Inverting singlet and triplet excited states using strong light-matter coupling
Inverting singlet and triplet excited states using strong light-matter coupling
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DOI：
10.1126/sciadv.aax4482
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发表时间：
2019-12-01
期刊：
影响因子：
13.6
通讯作者：
Kena-Cohen, Stephane
中科院分区：
文献类型：
--
作者：
Eizner, Elad;Martinez-Martinez, Luis A.;Kena-Cohen, Stephane
在有机微腔中，混合轻物质状态可以形成与裸分子激发能相差近1 eV的能量。考虑到热激活延迟荧光材料开发的最新进展，一个及时的问题是，是否可以使用强的光-物质耦合来反转单重态和三重态的顺序，此外，还可以提高反向系间穿越（RISC）速率。在这里，我们证明了一个完整的反转的单重态较低的极化激元和三重态激发态。我们还明确地测量RISC率在强耦合的有机微腔，并发现，无论大的能级位移，它是不变的相比，裸分子的薄膜。这一观察结果是由于跨许多分子的状态的离域性质以及无法与RISC竞争暗激子库而导致的RISC到较低极化激元的缓慢的结果。
In organic microcavities, hybrid light-matter states can form with energies that differ from the bare molecular excitation energies by nearly 1 eV. A timely question, given the recent advances in the development of thermally activated delayed fluorescence materials, is whether strong light-matter coupling can be used to invert the ordering of singlet and triplet states and, in addition, enhance reverse intersystem crossing (RISC) rates. Here, we demonstrate a complete inversion of the singlet lower polariton and triplet excited states. We also unambiguously measure the RISC rate in strongly coupled organic microcavities and find that, regardless of the large energy level shifts, it is unchanged compared to films of the bare molecules. This observation is a consequence of slow RISC to the lower polariton due to the delocalized nature of the state across many molecules and an inability to compete with RISC to the dark exciton reservoir.