Accurately Stoichiometric Regulating Oxidation States in Hole Transporting Material to Enhance the Hole Mobility of Perovskite Solar Cells. Issue 6 (23rd April 2020)

• Record Type: Journal Article
• Authors: Chen, Cheng; Liu, Sizhou; Li, Zhipeng; Wang, Fangfang; Xu, Wenxin; Ma, Hongzhuang; Zhang, Shitong; Wang, Lingling; Gu, Cheng; Pang, Shuping; Huang, Wei; Qin, Tianshi
• Is Part Of: Solar RRL. Volume 4:Issue 6(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-04-23
• Subjects: hole mobilities -- hole transport materials -- perovskite solar cells -- phenothiazine -- radical cations; Solar energy -- Periodicals; Photovoltaic power generation -- Periodicals; Solar energy -- Research -- Periodicals; Photovoltaic power generation -- Research -- Periodicals; Periodicals; 333.7923
• DOI: 10.1002/solr.202000127
• Languages: English
• ISSNs: 2367-198X

Abstract

Abstract : In traditional n‐i‐p‐type perovskite solar cells (PSCs), most hole transporting materials (HTMs) rely on an uncontrolled oxidative process using Li salt and Co (III) complex to achieve sufficient hole mobilities. Herein, a stabilized oxidized phenothiazine‐based HTM (OPTZ) synthesized from its neutral form (NPTZ) through a photoredox reaction is demonstrated. This controllable and stable oxidation state is mainly derived from the planar structure and π conjugation of phenothiazine core in OPTZ. The energy gap between the singly occupied molecular orbital (SOMO) of OPTZ and highest occupied molecular orbital (HOMO) of NPTZ suitably promotes hole hopping in hole transporting layers. Using an optimized ratio of OPTZ as the dopant in NPTZ, the hole transporting mobility is effectively enhanced due to an intra‐ and intermolecular charge transfer process, resulting in an enhancement in the fill factor of the PSCs. Herein, a new strategy to obtain stabilized oxidized HTMs, which deliver significantly enhanced hole mobilities of HTMs in PSCs, is provided. Abstract : An oxidized phenothiazine‐based (OPTZ) hole transporting material (HTM) synthesized from its neutral form (NPTZ) is used to accurately tune the concentration of radical cations in HTMs via its stoichiometric ratio. Using the optimized ratio of OPTZ as the dopant in the HTM, the hole transporting mobility is effectively enhanced, due to the intra‐and intermolecular charge transfer process, thus increasing the fill‐factor of perovskite solar cells.