Rashidi Kamyar, Michail Evripidis, Salcido-Santacruz Bernardo, Paudel Yamuna, Menon Vinod M, Sfeir Matthew Y
Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY, USA.
Department of Physics, Graduate Center, City University of New York, New York, NY, USA.
Nat Nanotechnol. 2025 Aug 14. doi: 10.1038/s41565-025-01995-0.
Hybrid light-matter molecular exciton-polariton states have been proposed as a strategy to directly modify the efficiency and rate of photoinduced molecular charge transfer reactions. However, the efficacy of polariton-driven photochemistry remains an open question owing to the experimental challenges to tease out this effect. Here we demonstrate conditions under which photoinduced polaritonic charge transfer can be achieved and visualized using momentum-resolved ultrafast spectroscopy. Key conditions for charge transfer are satisfied using Bloch surface wave polaritons, which exhibit favourable dispersion characteristics that permit the selective pumping of hybrid states with long lifetimes (100-400 fs) that permit vibrationally assisted charge transfer between a donor and an acceptor molecule dispersed in a polymer matrix. Using this approach, we tune the energetic driving force for charge separation, reducing it by as much as 0.5 eV compared with the bare exciton pumping with an internal quantum efficiency of 0.77. These results corroborate the notion that tunable and efficient polariton-driven molecular charge transfer is indeed possible using carefully constructed photonic systems.
混合光-物质分子激子-极化激元态已被提出作为一种直接改变光致分子电荷转移反应效率和速率的策略。然而，由于在实验上难以区分这种效应，极化激元驱动的光化学的功效仍是一个悬而未决的问题。在此，我们展示了在何种条件下可以利用动量分辨超快光谱实现并可视化光致极化激元电荷转移。使用布洛赫表面波光极化激元满足了电荷转移的关键条件，其展现出有利的色散特性，允许选择性泵浦具有长寿命（100 - 400飞秒）的混合态，这种混合态允许在分散于聚合物基质中的供体和受体分子之间进行振动辅助电荷转移。利用这种方法，我们调节电荷分离的能量驱动力，与裸激子泵浦相比，将其降低了多达0.5电子伏特，内部量子效率为0.77。这些结果证实了这样一种观点，即使用精心构建的光子系统确实可以实现可调谐且高效的极化激元驱动的分子电荷转移。
