光致发光
材料科学
纳米晶
激光线宽
量子点
钝化
光电子学
热稳定性
纳米技术
硫系化合物
壳体(结构)
化学工程
激光器
光学
复合材料
物理
工程类
图层(电子)
作者
Aurelio A. Rossinelli,Henar Rojo,Aniket S. Mule,Marianne Aellen,Ario Cocina,Eva De Leo,R. Schäublin,David J. Norris
标识
DOI:10.1021/acs.chemmater.9b04220
摘要
Colloidal semiconductor nanoplatelets exhibit exceptionally narrow photoluminescence spectra. This occurs because samples can be synthesized in which all nanoplatelets share the same atomic-scale thickness. As this dimension sets the emission wavelength, inhomogeneous linewidth broadening due to size variation, which is always present in samples of quasispherical nanocrystals (quantum dots), is essentially eliminated. Nanoplatelets thus offer improved, spectrally pure emitters for various applications. Unfortunately, because of their nonequilibrium shape, nanoplatelets also suffer from low photo-, chemical, and thermal stability, which limits their use. Moreover, their poor stability hampers the development of efficient synthesis protocols for adding high-quality protective inorganic shells, a well-known strategy to improve the performance of quantum dots. Herein, we report a general synthesis approach to highly emissive and stable core/shell nanoplatelets with various shell compositions, including CdSe/ZnS, CdSe/CdS/ZnS, CdSe/CdxZn1–xS, and CdSe/ZnSe. Motivated by previous work on quantum dots, we find that slow, high-temperature growth of shells containing a compositional gradient reduces strain-induced crystal defects and minimizes the emission linewidth while maintaining good surface passivation and nanocrystal uniformity. Indeed, our best core/shell nanoplatelets (CdSe/CdxZn1–xS) show photoluminescence quantum yields of 90% with linewidths as low as 56 meV (19.5 nm) at 655 nm. To confirm the high quality of our different core/shell nanoplatelets for a specific application, we demonstrate their use as gain media in low-threshold ring lasers. More generally, the ability of our synthesis protocol to engineer high-quality shells can help further improve nanoplatelets for optoelectronic devices.
科研通智能强力驱动
Strongly Powered by AbleSci AI