Charge-Selective, Narrow-Gap Indium Arsenide Quantum Dot Layer for Highly Stable and Efficient Organic Photovoltaics

The past decade has seen a dramatic surge in the power conversion efficiency (PCE) of next-generation solution-processed thin-film solar cells rapidly closing the gap in PCE of commercially-available photovoltaic (PV) cells. Yet the operational stability of such new PVs leaves a lot to be desired. Specifically, chemical reaction with absorbers via high-energy photons transmitted through the typically-adapted metal oxide electron transporting layers (ETLs), and photocatalytic degradation at interfaces are considered detrimental to the device performance. Herein, the authors introduce a device architecture using the narrow-gap, Indium Arsenide colloidal quantum dots (CQDs) with discrete electronic states as an ETL in high-efficiency solution-processed PVs. High-performing PM6:Y6 organic PVs (OPVs) achieve a PCE of 15.1%. More importantly, as the operating stability of the device is significantly improved, retaining above 80% of the original PCE over 1000 min under continuous illumination, a Newport-certified PCE of 13.1% is reported for nonencapsulated OPVs measured under ambient air. Based on operando studies as well as optical simulations, it suggested that the InAs CQD ETLs with discrete energy states effectively cut-off high-energy photons while selectively collecting electrons from the absorber. The findings of this works enable high-efficiency solution-processed PVs with enhanced durability under operating conditions.