Regulating Optical Activity and Anisotropic Second-Harmonic Generation in Zero-Dimensional Hybrid Copper Halides
Zhihang Guo, Junzi Li, Jiechun Liang, Changshun Wang, Xi Zhu, Tingchao He
Abstract
Structural engineering permits the introduction of chirality into organic–inorganic hybrid metal halides (HMHs), which creates a promising and exclusive material for applications in various optoelectronics. However, the optical activity regulation of chiral HMHs remains largely unexplored. In this work, we have synthesized two pairs of lead-free chiral HMHs with a zero-dimensional tetrahedral arrangement, i.e., (R- and S-1-(1-naphthyl)ethylammonium)2CuCl4 and (R- and S-1-(2-naphthyl)ethylammonium)2CuCl4. The magnitude of optical activity in these HMHs can be efficiently modulated as a result of the different magnetic transition dipole moments. Furthermore, these HMHs exhibited effective second-harmonic generation (SHG) and distinct SHG-circular dichroism (CD), with (R-1-(1-naphthyl)ethylammonium)2CuCl4 having an anisotropy factor (gSHG-CD) of up to 0.41. This work not only provides insights into regulating the optical activity and anisotropic SHG effect of lead-free chiral HMHs but also confirms the feasibility of SHG-CD spectroscopy as a promising tool for characterizing the intrinsic optical activity of chiral materials.