The overall goal of this procedure is to produce and characterize functional upconverting desensitized solar cells. This is accomplished by first creating a solar cell with a double chamber assembly. The second step is to fill the chambers with electrolyte and the up conversion solution respectively.
Next, perform measurements of the device incident photon to current efficiency using a pump light source. The final step is to model the results and use data to confirm the up conversion effect is real. Ultimately, the experiment allows comparison with other up conversion devices using a figure of merit.
The main advantage of this technique over existing methods, such as our previously reported devices, is that this offers a fully integrated device. This method demonstrates that liquid up converter can be integrated into a standard photovoltaic device. Through the ization aspect of this method, one can provide insights into wheel versus artifact based up conversion effect.
This can also be applied to other systems, particularly in up conversion and enhanced photo takes. We developed a slanted pump beam technique. When you realize that our model system wasn't matching our data, The first step is to prepare a working electrode using a whole sheet of clean fluorine, doped tin oxide coated glass.
The sheet should measure 110 millimeter square and 2.3 millimeters thick to deposit a dense layer of titanium oxide on the sheet. Place the dry sheet on a hot plate with its conductive side up. Heat the glass to 450 degrees Celsius as the glass heats ready.
A one to nine solution of titanium dye, isop prop oxide, bis, acetyl acetate, and ethanol in a spray container. Once the glass is at 450 degrees Celsius, spray the solution onto it from a distance of about 100 millimeters with five sprays over its surface. Repeat this every 10 seconds for a total of 12 rounds.
Maintain the glass at 450 degrees Celsius for another five minutes. Then allow it to slowly cool to room temperature on the hot plate. Once cooled, place the glass conductive site up onto the screen printer table and use titanium dioxide paste to print one layer of the pattern shown.
After centering, cut the master plate into individual electrodes. The electrodes should have sufficient room around the printed film. For the later edition of a gasket, prepare a 20 millimolar titanium tetrachloride solution.
Immerse the electrodes and place in a preheated oven at 70 degrees Celsius. After recovering and thoroughly washing the electrodes, center them at 500 degrees Celsius for 30 minutes. Then allow them to slowly cool.
Prepare a 0.5 millimolar dye solution in this case, D 1 49 in a one to one mixture of nitrile and tur butanol. When the electrodes have cooled below 110 degrees Celsius, immerse them in the dye solution and leave overnight. After at least eight hours, remove the electrodes from the dye and thoroughly rinse them in acetyl nitrile.
Before drying with compressed air, prepare the counter electrodes using another sheet of 2.3 millimeter thick fluorine doped tin oxide coated glass. Cut into 18.3 millimeter by 27.5 millimeter pieces to create a filling port in each. Use a diamond tip dental burr in a small bench drill before drilling, immerse each counter electrode in water.
Then partially drill a small hole in the corner. Turn the piece over to complete the hole. After cleaning and drying the counter electrode, place it on a tile with a conductive side up.
Apply one drop of platic acid solution and spread with the end of a pipette. Place the tile onto a preheated 400 degrees Celsius hot plate for 15 minutes. Now turn to making the reflector use two millimeter thick, non-conductive glass.
Cut into 18.3 millimeter by 27.5 millimeter pieces with two holes drilled in adjacent corners along one long edge of the piece. After cleaning and drying the glass, use a low residue tape to affix it to the bench on three sides. With a glass in place, apply a drop of aluminum oxide paste.
Then draw the paste down with a glass rod. Once the film is dry, remove the tape and center at 500 degrees Celsius for 30 minutes. Begin assembly of the devices by preparing two batches of hot melt adhesive gaskets.
One batch is for the desensitized solar cells and is 25 micrometers thick. The other batch is for the up conversion chamber and is 120 micrometers thick. After placing the solar cell gasket on the corner of the counter electrode, the filling port should remain accessible.
Next place the working electrode over this with the printed area entirely inside the gasket. Be certain to obtain a good seal. Move the assembly to a hot plate that is at 120 degrees Celsius.
Apply pressure until the gasket softens and melts. Once that happens, remove the assembly from the hot plate and allow it to cool when.Cool. Place the second gasket on the reflector and be certain the filling ports are not covered.
Next place the desensitized solar cell on top with its printed area directly in front of the printed Illumina reflector. Heat the device on the hot plate while applying pressure until the gasket softens and adheres. For the next step, have the electrolyte solution prepared with the counter electrode facing up.
Place the device in a small plastic container with a vacuum tube attached. Put a drop of the electrolyte solution over the hole of the counter electrode. Next, place a piece of glass on top.
Seal the container and apply a vacuum for a few seconds. To draw electrolyte into the desensitized solar cell cavity. Produce the seals with gasket material that has been laminated onto aluminum foil, placed on a hot plate at 120 degrees Celsius.
Gasket material side up. After cleaning the back of the counter electrode thoroughly press the device against the gasket material for about five seconds to create a seal with the seal made. Move the assembly into a glove box there.
Introduced the triplet triplet annihilation up conversion solution into the back cavity. Once it is full, clean the surface and seal with aluminum backed gasket material working outside of the glove box. The next step is to create the electrical contacts with a sonic soldering iron.
Apply solder appropriate for use with glass to the exposed conducting coating of the working counter electrodes. Then apply normal solder to attach wires to the anode and cathode. Here, both anode and cathode wires have been attached to the device.
For additional encapsulation, apply UV curable epoxy to the open edges of the device. Once the epoxy has been cured, attach the anode and cathode wire to an open-ended BNC cable through a terminal block. The device is now ready for the measurement protocol.
The experimental setup for measuring device efficiency is depicted in this schematic. The measurements involve two light sources. One is a 670 nanometer continuous wave laser beam.
The pump beam, the second source is an incoherent quasi monochromatic probe beam generated by a xenon lamp. The laser beam passes through a neutral density filter and is reflected onto the device held in the sample holder. The lamp output is passed through a 405 nanometer of long pass filter and a chopper wheel operating at 29 hertz.
It then goes through a monochromator and a 4%beam splitter. One output of the beam splitter goes to a photo diode to record the power variation of the probe beam. The other is reflected onto the device mount the device in the sample holder and adjust the beams for the experiment.
This representation of the device will show how the light sources are used. Shine the pump beam onto the device so it is incident at an angle at which it only illuminates the up conversion layer. Align the prob beam to go through the desensitized cell active layer and intersect with the pump in the triplet triplet annihilation up conversion layer.
Make use of a dynamic signal acquisition device and current amplifier. To measure the short circuit current from the device. Use the output of the photo DDE to correct the solar cell Current density measurement.
Take measurements by scanning the prob beam across the visible spectrum in five nanometer increments. After making measurements using both the pump and prob beams, turn off the pump beam source and measure the integrated device current density. When this has been done, reconfigure the experiment to find the probe beam power incident on the device.
Do this by removing the device and placing the photo diode in the sample position to measure the current generated by the probe. The first measurements were done with the pump beam adjusted to arrive at the up conversion layer at a greater angle than the probe beam to avoid laser biasing of the desensitized cell. This plot of the incident photon to current efficiency enhancement as a function of wavelength demonstrates that enhancement takes place without significant biasing.
The inset gives the normalized gain in raw response. The difference in the current reflects the absorption peak of the sensitizer at 675 nanometers and is otherwise lost in the noise. Overall, the data compares favorably with a model of the incident photon to current efficiency.
Other measurements were made with the pump and probe beams, both going through the desensitized cell. In this case, there is a significant efficiency enhancement in the inset. The effect of the sensitizer is no longer seen at 675 nanometers.
The common path of the beams seems to enhance the performance across the entire visible spectrum and suggests laser biasing to test the effect of laser bias. A third set of measurements were made using an integrated device with the up conversion chamber left empty, but otherwise analogous to the one used in the first two measurements. In this case, the biasing effect is seen to be more significant due to the laser light being reflected back to the device.
While attending these procedures, it is important to remember to be critical of the data you collect. Don't forget that benzene are hazardous substance, so be sure to take all the appropriate precautions when handling it. After watching this video, you should be able to construct and characterize a fully integrated up conversion assisted DSC.
This technique allows for a fair comparison between DSCs with integrated up converters.
