Design and synthesis of anisotropic crystals with π-conjugated rings toward giant birefringence
Abstract
Birefringent crystals play a significant role in linear optical devices due to their ability to modulate the polarization of light. Commercial birefringent crystals MgF2, α-BaB2O4, CaCO3, YVO4, TiO2, and LiNbO3 have been widely used as polarization devices in the past decades. A variety of crystals have been developed to meet the requirements of large birefringence and have great potential as optical functional crystals. However, a key question is how to balance the conflict between the energy gap and birefringence. In this review, aiming to better judge the integrated properties of optical crystals, we came up with the birefringent quality factor. We also summarised our recent findings on the birefringent crystals, which contain structural units similar to [B3O6]3− rings, from these perspectives, including crystal structure features, optical performances, and structure–property relationships. We summarised the strategy to achieve the balance between the energy gap and birefringence by adjusting the delocalized π-conjugation and the confined π-conjugation to improve the performance of birefringent crystals, which will open up a new window for the exploration of novel birefringent crystals.
- This article is part of the themed collections: 2023 Materials Chemistry Frontiers Review-type Articles and 2023 Materials Chemistry Frontiers HOT articles