Kaur Manpreet, Sharma Ashma, Olutas Murat, Erdem Onur, Kumar Akshay, Sharma Manoj, Demir Hilmi Volkan
Department of Nanotechnology, Sri Guru Granth Sahib World University, Punjab, 140406, India.
Department of Electrical and Electronics Engineering, Department of Physics, and UNAM-Institute of Materials Science and Nanotechnology, Bilkent University, 06800, Ankara, Turkey.
Nanoscale Res Lett. 2018 Jun 18;13(1):182. doi: 10.1186/s11671-018-2599-x.
Here, we report efficient composition-tunable Cu-doped ZnInS/ZnS (core and core/shell) colloidal nanocrystals (CNCs) synthesized by using a colloidal non-injection method. The initial precursors for the synthesis were used in oleate form rather than in powder form, resulting in a nearly defect-free photoluminescence (PL) emission. The change in Zn/In ratio tunes the percentage incorporation of Cu in CNCs. These highly monodisperse Cu-doped ZnInS CNCs having variable Zn/In ratios possess peak emission wavelength tunable from 550 to 650 nm in the visible spectrum. The quantum yield (QY) of these synthesized Cd-free CNCs increases from 6.0 to 65.0% after coating with a ZnS shell. The CNCs possessing emission from a mixed contribution of deep trap and dopant states to only dominant dopant-related Stokes-shifted emission are realized by a careful control of stoichiometric ratio of different reactant precursors during synthesis. The origin of this shift in emission was understood by using steady state and time-resolved fluorescence (TRF) spectroscopy studies. As a proof-of-concept demonstration, these blue excitable Cu-doped ZnInS/ZnS CNCs have been integrated with commercial blue LEDs to generate white-light emission (WLE). The suitable combination of these highly efficient doped CNCs results led to a Commission Internationale de l'Enclairage (CIE) color coordinates of (0.33, 0.31) at a color coordinate temperature (CCT) of 3694 K, with a luminous efficacy of optical radiation (LER) of 170 lm/W and a color rendering index (CRI) of 88.
在此，我们报道了通过胶体非注入法合成的高效成分可调的铜掺杂硫化锌铟/硫化锌（核以及核/壳）胶体纳米晶体（CNCs）。合成的初始前驱体采用油酸盐形式而非粉末形式，从而实现了几乎无缺陷的光致发光（PL）发射。锌/铟比例的变化调节了铜在CNCs中的掺入百分比。这些具有可变锌/铟比例的高度单分散铜掺杂硫化锌铟CNCs在可见光谱中的峰值发射波长可从550纳米调至650纳米。这些合成的无镉CNCs在包覆硫化锌壳层后，量子产率（QY）从6.0%提高到了65.0%。通过在合成过程中仔细控制不同反应物前驱体的化学计量比，实现了从深陷阱和掺杂剂态的混合贡献发射到仅为主导的与掺杂剂相关的斯托克斯位移发射的转变。通过稳态和时间分辨荧光（TRF）光谱研究，理解了这种发射位移的起源。作为概念验证演示，这些蓝色可激发的铜掺杂硫化锌铟/硫化锌CNCs已与商用蓝色发光二极管集成，以产生白光发射（WLE）。这些高效掺杂CNCs的合适组合产生了在3694K的色坐标温度（CCT）下，国际照明委员会（CIE）色坐标为（0.33，0.31），光辐射发光效率（LER）为170 lm/W且显色指数（CRI）为88的结果。
