1D Van der Waals Polymers with Nonlinear Optical Performance Approaching Theoretical Upper Limit

Abstract

Nonlinear optical (NLO) materials are of great importance for applications in lasers, atomic clocks, free‐space communication, etc. Herein, inspired by the recent prediction of excellent second harmonic generation (SHG) performance in van der Waals (vdW) materials with 1D building blocks, 14 new NLO materials are found from 244 bulk crystals constructed with 1D polymers using high‐throughput first‐principles calculations. Nearly half of the new NLO materials exhibit superior NLO performance with SHG susceptibilities approaching the theoretical upper limit. The 2D form of 11 candidates inherits the NLO property covering UV, visible, and infrared regions. Bader charge analysis reveals that the SHG susceptibility is determined by the charge difference of ions on the chains. Finally, it is proposed that superior NLO materials can be found in materials with proper bandgaps and large charge differences on the chains. This work not only screens out candidates with outstanding NLO performance in vdW materials with 1D building blocks but also provides a guideline for the search and design of NLO vdW 1D polymer patterns with excellent NLO properties.

GaSI: A Wide-Gap Non-centrosymmetric Helical Crystal

“…These experimental findings unequivocally validate the absence of inversion symmetry within the GaSI crystal structure (Figure S12). Low-dimensional solids exhibiting NLO properties remain a rarity, and materials that approach the theoretical limit have remained in silico . , To our knowledge, GaSI is one of the first exfoliable 1D vdW solids to have experimental evidence for SHG and, in contrast to GaSeI, is significantly more air stable (Figure S4). We discuss the prospects of accessing enantiopure analogues of III–VI–VII 1D vdW helices in the Supporting Information (Figure S9; Supplementary Text C).…”