Improving Buried Interface Contact by Bidentate Anchoring for Inverted Perovskite Solar Cells

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 20; no. 38; pp. e2401256 - n/a
• Main Authors: Chen, Xian‐Min, Ye, Yong‐Chun, Feng, Shi‐Chi, Lv, Bing‐Hao, Wang, Jiang‐Ying, Tang, Jian‐Xin, Dou, Wei‐Dong
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.09.2024
• Subjects: bidentate ligands; buried interface modification; defect passivation; Energy conversion efficiency; Interface stability; inverted perovskite solar cells; Lewis base; Perovskites; Photovoltaic cells; Relative humidity; Solar cells; bidentate ligands; buried interface modification; inverted perovskite solar cells; defect passivation
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202401256

Nickel oxide (NiOx) is a promising hole transport layer (HTL) to fabricate efficient and large‐scale inverted perovskite solar cells (PSCs) due to its low cost and superior chemical stability. However, inverted PSCs based on NiOx are still lagging behind that of other HTL because of the poor quality of buried interface contact. Herein, a bidentate ligand, 4,6‐bis (diphenylphosphino) phenoxazine (2DPP), is used to regulate the NiOx surface and perovskite buried interface. The diphosphine Lewis base in the 2DPP molecule can coordinate both with NiOx and lead ions at NiOx/perovskite interface, leading to high‐quality perovskite films with minimized defects. It is found that the inverted PSCs with 2DPP‐modified buried interface exhibit double advantages of being both fast charge extraction and reduced nonradiative recombination, which is a combination of multiple factors including favorable energetic alignment, improved interface contact and strong binding between NiOx/2DPP and perovskite. The optimal PSC based on 2DPP modification yields a champion power conversion efficiency (PCE) of 21.9%. The unencapsulated PSC maintains above 75% of its initial PCE in the air with a relative humidity (RH) of 30–40% for 1000 h. A favorable buried interface is developed by the designed bidentate ligand (4,6‐bis (diphenylphosphino) phenoxazine, 2DPP) to construct a homogeneous buried interface, reduce defect‐induced recombination, and enhance interfacial carrier transport. The perovskite solar cells obtain a power conversion efficiency (PCE) of 21.9%. In addition, the device with 2DPP modification also exhibits excellent stability.