RESUMO
Metal halide perovskites, a cost-effective class of semiconductos, hold great promise for display technologies that demand high-efficiency, color-pure light-emitting diodes (LEDs). Early research on three-dimensional (3D) perovskites showed low radiative efficiencies due to modest exciton binding energies. To inprove luminescence, reducing dimensionality or grain size has been a common approach. However, dividing the perovskite lattice into smaller units may hinder carrier transport, compromising electrical performance. Moreover, the increased surface area introduce additional surface trap states, leading to greater non-radiative recombination. Here, an ions-induced growth method is employed to assembe lattice-anchored perovskite nanocomposites for efficient LEDs with high color purity. This approach enables the nanocomposite thin films, composed of 3D CsPbBr3 and its variant of zero-dimensional (0D) Cs4PbBr6, to feature significant low trap-assisted nonradiative recombination, enhanced light out-coupling with a corrugated surface, and well-balanced charge carrier transport. Based on the resultant 3D/0D perovskite nanocomposites, the perovskite LEDs (PeLEDs) achieving an remarkable external quantum efficiency of 31.0% at the emission peak of 521 nm with a narrow full width at half-maximum of only 18 nm. This sets a new benchmark for color purity in high performance PeLED research, highlighting the significant advantage of this approach.
RESUMO
Metal halide perovskites hold great potential for next-generation light-emitting diodes (PeLEDs). Despite significant progress, achieving high-performance PeLEDs hinges on optimizing the interface between the perovskite crystal film and the charge transport layers, especially the buried interface, which serves as the starting point for perovskite growth. Here, we develop a bottom-up perovskite film modulation strategy using formamidine acetate (FAAc) to enhance the buried interface. This multifaceted approach facilitates the vertical-oriented growth of high-quality perovskites with minimized defects. Meanwhile, the in situ deprotonation between FA+ and ZnO could eliminate the hydroxyl (-OH) defects and modulate the energy level of ZnO. The resulting FAPbI3-PeLED exhibits a champion EQE of 23.84% with enhanced operational stability and suppressed EQE roll-off. This strategy is also successfully extended to other mixed-halide PeLEDs (e.g., Cs0.17FA0.83Pb(I0.75Br0.25)3), demonstrating its versatility as an efficient and straightforward method for enhancing the PeLEDs' performance.