在TADF中比较电荷转移激发状态的发电者: ΔDFT在排放能量方面表现优于TD-DFT
Thomas Froitzheim1, Lukas Kunze1, Stefan Grimme1
1Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstr. 4, 53115 Bonn, Germany.
The journal of physical chemistry. A
|July 19, 2024
概括
在有机发光二极管中准确地建模电荷转移激发状态是具有挑战性的. 国家特定的不受限制的Kohn-Sham DFT与溶解模型为排放能量提供了特殊的准确性,性能优于TDA-DFT.
科学领域:
- 计算化学的计算化学
- 材料科学 材料科学 材料科学
- 有机电子 有机电子
背景情况:
- 电荷转移 (CT) 激发状态对于有机发光二极管 (OLED) 来说至关重要,特别是那些使用热激活延迟光 (TADF) 的 OLED.
- 精确的CT状态的理论建模,特别是在介电环境中,仍然是 (时间依赖) 密度函数理论[TD-DFT]方法的一个重大挑战.
- 此前开发的STGABS27基准集是为了使用准确的实验参考来评估亚亚巴特单元-三元能量差距 (ΔEST).
研究的目的:
- 通过将实验性排放能量 (Eem) 纳入STGABS27基准,扩大STGABS27的基准,创建STGABS27-EMS基准.
- 重新评估和比较各种基于DFT的方法的性能,以预测激发状态属性,特别是排放能量.
- 确定当前TD-DFT方法的缺陷,并为OLED材料中的CT状态提出改进的计算策略.
主要方法:
- 开发STGABS27-EMS基准集,包括多种分子的实验性排放能量.
- 应用和评估国家特定的不受限制的开放Kohn-Sham (U/ROKS) DFT与扰动性国家特定的非平衡溶解模型 (ptSS-PCM) 相结合.
- 与Tamm-Dancoff近似的TD-DFT (TDA-DFT) 计算进行比较,同样使用ptSS-PCM溶解模型.
主要成果:
- 使用ptSS-PCM进行国家特定的U/ROKS DFT,在广泛的密度函数中,在预测排放能量 (Eem) 方面表现出极高的准确性.
- 在该领域的常用方法TDA-DFT与ptSS-PCM配对时,显示精度明显降低,并且高度依赖所选择的功能.
- 与TDA-DFT不同,TDA-DFT需要不同的函数来进行最佳的ΔEST和Eem预测,U/ROKS/PCM方法使用各种函数实现了两种属性的卓越准确性.
结论:
- 与ptSS-PCM相结合的时间独立的U/ROKS DFT成为模拟OLED材料中电荷转移激发状态的高度准确和多功能方法.
- 这种方法提供了可靠的预测,既可靠的能量差距和排放能量,克服了TDA-DFT的局限性.
- 这些发现表明了改善激发状态属性的理论预测的有希望的方向,这对于设计高效的TADF OLED至关重要.
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