Solution-processed colloidal quantum dot/organic hybrid tandem photovoltaic devices with 8.3% efficiency

Abstract

High-efficiency colloidal quantum dot (CQD)/organic hybrid tandem photovoltaic devices (HT-PVs) are developed through a low-temperature solution process. PbS-CQDs and blends of PTB7-Th/PC71BM are used as the active materials for front-and back-cells, respectively. The effective series connection of the two heterogeneous sub-cells is successfully achieved using MoOx/Au/ZnO-based intermediate recombination layers (IMLs). By fine-tuning the current densities in the sub-cells and optimizing the IMLs by balancing the optical and electrical properties, HT-PVs with power conversion efficiency (PCE) of 8.27% (V-OC of 1.27 V, J(SC) of 10.36 mA cm(-2), and FF of 0.63) are achieved. Furthermore, the fabrication of HT-PVs is achievable in ambient atmospheric conditions without thermal annealing that have comparable PCE (7.64%). The PCEs exhibited by these HT-PVs are thus far the highest values reported for CQD-based tandem photovoltaic devices.