Defect Passivating Hole Transporting Material for Large-Area and Stable Perovskite Quantum-Dot Light-Emitting Diodes

Area of Science:

• Materials Science
• Organic Electronics
• Optoelectronics

Background:

• Organic hole-transporting materials (HTMs) are crucial for high-performance perovskite optoelectronics.
• Defect passivation is key to improving the stability and efficiency of perovskite quantum dot light-emitting diodes (Pe-QLEDs).

Purpose of the Study:

• To design and synthesize novel small-molecule HTMs with defect-passivating capabilities.
• To investigate the impact of methylthio (SMe) groups on HTM-perovskite interactions and Pe-QLED performance.

Main Methods:

• Design and synthesis of two small-molecule HTMs, X13 and X15, featuring SMe groups.
• Fabrication and characterization of Pe-QLEDs using X13 and X15 as HTMs.
• Performance evaluation of Pe-QLEDs, including external quantum efficiency (EQE) and device stability.

Main Results:

• X15 demonstrated enhanced interaction and superior defect passivation with perovskite quantum dots due to SMe groups at the para-position of the carbazole unit.
• Pe-QLEDs utilizing X15 achieved a maximum EQE of 22.89% for small-area devices (0.09 cm²).
• Large-area Pe-QLEDs (1 cm²) with X15 exhibited an EQE of 21.10% and uniform emission, outperforming PTAA-based devices.

Conclusions:

• The molecular design incorporating SMe groups is effective for creating defect-passivating HTMs.
• X15 represents a promising HTM for advancing the performance and scalability of Pe-QLEDs.
• This study offers insights for developing next-generation small-molecule HTMs for perovskite optoelectronics.