A saddle-shaped o-tetraphenylene based molecular semiconductor with a high glass transition temperature for perovskite solar cells

Abstract

The application of exotic conjugated skeletons in organic semiconductors is alluring due to the topology related optoelectronic peculiarities. In this paper we explore the design of molecular semiconductors starting from the saddle-shaped o-tetraphenylene (OTP) for the first time. The in silico tailored molecular semiconductor OTPE-OMeTPA with extended π-conjugation presents an improved hole mobility in comparison with its counterpart OTP-OMeDPA, due to the reduced reorganization energy and the larger intermolecular centroid distance. Molecular dynamics simulations clarify the atomic-scale microscopic origins of glass transition in the pristine materials and their p-doping promotor containing composites, being associated with the torsional motion of central OTP and the translational motion of all centroids, respectively. The OTPE-OMeTPA based organic composite displays desirable combined properties of conductivity, glass transition temperature, solution processibility, and interfacial charge transfer kinetics, allowing for the fabrication of thermostable perovskite solar cells with 21.5% power conversion efficiency. A comprehensive comparison of device degradation is also performed by joint experimental measurements and theoretical modeling, laying a solid foundation for further materials and device development.