Eco-Friendly AgBiS_2 Nanocrystal/ZnO Nanowire Heterojunction Solar Cells with Enhanced Carrier Collection

摘要

Solution-process compatibility and size-dependent bandgap tunability of colloidal quantum dots (CQDs) make them low-cost promising materials for next generation solar cells. Among CQD-based solar cells, heterojunction devices formed with PbS CQDs and ZnO exhibit impressive solar cell performance. However, the hazardous impact of Pb is causing concern. In addition, researches on CQD-based solar cells fabricated using non-toxic and abundant elements are still very limited. Therefore, eco-friendly CQDs for solar cell have drawn much attention. AgBiS_2 colloidal nanocrystals with a wide absorption band (0.4-1.2 μm) are one of the alternatives to PbS CQDs. However, the power conversion efficiencies of planar-type heterojunction solar cells using AgBiS_2 nanocrystals (NCs) (ITO/ZnO dense layer/AgBiS_2 NC layer/hole transport layers (eg. PTB7:MoO_x)/Ag) have been at most approximately 6% mainly due to the short carrier diffusion length of AgBiS_2.