Surface passivation of CsPbBr₃ nanoplates via multifunctional organic sulfate for enhanced photoluminescence, stability, and efficiency in blue-emitting perovskite-based devices

Pure blue-emitting CsPbBr₃ perovskite nanoplates (NPLs) show great potential for next-generation ultra-high-definition displays due to their narrow linewidth and wide color gamut. However, challenges such as poor stability and luminous efficiency have hindered their widespread application, especially in comparison to perovskite quantum dots. In this study, we introduce a novel surface passivation approach using PPA₂SO₄ to significantly enhance the photoluminescence quantum yield (PLQY) of CsPbBr₃ NPLs to 96 %. The PPA₂SO₄ precursor forms strong bonds with the CsPbBr₃ surface via sulfate ion coordination, effectively passivating surface defects (V_Br) and improving photoluminescence stability by mitigating tail states and suppressing non-radiative recombination. As a result, the PPA₂SO₄-modified NPLs exhibit improved photophysical properties, including longer lifetimes (9.7 ns) and increased UV stability, with 89 % resistance after 15 h of continuous UV irradiation. Additionally, a white-light emitting diodes (WLEDs) device based on the modified NPLs demonstrates impressive color gamut coverage (140.1 % of NTSC and 94.8 % of Rec. 2020) and long-term stability, with only 11 % brightness loss after 15 h of continuous operation at 2986 cd m⁻². This surface modification strategy offers a promising route for enhancing the efficiency and stability of perovskite materials, paving the way for their practical applications in displays and lighting.