Improved performance of all-solution-processed quantum dot light-emitting diodes with TFB/PVK double-hole transport
Jaeyeop Lee1, Woon Ho Jung2, Kyoungeun Lee1
1Department of Electrical Engineering, Pusan National University 2 Busandaehak-ro 63 beon-gil, Geumjeong-gu Busan 46241 Republic of Korea jkroh@pusan.ac.kr.
Nanoscale Advances
|April 25, 2025
Summary
Achieving balanced charge injection in solution-processed quantum dot light-emitting diodes (QD-LEDs) is challenging. This study identifies 1,2-dichloroethane as an optimal solvent for creating double-hole transport layers, significantly boosting QD-LED performance.
Area of Science:
- Materials Science
- Organic Electronics
- Nanotechnology
Background:
- High-performance quantum dot light-emitting diodes (QD-LEDs) require balanced electron and hole injection for efficient operation.
- Solution-processed fabrication of QD-LEDs is desirable for cost-effectiveness but presents challenges in achieving balanced charge injection.
- Double-hole transport layers (D-HTLs) using polymers like poly(9-vinylcarbazole) (PVK) and poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine))] (TFB) are effective for improving hole injection.
Purpose of the Study:
- To investigate solvent orthogonality for constructing TFB/PVK double-hole transport layers (D-HTLs) in all-solution-processed QD-LEDs.
- To identify an optimal solvent for depositing PVK onto a TFB layer without causing damage, ensuring effective D-HTL formation.
- To demonstrate the performance enhancement of QD-LEDs fabricated using the optimized D-HTL strategy.
Main Methods:
- Systematic investigation of various solvents for PVK deposition, evaluating their polarity, solubility, and impact on the underlying TFB layer.
- Fabrication of QD-LEDs utilizing the optimized TFB/PVK D-HTLs formed with the identified optimal solvent.
- Performance characterization of the fabricated QD-LEDs, including external quantum efficiency (EQE) measurements.
Main Results:
- 1,2-dichloroethane (1,2-DCE) was identified as the optimal solvent for forming TFB/PVK D-HTLs with minimal damage to the TFB layer.
- All-solution-processed QD-LEDs employing the TFB/PVK D-HTLs exhibited a 1.5-fold increase in external quantum efficiency compared to devices with a single hole transport layer.
- The identified solvent, 1,2-DCE, also proved effective in inverted QD-LED architectures, protecting the emissive layer during subsequent processing steps.
Conclusions:
- Solvent selection is critical for successful fabrication of multi-layer solution-processed organic electronic devices.
- 1,2-DCE enables the efficient formation of TFB/PVK D-HTLs, leading to significantly improved QD-LED performance.
- The findings offer a versatile solution for enhancing charge injection and device efficiency in various QD-LED architectures through all-solution processing.
