Stam Maarten, Almeida Guilherme, Ubbink Reinout F, van der Poll Lara M, Vogel Yan B, Chen Hua, Giordano Luca, Schiettecatte Pieter, Hens Zeger, Houtepen Arjan J
Optoelectronic Materials Section, Faculty of Applied Sciences, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands.
Physics and Chemistry of Nanostructures, Department of Chemistry, Ghent University, 9000 Gent, Belgium.
ACS Nano. 2024 Jun 4;18(22):14685-14695. doi: 10.1021/acsnano.4c03290. Epub 2024 May 22.
Indium phosphide (InP) quantum dots (QDs) are considered the most promising alternative for Cd and Pb-based QDs for lighting and display applications. However, while core-only QDs of CdSe and CdTe have been prepared with near-unity photoluminescence quantum yield (PLQY), this is not yet achieved for InP QDs. Treatments with HF have been used to boost the PLQY of InP core-only QDs up to 85%. However, HF etches the QDs, causing loss of material and broadening of the optical features. Here, we present a simple postsynthesis HF-free treatment that is based on passivating the surface of the InP QDs with InF For optimized conditions, this results in a PLQY as high as 93% and nearly monoexponential photoluminescence decay. Etching of the particle surface is entirely avoided if the treatment is performed under stringent acid-free conditions. We show that this treatment is applicable to InP QDs with various sizes and InP QDs obtained different synthesis routes. The optical properties of the resulting core-only InP QDs are on par with InP/ZnSe/ZnS core-shell QDs, with significantly higher absorption coefficients in the blue, and with potential for faster charge transport. These are important advantages when considering InP QDs for use in micro-LEDs or photodetectors.
磷化铟（InP）量子点（QDs）被认为是用于照明和显示应用的基于镉和铅的量子点最有前景的替代品。然而，虽然CdSe和CdTe的仅核心量子点已制备出接近单位的光致发光量子产率（PLQY），但InP量子点尚未实现这一点。用HF处理已被用于将InP仅核心量子点的PLQY提高到85%。然而，HF会蚀刻量子点，导致材料损失和光学特征变宽。在这里，我们提出一种简单的无HF后合成处理方法，该方法基于用InF钝化InP量子点的表面。在优化条件下，这会导致PLQY高达93%，并且光致发光衰减几乎为单指数形式。如果在严格的无酸条件下进行处理，则完全避免颗粒表面的蚀刻。我们表明，这种处理方法适用于各种尺寸的InP量子点以及通过不同合成路线获得的InP量子点。所得仅核心InP量子点的光学性质与InP/ZnSe/ZnS核壳量子点相当，在蓝色区域具有显著更高的吸收系数，并且具有更快电荷传输的潜力。在考虑将InP量子点用于微型发光二极管或光电探测器时，这些都是重要的优势。
