Turning on TTA: Tuning the Energy Landscape by Intermolecular Coupling
Turning on TTA: Tuning the Energy Landscape by Intermolecular Coupling
复制标题
DOI：
10.1021/acs.chemmater.3c02349
复制
发表时间：
2023-12
影响因子：
8.6
通讯作者：
Colette M. Sullivan;L. Nienhaus
中科院分区：
文献类型：
--
作者：
Colette M. Sullivan;L. Nienhaus
高效的固态光子上转换（UC）器件的开发对于该技术的实际应用仍然至关重要。近年来，将钙钛矿薄膜作为三重态敏化剂用于基于三重态-三重态湮灭（TTA）的UC提供了有前途的解决方案。在寻求“理想的零化子”，以最大限度地提高表观反斯托克斯位移，我们调查萘并[2，3-a]芘（NaPy）作为零化子在基于溶液和钙钛矿敏化TTA-UC系统。令人惊讶的是，我们观察到不同的发射行为的NaPy在固态的基础上的激发波长。在直接激发下，高能量跃迁S1“主导发射光谱，而UC导致从较低的激发态S1”的发射增加。我们认为，这是聚合相关的降低单重态激发态的结果，从而改变了TTA的基本能量景观。聚集将单重态能量降低到三重态对1（TT）的能级以下，通过热或熵驱动的TTA-UC，从聚集的单重态S1“产生能量上有利的发射，并从更高的单重态S1”产生弱发射。
The development of efficient solid-state photon upconversion (UC) devices remains paramount for practical applications of the technology. In recent years, the incorporation of perovskite thin films as triplet sensitizers for triplet–triplet annihilation (TTA)-based UC has provided a promising solution. In the pursuit of finding an “ideal annihilator” to maximize the apparent anti-Stokes shift, we investigate naphtho[2,3-a]pyrene (NaPy) as an annihilator in both solution-based and perovskite-sensitized TTA-UC systems. Surprisingly, we observe different emission behaviors of NaPy in the solid state based on the excitation wavelength. Under direct excitation, a high-energy transition S1' dominates the emission spectrum, while UC results in increased emission from a lower lying state S1''. We propose that this is the result of aggregation-related lowering of the singlet excited state thus changing the fundamental energetic landscape underlying TTA. Aggregation decreases the singlet energy below the energy level of the triplet pair state1(TT), yielding energetically favorable emission from the aggregated singlet state S1'' and weak emission from the higher lying singlet state S1' through thermally or entropically driven TTA-UC.