Efficient Bidentate Molecules Passivation Strategy for High‐Performance and Stable Inorganic CsPbI2Br Perovskite Solar Cells. Issue 10 (14th July 2020)

• Record Type: Journal Article
• Authors: Li, Hui; Yin, Longwei
• Is Part Of: Solar RRL. Volume 4:Issue 10(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-07-14
• Subjects: defect passivation -- inorganic perovskites -- nonradiative recombination -- solar cells; Solar energy -- Periodicals; Photovoltaic power generation -- Periodicals; Solar energy -- Research -- Periodicals; Photovoltaic power generation -- Research -- Periodicals; Periodicals; 333.7923
• DOI: 10.1002/solr.202000268
• Languages: English
• ISSNs: 2367-198X

Abstract

Abstract : All inorganic mixed‐halide CsPbI2 Br perovskites with suitable bandgap and superior thermal durability have ignited rising interests in the field of perovskite solar cells (PSCs). However, the serious energy losses derived from deleterious trap‐assisted defects–induced notorious nonradiative recombination and inferior moisture durability are still the primary hindrance on the way to develop high‐performance CsPbI2 Br PSCs. Herein, a novel passivation strategy is presented by introducing dual‐functionalized bidentate molecule 2‐(2′‐thienyl)pyridine (2‐ThPy) to modulate perovskite crystallization and passivate halogen vacancy defects. Compared with monodentate counterparts, 2‐ThPy can anchor Pb 2+ sites via S and N atomic bonding simultaneously, and the synthesized CsPbI2 Br films exhibit enlarged grain size, show advantages to passivate defect states, and dramatically reduce trap density, thereby lessening the detrimental carrier recombination. Consequently, a champion power conversion efficiency (PCE) of 12.69% with negligible hysteresis is delivered for the fabricated CsPbI2 Br PSCs treated with 2‐ThPy. Moreover, the moisture stability of CsPbI2 Br PSCs with 2‐ThPy is also greatly enhanced, and the device without encapsulation retains 92% of initial PCE value after 30 days aging under 25 °C and 40% relative humidity in ambient environment. The bidentate molecules passivation strategy paves a promising avenue to implement efficient and stable inorganic PSCs. Abstract : A dual‐functionalized bidentate molecule 2‐(2′‐thienyl)pyridine (2‐ThPy) is introduced to modulate perovskite crystallization and passivate halogen vacancy defects. Compared with monodentate counterparts, 2‐ThPy can anchor Pb 2+ sites via S and N atomic bonding simultaneously. Consequently, 2‐ThPy‐treated CsPbI2 Br perovskite solar cells achieve a champion power conversion efficiency of 12.69% with negligible hysteresis and exhibit prominent moisture stability.