采用核壳结构的绿光CdSSe/ZnS量子点成功制备了顶发射绿光量子点器件,并详细研究了它的光电特性.与具有相同结构的底发射器件相比,顶发射器件在亮度、效率、色纯度、光谱的电压稳定性上都得到了显著提高.在相同电压7V下,尽管底发射具有更大的电流密度,但亮度仅为831 cd/m2,而顶发射器件的亮度则可达到1 350 cd/m2,并且顶发射器件的最高亮度可达到7 112 cd/m2.在效率上,顶发射器件的最大电流效率可达6.54 cd/A,远大于底发射器件的1.89 cd/A.在光谱方面,在底发射器件中出现的红蓝部分的杂光在顶发射器件中完全被抑制,而且顶发射光谱的半高宽显著窄化,具有更高的色纯度.当电压从4V变化到9V时,顶发射器件光谱始终保持稳定,色坐标移动仅为(-0.005,-0.001).结果表明,顶发射结构有利于提高量子点器件的亮度、效率、色纯度以及光谱的电压稳定性.%Green top emitting OLEDs were fabricated by using green CdSSe/ZnS quantum dots with core-shell structure.The photoelectric properties of the devices were studied in detail.Compared to the bottom emitting device with the similar structure,the top emitting device was significantly improved in brightness,efficiency,color purity,and voltage stability of the spectrum.Under the same voltage of 7 V,although the bottom emitting device has greater current density,the brightness is only 831 cd/m2,while the brightness of the top emitting device can reach 1 350 cd/m2,and the highest brightness can reach 7 112 cd/m2.In efficiency,the maximum current efficiency of the top emitting device can reach 6.54 cd/A,which is far greater than 1.89 cd/A of the bottom emitting device.In terms of spectrum,the red and blue parts of the bottom emitting devices are completely suppressed in the top emitting devices,and the half height width of the top emission spectrum is significantly narrowed with higher color purity.When the voltage varies from 4 V to 9 V,the spectrum of the top emitting device remains stable,and the color coordinates move only (-0.005,-0.001).The results show that the top emission structure is beneficial to improve the luminance,efficiency,color purity and voltage stability of the quantum dots.
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