Lowering Molecular Symmetry To Improve the Morphological Properties of the Hole‐Transport Layer for Stable Perovskite Solar Cells. Issue 38 (23rd August 2018)

• Record Type: Journal Article
• Authors: Wang, Xuchao; Zhang, Jing; Yu, Shuwen; Yu, Wei; Fu, Ping; Liu, Xuan; Tu, Dandan; Guo, Xin; Li, Can
• Is Part Of: Angewandte Chemie international edition. Volume 57:Issue 38(2018)
• Page Start: 12529
• Page End: 12533
• Publication Date: 2018-08-23
• Subjects: hole-transporting materials -- perovskite solar cells -- spiro compounds -- symmetry -- synthesis design; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201807402
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Inspired by the structural feature of the classical hole‐transport material (HTM), Spiro‐OMeTAD, many analogues based on a highly symmetrical spiro‐core were reported for perovskite solar cells (PSCs). However, these HTMs were prone to crystallize because of the high molecular symmetry, forming non‐uniform films, unfavorable for the device stability and large‐area processing. By lowering the symmetry of spiro‐core, we report herein a novel spirobisindane‐based HTM, Spiro‐I, which could form amorphous films with high uniformity and morphological stability. Compared to the Spiro‐OMeTAD‐based PSCs, those containing Spiro‐I exhibit similar efficiencies for small area but higher ones for large area (1 cm 2 ), and especially much higher air stability (retaining 80 % of initial PCE after 2400 h storage without encapsulation). Moreover, the Spiro‐I can be synthesized from a cheap starting material bisphenol A and used with a small amount for the device fabrication. Abstract : Moving holes : A novel hole transporting material (HTM), Spiro‐I, derived from a spirobisindane (SI) core with a lower symmetry than the traditional spirobifluorene (SF) core for Spiro‐OMeTAD (Spiro‐F), was designed and synthesized for perovskite solar cells. The Spiro‐I can form uniform pinhole‐free films with high morphological stability. The devices based on the Spiro‐I exhibit comparable efficiency and higher stability than those from the Spiro‐OMeTAD.