Quest for robust electron transporting materials towards efficient, hysteresis-free and stable perovskite solar cells

This review describes the critical role that electron transporting materials (ETMs) play in perovskite solar cells (PSCs) and our views on future prospects of ETMs, focusing on approaches to obtain highly efficient, hysteresisfree and stable devices. Strategies regarding morphological-control and modulation of chemical interaction/ electronic coupling of the ETMs with corresponding materials are discussed, including potentials for the realization of highly efficient devices through photon- and charge-management. The microstructure-hybridization and interfacial-engineering that modulate imbalanced-charge-transport, trap-induced charge recombination and charge-accumulation from the ETMs perspectives are evaluated in order to address hysteresis issue in PSCs. In addition to the inherent stability of the ETMs themselves, the interfacial stability-driven approaches towards highly stable PSCs are scrutinized. Looking at the latest cutting-edge research, we present a novel conceptual design of organic-metal-organic assembly (OMOA) to be conducted for the realization of robust ETMs for highperformance perovskite-based photovoltaic.