Abstract:

AgInS₂ quantum dots (AIS QDs) have shown broad application prospects in the field of optoelectronics and biomedicine due to the advantages of environmental friendliness, tunable emission wavelength, long fluorescence lifetime and large Stokes shift. In this study, AIS quantum dots were prepared in octadecene solvent by microwave-assisted heating method. The effects of reaction time on the phase, morphology and fluorescence properties of AIS QDs were systematically investigated by X-ray diffraction, transmission electron microscope, and photoluminescence spectroscopy, respectively. The surface bonding of the AIS QDs was characterized by Fourier infrared spectroscopy and X-ray photoelectron spectroscopy. The results showed that AIS QDs could be synthesized within 5—25 min when the microwave power was 800 W. With the increase of reaction time, the particle size of AIS QDs increased gradually from 3 nm to 4 nm, and the PL peak position could be tuned in the range of 592.0—619.6 nm. The fluorescence intensity increased simultaneously and reached the maximum value at 15 min with photoluminescence quantum yield (PLQY) of 16.16%, In addition, the fluorescence properties of QDs were further improved by ZnS surface modification to passivate the defects, resulting in the enhanced PLQY of 31.21%. Furthermore, white light-emitting diode (WLED) devices were fabricated by using AIS@ZnS QDs and commercial phosphors as light conversion layer. The luminous efficiency (LE) of the fabricated WLED device was as high as 74.90 lm/W under the driving current of 20 mA, and the corresponding color rendering index (CRI) and correlated color temperature (CCT) were 83.31 and 3823 K respectively, indicating that the prepared QDs have great applications in solid-state lighting.

Key words: white light-emitting diodes, quantum dot, composites, nanostructure, organic phase microwave synthesis

摘要：

AgInS₂量子点(AIS QDs)由于具有绿色环保、发射波长可调、荧光寿命长、斯托克斯位移大等优势，在光电和生物医药领域具有广阔的应用前景。采用微波辅助加热法在十八烯溶剂中制备了AIS QDs。通过X射线衍射、透射电子显微镜、光致发光光谱系统研究了反应时间对AIS QDs的物相、形貌及荧光性能的影响，采用傅里叶红外光谱和X射线光电子能谱表征了量子点表面结合的情况。实验结果表明：当微波功率为800 W、反应时间为5~25 min时均可以制备出AIS QDs。随着反应时间的延长，AIS QDs的粒径由3 nm增加至4 nm，发光峰位在592.0~619.6 nm范围内调谐；同时AIS QDs的荧光强度逐渐提高，并在15 min达到峰值，量子产率(PLQY)达到16.16%。进一步采用ZnS作为包覆壳层有效钝化量子点表面缺陷、提高荧光性能，制备出的AIS@ZnS QDs的PLQY增加至31.21%。将AIS@ZnS QDs和商用荧光粉共同作为发光层制备成白光发光二极管(WLED)器件，在20 mA电流驱动下发光效率(LE)为74.90 lm/W，显色指数(CRI)和色温(CCT)分别为83.31和3823 K，表明制备的量子点在固态照明领域具有潜在的应用前景。

关键词: 白光发光二极管, 量子点, 复合材料, 纳米结构, 有机相微波合成