Controllable lasing performance in solution-processed organic–inorganic hybrid perovskites

Abstract

Solution-processed organic-inorganic perovskites are fascinating due to their remarkable photo-conversion efficiency and great potential in the cost-effective, versatile and large-scale manufacturing of optoelectronic devices. In this paper, we demonstrate that the perovskite nanocrystal sizes can be simply controlled by manipulating the precursor solution concentrations in a two-step sequential deposition process, thus achieving the feasible tunability of excitonic properties and lasing performance in hybrid metal-halide perovskites. The lasing threshold is at around 230 μJ cm in this solution-processed organic-inorganic lead-halide material, which is comparable to the colloidal quantum dot lasers. The efficient stimulated emission originates from the multiple random scattering provided by the micro-meter scale rugged morphology and polycrystalline grain boundaries. Thus the excitonic properties in perovskites exhibit high correlation with the formed morphology of the perovskite nanocrystals. Compared to the conventional lasers normally serving as a coherent light source, the perovskite random lasers are promising in making low-cost thin-film lasing devices for flexible and speckle-free imaging applications.

Amplified Spontaneous Emission and Lasing in Lead Halide Perovskites: State of the Art and Perspectives

“…A possible approach in this direction is based on the variation of the sample preparation conditions, in order to modify its morphology. For example, Cao et al compared the emission properties of MAPbI 3 films obtained by a two step spin coating process, using four different concentrations of the PbI 2 DMF solution (namely 10%, 20%, 30% and 40% in weight) [41]. The films morphology showed an inhomogeneous substrate coverage, with a rugged surface and randomly distributed grains when the 10% PbI 2 solution was used and a progressive morphology improvement for higher concentrations.…”

Inorganic and Hybrid Perovskite Based Laser Devices: A Review

“…An important figure of merit of any type of laser device is its laser threshold; it should be as low as possible in order to maximize the conversion of the pumping energy to output power. Kao et al [52] discovered that the relative concentration of the PbI 2 played a major role in the determination of the excitonic and lasing performance of the MAPbI 3 materials. Specifically, the increase of the concentration of the PbI 2 up to 30 wt.% resulted in the lowering of the lasing threshold, mainly due to (a) increased volume of the gain media; (b) the enhancement of the generated scattering effects (that provide the necessary optical feedback to observe stimulated emission—random lasing) between the grain boundaries; and (c) the higher exciton binding energy (as thermal PL measurements showed).…”

Inorganic and Hybrid Perovskite Based Laser Devices : A Review

“…T.S. Kao et al [32] discovered that the relative concentration of the PbI2 played a major role in the determination of the excitonic and lasing performance of the MAPbI3 materials. More particular the increase of the concentration of the PbI2 up to 30 wt% resulted the lowering of the lasing threshold, mainly due to (a) increased volume of the gain media; (b) to the enhancement of the generated scattering effects (that provide the necessary optical feedback to observe stimulated emission) between the grain boundaries; and (c) the higher exciton binding energy (as thermal PL measurements showed).…”