Ultrafast directional hot carrier transfer in bilayer perovskite heterojunctions.
basic_science · Level V
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- Record sourced from PubMed, PMID 42706280.
- Also identified by DOI 10.1038/s41467-026-76790-z.
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Abstract
Hot carrier dynamics in semiconductors govern unique mechanisms in high-performance devices with potential to exceed thermodynamic limits of optoelectronic device efficiency. Here, we report ultrafast directional transfer of hot carriers within laminated bilayer CsPbBr<sub>3</sub>/FAPbBr<sub>3</sub> perovskite heterojunctions. Using ultrafast spectroscopy, we show that hot carriers generated in the FAPbBr<sub>3</sub> layer are directed to the CsPbBr<sub>3</sub> layer within picoseconds. This process is driven by differences in cooling pathways that create density gradients for directional hot carrier transfer. Such ultrafast hot carrier inter-junction transfer boosts the carrier density in CsPbBr<sub>3</sub> layer to the level of population inversion. By fabricating perovskite heterojunction vertical-cavity surface-emitting lasers, we achieve hot-carrier laser devices with threshold down to 1.4 μJ cm<sup>-2</sup> under nanosecond pulsed excitation, five times lower than that of individual perovskite layers. Our findings establish hot carrier transfer in hybrid perovskites as a promising strategy for high-performance hot-carrier lasers, ultrafast laser diodes, and photodetectors.