An energetics assessment of benzo[ a ]tetracene and benzo[ a ]pyrene as triplet–triplet annihilation emitters
An energetics assessment of benzo[ a ]tetracene and benzo[ a ]pyrene as triplet–triplet annihilation emitters
复制标题
苯并[a]并四苯和苯并[a]芘作为三重态-三重态湮没发射体的能量学评估
DOI：
10.1039/d2me00004k
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发表时间：
2022
影响因子：
3.6
通讯作者：
Marom, Noa
中科院分区：
文献类型：
--
作者：
Wang, Xiaopeng;Marom, Noa
低能光子到高能光子的光学上转换（UC）使得太阳能电池能够收集能量低于吸收体带隙的光子，从而降低传输损耗。基于有机发色团中的三重态-三重态湮灭（TTA）的UC可以上转换来自太阳光的光子，尽管转换效率低。我们利用三个基于能量的标准来评估TTA发射体的量子产率（QY）和反斯托克斯位移方面的UC潜力。发射体遭遇复合物的单线态途径中的能量损失（其中发射高能光子）决定了发色团是否可以进行TTA。作为主要竞争过程的三联体途径中的能量损失影响TTA QY。TTA发射体中的最低单重态和三重态激发态之间的能量差设定了TTA-UC的反斯托克斯位移的上限。使用含时密度泛函理论（TDDFT）计算评估的能量标准，我们发现，苯并[a]并四苯，苯并[a]芘，及其衍生物是有前途的TTA发射体。能量学评估和计算机模拟可以用来有效地发现和设计更多的候选高性能TTA发射器。
Optical upconversion (UC) of low energy photons into high energy photons enables solar cells to harvest photons with energies below the band gap of the absorber, reducing the transmission loss. UC based on triplet–triplet annihilation (TTA) in organic chromophores can upconvert photons from sunlight, albeit with low conversion efficiency. We utilize three energy-based criteria to assess the UC potential of TTA emitters in terms of the quantum yield (QY) and the anti-Stokes shift. The energy loss in the singlet pathway of an emitter encounter complex, where a high energy photon is emitted, determines whether a chromophore may undergo TTA. The energy loss in the triplet pathway, which is the main competing process, impacts the TTA QY. The energy difference between the lowest singlet and triplet excitation states in TTA emitters sets an upper bound for the anti-Stokes shift of TTA-UC. Using the energetic criteria evaluated by time-dependent density functional theory (TDDFT) calculations, we find that benzo[a]tetracene, benzo[a]pyrene, and their derivatives are promising TTA emitters. The energetics assessment and computer simulations could be used to efficiently discover and design more candidate high-performance TTA emitters.