Sintered CdTe Nanocrystal Thin Films: Determination of Optical Constants and Application in Novel Inverted Heterojunction Solar Cells

• Published in: IEEE transactions on nanotechnology Vol. 13; no. 3; pp. 551 - 556
• Main Authors: Woojun Yoon, Townsend, Troy K., Lumb, Matthew P., Tischler, Joseph G., Foos, Edward E.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.05.2014; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Cadmium selenides; Cadmium tellurides; CdSe; CdTe; Glass; heterojunction; Heterojunctions; Indium tin oxide; Intermetallics; nanocrystal; Nanocrystals; Optical films; photovoltaic (PV); Photovoltaic cells; quantum dot; Schottky barrier; Sintering; solar cell; Solar cells; Thin films
• ISSN: 1536-125X; 1941-0085
• DOI: 10.1109/TNANO.2014.2310139

In this paper, we report a novel heterojunction solar cell based on sintered CdTe and CdSe nanocrystal thin films using solution-based deposition. For the absorber layer, CdTe thin films were made using a layer-by-layer deposition process consisting of spin coating colloidal CdTe nanocrystals followed by a sintering step. The optical constants for these sintered CdTe films were accurately determined through a combination of optical modeling and measurements. For the all-solution processed p-n heterojunction, we focus on CdSe nanocrystal thin films due to their excellent compatibility with solution processing. For the optimized inverted structure (glass/ITO/CdSe/CdTe/Cr/Au), a high open-circuit voltage (V oc ) of 593 ± 32 mV with an efficiency of 1.9 ± 0.2% was obtained under simulated one sun illumination. These preliminary results demonstrate that this novel inverted heterojunction structure has the potential to produce a high-quality CdSe/CdTe junction for utilization in heterojunction solar cells.