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Reconfiguration of Interfacial and Bulk Energy Band Structure for High‐Performance Organic and Thermal–Stability Enhanced Perovskite Solar Cells
Author(s) -
Guo Yaxiong,
Lei Hongwei,
Wang Changlei,
Ma Junjie,
Chen Cong,
Zheng Xiaolu,
Yang Guang,
Xiong Liangbin,
Tan Zuojun
Publication year - 2020
Publication title -
solar rrl
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.544
H-Index - 37
ISSN - 2367-198X
DOI - 10.1002/solr.201900482
Subject(s) - materials science , perovskite (structure) , energy conversion efficiency , dangling bond , chemical engineering , iodide , thermal stability , solar cell , perovskite solar cell , band gap , nanotechnology , optoelectronics , inorganic chemistry , chemistry , silicon , engineering
Tin oxide (SnO 2 ) offers its advantages in widespread applications that require efficient carrier transport. However, the usages of SnO 2 in organic solar cells are hindered because of dangling bonds on the surface of SnO 2 . Herein, PFN‐Br as an interfacial layer to tailor the work function of SnO 2 is adopted, making it an ideal candidate for interfacial material in organic electronics. Meanwhile, such an efficient SnO 2 /PFN‐Br electron transport layer (ETL) can also be applied to perovskite devices and achieve competitive efficiency. To eliminate current–voltage hysteresis and improve poor thermodynamic stability of perovskite solar cells (PSCs), 5 mol% of guanidinium iodide (GAI) into the (MA) x (FA) 1 − x PbI 3 precursor solution is incorporated, enabling the formation of triple‐cation perovskite films with excellent optoelectronic quality and stability. The combination of an SnO 2 /PFN‐Br ETL and GAI doping strategy finally delivers power conversion efficiencies over 21% and negligible current–voltage hysteresis in planar PSCs. These improvements arise from the strong hydrogen bonding caused by the incorporation of GA + . It can stiffen the inorganic Pb–I lattice of the unit cell and restrain the formation of iodine vacancies defects. Moreover, the strong hydrogen bonding can immobilize iodide ion and thus enhance the thermal stability of the corresponding device.