Liu Jingjing, Lu Zhangbo, Zhang Xianju, Zhang Yangyi, Ma Haiguang, Ji Yang, Xu Xiangxing, Yu Linwei, Xu Jun, Chen Kunji
National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, Nanjing University, Nanjing 210093, China.
Nanomaterials (Basel). 2018 Nov 26;8(12):974. doi: 10.3390/nano8120974.
Inorganic perovskites have emerged as a promising candidate for light-emitting devices due to their high stability and tunable band gap. However, the power consumption and brightness have always been an issue for perovskite light-emitting diodes (PeLEDs). Here, we improved the luminescence intensity and decreased the current density of the PeLEDs based on CsPbI₃ quantum dots (QDs) and p-type Si substrate through an alternating current (AC) driving mode. For the different driving voltage modes (under a sine pulsed bias or square pulsed bias), a frequency-dependent electroluminescent (EL) behavior was observed. The devices under a square pulsed bias present a stronger EL intensity under the same voltage due to less thermal degradation at the interface. The red PeLEDs under a square pulsed bias driving demonstrate that the EL intensity drop-off phenomenon was further improved, and the integrated EL intensity shows the almost linear increase with the increasing driving voltage above 8.5 V. Additionally, compared to the direct current (DC) driving mode, the red PeLEDs under the AC condition exhibit higher operating stability, which is mainly due to the reducing accumulated charges in the devices. Our work provides an effective approach for obtaining strong brightness, low power consumption, and high stability light-emitting devices, which will exert a profound influence on coupling LEDs with household power supplies directly.
无机钙钛矿因其高稳定性和可调节的带隙，已成为发光器件的一个有前景的候选材料。然而，功耗和亮度一直是钙钛矿发光二极管（PeLEDs）的一个问题。在此，我们通过交流（AC）驱动模式提高了基于CsPbI₃量子点（QDs）和p型硅衬底的PeLEDs的发光强度并降低了电流密度。对于不同的驱动电压模式（在正弦脉冲偏置或方波脉冲偏置下），观察到了频率依赖的电致发光（EL）行为。在相同电压下，方波脉冲偏置下的器件由于界面处的热降解较少而呈现出更强的EL强度。方波脉冲偏置驱动下的红色PeLEDs表明，EL强度下降现象得到了进一步改善，并且在高于8.5 V的驱动电压下，积分EL强度几乎呈线性增加。此外，与直流（DC）驱动模式相比，交流条件下的红色PeLEDs表现出更高的工作稳定性，这主要是由于器件中积累电荷的减少。我们的工作为获得高亮度、低功耗和高稳定性的发光器件提供了一种有效方法，这将对直接将发光二极管与家用电源耦合产生深远影响。
