Constructing Urbach-Tail-Free and Low-Threshold Perovskite Heteronanowire Lasers toward All-Optical Switching

Semiconductor nanowires are promising for developing all-optical switches, which, however, are facing challenges including limited reproducibility and high operation power. Herein, we seek a solution for these issues by utilizing inorganic lead halide perovskite (ILHP) nanowires as the active component because of their superior optical properties. We reveal that the Urbach tail effect is non-negligible in ILHP nanowires, making the lasing signal to fluctuate beyond 12 nm as the nanowire length changes. In view of this, we construct a triblock nanowire heterostructure forming an acceptor-donor-acceptor configuration. Such a scheme enables the unidirectional energy routing and facilitates obtaining the length-independent optical gain spectra, which enable the device reproducibility in a mass-productive manner. Furthermore, by virtue of the photon conversion and carrier transfer processes, the heteronanowire lasers show an order-of-magnitude lower threshold than the pristine ones. Accordingly, the heteronanowire-based all-optical switch can operate at a recordlow pump intensity of 1.07 mu J/cm(2). These results could greatly advance the development of integrated photonics.