Silica‐Coated Hybrid Perovskite Catalysts for Well‐Controlled <scp>PET</scp>‐<scp>RAFT</scp> Polymerization in Polar Solvents

ABSTRACT Lead halide perovskite has currently emerged as a research hotspot in the field of photocatalysis due to its exceptional photovoltaic characteristics. Despite its potential, the susceptibility to degradation under harsh conditions such as light, humidity, and polar solvents poses a significant challenge. To counteract this, a strategy employing silica to shield the perovskite surface is conducted, thereby enhancing its stability. The resulting composite MAPbBr 3 @SiO 2 is then deployed as a photocatalyst in the photoinduced electron/energy transfer reversible addition fragmentation chain transfer (PET‐RAFT) polymerization of butyl acrylate within polar solvents. The catalytic performance across different RAFT polymerization systems including varying the RAFT reagents, catalyst concentrations, and solvent types is meticulously examined. Remarkably, with a photocatalyst loading of merely 0.004 wt% and under a blue light intensity of 6 mW/cm 2 , over 80% monomer conversion can be achieved in 4 h. Moreover, the molecular weight distribution ( Đ ) consistently remains within the narrow range of 1.0–1.2 across all experimental setups, which proves the controllable nature of the PET‐RAFT process. Owning the advantages of low photocatalyst requirement, compatibility with polar solvents, and narrow molecular weight distribution, PET‐RAFT polymerization mediated by MAPbBr 3 @SiO 2 holds promise for scalable manufacturing and industrial‐scale applications.