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arXiv · 2504.02331

In situ and real-time ultrafast spectroscopy of photoinduced reactions in perovskite nanomaterials

Gi Rim Han·Mai Ngoc An·Hyunmin Jang·Noh Soo Han·JunWoo Kim·Kwang Seob Jeong·Tai Hyun Yoon·Minhaeng Cho
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Abstract

Employing two synchronized mode-locked femtosecond lasers and interferometric detection of the pump-probe spectra -- referred to as asynchronous and interferometric transient absorption (AI-TA) -- we have developed a method for broad dynamic range and rapid data acquisition. Using AI-TA, we examined photochemical changes during femtosecond pump-probe experiments on all-inorganic cesium lead halide nanomaterials, including perovskite nanocrystals (PeNCs) and nanoplatelets (PeNPLs). The laser pulse train facilitates photoreactions while allowing real-time observation of charge carrier dynamics. In PeNCs undergoing halide anion photo-substitution, transient absorption spectra showed increasing bandgap energy and faster relaxation dynamics as the Cl/Br ratio increased. For colloidal PeNPLs, continuous observation revealed both spectral and kinetic changes during the light-induced coalescence of nanoplatelets, by analyzing temporal segments. This integrated technique not only deepens understanding of exciton dynamics and environmental influences in perovskite nanomaterials but also establishes AI-TA as a transformative tool for real-time observation of photochemical dynamics.

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Gi Rim Han, Mai Ngoc An, Hyunmin Jang, Noh Soo Han, JunWoo Kim, Kwang Seob Jeong, Tai Hyun Yoon, Minhaeng Cho. 2025-04-03. In situ and real-time ultrafast spectroscopy of photoinduced reactions in perovskite nanomaterials. https://arxiv.org/abs/2504.02331

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