperature, again in the absence of light, for future use.</li>
</ol>
3. Fabrication of the Photoactive Layer
<ol>
	<li>Deposit the film by spin-coating.
	<ol>
		<li>Heat the precursor solution of the photoactive layer and the ITO/glass piece to 70 &#176;C. For 10 min, heat the precursor solution on a magnetic hot stirrer heated to 70 &#176;C and use a stir bar at a rotational speed of 700 rpm. Heat the ITO/glass piece on a ceramic hot plate heated to 70 &#176;C for 5 min.</li>
		<li>Place the ITO/glass piece at the center of the vacuum stage of the spin coater, heat it with a heat gun to around 70 &#176;C, and turn on the vacuum. 
		NOTE: The vacuum is created by using a vacuum pump with a pumping speed of 30 L/min. The ultimate pressure of the vacuum pump is 26.6 &#215; 103 Pa.</li>
		<li>Pour a few drops of the precursor solution of the photoactive layer onto the ITO/glass piece and start the spin coater at 2,000-6,000 rpm for 60 s in air. 
		NOTE: The volume of precursor solution is 0.5 mL, measured with a 1-mL spuit.</li>
		<li>Dry the surface of the photoactive layer for 10 min at room temperature in an air atmosphere in the absence of light to obtain a 50 nm-thick film as the photoactive layer.</li>
	</ol>
	</li>
	<li>Remove the extra film.
	<ol>
		<li>Wipe the extra photoactive layer from the surface of the ITO/glass piece with a cotton swab wetted with chlorobenzene.</li>
		<li>Dry the photoactive layer again for 10 min at room temperature in an air atmosphere in the absence of light. 
		NOTE: The temperature of our experiment room is maintained at 25 &#176;C.</li>
	</ol>
	</li>
</ol>
4. Fabrication of the Electrode
<ol>
	<li>Print the organic electrode.
	<ol>
		<li>Using a screen printer, print an organic electrode by placing poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) on the photoactive layer22. The metal mask is 50 &#181;m-thick, and the printing area is 5 mm &#215; 20 mm.</li>
		<li>Dry the organic electrode for 30 min at room temperature in an air atmosphere in the absence of light.</li>
	</ol>
	</li>
</ol>
5. Lamination for the Solar Cells
<ol>
	<li>Cut the glass substrate into pieces with dimensions of 1.5 cm &#215; 2.5 cm using a diamond cutter. Spread an epoxy resin onto the glass substrate using a plastic spatula. Place the glass substrate with epoxy resin on the photoactive layer to protect it.</li>
</ol>
6. Preparation for Measuring the Solar-cell Performance
<ol>
	<li>Clean the electrodes by wiping them with a cotton swab wetted with acetone. Attach a supporting electrode onto the ITO using an ultrasonic soldering system. Operate the soldering iron at a 42-kHz frequency and at 230 &#176;C.</li>
</ol>
7. Measurement of the Solar-cell Performance
<ol>
	<li>Measure the current&#8211;voltage (J-V) characteristics of the solar cells by using a direct-current voltage current source/monitor integrated system, with the solar simulator calibrated to provide a simulated AM1.5G of 100 mW/cm2 by the silicon photodiode. 
	NOTE: More detailed information about the measurement of the J-V curves can be found elsewhere23, 24.</li>
</ol>
8. Analysis of the Phase-separation structure
<ol>
	<li>Prepare individual films of photoactive layers constructed with Ti-alkoxide and PFO-DBT, using same method for solar-cell fabrication, without the organic electrode and without the lamination process.</li>
	<li>Use an optical microscope or a scanning electron microscope (SEM) to observe the morphology of the photoactive layer at a high magnification (50,000&#215;) in order to analyze the phase-separation structure. 
	NOTE: More detailed information about SEM operation can be found elsewhere25, 26.</li>
</ol>

<ol>
	<li>Price, C. S., Stuart, C. A., Yang, L., Zhou, H., You, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorine+substituted+conjugated+polymer+of+medium+band+gap+yields+7%+efficiency+in+polymer-fullerene+solar+cells.">Fluorine substituted conjugated polymer of medium band gap yields 7% efficiency in polymer-fullerene solar cells.</a> J. Am. Chem. Soc. 133 (12), 4625-4631 (2011).</li><li>Liang, Y. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=For+the+bright+future-Bulk+heterojunction+polymer+solar+cells+with+power+conversion+efficiency+of+7.4%.">For the bright future-Bulk heterojunction polymer solar cells with power conversion efficiency of 7.4%.</a> Adv. Mater. 22, 135-138 (2010).</li><li>Chu, T. -. Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bulk+heterojunction+solar+cells+using+thieno[3,4-c]pyrrole-4,6-dione+and+dithieno[3,2-b:2',3'-d]silole+copolymer+with+a+power+conversion+efficiency+of+7.3%.">Bulk heterojunction solar cells using thieno[3,4-c]pyrrole-4,6-dione and dithieno[3,2-b:2',3'-d]silole copolymer with a power conversion efficiency of 7.3%.</a> J. Am. Chem. Soc. 133 (12), 4250-4253 (2011).</li><li>Zhou, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+fluorinated+benzothiadiazole+as+a+structural+unit+for+a+polymer+solar+cell+of+7%+efficiency.">Development of fluorinated benzothiadiazole as a structural unit for a polymer solar cell of 7% efficiency.</a> Angew. Chem. Int. Ed. 50 (13), 2995-2998 (2011).</li><li>Janssen, J. A. R., Nelson, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Factors+limiting+device+efficiency+in+organic+photovoltaics.">Factors limiting device efficiency in organic photovoltaics.</a> Adv. Mater. 25 (13), 1847-1858 (2012).</li><li>Nelson, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polymer:fullerene+bulk+heterojunction+solar+cells.">Polymer:fullerene bulk heterojunction solar cells.</a> Mater. Today. 14 (10), 462-470 (2011).</li><li>He, Z., Zhong, C., Su, S., Xu, M., Wu, H., Cao, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enhanced+power-conversion+efficiency+in+polymer+solar+cells+using+an+inverted+device+structure.">Enhanced power-conversion efficiency in polymer solar cells using an inverted device structure.</a> Nat. Photonics. 6, 591-595 (2012).</li><li>Baena, J. P. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+efficient+planar+perovskite+solar+cells+through+band+alignment+engineering.">Highly efficient planar perovskite solar cells through band alignment engineering.</a> Energy Environ. Sci. 8, 2928-2934 (2015).</li><li>Shuttle, G. C., Hamilton, R., O'Regan, B. C., Nelson, J., Durrant, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Charge-density-based+analysis+of+the+current-voltage+response+of+polythiophene/fullerene+photovoltaic+devices.">Charge-density-based analysis of the current-voltage response of polythiophene/fullerene photovoltaic devices.</a> Proc. Natl. Acad. Sci. U.S.A. 107, 16448-16452 (2010).</li><li>Dibb, G. F. A., Kirchartz, T., Credgington, D., Durrant, R. J., Nelson, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analysis+of+the+relationship+between+linearity+of+corrected+photocurrent+and+the+order+of+recombination+in+organic+solar+cells.">Analysis of the relationship between linearity of corrected photocurrent and the order of recombination in organic solar cells.</a> J. Phys. Chem. Lett. 2 (19), 2407-2411 (2011).</li><li>Maurano, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transient+optoelectronic+analysis+of+charge+carrier+losses+in+a+selenophene:fullerene+blend+solar+cell.">Transient optoelectronic analysis of charge carrier losses in a selenophene:fullerene blend solar cell.</a> J. Phys. Chem. C. 115, 5947-5957 (2011).</li><li>Yuan, Y., Michinobu, T., Oguma, J., Kato, T., Miyake, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Attempted+inversion+of+semiconducting+features+of+platinum+polyyne+polymers:+A+new+approach+for+all-polymer+solar+cells.">Attempted inversion of semiconducting features of platinum polyyne polymers: A new approach for all-polymer solar cells.</a> Macromol. Chem. Phys. 214 (13), 1465-1472 (2013).</li><li>Granstr&#246;m, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laminated+fabrication+of+polymeric+photovoltaic+diodes.">Laminated fabrication of polymeric photovoltaic diodes.</a> Nature. 395, 257-260 (1998).</li><li>Hal, A. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photoinduced+electron+transfer+and+photovoltaic+response+of+a+MDMO-PPV:TiO2+bulk-heterojunction.">Photoinduced electron transfer and photovoltaic response of a MDMO-PPV:TiO2 bulk-heterojunction.</a> Adv. Mater. 15 (2), 118-121 (2003).</li><li>Das, K. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Controlling+the+processable+ZnO+and+polythiophene+interface+for+dye-densitized+thin+film+organic+solar+cells.">Controlling the processable ZnO and polythiophene interface for dye-densitized thin film organic solar cells.</a> Thin Solid Films. , 302-307 (2013).</li><li>Campoy-Quiles, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Morphology+evolution+via+self-organization+and+lateral+and+vertical+diffusion+in+polymer:fullerene+solar+cell+blends.">Morphology evolution via self-organization and lateral and vertical diffusion in polymer:fullerene solar cell blends.</a> Nature Materials. 7, 158-164 (2008).</li><li>Schmidt-Hansberg, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Moving+through+the+phase+diagram:+morphology+formation+in+solution+cast+polymer-fullerene+blend+films+for+organic+solar+cells.">Moving through the phase diagram: morphology formation in solution cast polymer-fullerene blend films for organic solar cells.</a> ACS Nano. 5 (11), 8579-8590 (2011).</li><li>Hou, Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+red-emitting+fluorene-based+copolymers.">Novel red-emitting fluorene-based copolymers.</a> J. Mater. Chem. 12, 2887-2892 (2002).</li><li>Zheng, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+C60+derivatives+for+polymer+photovoltaic+cell.">Synthesis of C60 derivatives for polymer photovoltaic cell.</a> Synth. Met. 135, 827-828 (2003).</li><li>Svensson, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High-performance+polymer+solar+cells+of+an+alternating+polyfluorene+copolymer+and+a+fullerene+derivative.">High-performance polymer solar cells of an alternating polyfluorene copolymer and a fullerene derivative.</a> Adv. Mater. 15 (12), 988-991 (2003).</li><li>Kato, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Morphology+control+for+highly+efficient+organic-inorganic+bulk+heterojunction+solar+cell+based+on+Ti-alkoxide.">Morphology control for highly efficient organic-inorganic bulk heterojunction solar cell based on Ti-alkoxide.</a> Thin Solid Films. 600, 98-102 (2016).</li><li>Shibata, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quasi-solid+dye+sensitized+solar+cells+with+ionic+liquid+Increase+in+efficiencies+by+specific+interaction+between+conductive+polymers+and+gelators.">Quasi-solid dye sensitized solar cells with ionic liquid Increase in efficiencies by specific interaction between conductive polymers and gelators.</a> Chem. Comm. 21, 2730-2731 (2003).</li><li>Wu, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+thermoplastic+gel+electrolyte+for+stable+quasi-solid-state+dye-sensitized+solar+cells.">A thermoplastic gel electrolyte for stable quasi-solid-state dye-sensitized solar cells.</a> Adv. Funct. Mater. 17 (15), 2645-2652 (2007).</li><li>Johansson, J. M. E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photovoltaic+and+interfacial+properties+of+heterojunctions+containing+dye+sensitized+dense+TiO2+and+Tri-arylamine+derivatives.">Photovoltaic and interfacial properties of heterojunctions containing dye sensitized dense TiO2 and Tri-arylamine derivatives.</a> Chem. Mater. 19 (8), 2017-2078 (2007).</li><li>Echlin, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Handbook of Sample Preparation for Scanning Electron Microscopy and X-Ray Microanalysis. , (2011).</li><li>Flegler, S. L., Heckman, J. W., Klomparens, K. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Scanning and Transmission Electron Microscopy: An Introduction. , (1993).</li><li>Cowan, R. S., Roy, A., Heeger, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recombination+in+polymer-fullerene+bulk+heterojunction+solar+cells.">Recombination in polymer-fullerene bulk heterojunction solar cells.</a> Phys. Rev. B. 82 (24), 245207 (2010).</li><li>Street, A. R., Cowan, S., Heeger, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+test+for+geminate+recombination+applied+to+organic+solar+cells.">Experimental test for geminate recombination applied to organic solar cells.</a> Phys. Rev. B. 82 (12), 121301 (2010).</li><li>Shuttle, G. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Charge+extraction+analysis+of+charge+carrier+densities+in+a+polythiophene/fullerene+solar+cell:+Analysis+of+the+origin+of+the+device+dark+current.">Charge extraction analysis of charge carrier densities in a polythiophene/fullerene solar cell: Analysis of the origin of the device dark current.</a> Appl. Phys. Lett. 93, 183501 (2008).</li><li>Shuttle, G. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bimolecular+recombination+losses+in+polythiophene:+Fullerene+solar+cells.">Bimolecular recombination losses in polythiophene: Fullerene solar cells.</a> Phys. Rev. B. 78, 113201 (2008).</li><li>Reyes-Reyes, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methanofullerene+elongated+nanostructure+formation+for+enhanced+organic+solar-cells.">Methanofullerene elongated nanostructure formation for enhanced organic solar-cells.</a> Thin Solid Films. 516 (1), 52-57 (2007).</li><li>Shuttle, G. C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+determination+of+the+rate+law+for+charge+carrier+decay+in+a+polythiophene:+Fullerene+solar+cell.">Experimental determination of the rate law for charge carrier decay in a polythiophene: Fullerene solar cell.</a> Appl. Phys. Lett. 92, 093311 (2008).</li><li>Mori, D., Benten, H., Ohkita, H., Ito, S., Miyake, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polymer/polymer+blend+solar+cells+improved+by+using+high-molecular-weight+fluorene-based+copolymer+as+electron+acceptor.">Polymer/polymer blend solar cells improved by using high-molecular-weight fluorene-based copolymer as electron acceptor.</a> ACS Appl. Mater. Interfaces. 4 (7), 3325-3329 (2012).</li><li>You, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+polymer+tandem+solar+cell+with+10.6%+power+conversion+efficiency.">A polymer tandem solar cell with 10.6% power conversion efficiency.</a> Nature Commun. 4, 1446 (2013).</li></ol>

The authors declare that they have no competing financial interests.

In order to utilize the molecule&#39;s bulkiness in this method, it is important to know the conditions for film formation by spin coating. First, the p-type and n-type semiconductors must be able to be dissolved in the solvents. When some material remains, it will become the large core of the domains in the photoactive layer. The use of an adequate commercial filter for individual solvents is recommended to remove the remaining material. Next, the precursor solution in which the molecules dissolve must be uniformly and ...

Organic photovoltaic devices are considered promising renewable energy sources due to their low manufacturing cost and light weight1-7. Because of these advantages, a large number of scientists have been immersed in this promising area. In the past decade, dye-sensitized, organic thin-film, and perovskite-sensitized solar cells have achieved significant progress in power conversion efficiency in this area8.
Specifically, organic thin-film solar cells and BHJ organic thin-film solar-cell technology are efficient and cost-effective solutions for the utilization of solar energy. Furthermore, the energy conversion efficiency has reached over 10% with the use of low-band-gap polymers as the electron donor and fullerene derivatives as the electron acceptor (Phenyl-C61-Butyric-Acid-Methyl Ester: [60]PCBM or Phenyl-C71-Butyric-Acid-Methyl Ester: [70]PCBM)9-11. Moreover, some researchers have already reported the importance of the BHJ structure in the photoactive layer, which is constructed with low-band-gap polymers and fullerene derivatives to obtain a high overall efficiency. However, fullerene derivatives are air-sensitive. Therefore, an air-stable electron-accepting material is required as an alternative. A few reports previously suggested new types of organic photovoltaic cells that used n-type semiconducting polymers or metal oxides as electron acceptors. These reports supported the development of air-stable, fullerene-free, organic thin-film solar cells12-15.
However, in contrast to fullerene systems or n-type semiconducting polymer systems, obtaining a satisfactory performance of the BHJ structure in the photoactive layer, which has charge separation and charge transfer abilities, is difficult in metal oxide systems16-17. Furthermore, fullerene derivatives and n-type semiconducting polymers have high solubility in many solvents. Therefore, it is easy to control the morphology of the photoactive layer by selecting an ink solution as the solvent, which is the precursor of the photoactive layer18-20. In contrast, in the case of metal alkoxide systems used in combination with an electron-donating polymer, both semiconductors are insoluble in almost all solvents. This is because metal alkoxides do not have a high solubility in the solvent. Therefore, the selectivity of solvents for morphology control is extremely low.
In this article, we report a method for controlling the morphology of the photoactive layer by using molecular bulkiness to fabricate printable and highly air-stable BHJ solar cells. We describe the importance of morphology control for the progress of fullerene-free BHJ solar cells.

<table border="0" cellpadding="0" cellspacing="0" width="625">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ti(IV) isopropoxide, 97%</td>
			<td style="width:103px;">Sigma Aldrich</td>
			<td style="width:119px;">205273</td>
			<td style="width:187px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ti(IV) ethoxide</td>
			<td style="width:103px;">Sigma Aldrich</td>
			<td style="width:119px;">244759</td>
			<td>Technical grade</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ti(IV) butoxide, 97%</td>
			<td style="width:103px;">Sigma Aldrich</td>
			<td style="width:119px;">244112</td>
			<td>Reagent grade</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ti(IV) butoxide polymer</td>
			<td style="width:103px;">Sigma Aldrich</td>
			<td style="width:119px;">510718</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole] (PFO-DBT)</td>
			<td style="width:103px;">Sigma Aldrich</td>
			<td style="width:119px;">754013</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">[6,6]-phenyl-C61 butyric acid methyl ester ([60]PCBM) 99.5%</td>
			<td style="width:103px;">Sigma Aldrich</td>
			<td style="width:119px;">684449</td>
			<td>Research grade</td>
		</tr>
		<tr height="84">
			<td height="84" style="height:84px;width:216px;">poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS)</td>
			<td style="width:103px;">Heraeus</td>
			<td style="width:119px;">Clevios S V3</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">1N Hydrochloric acid</td>
			<td style="width:103px;">Wako</td>
			<td style="width:119px;">083-01095</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Chlorobenzene 99.0%</td>
			<td style="width:103px;">Wako</td>
			<td style="width:119px;">032-07986</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Acetone 99.5%</td>
			<td style="width:103px;">Wako</td>
			<td style="width:119px;">016-00346</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Indium-tin oxide (ITO)-coated glass substrate</td>
			<td style="width:103px;">Geomatec</td>
			<td style="width:119px;">0002</td>
			<td>100&#215;100&#215;1.1t (mm)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Glass substrate</td>
			<td style="width:103px;">Matsunami Glass</td>
			<td style="width:119px;">S7213</td>
			<td>76&#215;26&#215;1.2t (mm)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Cotton tail&#160;</td>
			<td style="width:103px;">As one</td>
			<td style="width:119px;">1-8584-16</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Epoxy resin</td>
			<td style="width:103px;">Nichiban</td>
			<td style="width:119px;">AR-R30</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Plastic spatula</td>
			<td style="width:103px;">As one</td>
			<td style="width:119px;">2-3956-02</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ultrasonic cleaner</td>
			<td style="width:103px;">As one</td>
			<td style="width:119px;">AS482</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Magnetic hot&#160; stirrer</td>
			<td style="width:103px;">As one</td>
			<td style="width:119px;">RHS-1DN</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ceramic hotplate</td>
			<td style="width:103px;">As one</td>
			<td style="width:119px;">CHP-17DN</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Spin coater</td>
			<td style="width:103px;">Kyowariken</td>
			<td style="width:119px;">K-359 S1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Vacuum pump</td>
			<td style="width:103px;">ULVAC</td>
			<td style="width:119px;">DA-30S</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:216px;">UV-O3 cleaner</td>
			<td style="width:103px;">Filgen</td>
			<td style="width:119px;">UV253E</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Screen printer</td>
			<td style="width:103px;">Mitani Electronics</td>
			<td style="width:119px;">MEC-2400</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Ultrasonic Soldering system</td>
			<td style="width:103px;">Kuroda Techno</td>
			<td style="width:119px;">SUNBONDER USM-5</td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:216px;">Direct-current voltage and current source/monitor integrated system</td>
			<td style="width:103px;">San-Ei Electric</td>
			<td style="width:119px;">XES-40S1</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Scanning electron microscope</td>
			<td style="width:103px;">JEOL Ltd.</td>
			<td style="width:119px;">JSM-7800</td>
			<td></td>
		</tr>
	</tbody>
</table>

morphology control for fully printable organic&#8211;inorganic bulk-heterojunction solar cells based on a ti-alkoxide and semiconducting polymer

The photoactive layer of a typical organic thin-film bulk-heterojunction (BHJ) solar cell commonly uses fullerene derivatives as the electron-accepting material. However, fullerene derivatives are air-sensitive; therefore, air-stable material is needed as an alternative. In the present study, we propose and describe the properties of Ti-alkoxide as an alternative electron-accepting material to fullerene derivatives to create highly air-stable BHJ solar cells. It is well-known that controlling the morphology in the photoactive layer, which is constructed with fullerene derivatives as the electron acceptor, is important for obtaining a high overall efficiency through the solvent method. The conventional solvent method is useful for high-solubility materials, such as fullerene derivatives. However, for Ti-alkoxides, the conventional solvent method is insufficient, because they only dissolve in specific solvents. Here, we demonstrate a new approach to morphology control that uses the molecular bulkiness of Ti-alkoxides without the conventional solvent method. That is, this method is one approach to obtain highly efficient, air-stable, organic-inorganic bulk-heterojunction solar cells.

We have presented a protocol for fabricating fully printable organic-inorganic BHJ solar cells, as well as a method for controlling the phase-separation structure. The solar-cell performance has been extensively investigated27-31 when Ti(IV) isopropoxide and ethoxide were used as electron-accepting materials (Figure 1). These solar cells exhibited a short-circuit current density (Jsc) that is approximately eight times higher than that of devices using the &#34;...

Watch this Scientific Journal Video about Morphology Control for Fully Printable OrganicÃ¢â‚¬â€œInorganic Bulk-heterojunction Solar Cells Based on a Ti-alkoxide and Semiconducting Polymer at JoVE.com

Morphology Control for Fully Printable Organic&#8211;Inorganic Bulk-heterojunction Solar Cells Based on a Ti-alkoxide and Semiconducting Polymer

A method for fully printable, fullerene-free, highly air-stable, bulk-heterojunction solar cells based on Ti alkoxides as the electron acceptor and the electron-donating polymer fabrication is described here. Moreover, a method for controlling the morphology of the photoactive layer through the molecular bulkiness of the Ti-alkoxide units is reported.

The photoactive layer of a typical organic thin-film bulk-heterojunction (BHJ) solar cell commonly uses fullerene derivatives as the electron-accepting ...

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JoVE Journal

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9.0K Views.  National Institute of Technology, Oyama College. A method for fully printable, fullerene-free, highly air-stable, bulk-heterojunction solar cells based on Ti alkoxides as the electron acceptor and the electron-donating polymer fabrication is described here. Moreover, a method for controlling the morphology of the photoactive layer through the molecular bulkiness of the Ti-alkoxide units is reported.

Video: Morphology Control for Fully Printable Organic–Inorganic Bulk-heterojunction Solar Cells Based on a Ti-alkoxide and Semiconducting Polymer

Micropunching Lithography for Generating Micro- and Submicron-patterns on Polymer Substrates

Conducting polymers have attracted great attention since the discovery of high conductivity in doped polyacetylene in 19771. They offer the advantages of low weight, easy tailoring of properties and a wide spectrum of applications2,3. Due to sensitivity of conducting polymers to environmental conditions (e.g., air, oxygen, moisture, high temperature and chemical solutions), lithographic techniques present significant technical challenges when working with these materials4. For example, current photolithographic methods, such as ultra-violet (UV), are unsuitable for patterning the conducting polymers due to the involvement of wet and/or dry etching processes in these methods. In addition, current micro/nanosystems mainly have a planar form5,6. One layer of structures is built on the top surfaces of another layer of fabricated features. Multiple layers of these structures are stacked together to form numerous devices on a common substrate. The sidewall surfaces of the microstructures have not been used in constructing devices. On the other hand, sidewall patterns could be used, for example, to build 3-D circuits, modify fluidic channels and direct horizontal growth of nanowires and nanotubes.
A macropunching method has been applied in the manufacturing industry to create macropatterns in a sheet metal for over a hundred years. Motivated by this approach, we have developed a micropunching lithography method (MPL) to overcome the obstacles of patterning conducting polymers and generating sidewall patterns. Like the macropunching method, the MPL also includes two operations (Fig. 1): (i) cutting; and (ii) drawing. The "cutting" operation was applied to pattern three conducting polymers4, polypyrrole (PPy), Poly(3,4-ethylenedioxythiophen)-poly(4-styrenesulphonate) (PEDOT) and polyaniline (PANI). It was also employed to create Al microstructures7. The fabricated microstructures of conducting polymers have been used as humidity8, chemical8, and glucose sensors9. Combined microstructures of Al and conducting polymers have been employed to fabricate capacitors and various heterojunctions9,10,11. The "cutting" operation was also applied to generate submicron-patterns, such as 100- and 500-nm-wide PPy lines as well as 100-nm-wide Au wires. The "drawing" operation was employed for two applications: (i) produce Au sidewall patterns on high density polyethylene (HDPE) channels which could be used for building 3D microsystems12,13,14, and (ii) fabricate polydimethylsiloxane (PDMS) micropillars on HDPE substrates to increase the contact angle of the channel15.

A micropunching lithography approach is developed to generate micro- and submicron-patterns on top, sidewall and bottom surfaces of polymer substrates. It overcomes the obstacles of patterning conducting polymers and generating sidewall patterns. This method allows rapid fabrication of multiple features and is free of aggressive chemistry.

Conducting polymers have attracted great attention since the discovery of high conductivity in doped polyacetylene in 19771. They offer the advantages of ...

Integrating a Triplet-triplet Annihilation Up-conversion System to Enhance Dye-sensitized Solar Cell Response to Sub-bandgap Light

The poor response of dye-sensitized solar cells (DSCs) to red and infrared light is a significant impediment to the realization of higher photocurrents and hence higher efficiencies. Photon up-conversion by way of triplet-triplet annihilation (TTA-UC) is an attractive technique for using these otherwise wasted low energy photons to produce photocurrent, while not interfering with the photoanodic performance in a deleterious manner. Further to this, TTA-UC has a number of features, distinct from other reported photon up-conversion technologies, which renders it particularly suitable for coupling with DSC technology. In this work, a proven high performance TTA-UC system, comprising a palladium porphyrin sensitizer and rubrene emitter, is combined with a high performance DSC (utilizing the organic dye D149) in an integrated device. The device shows an enhanced response to sub-bandgap light over the absorption range of the TTA-UC sub-unit resulting in the highest figure of merit for up-conversion assisted DSC performance to date.

An integrated device, incorporating a dye-sensitized solar cell and triplet-triplet annihilation up-conversion unit was produced, affording enhanced light harvesting, from a wider section of the solar spectrum. Under modest irradiation levels a significantly enhanced response to low energy photons was demonstrated, yielding a record figure of merit for dye-sensitized solar cells.

The poor response of dye-sensitized solar cells (DSCs) to red and infrared light is a significant impediment to the realization of higher photocurrents ...

Printing Fabrication of Bulk Heterojunction Solar Cells and In Situ Morphology Characterization

Polymer-based materials hold promise as low-cost, flexible efficient photovoltaic devices. Most laboratory efforts to achieve high performance devices have used devices prepared by spin coating, a process that is not amenable to large-scale fabrication. This mismatch in device fabrication makes it difficult to translate quantitative results obtained in the laboratory to the commercial level, making optimization difficult. Using a mini-slot die coater, this mismatch can be resolved by translating the commercial process to the laboratory and characterizing the structure formation in the active layer of the device in real time and in situ as films are coated onto a substrate. The evolution of the morphology was characterized under different conditions, allowing us to propose a mechanism by which the structures form and grow. This mini-slot die coater offers a simple, convenient, material efficient route by which the morphology in the active layer can be optimized under industrially relevant conditions. The goal of this protocol is to show experimental details of how a solar cell device is fabricated using a mini-slot die coater and technical details of running in situ structure characterization using the mini-slot die coater.

Printing Fabrication of Bulk Heterojunction Solar Cells and In Situ Morphology Characterization

Here, we present a protocol to fabricate organic thin film solar cells using a mini-slot die coater and related in-line structure characterizations using synchrotron scattering techniques.

Polymer-based materials hold promise as low-cost, flexible efficient photovoltaic devices. Most laboratory efforts to achieve high performance devices ...

Monovalent Cation Doping of CH3NH3PbI3 for Efficient Perovskite Solar Cells

Here, we demonstrate the incorporation of monovalent cation additives into CH3NH3PbI3 perovskite in order to adjust the optical, excitonic, and electrical properties. The possibility of doping was investigated by adding monovalent cation halides with similar ionic radii to Pb2+, including Cu+, Na+, and Ag+. A shift in the Fermi level and a remarkable decrease of sub-bandgap optical absorption, along with a lower energetic disorder in the perovskite, was achieved. An order-of-magnitude enhancement in the bulk hole mobility and a significant reduction of transport activation energy within an additive-based perovskite device was attained. The confluence of the aforementioned improved properties in the presence of these cations led to an enhancement in the photovoltaic parameters of the perovskite solar cell. An increase of 70 mV in open circuit voltage for AgI and a 2 mA/cm2 improvement in photocurrent density for NaI- and CuBr-based solar cells were achieved compared to the pristine device. Our work paves the way for further improvements in the optoelectronic quality of CH3NH3PbI3 perovskite and subsequent devices. It highlights a new avenue for investigations on the role of dopant impurities in crystallization and controls the electronic defect density in perovskite structures.

Monovalent Cation Doping of CH3NH3PbI3 for Efficient Perovskite Solar Cells

Here, we present a protocol to adjust the properties of solution-processed CH3NH3PbI3 through the incorporation of monovalent cation additives in order to achieve highly efficient perovskite solar cells.

Here, we demonstrate the incorporation of monovalent cation additives into CH3NH3PbI3 perovskite in order to adjust the optical, excitonic, and electrical ...

Electrospinning of Photocatalytic Electrodes for Dye-sensitized Solar Cells

This work demonstrates a protocol to fabricate a fiber-based photoanode for dye-sensitized solar cells, consisting of a light-scattering layer made of electrospun titanium dioxide nanofibers (TiO2-NFs) on top of a blocking layer made of commercially available titanium dioxide nanoparticles (TiO2-NPs). This is achieved by first electrospinning a solution of titanium (IV) butoxide, polyvinylpyrrolidone (PVP), and glacial acetic acid in ethanol to obtain composite PVP/TiO2 nanofibers. These are then calcined at 500 &#176;C to remove the PVP and to obtain pure anatase-phase titania nanofibers. This material is characterized using scanning electron microscopy (SEM) and powder X-ray diffraction (XRD). The photoanode is prepared by first creating a blocking layer through the deposition of a TiO2-NPs/terpineol slurry on a fluorine-doped tin oxide (FTO) glass slide using doctor blading techniques. A subsequent thermal treatment is performed at 500 &#176;C. Then, the light-scattering layer is formed by depositing a TiO2-NFs/terpineol slurry on the same slide, using the same technique, and calcinating again at 500 &#176;C. The performance of the photoanode is tested by fabricating a dye-sensitized solar cell and measuring its efficiency through J-V curves under a range of incident light densities, from 0.25-1 Sun.

The overall goal of this project was to use electrospinning to fabricate a photoanode with improved performance for dye-sensitized solar cells.

This work demonstrates a protocol to fabricate a fiber-based photoanode for dye-sensitized solar cells, consisting of a light-scattering layer made of ...

In Situ Monitoring of the Accelerated Performance Degradation of Solar Cells and Modules: A Case Study for Cu(In,Ga)Se2 Solar Cells

The levelized cost of electricity (LCOE) of photovoltaic (PV) systems is determined by, among other factors, the PV module reliability. Better prediction of degradation mechanisms and prevention of module field failure can consequently decrease investment risks as well as increase the electricity yield. An improved knowledge level can for these reasons significantly decrease the total costs of PV electricity. 
In order to better understand and minimize the degradation of PV modules, the occurring degradation mechanisms and conditions should be identified. This should preferably happen under combined stresses, since modules in the field are also simultaneously exposed to multiple stress factors. Therefore, two 'Combined Stress test with in situ measurement' setups have been designed and constructed. These setups allow the simultaneous use of humidity, temperature, illumination, and electrical biases as independently controlled stress factors on solar cells and minimodules. The setups also allow real-time monitoring of the electrical properties of these samples. This protocol presents these setups and describes the experimental possibilities. Moreover, results obtained with these setups are also presented: various examples about the influence of both deposition and degradation conditions on the stability of thin film Cu(In,Ga)Se2 (CIGS) as well as Cu2ZnSnSe4 (CZTS) solar cells are described. Results on the temperature dependency of CIGS solar cells are also presented.

In Situ Monitoring of the Accelerated Performance Degradation of Solar Cells and Modules: A Case Study for CuIn,GaSe2 Solar Cells

Two &#39;Combined Stress test with in situ measurement&#39; setups, which allow real-time monitoring of accelerated degradation of solar cells and modules, were designed and constructed. These setups allow the simultaneous use of humidity, temperature, electrical biases, and illumination as independently controlled stress factors. The setups and various experiments executed are presented.

The levelized cost of electricity (LCOE) of photovoltaic (PV) systems is determined by, among other factors, the PV module reliability. Better prediction ...

Study of Siphon Breaker Experiment and Simulation for a Research Reactor

Under the design conditions of a research reactor, the siphon phenomenon induced by pipe rupture can cause continuous outward flow of water. To prevent this outflow, a control device is required. A siphon breaker is a type of safety device that can be utilized to control the loss of coolant water effectively.
To analyze the characteristics of siphon breaking, a real-scale experiment was conducted. From the results of the experiment, it was found that there are several design factors that affect the siphon breaking phenomenon. Therefore, there is a need to develop a theoretical model capable of predicting and analyzing the siphon breaking phenomenon under various design conditions. Using the experimental data, it was possible to formulate a theoretical model that accurately predicts the progress and the result of the siphon breaking phenomenon. The established theoretical model is based on fluid mechanics and incorporates the Chisholm model to analyze two-phase flow. From Bernoulli&#39;s equation, the velocity, quantity, undershooting height, water level, pressure, friction coefficient, and factors related to the two-phase flow could be obtained or calculated. Moreover, to utilize the model established in this study, a siphon breaker analysis and design program was developed. The simulation program operates on the theoretical model basis and returns the result as a graph. The user can confirm the possibility of the siphon breaking by checking the shape of the graph. Furthermore, saving the entire simulation result is possible and it can be used as a resource for analyzing the real siphon breaking system.
In conclusion, the user can confirm the status of the siphon breaking and design the siphon breaker system using the program developed in this study.

The siphon breaking phenomenon was investigated experimentally and a theoretical model was proposed. A simulation program based on the theoretical model was developed and the results of the simulation program were compared with experimental results. It was concluded that the results of the simulation program matched the experimental results well.

Under the design conditions of a research reactor, the siphon phenomenon induced by pipe rupture can cause continuous outward flow of water. To prevent ...

Indoor Experimental Assessment of the Efficiency and Irradiance Spot of the Achromatic Doublet on Glass (ADG) Fresnel Lens for Concentrating Photovoltaics

We present a method to characterize achromatic Fresnel lenses for photovoltaic applications. The achromatic doublet on glass (ADG) Fresnel lens is composed of two materials, a plastic and an elastomer, whose dispersion characteristics (refractive index variation with wavelength) are different. We first designed the lens geometry and then used ray-tracing simulation, based on the Monte Carlo method, to analyze its performance from the point of view of both optical efficiency and the maximum attainable concentration. Afterwards, ADG Fresnel lens prototypes were manufactured using a simple and reliable method. It consists of a prior injection of plastic parts and a consecutive lamination, together with the elastomer and a glass substrate to fabricate the parquet of ADG Fresnel lenses. The accuracy of the manufactured lens profile is examined using an optical microscope while its optical performance is evaluated using a solar simulator for concentrator photovoltaic systems. The simulator is composed of a xenon flash lamp whose emitted light is reflected by a parabolic mirror. The collimated light has a spectral distribution and an angular aperture similar to the real Sun. We were able to assess the optical performance of the ADG Fresnel lenses by taking photographs of the irradiance spot cast by the lens using a charge-coupled device (CCD) camera and measuring the photocurrent generated by several types of multi junction (MJ) solar cells, which have been previously characterized at a solar simulator for concentrator solar cells. These measurements have demonstrated the achromatic behavior of ADG Fresnel lenses and, as a consequence, the suitability of the modelling and manufacturing methods.

Indoor Experimental Assessment of the Efficiency and Irradiance Spot of the Achromatic Doublet on Glass ADG Fresnel Lens for Concentrating Photovoltaics

The achromatic doublet on glass (ADG) Fresnel lens makes use of two materials with differing dispersion to reduce chromatic aberration and increase attainable concentration. In this paper, a protocol for the complete characterization of the ADG Fresnel lens is presented.

We present a method to characterize achromatic Fresnel lenses for photovoltaic applications. The achromatic doublet on glass (ADG) Fresnel lens is ...

The Modular Design and Production of an Intelligent Robot Based on a Closed-Loop Control Strategy

Intelligent robots are part of a new generation of robots that are able to sense the surrounding environment, plan their own actions and eventually reach their targets. In recent years, reliance upon robots in both daily life and industry has increased. The protocol proposed in this paper describes the design and production of a handling robot with an intelligent search algorithm and an autonomous identification function.
First, the various working modules are mechanically assembled to complete the construction of the work platform and the installation of the robotic manipulator. Then, we design a closed-loop control system and a four-quadrant motor control strategy, with the aid of debugging software, as well as set steering gear identity (ID), baud rate and other working parameters to ensure that the robot achieves the desired dynamic performance and low energy consumption. Next, we debug the sensor to achieve multi-sensor fusion to accurately acquire environmental information. Finally, we implement the relevant algorithm, which can recognize the success of the robot&#39;s function for a given application.
The advantage of this approach is its reliability and flexibility, as the users can develop a variety of hardware construction programs and utilize the comprehensive debugger to implement an intelligent control strategy. This allows users to set personalized requirements based on their needs with high efficiency and robustness.

We present a protocol on modular design and production of intelligent robots to help scientific and technical workers design intelligent robots with special production tasks based on personal needs and individualized design.

Intelligent robots are part of a new generation of robots that are able to sense the surrounding environment, plan their own actions and eventually reach ...

Installation Method to Enhance Quality Control for Fiber Reinforced Polymer Spike Anchors

Fiber reinforced polymer (FRP) anchors are a promising way to enhance the performance of externally-bonded FRPs applied to existing structures, as they can delay or even prevent debonding failure. However, a major concern faced by designers is the premature failure of the anchors due to stress concentration. Poor installation quality and preparation of the clearance holes can result in stress concentration that provokes this premature failure. This paper deals with an installation method that aims to reduce the impact of the stress concentration and to provide a proper quality control of the preparation of the drill hole. The method involves three parts: the drilling and cleaning of the holes, the smoothing of the hole edges with a customized drill bit, and the installation of the anchor itself, including the impregnation of the anchor dowel and its insertion. Anchor fans (the free length of the spikes) are then bonded to the external FRP reinforcement. For the end anchorage, and in the case of reinforcements with multiple plies, it is recommended that the anchor fan be inserted between two plies to assist the stress-transfer mechanism. 
The proposed procedure is complemented with a design approach for spike anchors, based on an extensive database. It is proposed that the design follow a number of steps, namely: selection of the anchor diameter and subsequent tensile strength of the connector (that is to say, the anchor before fanning out the free end), evaluation of the reduction in the tensile strength due to bending, provision of enough embedment to prevent slippage failure, and consideration of the number and spacing of anchors for a given reinforcement. In this sense, it should be noted that further research is needed in order to obtain a general expression for the contribution of spike anchors to overall bond strength of FRP reinforcements.

This manuscript presents a method for controlling the quality of installation for spike anchors designed to delay delamination of externally bonded fiber reinforced polymers. The protocol includes the preparation of the drill hole and the insertion process. The most influential parameters on the efficiency of the anchors are discussed.

Fiber reinforced polymer (FRP) anchors are a promising way to enhance the performance of externally-bonded FRPs applied to existing structures, as they ...