Fluorinated ionic molecule enables synergistic surface passivation and charge balancing for efficient green perovskite quantum-dot light-emitting diodes

TrTPFB is successfully introduced as a fluorinated ionic molecule into FAPbBr₃ PeQDs. • Multi-site interactions stabilize the PeQD surface and suppress nonradiative recombination. • TrTPFB induces p-type modulation, reducing interfacial charge accumulation. • Threefold enhancement in T₅₀ lifetime highlights improved device stability. Perovskite quantum-dot light-emitting diodes (PeQLEDs) remain limited by coupled surface and interfacial losses: labile ligand binding produces trap-rich perovskite quantum dot (PeQD) surfaces while unbalanced carrier injection accelerates interfacial charge accumulation and nonradiative recombination. Here, triphenylmethylium tetrakis(pentafluorophenyl)borate (TrTPFB) is introduced as a fluorinated ionic molecule to synergistically regulate both the surface coordination and charge-injection behavior of FAPbBr₃ PeQDs. Density functional theory (DFT) calculations reveal pronounced charge redistribution between TrTPFB and the PeQD surface. Experimental results show that the fluorinated tetrakis(pentafluorophenyl)borate (TPFB − ) anion and the positively charged triphenylmethylium (Tr + ) cation cooperatively stabilize the surface coordination environment and suppress trap-mediated nonradiative recombination. TrTPFB also induces p-type electronic modulation of the PeQD film, shifts the Fermi level toward the valence band, lowers the hole-injection barrier, and mitigates interfacial charge accumulation. Consequently, The combined operation of these mechanisms significantly improves the photoluminescence quantum yield (PLQY) of perovskite films to an impressive 98.50%. The corresponding green PeQLED achieves a peak external quantum efficiency of 17.50%, a maximum luminance of 80,859.28 cd m −2 , and an approximately threefold increase in the average T₅₀ lifetime compared with the control device. This work establishes a fluorinated ionic molecular strategy that integrates surface passivation and charge-injection regulation for efficient and stable PeQLEDs. Download: Download high-res image (115KB) Download: Download full-size image