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Grain Boundary Defect Passivation in Quadruple Cation Wide‐Bandgap Perovskite Solar Cells
Author(s) -
Reza Khan Mamun,
Gurung Ashim,
Bahrami Behzad,
Chowdhury Ashraful Haider,
Ghimire Nabin,
Pathak Rajesh,
Rahman Sheikh Ifatur,
Laskar Md Ashiqur Rahman,
Chen Ke,
Bobba Raja Sekhar,
Lamsal Buddhi Sagar,
Biswas Liton Kumar,
Zhou Yue,
Logue Brian,
Qiao Quinn
Publication year - 2021
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.202000740
Subject(s) - passivation , formamidinium , perovskite (structure) , grain boundary , band gap , materials science , optoelectronics , nanotechnology , chemistry , crystallography , metallurgy , microstructure , layer (electronics)
Development of high‐performance wide‐bandgap perovskites is a key component to enable tandem solar cells with either a silicon or low‐bandgap perovskites. However, the presence of defects in the Br‐rich wide‐bandgap perovskites, especially in the grain boundaries (GBs) has been particularly challenging and limits its performance. Herein, to accomplish the passivation of these defects, a combination of cation management with rubidium (Rb) introduction into the triple cation combination of cesium/formamidinium/methylammonium (CsFAMA) is exercised. Passivation is further enhanced by secondary growth (SG) using guanidinium iodide. In‐depth assessments of GB defect passivation are performed using Kelvin probe force microscopy (KPFM) and nanoscale charge‐carrier dynamics mappings provide insightful details on the presence of GBs defects and their suppression by the cation management and SG techniques. Reduction of unreacted PbX 2 to realize a highly crystalline perovskite surface is achieved after incorporating Rb and SG treatment. As a result, a champion cell for 1.78 eV (FA 0.79 MA 0.16 Cs 0.05 ) 0.95 Rb 0.05 Pb(I 0.6 Br 0.4 ) 3 wide‐bandgap perovskite with an efficiency of 17.71% along with enhancement in all photovoltaic parameters is achieved. This study introduces a new way to analyze GB defects and reveals the consequence of defect passivation on charge‐carrier dynamics for realizing efficient perovskites.