Pyridine‐functionalized fullerene derivative as an independent electron transport layer enabling efficient and hysteresis‐free regular perovskite solar cells. Issue 11 (4th May 2021)

• Record Type: Journal Article
• Authors: Wang, Ye; Li, Bairu; Jia, Lingbo; Zhang, Bo; Zhang, He; Liang, Panfei; Chen, Muqing; Yang, Hua; Wang, Xinqing; Yang, Shangfeng
• Is Part Of: Nano select. Volume 2:Issue 11(2021)
• Page Start: 2192
• Page End: 2200
• Publication Date: 2021-05-04
• Subjects: electron transport layer -- fullerene -- interfacial engineering -- perovskite solar cells -- pyridine; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.5
• DOI: 10.1002/nano.202100050
• Languages: English
• ISSNs: 2688-4011

Abstract

Abstract: Suitable electron transport materials bearing good interfacial contact, improved electron transport ability, and matched energy levels are indispensable for developing efficient perovskite solar cells (PSCs). Herein, regular (n‐i‐p) planar Cs0.05 FA0.83 MA0.12 PbI2.55 Br0.45 (CsFAMA) PSC devices were fabricated using a pyridine‐functionalized fullerene derivative (C60 ‐3‐BPy) as an independent electron transport layer (ETL), delivering a decent power conversion efficiency (PCE) of 18.22%, which is dramatically higher than that of the control device based on [6, 6]‐phenyl‐C61 ‐butyric acid methyl ester (PCBM) ETL (15.70%). The energy level offset between C60 ‐3‐BPy and the perovskite is smaller than that based on PCBM ETL, which is beneficial for efficient ohmic contact in ETL/perovskite interface and improved open‐circuit voltage ( Voc ). Moreover, C60 ‐3‐BPy affords strong coordination interactions with perovskite, leading to an improved film quality of the perovskite layer with enlarged grain size and decreased trap state density, which contribute to facilitated electron extraction as reflected by the increases of both the fill factor (FF) and the short‐circuit current ( Jsc ). C60 ‐3‐BPy‐facilitated electron extraction further results in hysteresis‐free devices. Abstract : Regular n‐i‐p CsFAMA perovskite solar cells using C60 ‐3‐BPy as an independent ETL afforded a decent PCE of 18.22% with negligible current‐voltage hysteresis, which outperformed the control device with PCBM ETL (15.70%) due to the improved film quality of perovskite layer, the matched energy alignment of the device through the modified work function of the ITO electrode and improved charge extraction.