Meng F.-YChen I.-HShen J.-YChang K.-HChou T.-CChen Y.-AChen Y.-TChen C.-LPI-TAI CHOU2022-12-142022-12-14202220411723https://www.scopus.com/inward/record.uri?eid=2-s2.0-85124447201&doi=10.1038%2fs41467-022-28489-0&partnerID=40&md5=f45ba17f44fe0cf0ec08ad8e0a6008c3https://scholars.lib.ntu.edu.tw/handle/123456789/626198We propose a new concept exploiting thermally activated delayed fluorescence (TADF) molecules as photosensitizers, storage units and signal transducers to harness solar thermal energy. Molecular composites based on the TADF core phenoxazine–triphenyltriazine (PXZ-TRZ) anchored with norbornadiene (NBD) were synthesized, yielding compounds PZDN and PZTN with two and four NBD units, respectively. Upon visible-light excitation, energy transfer to the triplet state of NBD occurred, followed by NBD → quadricyclane (QC) conversion, which can be monitored by changes in steady-state or time-resolved spectra. The small S1-T1 energy gap was found to be advantageous in optimizing the solar excitation wavelength. Upon tuning the molecule’s triplet state energy lower than that of NBD (61 kcal/mol), as achieved by another composite PZQN, the efficiency of the NBD → QC conversion decreased drastically. Upon catalysis, the reverse QC → NBD reaction occurred at room temperature, converting the stored chemical energy back to heat with excellent reversibility. © 2022, The Author(s).[SDGs]SDG7composite; energy storage; exploitation; optimization; solar power; steady-state equilibrium; thermal power; wavelengthjournal article10.1038/s41467-022-28489-0351451252-s2.0-85124447201