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

• Published in: Advanced energy materials 2022-06, Vol.12 (24), p.n/a
• Main Authors: Park, Youngsang, Bae, Sung Yong, Kim, Taewan, Park, Seongmin, Oh, Jae Taek, Shin, Daekwon, Choi, Mahnmin, Kim, Hyojung, Kim, Bora, Lee, Doh C., Song, Jung Hoon, Choi, Hyosung, Jeong, Sohee, Kim, Younghoon
• Format: Article
• Language: English
• Subjects: Absorbers; Chemical reactions; Computer architecture; device stability; Efficiency; Electron states; Electron transport; electron transport layers; Energy conversion efficiency; InAs quantum dots; Indium arsenides; Intermetallic compounds; Metal oxides; narrow‐gap; organic photovoltaics; Photodegradation; Photons; Photovoltaic cells; Quantum dots; Solar cells; Stability; Thin films
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.202104018

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. Narrow‐gap indium arsenide colloidal quantum dot (CQD) solids are employed as an electron transporting layer in nonfullerene‐based organic photovoltaics and lead to high‐efficiency, air‐ and photo‐stable devices under 1 sun illumination. The best‐performing InAs CQD‐based device shows a power conversion efficiency of 15.1% while retaining original efficiency of over 80% under continuous 1 sun illumination over 1000 min in ambient air.