<p>Colloidally quantum-confined CsPbBr<sub>3</sub> nanoplatelets (NPLs) exhibit narrow emission linewidths and thickness-tunable photoluminescence, making them ideal candidates for deep-blue perovskite light-emitting diodes (PeLEDs). However, the weak surface coordination of conventional long-chain ligands (<i>e.g</i>., oleylamine and oleic acid) leads to face-to-face stacking of the NPLs, resulting in undesirable emission redshifts in their PeLEDs. Herein, we report an efficient deep-blue PeLED based on colloidal CsPbBr<sub>3</sub> NPLs that meet the Rec.2020 color standard, enabled by an acid-assisted ligand passivation strategy. Surface chemical analysis reveals that hydrobromic acid facilitates proton-assisted stripping of the long-chain ligands, followed by the formation of stable Pb-S-P coordination bonds with thio-tributylphosphine, which exhibits a high adsorption energy (E<sub>ads</sub> = -1.13 eV). This approach significantly improves surface defect passivation, yielding a photoluminescence quantum yield of 96% and a narrow 13 nm full-width-at-half-maximum deep-blue emission. Enhanced exciton recombination and reduced defect state density are evidenced by a prolonged photoluminescence lifetime and slower absorption bleach recovery kinetics. The resulting PeLEDs achieve record-breaking performance among CsPbBr<sub>3</sub> NPL-based systems, with a maximum external quantum efficiency of 6.81% at 461 nm, a peak luminance of 143 cd m<sup>-2</sup>, and the CIE color coordinates (CIE-y = 0.046) that comply with Rec.2020 standards. This work presents an effective strategy for developing efficient and stable deep-blue perovskite emitters, demonstrating significant potential for the commercialization of perovskite nanomaterials in next-generation ultra-high-definition displays.</p>

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Efficient deep-blue LEDs based on colloidal CsPbBr3 nanoplatelets meeting the Rec.2020 standard

  • Yusheng Song,
  • Sheng Cao,
  • Yijie Wang,
  • Mingyan Chen,
  • Yu Zhang,
  • Qiuyan Li,
  • Shulin Han,
  • Yi Liang,
  • Lei Cai,
  • Jialong Zhao,
  • Bingsuo Zou

摘要

Colloidally quantum-confined CsPbBr3 nanoplatelets (NPLs) exhibit narrow emission linewidths and thickness-tunable photoluminescence, making them ideal candidates for deep-blue perovskite light-emitting diodes (PeLEDs). However, the weak surface coordination of conventional long-chain ligands (e.g., oleylamine and oleic acid) leads to face-to-face stacking of the NPLs, resulting in undesirable emission redshifts in their PeLEDs. Herein, we report an efficient deep-blue PeLED based on colloidal CsPbBr3 NPLs that meet the Rec.2020 color standard, enabled by an acid-assisted ligand passivation strategy. Surface chemical analysis reveals that hydrobromic acid facilitates proton-assisted stripping of the long-chain ligands, followed by the formation of stable Pb-S-P coordination bonds with thio-tributylphosphine, which exhibits a high adsorption energy (Eads = -1.13 eV). This approach significantly improves surface defect passivation, yielding a photoluminescence quantum yield of 96% and a narrow 13 nm full-width-at-half-maximum deep-blue emission. Enhanced exciton recombination and reduced defect state density are evidenced by a prolonged photoluminescence lifetime and slower absorption bleach recovery kinetics. The resulting PeLEDs achieve record-breaking performance among CsPbBr3 NPL-based systems, with a maximum external quantum efficiency of 6.81% at 461 nm, a peak luminance of 143 cd m-2, and the CIE color coordinates (CIE-y = 0.046) that comply with Rec.2020 standards. This work presents an effective strategy for developing efficient and stable deep-blue perovskite emitters, demonstrating significant potential for the commercialization of perovskite nanomaterials in next-generation ultra-high-definition displays.