Perdeuterated Conjugated Polymers for Ultralow‐Frequency Magnetic Resonance of OLEDs

Radio-wave Effect on Singlet Fission in Polycrystalline Tetracene near Zero Magnetic Field

A triplet-triplet pair is a key intermediate in singlet fission (SF), which has the potential to overcome the theoretical limit of solar cell efficiency. Here, we report a new spectroscopy to directly detect a short-lived triplet-triplet pair via the effects of radio-wave (RF) irradiation near zero magnetic field at room temperature. The fluorescence of polycrystalline powder of tetracene is reduced by RF irradiation at zero field, which is caused by a quasi-static RF field effect on spin mixing and electron-spin resonance among zero-field-splitting sublevels of the triplet-triplet pair. The curve for the quasi-static RF field effect can be reproduced numerically from that for the observed magnetophotoluminescence (MPL) effect. The simultaneous simulation of the RF and MPL effects using the density matrix formalism estimates rate constants of 1.2 × 10⁸ and 6.0 × 10⁸ s^-1 for the fusion and dissociation, respectively, of the triplet-triplet pair.

Rearrangement Strategy for the Preparation of Polymers With π-Conjugated Structures

π-Conjugated polymers are usually prepared by polymerization only. In this perspective article, typical synthesis methods of conjugated polymers are briefly summarized, and a novel strategy for preparing conjugated polymers by rearrangement is proposed. During the metalation process, many conjugated structures were generated in polybutadiene by double bond migration. The effects of reaction time, temperature, and catalyst dosage on the product structure were investigated. Moreover, the structure of the products was confirmed by FTIR, 1H NMR, and 2D HSQC NMR spectra. Thus, a possible reaction mechanism was proposed, in which polybutadiene generates allylic carbanions in the presence of n-butyllithium, and then the double bonds migrate through the carbanions rearrangement to generate many conjugated structures in the backbone chain. The method shows promise in facile and low-cost synthesis of conjugated polymers without the need for precious metal catalysts.