Electron-deficient 4-nitrophthalonitrile passivated efficient perovskite solar cells with efficiency exceeding 22%. Issue 8 (6th April 2021)

• Record Type: Journal Article
• Authors: Deng, Longhui; Zhang, Zhihao; Gao, Yifeng; Xiong, Qiu; Li, Zicheng; Xu, Jianbin; Zhang, Zilong; Chen, Jun; Gao, Peng
• Is Part Of: Sustainable energy & fuels. Volume 5:Issue 8(2021)
• Page Start: 2347
• Page End: 2353
• Publication Date: 2021-04-06
• Subjects: Renewable energy sources -- Periodicals; Fuel cells -- Periodicals; Electric batteries -- Periodicals; Electrochemistry -- Periodicals; 660.297
• DOI: 10.1039/d1se00188d
• Languages: English
• ISSNs: 2398-4902

Abstract

Abstract : We proved that electron-deficient 4-nitrophthalonitrile with σ–π accepting NO2 and –CN can passivate the charged defects in perovskite solar cells, which achieve a power conversion efficiency (PCE) of 22.1% and improved stability. Abstract : Perovskite solar cells (PSCs) have achieved tremendous success in advancing high power conversion efficiencies. However, defect-induced recombination at grain boundaries (GBs) and the surface of polycrystalline perovskites seriously hinder the further performance enhancement and environmental stability of PSCs. Here, a simple passivating molecule, 4-nitrophthalonitrile (4NPN) with σ–π accepting nitro (–NO2 ) and cyano groups (–CN), was employed to passivate the charged defects in perovskites. The addition of electron-deficient 4NPN into the perovskite layer of PSCs could not only enhance V OC and the FF, leading to high PCE over 22% but also improved environmental stability. These improvements were attributed to the effective passivation of the defects in the perovskite film by the strongly polarized nitro/cyano groups. In addition, the electron-deficient 4NPN could slightly adjust the energy level of the perovskite facilitating more efficient hole transfer. This work demonstrates the role of strong electron-withdrawing nitro/cyano groups in passivating the vacancy-defects of perovskites and 4NPN as a simple passivator conducive to obtaining high-performance PSCs.