While colloidal quantum dot photovoltaic devices (CQDPVs) can achieve a power conversion efficiency (PCE) of ≈12%, their insufficient optical absorption in the near-infrared (NIR) regime impairs efficient utilization of the full spectrum of visible light. Here, high-efficiency, solution-processed, hybrid series, tandem photovoltaic devices are developed featuring CQDs and organic bulk heterojunction (BHJ) photoactive materials for front- and back-cells, respectively. The organic BHJ back-cell efficiently harvests the transmitted NIR photons from the CQD front-cell, which reinforces the photon-to-current conversion at 350–1000 nm wavelengths. Optimizing the short-circuit current density balance of each sub-cell and creating a near ideal series connection using an intermediate layer achieve a PCE (12.82%) that is superior to that of each single-junction device (11.17% and 11.02% for the CQD and organic BHJ device, respectively). Notably, the PCE of the hybrid tandem device is the highest among the reported CQDPVs, including single-junction devices and tandem devices. The hybrid tandem device also exhibits almost negligible degradation after air storage for 3 months. This study suggests a potential route to improve the performance of CQDPVs by proper hybridization with NIR-absorbing photoactive materials.
Bibliographical noteFunding Information:
The authors gratefully acknowledge the support from the National Research Foundation (NRF) Grant funded by the Korean Government (MSIP, grant no. 2016R1A5A1012966 and 2019R1A2C2087218) and support from the Energy Technology Development Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant (no. 20163030013960 and 20163010012570.
© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
- colloidal quantum dot
- optical reinforcement
- organic bulk heterojunction
- solution process
- tandem solar cell
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)