Van Avermaet Hannes, Schiettecatte Pieter, Hinz Sandra, Giordano Luca, Ferrari Fabio, Nayral Céline, Delpech Fabien, Maultzsch Janina, Lange Holger, Hens Zeger
Physics and Chemistry of Nanostructures, Ghent University, Gent 9000, Belgium.
Center for Nano and Biophotonics, Ghent University, Gent 9000, Belgium.
ACS Nano. 2022 Jun 28;16(6):9701-9712. doi: 10.1021/acsnano.2c03138. Epub 2022 Jun 16.
Photoluminescent color conversion by quantum dots (QDs) makes possible the formation of spectrum-on-demand light sources by combining blue LEDs with the light generated by a specific blend of QDs. Such applications, however, require a near-unity photoluminescence quantum efficiency since self-absorption magnifies disproportionally the impact of photon losses on the overall conversion efficiency. Here, we present a synthesis protocol for forming InP-based QDs with +90% quantum efficiency across the full visible spectrum from blue/cyan to red. The central features of our approach are as follows: (1) the formation of InP core QDs through one-batch-one-size reactions based on aminophosphine as the phosphorus precursor, (2) the introduction of a core/shell/shell InP/Zn(Se,S)/ZnS structure, and (3) the use of specific interfacial treatments, most notably the saturation of the ZnSe surface with zinc acetate prior to ZnS shell growth. Moreover, we adapted the composition of the Zn(Se,S) inner shell to attain the intended emission color while minimizing line broadening induced by the InP/ZnS lattice mismatch. The protocol is established by analysis of the QD composition and structure using multiple techniques, including solid-state nuclear magnetic resonance spectroscopy and Raman spectroscopy, and verified for reproducibility by having different researchers execute the same protocol. The realization of full-spectrum, +90% quantum efficiency will strongly facilitate research into light-matter interaction in general and luminescent color conversion in particular through InP-based QDs.
通过量子点（QD）进行光致发光颜色转换，使得通过将蓝色发光二极管（LED）与特定量子点混合物产生的光相结合，形成按需光谱光源成为可能。然而，此类应用需要近乎统一的光致发光量子效率，因为自吸收会不成比例地放大光子损失对整体转换效率的影响。在此，我们提出了一种合成方案，用于形成基于InP的量子点，在从蓝/青色到红色的整个可见光谱范围内量子效率超过90%。我们方法的核心特点如下：（1）基于氨基膦作为磷前驱体，通过单批次单尺寸反应形成InP核量子点；（2）引入核/壳/壳InP/Zn(Se,S)/ZnS结构；（3）使用特定的界面处理方法，最显著的是在生长ZnS壳层之前，用醋酸锌使ZnSe表面饱和。此外，我们调整了Zn(Se,S)内壳层的组成，以获得预期的发射颜色，同时最小化由InP/ZnS晶格失配引起的谱线展宽。该方案通过使用多种技术（包括固态核磁共振光谱和拉曼光谱）分析量子点的组成和结构来确立，并通过让不同的研究人员执行相同的方案来验证其可重复性。全光谱、90%以上量子效率的实现将极大地促进一般光与物质相互作用的研究，特别是基于InP的量子点的发光颜色转换研究。
