摘要:
利用无机纳米材料与有机聚合物材料相结合的方法制备白光发光二极管器件,研究了蓝光量子点QDs(B)掺杂聚[2-甲氧基-5-(2-乙基己氧基-1,4-苯撑乙烯撑](MEH-PPV)复合体系的发光特性及量子点QDs(B)掺杂浓度(质量分数)不同对器件发光特性的影响。制备了ITO/PEDOT:PSS/MEH-PPV:QDs(B)/LiF/Al 结构的电致发光器件,测试了器件的电致发光光谱和电学、光学特性。当QDs掺杂浓度为40%,驱动电压为8 V时器件能得到较为理想的白光发射。同时,对比研究了非掺杂体系的发光特性,制备了结构为ITO/PEDOT:PSS/MEH-PPV/QDs(B)/LiF/Al的器件,掺杂体系相较于非掺杂体系,器件的最大亮度增大,启亮电压降低,并分析了掺杂体系器件性能改善的原因。
关键词:
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量子点
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MEH-PPV
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白光
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掺杂
Abstract:
The white light emitting diode (LED) devices, in which blue-emitting quantum dots doped in the polymer of poly [2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylene vinylene] (MEH-PPV) serve as the active layer, have been fabricated in a nitrogen-filled glove box; the devices have the structure of ITO/PEDOT/MEH-PPV:QDs(B)/LiF/Al. After a systematical investigation, we report the effect of different quantum dots (QDs) doping concentration (mass fraction) on the electroluminescent spectrum, current density, brightness, CIE coordinates of the devices and atomic force microscopy (AFM) characterizations of the emitting layer. With the increase of QDs doping concentration, we find that the QDs luminance intensity of the controlling devices continues to grow. When the QDs doping concentration is 40%, the normal white light emission is obtained in the devices. The CIE coordinates of the white QD-LED are (0.35, 0.32), which are close to the balanced white coordinates. Besides, we also fabricate the non-doped devices, in which the structure is ITO/PEDOT/MEH-PPV/QDs(B)/LiF/Al. After finishing the active layer’s preparation, the morphology of the films are investigated by AFM. By comparing the analysis, the doped system has a lower level on the root mean squared roughness. In addition, the doped devices demonstrate a superior performance, and exhibit a low turn-on voltage and a high maximum value of luminance.