Flexible Organometal–Halide Perovskite Lasers for Speckle Reduction in Imaging Projection

Abstract

Disorder is emerging as a strategy for fabricating random laser sources with very promising materials, such as perovskites, for which standard laser cavities are not effective or too expensive. We need, however, different fabrication protocols and technologies for reducing the laser threshold and controlling its emission. Here, we demonstrate an effectively solvent-engineered method for high-quality perovskite thin films on a flexible polyimide substrate. The fractal perovskite thin films exhibit excellent optical properties at room temperature and easily achieve lasing action without any laser cavity above room temperature with a low pumping threshold. The lasing action is also observed in curved perovskite thin films on flexible substrates. The lasing threshold can be further reduced by increasing the local curvature, which modifies the scattering strengths of the bent thin film. We also show that the curved perovskite lasers are extremely robust with respect to repeated deformations. Because of the low spatial coherence, these curved random laser devices are efficient and durable speckle-free light sources for applications in spectroscopy, bioimaging, and illumination.

Directing Random Lasing Emission Using Cavity Exciton-Polaritons

“…Due to the roughness of the MAPB layer, random lasing action is observed from the MAPB/PMMA sample. Such random lasing from perovskite polycrystalline thin films have already been demonstrated in the literature in MAPB thin layers [43,45]. The PL spectroscopy demonstrating the random lasing is shown in the section 2 of the supplementary.…”

“…directly from polycrystalline and nanocrystals thin films. This has indeed been demonstrated in iodine-based perovskites [27][28][29][30][31], chloride-based perovskites [32] and bromide-based perovskites [32][33][34][35][36][37][38][39][40][41][42][43][44][45].…”

In-plane stimulated emission of polycrystalline CH3NH3PbBr3 perovskite thin films

“…Finally, the natural properties that halide perovskite can be advanced to exible lasing devices will denitely broaden the material's prospects. 35,36 Convenient fabrication and natural large grains make MAPbBr 3 thin lms more accessible, affordable, and operable for further uses as in-plane light source.…”

Advances in inorganic and hybrid perovskites for miniaturized lasers

“…Meanwhile, the use of disordered gain materials has emerged as a strategy for fabricating random laser sources. Recently, Wang et al demonstrated a random laser in curved perovskite MAPbBr 3 thin films on flexible substrates by using the solvent-engineered method ( Figure 6E) [75]. Under 355 nm excitation with 0.5 ns and 1 kHz, the lasing threshold was 2.5 mJ/cm 2 with emission FWHM of ~1.8 nm, which can be further reduced by increasing the local curvature of the film arising from the variation of the scattering strengths of the bent thin film.…”