Molecular photoswitches that absorb sunlight and store it in the form of chemical energy are attractive for applications in molecular solar thermal energy storage (MOST) systems. Typically, these systems utilize the absorbed energy to photoisomerize into a metastable form, which acts as an energy reservoir. Diarylethenes featuring aromatic ethene pi-linkers have garnered research interest in recent years as a promising class of T-type photoswitches, which undergo photocyclization from an aromatic ring-open form into a less aromatic or non-aromatic ring-closed form. Based on several recent computational and experimental studies, this perspective analyzes the potential of these switches for MOST applications. Specifically, we discuss how they can be made to simultaneously achieve high energy-storage densities, long energy-storage times, and high photocyclization quantum yields by tuning the aromatic character of the ethene pi-linker.
Funding Agencies|Olle Engkvists Stiftelse [SUR/2022/001766]; Department of Science and Technology (DST), New Delhi, India [2019-03664]; Swedish Research Council [204-0183]; Olle Engkvist Foundation [CTS 20:102, CTS 21:1545, SRMAP/URG/SEED/2023-24/028]; Carl Trygger Foundation; SRM University-AP [2022-06725, 2018-05973]; National Academic Infrastructure for Supercomputing in Sweden - Swedish Research Council