Ultrafast Exciton Dynamics of CH 3 NH 3 PbBr 3 Perovskite Nanoclusters.
Vivien L CherretteKai-Chun ChouDavid ZeitzMelissa Guarino-HotzMariam KhvichiaJeremey BarnettAllison A WinFinn BabbeJin Zhong ZhangPublished in: The journal of physical chemistry letters (2024)
Exciton dynamics of perovskite nanoclusters has been investigated for the first time using femtosecond transient absorption (TA) and time-resolved photoluminescence (TRPL) spectroscopy. The TA results show two photoinduced absorption signals at 420 and 461 nm and a photoinduced bleach (PB) signal at 448 nm. The analysis of the PB recovery kinetic decay and kinetic model uncovered multiple processes contributing to electron-hole recombination. The fast component (∼8 ps) is attributed to vibrational relaxation within the initial excited state, and the medium component (∼60 ps) is attributed to shallow carrier trapping. The slow component is attributed to deep carrier trapping from the initial conduction band edge (∼666 ps) and the shallow trap state (∼40 ps). The TRPL reveals longer time dynamics, with modeled lifetimes of 6.6 and 93 ns attributed to recombination through the deep trap state and direct band edge recombination, respectively. The significant role of exciton trapping processes in the dynamics indicates that these highly confined nanoclusters have defect-rich surfaces.
Keyphrases
- energy transfer
- room temperature
- quantum dots
- dna damage
- dna repair
- solar cells
- sensitive detection
- electron transfer
- photodynamic therapy
- fluorescent probe
- single molecule
- escherichia coli
- molecular dynamics simulations
- zika virus
- mass spectrometry
- subarachnoid hemorrhage
- brain injury
- density functional theory
- perovskite solar cells
- soft tissue
- aedes aegypti
- solid state