近红外量子点的发光机理研究

Luminescence Mechanism of Near-Infrared Quantum Dots

近红外量子点具有独特的光学性质,如荧光量子产率高,荧光寿命长,荧光发射波长可调,半峰宽窄且斯托克斯位移较大,耐光漂白能力强等,及"近红外生物窗口"的优势,使它们在生物荧光标记、太阳能电池、量子化计算、光催化、化学分析、食品检测及活体成像等领域具有巨大的潜在应用价值。目前对近红外量子点的发光机理研究还不够完善,针对国内外的研究现状,重点对核/壳结构的量子点(CdTe/CdSe,CdSe/CdTe/ZnSe等)、三元量子点(Cu—In-Se,CuInS_2等)和掺杂型量子点(Cu:InP等)三种不同类型近红外量子点的发光机理进行了综述。其中,Type-Ⅱ型核/壳结构量子点的发光机理多为带间复合发光,三元量子点以本征缺陷型发光为主,掺杂型量子点多为杂质缺陷型发光。探讨了近红外量子点发光原理存在的问题及发展的方向。对近红外量子点的发光机理进行系统地研究不仅有助于我们理解近红外量子点的发光性质,而且对完善相似高品质量子点的合成方法具有重要意义。

Near-infrared quantum dots have unique optical properties ,such as high fluorescence quantum yield ,long fluorescent life ,tunable fluorescence emission wavelength ,half peak width and large stokes shift ,resisting light bleaching etc .The advan-tage of “near infrared biological window” gives them great potential application value in biological fluorescent tags ,solar cells , quantization calculation ,photocatalysis ,chemical analysis ,food detection ,vivo imaging and other fields .At present ,the lumi-nescence mechanism research of near-infrared quantum dots is still not comprehensive enough .In this paper ,the luminescent principle of three different types of near-infrared quantum dots is summarized ,including core/shell structure quantum dots （CdTe/CdSe ,CdSe/CdTe/ZnSe ,etc） ,ternary quantum dots （Cu-In-Se ,CuInS2 ,etc） and doped quantum dots （Cu∶ InP , etc） .The luminescence mechanism of Type Ⅱ core/shell structure is most likely to attribute to the interband recombination lu-minescence ,the ternary structure of quantum dots light emitting mechanism is considered to be due to the intrinsic structure de-fects ,and the luminescence mechanism of doped quantum dots is deemed to result from the impurity defects .The existing prob-lems of near-infrared luminescent principle of quantum dots are also discussed and their development tendency is explored t in this review .A systematic study of luminescence mechanism of near-infrared quantum dots will not only help to understand the lumi-nescent properties of near infrared quantum dots ,but also contribute to improve the synthesis methods of quantum dots with similarly high quality .