Probing Size-Driven\nExciton Behavior in InP Tetrapods\nvia Time-Resolved Spectroscopy

Quantum-confined\nnanocrystals (NCs) have garnered huge attention\nin various applications due to their unique optoelectronic properties\narising from quantum confinement effects. Recently, single-crystalline\nInP tetrapods have been proposed as an attractive system, allowing\nmodulation from single-photon to multiphoton emission by tuning the\nsize of the tetrapods. Herein, the size-driven exciton behavior in\ntetrapods is investigated through time-resolved spectroscopy to achieve\na fundamental understanding of their unique emission transition. The\nexperimental results reveal that the behavior of excitons and biexcitons\nexhibits distinct trends with varying sizes, showing a remarkable\n4-fold enhancement in the biexciton Auger lifetime as the size increases.\nOur findings clarify that the transition between single-photon and\nmultiphoton emission arises from a volume effect and the interplay\nbetween quantum confinement and Coulomb interactions. This research\nprovides fundamental knowledge of the optical properties of single-crystalline\ntetrapods and highlights the potential for functional selection in\nNCs based on size and shape control.