Unveiling Crystal Structure Landscapes and Morphology Modification Rules of Substituted Benzophenone Crystals

Abstract

The morphology of crystals has a significant impact on their applications. 4-Aminobenzophenone (4-NBZP) is a key material for nonlinear optical applications, but it is difficult to obtain large and defect-free morphologies of 4-NBZP, which limits its optical application. In this study, we have elucidated the influence of the rules of functional groups on the molecular stacking mode and morphology of 4-NBZP as well as its derivatives via a combined experimental and simulated investigation. Based on these findings, structurally similar additives, 4-chlorobenzophenone (4-ClBZP) and 4-bromobenzophenone (4-BrBZP), were selected to modulate the morphology of 4-NBZP crystals. It was demonstrated that large and defect-free 4-NBZP crystals could be obtained at a moderate additive concentration (25%). Simulations demonstrated that the introduction of the additive resulted in the disappearance of the (1 0 −1) facet, an increased ratio in the (1 0 0) facet, and a slightly increased occupancy in the (0 0 1) facet of the 4-NBZP crystals. The additive tends to adsorb on the (1 0 −1) and (1 0 0) facets, inhibiting their growth. However, 4-NBZP molecules in solution also prefer to adsorb on the (1 0 −1) facet, which accelerates its growth and results in the disappearance of the (1 0 −1) facet. Due to the weaker interaction between the (1 0 0) facet and 4-NBZP molecules, the additive efficiently hinders the growth of this facet, leading to an enlargement of the (1 0 0) facet. Furthermore, the analysis of mean square displacement indicates that the addition of the similarity additive can slow down the diffusion effect of 4-NBZP. This work provides new ideas on how to obtain large and defect-free crystals of substituted benzophenone, which further promotes their optical applications.