Spatially Engineering the Internal Microstructure of a Single Crystal via Nanoparticle Occlusion

Single crystals are characterized by their continuous, highly ordered atomic lattices. Therefore, introducing impurities or structural defects into their matrices presents a major challenge, particularly in a spatially-controlled manner. Herein, we demonstrate a nanoparticle occlusion approach that enables the microstructure of cuprous oxide (Cu₂O) single crystals to be engineered in a tunable way. This is achieved by directly incorporating poly(glycerol monomethacrylate)₅₁-block-poly(benzyl methacrylate)₁₀₀ [G₅₁-B₁₀₀] diblock copolymer nanoparticles into growing Cu₂O crystals, leading to the formation of G₅₁-B₁₀₀@Cu₂O composite crystals with structural defects localized at the G₅₁-B₁₀₀/Cu₂O interfaces. The spatial distribution of these defects can be systematically engineered, ranging from the surface region to the entire crystal. Remarkably, the G₅₁-B₁₀₀ occlusion endows the resulting composite crystals with excellent catalytic performance in dye degradation under dark conditions, with activity correlated to the extent of nanoparticle occlusion. This study offers a unique strategy to create interfacial defects in single crystals, imparting emerging functionalities to the resulting composites.