Zou Haoyang, Wang Deli, Gong Baijuan, Liu Yi
State Key Laboratory of Supramolecular Structure and Materials, Jilin University Changchun 130012 P. R. China
School of Life Sciences, Jilin University Changchun 130012 P. R. China
RSC Adv. 2019 Sep 30;9(53):30797-30802. doi: 10.1039/c9ra06254h. eCollection 2019 Sep 26.
Due to many unique and excellent optical properties, quantum dots (QDs) have been seen as one of the most promising color conversion materials in light-emitting diodes (LEDs). However, the Förster resonance energy transfer (FRET) among different colored QDs always causes a significant red-shift of the fluorescence emission, impeding the fabrication of LEDs with predicted photoluminescence (PL) emission spectra. In this work, we take advantage of CdTe superparticles (SPs), which are assembled by CdTe QDs, as the color conversion materials for the fabrication of WLEDs. Because of their submicron size, the distance between QDs with different emissions can be large enough to avoid the FRET process. More importantly, this method provides us with an opportunity to precisely design and regulate the PL emission spectra of LEDs. By easily overlapping the individual PL spectra of CdTe SPs with different emissions, the certain ratio of their usage for fabricating LEDs with desired PL emission spectra is identified. According to this idea, a WLED with a color rendering index (CRI) of 81, luminous efficacy of 27 lm W, and color coordinate at (0.33, 0.34) with the color temperature of 5742 K is achieved.
由于具有许多独特且优异的光学性质，量子点（QDs）被视为发光二极管（LEDs）中最有前途的颜色转换材料之一。然而，不同颜色量子点之间的福斯特共振能量转移（FRET）总是会导致荧光发射出现显著的红移，这阻碍了具有预测光致发光（PL）发射光谱的发光二极管的制造。在这项工作中，我们利用由碲化镉量子点组装而成的碲化镉超粒子（SPs）作为制造白光发光二极管（WLEDs）的颜色转换材料。由于它们的亚微米尺寸，不同发射波长的量子点之间的距离可以足够大，以避免福斯特共振能量转移过程。更重要的是，这种方法为我们提供了一个精确设计和调节发光二极管光致发光发射光谱的机会。通过轻松地将不同发射波长的碲化镉超粒子的各自光致发光光谱重叠，确定了它们用于制造具有所需光致发光发射光谱的发光二极管的特定比例。根据这一思路，实现了一种显色指数（CRI）为81、发光效率为27 lm/W、色坐标为（0.33, 0.34）且色温为5742 K的白光发光二极管。
