Promoting energy transfer via manipulation of crystallization kinetics of quasi-2D Dion–Jacobson phase perovskites for high-performance green lasers

The quasi-2D Dion–Jacobson perovskite exhibits significant photophysical properties and potential applications. However, the insufficient exciton energy transfer leads to nonradiative recombination that seriously hinders charge transport. Here, an efficient energy transfer is achieved by incorporating the alkali metal, which not only constrains the nucleation of high-n phases and promotes the growth of the middle-n phases but also optimizes the phase distribution and the crystal orientation to promote carrier transport. We achieve a green amplified spontaneous emission with a low threshold of 28.5 μJ/cm2 and a vertical-cavity laser operating in a single-mode configuration with a linewidth of 0.96 nm.