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Chiral Lead-Oxyiodide Nonlinear Optical Crystals Constructed on l -Malate Groups

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide The pursuit of nonlinear optical (NLO) crystals exhibiting an exceptional second-harmonic generation (SHG) response has been a persistent objective in scientific research. Herein, three chiral lead-oxyiodide NLO crystals, [Rb 2 I][PbI(LM)] (LM = L–OOCCH 2 CH(OH)COO) and A 2 [Pb 2 I 2 (LM) 2 ] (A = Rb, K), have been rationally synthesized by introducing the l -malate group into halide perovskites to substitute partial halide anions. All of them contain highly distorted lead-oxyiodide polyhedra with large hyperpolarizability and anisotropic polarization. In particular, the highly distorted [PbI 2 O 4 ] polyhedrons in [Rb 2 I][PbI(LM)] are shielded by more Rb + cations and aligned into a uniform arrangement. As a result, their microscopic second-order susceptibilities are optimally superposed. Remarkably, [Rb 2 I][PbI(LM)] exhibits a very strong SHG response of 7.3 × KDP that is nearly three times those of A 2 [Pb 2 I 2 (LM) 2 ] (A = Rb, K), as well as the largest among malates to date. Theoretical calculations demonstrate that their SHG responses mainly arise from highly distorted lead-oxyiodide polyhedrons. This study offers a viable strategy for the exploration of high-performance NLO crystals.

Source: Inorganic Chemistry

DOI: 10.1021/acs.inorgchem.5c03869