Giant Nonlinear Optical Response of Lead-Free All-inorganic CsSnBr₃ Nanoplates

The exploration of nonlinear optical (NLO) materials with a large NLO response promotes a diverse range of photonic applications. With excellent optoelectronics property, perovskite semiconductors have attracted more and more attention in the field of nonlinear optics. In this work, lead-free all-inorganic perovskites of CsSnBr 3 nanoplates are synthesized successfully on mica substrates by the solid-source chemical vapor deposition method for the first time. The thickness of as-prepared CsSnBr 3 nanoplates controlled well by adjusting the growth time demonstrates their important role in crystallinity, photoluminescence (PL), and NLO response. With the increase of thickness, the peak intensities of X-ray diffraction and PL increase, while the performance parameters of the NLO response, such as the nonlinear absorption coefficient, nonlinear refractive index, and so forth, decrease accordingly. A light self-absorption effect contributes to this opposite phenomenon of the NLO response. It is worth to pointing out that the reported nonlinear absorption coefficients of (−6.86 ± 0.10) × 10 4 cm·GW –1 at 532 nm and (2.39 ± 0.07) × 10 4 cm·GW –1 at 1064 nm are the few giant values among the reported NLO materials, promising the applications for pulsed lasers, optical switches, optical modulators, optical memories. and so forth.