혼합 용매를 사용한 정공수송층 및 이를 적용한 양자점발광 다이오드의 특성 향상 연구

초록

In this study, we introduce a mixed‐solvent strategy using chlorobenzene (CB) and 1,2-dichlorobenzene (DCB) to improve the film quality of the poly[(9,9-dioctylfluorene-alt-N-(4-sec-butylphenyl)-diphenylamine] (TFB), which is a typical material for the hole-transport layer (HTL) in quantum-dot light-emitting diodes (QLEDs). Variations in solution viscosity with solvent mixing ratio, combined with the Marangoni effect arising from the boiling-point difference between CB and DCB, yielded spin-coated TFB films with significantly enhanced morphology compared to those prepared using a single solvent. Notably, the TFB film fabricated with a DCB:CB ratio of 7:3 exhibited the lowest surface roughness. When this TFB HTL is integrated into QLED devices, it leads to reduced turn-on voltage, improved maximum external quantum efficiency, and suppressed leakage current. These results demonstrate that mixed-solvent engineering is a practical approach to improving solution-processed film quality and, consequently, the performance of optoelectronic devices. The findings highlight the broad applicability of mixed-solvent processing for various solution-processed electronic device technologies.

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