Open AccessEnhanced Near‐Infrared Photoresponse of Inverted Perovskite Solar Cells Through Rational Design of Bulk‐Heterojunction Electron‐Transporting Layers
Author(s) -
Chen ChihI,
Wu Shengfan,
Lu YenAn,
Lee ChiaChen,
Ho KuoChuan,
Zhu Zonglong,
Chen WenChang,
Chueh ChuChen
Publication year - 2019
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.201901714
Subject(s) - photocurrent , materials science , optoelectronics , polymer solar cell , heterojunction , fullerene , near infrared spectroscopy , perovskite (structure) , electron mobility , ternary operation , band gap , acceptor , energy conversion efficiency , optics , chemistry , computer science , physics , programming language , organic chemistry , crystallography , condensed matter physics
How to extend the photoresponse of perovskite solar cells (PVSCs) to the region of near‐infrared (NIR)/infrared light has become an appealing research subject in this field since it can better harness the solar irradiation. Herein, the typical fullerene electron‐transporting layer (ETL) of an inverted PVSC is systematically engineered to enhance device's NIR photoresponse. A low bandgap nonfullerene acceptor (NFA) is incorporated into the fullerene ETL aiming to intercept the NIR light passing through the device. However, despite forming type II charge transfer with fullerene, the blended NFA cannot enhance the device's NIR photoresponse, as limited by the poor dissociation of photoexciton induced by NIR light. Fortunately, it can be addressed by adding a p‐type polymer. The ternary bulk‐heterojunction (BHJ) ETL is demonstrated to effectively enhance the device's NIR photoresponse due to the better cascade‐energy‐level alignment and increased hole mobility. By further optimizing the morphology of such a BHJ ETL, the derived PVSC is finally demonstrated to possess a 40% external quantum efficiency at 800 nm with photoresponse extended to the NIR region (to 950 nm), contributing ≈9% of the overall photocurrent. This study unveils an effective and simple approach for enhancing the NIR photoresponse of inverted PVSCs.