Structural dimensionality makes a crucial role in determining electron distribution and corresponding macroscopic optical properties of crystals. Here, we present a new quasi-one-dimensional (1D) halide polymorph NH₄HgBr₃·H₂O (NHB), containing parallel 1D (HgBr₃)^- chain built from condensed and aligned (HgBr₄)^2- tetrahedron. The decreased dimensionality reduces the extent of orbital overlap in various directions and leads to band-gap widening. In addition, the quasi-1D structure of NHB results in the high density of states at top valence band and yield a large second harmonic generation (SHG) response (28 × KDP), high laser induced damage threshold (LIDT) (52.7×AGS), and large birefringence value ([email protected]), concurrently. Combining its scalable preparation in solution, NHB is a potential infrared nonlinear optical (NLO) candidate for practical applications. This work demonstrates a successful material design case in halide crystals and highlights dimensionality control as a good strategy in designing better NLO materials.

结构维数在决定晶体的电子分布和相应的宏观光学性质方面起着至关重要的作用。在这里，我们提出了一种新的准一维 (1D) 卤化物多晶型物 NH ₄ HgBr ₃ ·H ₂ O (NHB)，包含平行的 1D (HgBr ₃ ) ^-链由缩合和排列 (HgBr ₄ ) ^2-四面体。降低的维数减少了各个方向上轨道重叠的程度，并导致带隙加宽。此外，NHB 的准一维结构导致顶价带的高态密度并产生大的二次谐波产生 (SHG) 响应 (28 × KDP)、高激光诱导损伤阈值 (LIDT) (52.7 × AGS ) 和大双折射值 ( [email protected] )，同时进行。结合其在溶液中的可扩展制备，NHB 是实际应用中潜在的红外非线性光学 (NLO) 候选者。这项工作展示了卤化物晶体材料设计的成功案例，并强调了维数控制是设计更好 NLO 材料的良好策略。