Park Min Ho, Kim Min Gye, Ma Jin Hyun, Jeong Jun Hyung, Ha Hyoun Ji, Kim Wonsik, Park Soohyung, Kang Seong Jun
Department of Advanced Materials Engineering for Information and Electronics, Kyung Hee University, Yongin 17104, Republic of Korea.
Integrated Education Program for Frontier Materials (BK21 Four), Kyung Hee University, Yongin 17104, Republic of Korea.
Materials (Basel). 2023 Jan 20;16(3):972. doi: 10.3390/ma16030972.
Charge imbalance in quantum-dot light-emitting diodes (QLEDs) causes emission degradation. Therefore, many studies focused on improving hole injection into the QLEDs-emitting layer owing to lower hole conductivity compared to electron conductivity. Herein, CuCoO has a relatively higher hole conductivity than other binary oxides and can induce an improved charge balance. As the annealing temperature decreases, the valence band maximum (VBM) of CuCoO shifts away from the Fermi energy level (E), resulting in an enhanced hole injection through better energy level alignment with hole transport layer. The maximum luminance and current efficiency of the CuCoO hole injection layer (HIL) of the QLED were measured as 93,607 cd/m and 11.14 cd/A, respectively, resulting in a 656% improvement in luminous performance of QLEDs compared to conventional metal oxide HIL-based QLEDs. These results demonstrate that the electrical properties of CuCoO can be improved by adjusting the annealing temperature, suggesting that solution-processed spinel can be applied in various optoelectronic devices.
量子点发光二极管（QLED）中的电荷不平衡会导致发光性能下降。因此，由于空穴电导率低于电子电导率，许多研究都集中在改善空穴注入到QLED发光层的过程。在此，CuCoO具有比其他二元氧化物相对更高的空穴电导率，并且能够实现更好的电荷平衡。随着退火温度降低，CuCoO的价带最大值（VBM）远离费米能级（E），通过与空穴传输层更好的能级对齐，导致空穴注入增强。QLED的CuCoO空穴注入层（HIL）的最大亮度和电流效率分别测量为93,607 cd/m²和11.14 cd/A，与传统金属氧化物HIL基QLED相比，QLED的发光性能提高了656%。这些结果表明，通过调节退火温度可以改善CuCoO的电学性能，这表明溶液处理的尖晶石可应用于各种光电器件。
