Name: fabrication of robust nanoscale contact between a silver nanowire electrode and cds buffer layer in cu(in,ga)se2 thin-film solar cells
Uploaded: 2019-07-19T14:30:00
Description: Watch this Scientific Journal Video about Fabrication of Robust Nanoscale Contact between a Silver Nanowire Electrode and CdS Buffer Layer in CuIn,GaSe2 Thin-film Solar Cells at JoVE.com

This research was supported by the In-House Research and Development Program of the Korea Institute of Energy Research (KIER) (B9-2411) and the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (Grant NRF-2016R1D1A1B03934840).

1. Preparation of Mo-coated glass by DC magnetron sputtering
<ol>
	<li>Load cleaned glass substrates into a DC magnetron and pump down to below 4 x 10-6 Torr.</li>
	<li>Flow Ar gas and set the working pressure to 20 mTorr.</li>
	<li>Turn on plasma and increase the DC output power to 3 kW.</li>
	<li>After pre-sputtering of 3 min for target cleaning, begin the Mo deposition until the Mo film thickness reaches approximately 350 nm.</li>
	<li>Set the working pressure to 15 mTorr while maintaining the same output...

<ol>
	<li>Lee, 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=Determination+of+the+lateral+collection+length+of+charge+carriers+for+silver-nanowire-electrode-based+Cu(In,Ga)Se2+thin-film+solar+cells.">Determination of the lateral collection length of charge carriers for silver-nanowire-electrode-based Cu(In,Ga)Se2 thin-film solar cells.</a> Solar Energy. 180, 519-523 (2019).</li><li>Langley, D., 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=Flexible+transparent+conductive+materials+based+on+silver+nanowire+networks:+a+review.">Flexible transparent conductive materials based on silver nanowire networks: a review.</a> Nanotechnology. 24 (45), 452001 (2013).</li><li>Chung, C. -. 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=Silver+nanowire+composite+window+layers+for+fully+solution-deposited+thin-film+photovoltaic+devices.">Silver nanowire composite window layers for fully solution-deposited thin-film photovoltaic devices.</a> Advanced Materials. 24 (40), 5499-5504 (2012).</li><li>Liu, C. -. H., Yu, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Silver+nanowire-based+transparent,+flexible,+and+conductive+thin+film.">Silver nanowire-based transparent, flexible, and conductive thin film.</a> Nanoscale Research Letters. 6 (1), (2011).</li><li>Yu, Z., 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+flexible+silver+nanowire+electrodes+for+shape-memory+polymer+light-emitting+diodes.">Highly flexible silver nanowire electrodes for shape-memory polymer light-emitting diodes.</a> Advanced Materials. 23 (5), 664-668 (2011).</li><li>Chung, C. -. H., Hong, K. -. H., Lee, D. -. K., Yun, J. H., Yang, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ordered+vacancy+compound+formation+by+controlling+element+redistribution+in+molecular-level+precursor+solution+processed+CuInSe2+thin+films.">Ordered vacancy compound formation by controlling element redistribution in molecular-level precursor solution processed CuInSe2 thin films.</a> Chemistry of Materials. 27 (21), 7244-7247 (2015).</li><li>Kim, A., Won, Y., Woo, K., Kim, C. -. H., Moon, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+transparent+low+resistance+ZnO/Ag+Nanowire/ZnO+composite+electrode+for+thin+film+solar+cells.">Highly transparent low resistance ZnO/Ag Nanowire/ZnO composite electrode for thin film solar cells.</a> ACS Nano. 7 (2), 1081-1091 (2013).</li><li>Singh, M., Jiu, J., Sugahara, T., Suganuma, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thin-film+copper+indium+gallium+selenide+solar+cell+based+on+low-temperature+all-printing+process.">Thin-film copper indium gallium selenide solar cell based on low-temperature all-printing process.</a> ACS Applied Materials and Interfaces. 6 (18), 16297-16303 (2014).</li><li>Kim, A., Won, Y., Woo, K., Jeong, S., Moon, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=All-solution-processed+indium-free+transparent+composite+electrodes+based+on+Ag+Nanowire+and+Metal+Oxide+for+thin-film+solar+cells.">All-solution-processed indium-free transparent composite electrodes based on Ag Nanowire and Metal Oxide for thin-film solar cells.</a> Advanced Functional Materials. 24 (17), 2462-2471 (2014).</li><li>Shin, D., Kim, T., Ahn, B. T., Han, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Solution-processed+Ag+Nanowires+++PEDOT:PSS+hybrid+electrode+for+Cu(In,Ga)Se2+thin-film+solar+cells.">Solution-processed Ag Nanowires + PEDOT:PSS hybrid electrode for Cu(In,Ga)Se2 thin-film solar cells.</a> ACS Applied Materials and Interfaces. 7 (24), 13557-13563 (2015).</li><li>Wang, M., Choy, 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=All-nonvacuum-processed+CIGS+solar+cells+using+scalable+Ag+NWs/AZO-based+transparent+electrodes.">All-nonvacuum-processed CIGS solar cells using scalable Ag NWs/AZO-based transparent electrodes.</a> ACS Applied Materials and Interfaces. 8 (26), 16640-16648 (2016).</li><li>Jang, 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=Cu(In,Ga)Se2+thin+film+solar+cells+with+solution+processed+silver+nanowire+composite+window+layers:+buffer/window+junctions+and+their+effects.">Cu(In,Ga)Se2 thin film solar cells with solution processed silver nanowire composite window layers: buffer/window junctions and their effects.</a> Solar Energy Materials and Solar Cells. 170, 60-67 (2017).</li><li>Chung, C. -. H., Bob, B., Song, T. -. B., Yang, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Current-voltage+characteristics+of+fully+solution+processed+high+performance+CuIn(S,Se)2+solar+cells:+crossover+and+red+kink.">Current-voltage characteristics of fully solution processed high performance CuIn(S,Se)2 solar cells: crossover and red kink.</a> Solar Energy Materials and Solar Cells. 120, 642-646 (2014).</li><li>Lee, 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=Robust+nanoscale+contact+of+silver+nanowire+electrodes+to+semiconductors+to+achieve+high+performance+chalcogenide+thin+film+solar+cells.">Robust nanoscale contact of silver nanowire electrodes to semiconductors to achieve high performance chalcogenide thin film solar cells.</a> Nano Energy. 53, 675-682 (2018).</li></ol>

Note that the deposition time of the 2nd CdS layer must be optimized to achieve the optimal cell performance. As the deposition time increases, the thickness of the 2nd CdS layer increases, and consequently, the electrical contact will improve. However, further deposition of the 2nd CdS layer will result in a thicker layer that reduces light absorption, and the device efficiency will decrease. We achieved the best cell performance with 10 min of deposition time for the 2nd CdS ...

Silver nanowire (AgNW) networks have been extensively studied as an alternative to indium tin oxide (ITO) transparent conducting thin films due to their advantages over conventional transparent conducting oxides (TCOs) in terms of lower processing cost and better mechanical flexibility. Solution-processed AgNW network transparent conducting electrodes (TCEs) have thus been employed in Cu(In,Ga)Se2 (CIGS) thin-film solar cells1,2,3,4,5,6. Solution-processed AgNW TCEs are normally fabricated in the form of embedded-AgNW or sandwich-AgNW structures in a conductive matrix such as PEDOT:PSS, ITO, ZnO, etc.7,8,9,10,11 The matrix layers can enhance that the collection of the charge carriers present in the empty spaces of the AgNW network.
However, the matrix layers can generate interfacial defects between the matrix layer and underlying CdS buffer layer in CIGS thin-film solar cells12,13. The interfacial defects often cause a kink in the current density-voltage (J-V) curve, resulting in a low fill factor (FF) in the cell, which is detrimental to solar cell performance. We previously reported a method to resolve this issue by selectively depositing an additional thin CdS layer (2nd CdS layer) between the AgNWs and the CdS buffer layer14. The incorporation of an additional CdS layer enhanced the contact properties in the junction between the AgNW and CdS layers. Consequently, the carrier collection in the AgNW network was greatly improved, and the cell performance was enhanced. In this protocol, we describe the experimental procedure to fabricate robust electrical contact between the AgNW network and the CdS buffer layer using a 2nd CdS layer in a CIGS thin-film solar cell.

<table border="0" cellpadding="0" cellspacing="0" style="width:616px;" width="617">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Mo</td>
			<td style="width:115px;">Materion</td>
			<td style="width:119px;">Purity: 3N5</td>
			<td style="width:167px;">Mo sputtering</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Cu</td>
			<td style="width:115px;">5N Plus</td>
			<td style="width:119px;">Purity: 4N7</td>
			<td>CIGS deposition</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">In</td>
			<td style="width:115px;">5N Plus</td>
			<td style="width:119px;">Purity: 5N</td>
			<td>CIGS deposition</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ga</td>
			<td style="width:115px;">5N Plus</td>
			<td style="width:119px;">Purity: 5N</td>
			<td>CIGS deposition</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Se</td>
			<td style="width:115px;">5N Plus</td>
			<td style="width:119px;">Purity: 5N</td>
			<td>CIGS deposition</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ammonium acetate</td>
			<td style="width:115px;">Alfa Aesar</td>
			<td style="width:119px;">11599</td>
			<td>CdS reaction solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Ammonium hydroxide</td>
			<td style="width:115px;">Alfa Aesar</td>
			<td style="width:119px;">L13168</td>
			<td>CdS reaction solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Cadmium acetate dihydrate</td>
			<td style="width:115px;">Sigma-Aldrich</td>
			<td style="width:119px;">289159</td>
			<td>CdS reaction solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Thiourea</td>
			<td style="width:115px;">Sigma-Aldrich</td>
			<td style="width:119px;">T8656</td>
			<td>CdS reaction solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Silver Nanowire</td>
			<td style="width:115px;">ACSMaterial</td>
			<td style="width:119px;">AgNW-L30</td>
			<td>AgNW dispersion</td>
		</tr>
	</tbody>
</table>

fabrication of robust nanoscale contact between a silver nanowire electrode and cds buffer layer in cu(in,ga)se2 thin-film solar cells

Silver nanowire transparent electrodes have been employed as window layers for Cu(In,Ga)Se2 thin-film solar cells. Bare silver nanowire electrodes normally result in very poor cell performance. Embedding or sandwiching silver nanowires using moderately conductive transparent materials, such as indium tin oxide or zinc oxide, can improve cell performance. However, the solution-processed matrix layers can cause a significant number of interfacial defects between transparent electrodes and the CdS buffer, which can eventually result in low cell performance. This manuscript describes how to fabricate robust electrical contact between a silver nanowire electrode and the underlying CdS buffer layer in a Cu(In,Ga)Se2 solar cell, enabling high cell performance using matrix-free silver nanowire transparent electrodes. The matrix-free silver nanowire electrode fabricated by our method proves that the charge-carrier collection capability of silver nanowire electrode-based cells is as good as that of standard cells with sputtered ZnO:Al/i-ZnO as long as the silver nanowires and CdS have high-quality electrical contact. The high-quality electrical contact was achieved by depositing an additional CdS layer as thin as 10 nm onto the silver nanowire surface.

The layer structures of the CIGS solar cells with (a) standard ZnO:Al/i-ZnO and (b) AgNW TCE are shown in Figure 3. The surface morphology of CIGS is rough, and a nanoscale gap can form between the AgNW layer and the underlying CdS buffer layer. As highlighted in Figure 3A, the 2nd CdS layer can be selectively deposited onto the nanoscale gap to create a stable electrical contact. The detailed explanation on the format...

Watch this Scientific Journal Video about Fabrication of Robust Nanoscale Contact between a Silver Nanowire Electrode and CdS Buffer Layer in CuIn,GaSe2 Thin-film Solar Cells at JoVE.com

Fabrication of Robust Nanoscale Contact between a Silver Nanowire Electrode and CdS Buffer Layer in CuIn,GaSe2 Thin-film Solar Cells

In this protocol, we describe the detailed experimental procedure for the fabrication of a robust nanoscale contact between a silver nanowire network and CdS buffer layer in a CIGS thin-film solar cell.

Fabrication of Robust Nanoscale Contact between a Silver Nanowire Electrode and CdS Buffer Layer in Cu(In,Ga)Se2 Thin-film Solar Cells

Silver nanowire transparent electrodes have been employed as window layers for Cu(In,Ga)Se2 thin-film solar cells. Bare silver nanowire electrodes ...

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