In situ growth of alpha-CsPbI3 perovskite nanocrystals on the surface of reduced graphene oxide with enhanced stability and carrier transport quality

Herein, an in situ solution growth method to prepare preferentially assembled and well-distributed alpha-CsPbI3 nanocrystals (NCs)/reduced graphene oxide (rGO) heterostructures is presented. Owing to its excellent thermal conductivity, carrier mobility, hydrophobic nature and passivation effect, rGO could reduce the number of ligands on the surface of alpha-CsPbI3 NCs, provide protection against air and moisture, and enhance the carrier separation and carrier transport properties of nanocrystals. The homogeneous growth of nanocrystals and their distribution along the surface of rGO also improved the stability and carrier transport quality compared to that of alpha-CsPbI3 NCs. Particularly, alpha-CsPbI3 NCs/rGO heterostructures show a suitable band gap of B1.74 eV, an acceptable photoluminescence (PL) intensity and a PL quantum yield (PLQY) of similar to 10.7%. The decay lifetime of these heterostructures was maintained at similar to 43.5 ns and PLQY was maintained at similar to 68% of the initial value when stored in ambient conditions for similar to 4 weeks. Finally, we demonstrate the inkjet printing of these heterostructures, manifesting their favorable dispersibility in organic solvents, and showing their utility as optically active materials for applications in optoelectronic devices.