Amide­Catalyzed Phase­Selective Crystallization Reduces Defect Density in Wide­Bandgap Perovskites

Title
Amide­Catalyzed Phase­Selective Crystallization Reduces Defect Density in Wide­Bandgap Perovskites
Authors
김정환Makhsud I. SaidaminovHairen TanYicheng ZhaoYounghoon KimJongmin ChoiJea Woong JoJames FanRafael Quintero-BermudezZhenyu YangLi Na QuanMingyang WeiOleksandr VoznyyEdward H. Sargent
Issue Date
2018-03
Publisher
Advanced materials
Citation
VOL 30, NO 13-0000-06
Abstract
Wide-bandgap (WBG) formamidinium-cesium (FA-Cs) lead iodide-bromide mixed perovskites are promising materials for front cells well-matched with crystalline silicon to form tandem solar cells. They offer avenues to augment the performance of widely deployed commercial solar cells. However, phase instability, high open-circuit voltage (V-oc) deficit, and large hysteresis limit this otherwise promising technology. Here, by controlling the crystallization of FA-Cs WBG perovskite with the aid of a formamide cosolvent, light-induced phase segregation and hysteresis in perovskite solar cells are suppressed. The highly polar solvent additive formamide induces direct formation of the black perovskite phase, bypassing the yellow phases, thereby reducing the density of defects in films. As a result, the optimized WBG perovskite solar cells (PSCs) (Eg approximate to 1.75 eV) exhibit a high Voc of 1.23 V, reduced hysteresis, and a power conversion efficiency (PCE) of 17.8%. A PCE of 15.2% on 1.1 cm(2) solar cells, the highest among the reported efficiencies for large-area PSCs having this bandgap is also demonstrated. These perovskites show excellent phase stability and thermal stability, as well as long-term air stability. They maintain approximate to 95% of their initial PCE after 1300 h of storage in dry air without encapsulation.
URI
http://pubs.kist.re.kr/handle/201004/68196
ISSN
0935-9648
Appears in Collections:
KIST Publication > Article
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