Enhancing Photostability of Sn‐Pb Perovskite Solar Cells by an Alkylammonium Pseudo‐Halogen Additive. Issue 15 (1st March 2023)

• Record Type: Journal Article
• Authors: Wang, Jiantao; Uddin, Md Aslam; Chen, Bo; Ying, Xingjian; Ni, Zhenyi; Zhou, Ying; Li, Mingze; Wang, Mengru; Yu, Zhenhua; Huang, Jinsong
• Is Part Of: Advanced energy materials. Volume 13:Issue 15(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-03-01
• Subjects: efficiency -- photostability -- pseudo‐halogens -- Sn‐Pb perovskites -- solar cells; Energy harvesting -- Materials -- Periodicals; Energy conversion -- Materials -- Periodicals; Energy storage -- Materials -- Periodicals; Photovoltaics -- Periodicals; Fuel cells -- Periodicals; Thermoelectric materials -- Periodicals; 621.31
• DOI: 10.1002/aenm.202204115
• Languages: English
• ISSNs: 1614-6832

Abstract

Abstract: High‐performance tin‐lead perovskite solar cells (PSCs) are needed for all‐perovskite‐tandem solar cells. However, iodide related fast photodegradation severely limits the operational stability of Sn‐Pb perovskites despite the demonstrated high efficiency and thermal stability. Herein, this work employs an alkylammonium pseudo‐halogen additive to enhance the power conversion efficiency (PCE) and photostability of methylammonium (MA)‐free, Sn‐Pb PSCs. Density functional theory (DFT) calculations reveal that the pseudo‐halogen tetrafluoroborate (BF4 − ) has strong binding capacity with metal ions (Sn 2+ /Pb 2+ ) in the Sn‐Pb perovskite lattice, which lowers iodine vacancy formation. Upon combining BF4 − with an octylammonium (OA + ) cation, the PCE of the device with a built‐in light‐scattering layer is boosted to 23.7%, which represents a new record for Sn‐Pb PSCs. The improved efficiency benefits from the suppressed defect density. Under continuous 1 sun illumination, the OABF4 embodied PSCs show slower generation of interstitial iodides and iodine, which greatly improves the device photostability under open‐circuit condition. Moreover, the device based on OABF4 retains 88% of the initial PCE for 1000 h under the maximum‐power‐point tracking (MPPT) without cooling. Abstract : An octylammonium tetrafluoroborate (OABF4 ) additive is reported to enhance the efficiency and photostability for Sn‐Pb PSCs. OABF4 suppresses the iodide defect density in Sn‐Pb perovskite films, boosting the efficiency to 23.7%. The OABF4 ‐based perovskite solar cells show less interstitial‐iodides and I2 generation under light soaking, leading to greatly enhanced photostability, retaining 88% of the initial power conversion efficiency for 1000 h under 1‐sun operation.