Efficient and stable blue perovskite light-emitting diodes enabled by the synergistic incorporation of dual additives

Perovskite materials have garnered significant attention in the field of light-emitting diodes (LEDs) due to their low cost, solution processing, straightforward fabrication, tunable emission wavelengths, narrow emission linewidths, and high photoluminescence quantum yield. However, blue perovskite light-emitting diodes (PeLEDs) currently face challenges of low efficiency and poor stability, which hinder their application in full-color display technology. It is understood that the quality of the perovskite film is considered a key factor affecting the performance of PeLEDs. To achieve high-quality perovskite films and high-performance PeLEDs, benzoic acid potassium (BAP) and guanidinium chloride (GACl) were employed as dual additives in the precursor solution of a quasi-two-dimensional perovskite (PEA₂Cs_n-1Pb_nX_3n+1). By utilizing the coordination of BA^- from BAP with uncoordinated Pb²⁺ and the formation of hydrogen bonds between GA⁺ from GACl and halide ions, the perovskite surface defects are effectively passivated, along with the inhibition of the migration of halide ions. This approach reduces non-radiative recombination and enhances the spectral stability of perovskite films. By fine-tuning the concentrations of BAP and GACl, optimal PeLEDs are achieved at a BAP concentration of 3% and a GACl concentration of 10%, with the spectrum stabilized at 476 nm and a maximum external quantum efficiency (EQE_max) of 4.47%, which is 2.54 times that of the control device (EQE_max of 1.76%). The findings in this study provide a new approach for the fabrication of highly efficient and spectrally stable blue PeLEDs.