A Strain-Free Semicoherent Interface Achieved via Epitaxial Growth of CsPbBr3 on CdS Quantum Dots

The epitaxial growth of heterojunctions can reduce interface defects and enhance the stability of the crystal structures. However, a higher lattice mismatch can cause local lattice distortions at the interface, resulting in relaxed strains that eventually evolve into structural defects. Herein, a nearly zero-mismatch semicoherent interface was formed with a lattice mismatch (0.3%) by epitaxial growth CsPbBr3 on CdS quantum dots (QDs), leading to a strain-free semicoherent interface. Results demonstrated that CdS/CsPbBr3 heteronanocrystals (HNCs) had excellent stability and high photocatalytic performance compared with CsPbBr3. Theoretical calculations show that the Br–Cd bond forms strong electron coupling, which not only facilitates rapid electron transfer but also provides better structural stability. Compared to the individual CsPbBr3 nanocrystals (NCs), the CdS/CsPbBr3 HNCs exhibited higher stability and 2.1 times higher photocatalytic activity. It suggests that CdS/CsPbBr3 HNCs have potential application value in energy and environmental fields.