In situ growth of α-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 α-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 α-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 α-CsPbI₃ NCs. Particularly, α-CsPbI₃ NCs/rGO heterostructures show a suitable band gap of ∼1.74 eV, an acceptable photoluminescence (PL) intensity and a PL quantum yield (PLQY) of ∼10.7%. The decay lifetime of these heterostructures was maintained at ∼43.5 ns and PLQY was maintained at ∼68% of the initial value when stored in ambient conditions for ∼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.