Stable Multi-Wavelength Lasing in Single Perovskite Quantum Dot Superlattice

摘要

Single perovskite alloy micro-nano structure capable of emitting multi-wavelengthtunable lasing is desirable for its potential application in highly integratedphotonic devices. However, owing to the soft and dynamic crystal latticeof perovskite and the low mobility energy of halide anion, it is still a challengeto obtain alloy micro-nano structures with a stable bandgap gradient. Herein,based on the highly ordered superlattice consisting of well-separated individualquantum dots and precise anion exchange strategy, a single perovskite alloysuperlattice is obtained with a widely tunable bandgap. The photoluminescence(PL) spectra results indicate that the stability of the bandgap difference ofthe alloy superlattice sample is approximately 10 times higher than that of thepreviously reported perovskite single-crystal alloy nanowires. By combination ofquantitative study based on confocal PL measurements and theoretical calculations,the kinetics and atomic-scale anion exchange mechanism are analyzed,the latter being responsible for the formation of stable bandgap gradient inthe alloy superlattice. Multi-wavelength lasing is further realized in single alloysuperlattice. In addition, carrier transportation dynamics reveals the energytransferprocess in the alloy superlattice, explaining the difficulties of realizingmulticolor lasing. The work provides a new approach to solving problems inthe field of stable multicolor microlasers.