• Yang, Terry Chien Jen
• Wilson, Gregory J.
• Jain, Sagar M.

Abstract

<p>There has been considerable progress over the last decade in development of the perovskite solar cells (PSCs), with reported performances now surpassing 25.2% power conversion efficiency. Both long-term stability and component costs of PSCs remain to be addressed by the research community, using hole transporting materials (HTMs) such as 2,2′,7,7′-tetrakis(N,N′-di-pmethoxyphenylamino)-9,9′-spirbiuorene(Spiro-OMeTAD) and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA). HTMs are essential for high-performance PSC devices. Although effective, these materials require a relatively high degree of doping with additives to improve charge mobility and interlayer/substrate compatibility, introducing doping-induced stability issues with these HTMs, and further, additional costs and experimental complexity associated with using these doped materials. This article reviews dopant-free organic HTMs for PSCs, outlining reports of structures with promising properties toward achieving low-cost, effective, and scalable materials for devices with long-term stability. It summarizes recent literature reports on non-doped, alternative, and more stable HTMs used in PSCs as essential components for high-efficiency cells, categorizing HTMs as reported for different PSC architectures in addition to use of dopant-free small molecular and polymeric HTMs. Finally, an outlook and critical assessment of dopant-free organic HTMs toward commercial application and insight into the development of stable PSC devices is provided.</p>

Topics

• perovskite
• impedance spectroscopy
• mobility
• amine
• power conversion efficiency