中科院苏州纳米所王强斌团队合成了在NIR-II窗口中具有高光致发光量子产率的胶体合金量子点。相关研究成果于2021年2月5日发表于国际一流学术期刊《美国化学会杂志》。

半导体量子点（QDs）在900-1700nm范围内（NIR-II称为第二近红外窗口）具有较低的光子吸收和散射特性，引起了生物医学成像和近红外器件领域的广泛研究。然而，开发具有高光致发光量子产率（PLQY）和良好生物相容性的NIR-II量子点具有很大的挑战性。

研究人员设计合成了一种发光范围为820～1170nm的合金化硒化银金量子点（AgAuSe），在无有毒元素的NIR-II量子点中，在978nm处获得了65.3%的绝对PLQY和4.58μs的长寿命。结果表明，高PLQY和长寿命的主要原因是由于阻止了激子的无辐射跃迁，这可能是由于合金化Au原子使Ag离子的高迁移率抑制了阳离子空位和晶体缺陷所致。

研究人员开发的含有无毒重金属的高PLQY量子点在生物成像、发光二极管（led）和光伏器件等方面具有巨大的应用潜力。

附：英文原文

Title: Colloidal Alloyed Quantum Dots with Enhanced Photoluminescence Quantum Yield in the NIR-II Window

Author: Hongchao Yang, Renfu Li, Yejun Zhang, Mengxuan Yu, Zan Wang, Xi Liu, Wenwu You, Datao Tu, Ziqiang Sun, Rong Zhang, Xueyuan Chen, Qiangbin Wang

Issue&Volume: February 5, 2021

Abstract: Semiconductor quantum dots (QDs) with photoluminescence (PL) emission at 900–1700 nm (denoted as the second near-infrared window, NIR-II) exhibit much-depressed photon absorption and scattering, which has stimulated extensive researches in biomedical imaging and NIR devices. However, it is very challenging to develop NIR-II QDs with a high photoluminescence quantum yield (PLQY) and excellent biocompatibility. Herein, we designed and synthesized an alloyed silver gold selenide (AgAuSe) QD with a bright emission from 820 to 1170 nm and achieved a record absolute PLQY of 65.3% at 978 nm emission among NIR-II QDs without a toxic element and a long lifetime of 4.58 μs. It is proved that the high PLQY and long lifetime are mainly attributed to the prevented nonradiative transition of excitons, probably resulted from suppressing cation vacancies and crystal defects from the high mobility of Ag ions by alloying Au atoms. These high-PLQY QDs with nontoxic heavy metal exhibit great application potential in bioimaging, light emitting diodes (LEDs), and photovoltaic devices.

DOI: 10.1021/jacs.0c13071

Source: https://pubs.acs.org/doi/10.1021/jacs.0c13071