Bandgap-Engineered CsPbBr_3xI_3-3x Alloy Nanowires for Broadly Tunable Nanoscale Lasers

Halide perovskite nanowires (NWs) have excellent photoelectric properties, such as high quantum efficiency and carrier mobility, and are ideal candidates for next-generation optoelectronic devices and circuits. In particular, all-inorganic perovskite materials have a soft and dynamic crystal lattice, tunable bandgaps, better thermal stability, etc., which make them ideal candidates for wavelength-tunable emitters and full-color displays. Here, we reported an anion exchange method to synthesize bandgap-modulated CsPbBr_3xI_3-3x alloy NWs on SiO₂/Si substrate. These NWs have smooth end surfaces and exhibit NW lasing with a threshold of 18.09 μJ cm^-2 and a high-quality factor of 633-1075. Moreover, under a 355 nm pulse laser illumination, room-temperature wavelength continuous tunable lasing ranging from 538 to 699 nm is realized using these bandgap-tunable perovskite NWs. The growth strategies of these bandgap-graded structures may offer an interesting system for enriching the synthesis methods of alloy perovskites and exploring applications in multifunctional nanophotonic and optoelectronic devices.