Kalyani Thakur, Bas van der Zee, Oskar Sachnik, Constantin Haese, Robert Graf, Jasper J. Michels, Gert-Jan A. H. Wetzelaer, Charusheela Ramanan, Paul W. M. Blom
{"title":"Effect of tert-Butylation on the Photophysics of Thermally Activated Delayed Fluorescence Emitters","authors":"Kalyani Thakur, Bas van der Zee, Oskar Sachnik, Constantin Haese, Robert Graf, Jasper J. Michels, Gert-Jan A. H. Wetzelaer, Charusheela Ramanan, Paul W. M. Blom","doi":"10.1002/adpr.202400022","DOIUrl":null,"url":null,"abstract":"<p>Thermally activated delayed fluorescence (TADF) emitters potentially can provide organic light-emitting diodes with 100% internal quantum efficiency by harvesting triplet excitons. Generally, TADF emitters are small molecules that are not applicable for solution processability. The addition of <i>tert</i>-butyl groups to the periphery of TADF emitters has proven to improve their solubility in various organic solvents, reduce aggregation-induced quenching, and enhance the photoluminescence quantum yield (PLQY). This article studies the photophysical influence of the <i>tert</i>-butyl group attached to an emitter with a carbazole acceptor and a triazine donor. The resulting t3CzTrz-F is a blue–green TADF emitter, in which the addition of a <i>tert</i>-butyl group increases the rate of reverse intersystem crossing (rISC), while simultaneously decreasing the nonradiative decay rate substantially. In addition, dilution of t3CzTrz-F in a host matrix in film results in an enhanced PLQY, which is associated with a decrease in the nonradiative decay constant, while there is no change in the rISC rate. Through a solid-state NMR study, the change in rISC and nonradiative rate upon <i>tert</i>-butylation by enlarged intermolecular spacing and reduced vibrational and rotational freedom is rationalized, resulting in improved photophysical performance.</p>","PeriodicalId":7263,"journal":{"name":"Advanced Photonics Research","volume":"5 11","pages":""},"PeriodicalIF":3.7000,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/adpr.202400022","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Advanced Photonics Research","FirstCategoryId":"1085","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/adpr.202400022","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Thermally activated delayed fluorescence (TADF) emitters potentially can provide organic light-emitting diodes with 100% internal quantum efficiency by harvesting triplet excitons. Generally, TADF emitters are small molecules that are not applicable for solution processability. The addition of tert-butyl groups to the periphery of TADF emitters has proven to improve their solubility in various organic solvents, reduce aggregation-induced quenching, and enhance the photoluminescence quantum yield (PLQY). This article studies the photophysical influence of the tert-butyl group attached to an emitter with a carbazole acceptor and a triazine donor. The resulting t3CzTrz-F is a blue–green TADF emitter, in which the addition of a tert-butyl group increases the rate of reverse intersystem crossing (rISC), while simultaneously decreasing the nonradiative decay rate substantially. In addition, dilution of t3CzTrz-F in a host matrix in film results in an enhanced PLQY, which is associated with a decrease in the nonradiative decay constant, while there is no change in the rISC rate. Through a solid-state NMR study, the change in rISC and nonradiative rate upon tert-butylation by enlarged intermolecular spacing and reduced vibrational and rotational freedom is rationalized, resulting in improved photophysical performance.