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Stabilizing the Efficiency Beyond 20% with a Mixed Cation Perovskite Solar Cell Fabricated in Ambient Air under Controlled Humidity
Author(s) -
Singh Trilok,
Miyasaka Tsutomu
Publication year - 2018
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201700677
Subject(s) - materials science , energy conversion efficiency , perovskite (structure) , perovskite solar cell , halide , grain size , chemical engineering , annealing (glass) , optoelectronics , inorganic chemistry , composite material , chemistry , engineering
Perovskite solar cells have evolved to have compatible high efficiency and stability by employing mixed cation/halide type perovskite crystals as pinhole‐free large grain absorbers. The cesium (Cs)–formamidium–methylammonium triple cation‐based perovskite device fabricated in a glove box enables reproducible high‐voltage performance. This study explores the method to reproduce stable and high power conversion efficiency (PCE) of a triple cation perovskite prepared using a one‐step solution deposition and low‐temperature annealing fully conducted in controlled ambient humidity conditions. Optimizing the perovskite grain size by Cs concentration and solution processes, a route is created to obtain highly uniform, pinhole‐free large grain perovskite films that work with reproducible PCE up to 20.8% and high preservation stability without cell encapsulation for more than 18 weeks. This study further investigates the light intensity characteristics of open‐circuit voltage ( V oc ) of small (5 × 5 mm 2 , PCE > 20%) and large (10 × 10 mm 2 , PCE of 18%) devices. Intensity dependence of V oc shows an ideality factor in the range of 1.7‐1.9 for both devices, implying that the triple cation perovskite involves trap‐assisted recombination loss at the hetero junction interfaces that influences V oc . Despite relatively high ideality factor, perovskite device is capable of supplying high power conversion efficiency under low light intensity (0.01 Sun) whereas maintaining V oc over 0.9 V.