基于荧光材料DPVBi的蓝光有机电致发光器件的制备及发光性能研究

Preparation and Photoluminescence Properties of Blue High-efficiency Organic Light-emitting Diodes Based on DPVBi

我们使用高效荧光蓝光有机材料DPVBi制作了高效的蓝光有机发光器件,结构为ITO/HATCN/NPB/DPVBi/Bphen/LiF/Al。通过控制发光层DPVBi和电子传输层材料Bphen的厚度,我们发现在厚度变化时,器件效率也随之变化,说明随着厚度的改变,调节了电子注入,载流子在发光区的平衡分布发生变化,电子与空穴形成激子的复合发光实现可控。当发光层厚度为15nm,电子传输层厚度为50nm时,器件的发光性能最佳,最大亮度为7127cd/m^2,最大电流密度为4.23cd/A。与发光层厚度为5nm,电子传输层厚度为50nm的器件相比,效率提高了35%。该器件在亮度为1000cd/m^2时,电流效率为2.97cd/A,对应的色坐标为(0.14,0.17),处于色度图中的蓝光区。

We use efficient fluorescent blue organic material DPVBi to prepare a high-efficiency blue organic light-emitting diodes, the structure is ITO/HAT-CN/NPB/DPVBi/Bphen/LiF/Al. By controlling the thickness of electron transporting material Bphen, we discover that with the increase of thickness, the efficiency of our device is improved.This performance indicate that the thick Bphen improved the injection of electrons and the distribution of balanced carriers in emitting zone. The more electrons attract holes to form a lot of excitons, which expand the recombination region. When the thickness of electron transporting layer is 50 nm, the photoluminescence property of device is best, the maximum luminance is 7354 cd/m^2, the max current efficiency is 3. 4 cd/A. Compared to the device with 35 nm electron tran sporting layer, the efficiency is improved by 26 %. The current efficiency is 2. 9 cd/A at the luminance of 1000 cd/m^2,the corresponding CIE 1931 chromaticity coordinates is（0. 14, 0. 17）, which locate the blue zone in chromaticity diagram.