Solution-deposited CdTe nanocrystal thin-films for heterojunction solar cells

In this work, we develop a heterojunction solar cell using solution-based CdTe and CdSe deposition techniques. For the p-type absorber layer, CdTe thin-films were made using a layer-by-layer deposition process consisting of spin or spray coated colloidal CdTe nanocrystals followed by a sintering step. Among various buffer materials, we focus on CdSe nanocrystal thin-films due to excellent compatibility with solution processing. For the CdSe/CdTe heterojunction devices (Glass/ITO/CdSe/CdTe/Au) fabricated through spray processing, an improved open-circuit voltage of 549±8 mV with a fill factor of 50.1±1.3% was obtained under simulated one sun illumination, compared to the device with spin coating of CdTe. While the efficiency of the spray deposited device needs to be further improved, we demonstrate that spray-deposition has a potential to produce high junction quality for an efficient heterojunction solar cell.