倒置器件结构及局域等离子体效应对CdSe量子点LED发光性能的改进

Improvement of Performance for CdSe Quantum Dot LEDs by Using An Inverted Device Structure and Localized Surface Plasmon Resonance

研究了倒置器件结构以及CdSe量子点发光材料与金属纳米粒子之间的相互作用对量子点的电致发光性能的影响。利用TiO2作为电子传输/注入层,成功地制备了倒置结构的量子点电致发光器件。通过对单载流子器件电压-电流特性的分析,证明了ITO作为阴极到TiO2的电子注入特性与Al作为阴极时的效果几乎相同。观察到金属纳米粒子产生的局域等离子体效应提高了器件的效率,使得效率随电流增大而降低的速度明显减小。在电流密度为200 mA/cm2时,电致发光器件的效率大约提高了42%。

The improvement of the performance for CdSe quantum dot light emitting diodes（QD-LEDs） was studied by using the inverted device structure and localized surface plasmon resonant（LSPR） coupling of Au nanoparticles with the QDs.We fabricated inverted QD-LEDs with TiO2 as the electron injection/transport layer.The current density-voltage characteristics of electron-only device were studied.The electron-injection current from the top Al electrode with the forward-bias voltage（Al was used as the cathode） was symmetrical with that of the bottom ITO electrode with reverse-bias voltage（ITO was used as the cathode）,indicating the electron injection from ITO to TiO2 is facilitated like the case from Al cathode.It was noticed that the efficiency of QD-LEDs with Au nanoparticles was enhanced while the drop rate of the efficiency was clearly reduced with increasing the current density.A significant enhancement of 42% for current efficiency of the LEDs was achieved under high current density of 200 mA/cm2.