Park Jin Young, Advincula Rigoberto C
Department of Polymer Science and Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, 702-701 Republic of Korea.
Phys Chem Chem Phys. 2014 May 14;16(18):8589-93. doi: 10.1039/c4cp00066h.
The photo- (PL) and electroluminescence (EL) properties of CdSe-TOPO quantum dots (QDs) doped into a PVK:PBD host matrix with a double-layer device configuration [PEDOT:PSS/PVK:PBD/QDs/LiF/Al] are investigated. Depending on the concentrations of CdSe-TOPO QDs, EL properties are changed including the emitted colors. At a low QD concentration (1 wt%), QD-light emitting diode (QD-LED) shows a broad EL band with dominant QD emission and minor emissions (electromer from PVK and exciplex from the PVK:PBD blend). However, at a higher QD concentration (5 wt%) there are two competitive emission peaks observed in the EL spectrum, arising from exciplex emission in the PVK:PBD blend (shorter wavelength) and QD emission at CdSe-TOPO. These EL peaks are closely related to Förster energy transfer and charge transfer, respectively. With increasing bias voltage, the EL peak at shorter wavelength gradually decreases and the emitted color is changed from blue to dark green in the QD-LED. As a result, both the concentration and applied bias voltage are important tunable factors in the emitted colors.
研究了掺杂在具有双层器件结构[PEDOT:PSS/PVK:PBD/QDs/LiF/Al]的PVK:PBD主体基质中的CdSe-TOPO量子点（QD）的光致发光（PL）和电致发光（EL）特性。根据CdSe-TOPO量子点的浓度，电致发光特性会发生变化，包括发射颜色。在低量子点浓度（1 wt%）下，量子点发光二极管（QD-LED）显示出一个宽的电致发光带，主要是量子点发射，还有少量发射（来自PVK的电异构体和来自PVK:PBD共混物的激基复合物）。然而，在较高的量子点浓度（5 wt%）下，在电致发光光谱中观察到两个竞争发射峰，分别来自PVK:PBD共混物中的激基复合物发射（较短波长）和CdSe-TOPO处的量子点发射。这些电致发光峰分别与福斯特能量转移和电荷转移密切相关。随着偏置电压的增加，较短波长处的电致发光峰逐渐降低，并且在量子点发光二极管中发射颜色从蓝色变为深绿色。因此，浓度和施加的偏置电压都是发射颜色的重要可调因素。
