Tavakoli Mostafa, Ahmadvand Hossein, Alaei Mojtaba, Ranjbari Mohammad Amin
Department of Physics, Isfahan University of Technology, Isfahan 84156-83111, Iran.
Department of Physics, Isfahan University of Technology, Isfahan 84156-83111, Iran.
Spectrochim Acta A Mol Biomol Spectrosc. 2021 Feb 5;246:118952. doi: 10.1016/j.saa.2020.118952. Epub 2020 Sep 17.
In this work, we present a computational study on 105 selected organic molecules in order to find suitable candidates for using as thermally activated delayed fluorescent (TADF) emitters in organic light emitting diodes (OLEDs), in the emission range of red light. Based on time-dependent density functional theory (TD-DFT) computations, three promising candidates were found, predicted to have low singlet-triplet splittings, lower than 0.06 eV, and TADF rates of 0.124, 0.154 and 0.231 1/μs. Then, using an experimental-theory calibration approach, the emission wavelength of the molecules were estimated to be 570, 476, and 623 nm, respectively. For the molecule whose emission wavelength (623 nm) is predicted to be in our desired range, we measured the photoluminescence (PL) spectrum and find out that its emission peak is within the predicted accuracy of the employed method. Moreover, we benchmarked the performance of density functional based tight-binding (DFTB) method for future screening works and find out that, this method is an efficient pre-screening tool, useful in searching for molecules with desired emission wavelengths.
在这项工作中，我们对105种选定的有机分子进行了计算研究，以便在红光发射范围内找到适合用作有机发光二极管（OLED）中热激活延迟荧光（TADF）发射体的候选分子。基于含时密度泛函理论（TD-DFT）计算，发现了三种有前景的候选分子，预计其单重态-三重态分裂较低，低于0.06 eV，TADF速率分别为0.124、0.154和0.231 1/μs。然后，使用实验-理论校准方法，估计这些分子的发射波长分别为570、476和623 nm。对于发射波长（623 nm）预计在我们所需范围内的分子，我们测量了其光致发光（PL）光谱，发现其发射峰在所采用方法的预测精度范围内。此外，我们对基于密度泛函紧束缚（DFTB）方法在未来筛选工作中的性能进行了基准测试，发现该方法是一种有效的预筛选工具，有助于寻找具有所需发射波长的分子。
