Couto Rafael C, Kowalewski Markus
Department of Physics, Stockholm University, Albanova University Center, SE-106 91 Stockholm, Sweden.
Phys Chem Chem Phys. 2022 Aug 17;24(32):19199-19208. doi: 10.1039/d2cp00774f.
The lifetimes of electronic excited states have a strong influence on the efficiency of organic solar cells. However, in some molecular systems a given excited state lifetime is reduced due to the non-radiative decay through conical intersections. Several strategies may be used to suppress this decay channel. The use of the strong light-matter coupling provided in optical nano-cavities is the focus of this paper. Here, we consider the --butyl-4,4-difluoro-4-bora-3,4-diaza--indacene molecule (--butyl-BODIPY) as a showcase of how strong and ultrastrong coupling might help in the development of organic solar cells. The --butyl-BODIPY is known for its low fluorescence yield caused by the non-radiative decay through a conical intersection. However, we show here that, by considering this system within a cavity, the strong coupling can lead to significant changes in the multidimensional landscape of the potential energy surfaces of --butyl-BODIPY, suppressing almost completely the decay of the excited state wave packet back to the ground state. By means of multi configuration electronic structure calculations and nuclear wave packet dynamics, the coupling with the cavity is analyzed in-depth to provide further insight of the interaction. By fine-tuning the cavity field strength and resonance frequency, we show that one can change the nuclear dynamics in the excited state, and control the non-radiative decay. This may lead to a faster and more efficient population transfer or the suppression of it.
电子激发态的寿命对有机太阳能电池的效率有很大影响。然而，在一些分子体系中，由于通过锥形交叉点的非辐射衰变，给定激发态的寿命会缩短。可以采用几种策略来抑制这种衰变通道。利用光学纳米腔中提供的强光 - 物质耦合是本文的重点。在这里，我们将正丁基 - 4,4 - 二氟 - 4 - 硼 - 3,4 - 二氮杂 - 茚分子（正丁基 - BODIPY）作为一个例子，来说明强耦合和超强耦合如何有助于有机太阳能电池的发展。正丁基 - BODIPY因其通过锥形交叉点的非辐射衰变导致荧光产率低而闻名。然而，我们在此表明，通过在腔内考虑这个体系，强耦合可以导致正丁基 - BODIPY势能面的多维景观发生显著变化，几乎完全抑制激发态波包向基态的衰变。通过多组态电子结构计算和核波包动力学，深入分析了与腔的耦合，以进一步了解这种相互作用。通过微调腔场强度和共振频率，我们表明可以改变激发态中的核动力学，并控制非辐射衰变。这可能导致更快、更有效的布居转移或对其进行抑制。
