Wavelength-Tunable Band-Edge Photoluminescence of Nonstoichiometric Ag-In-S Nanoparticles via Ga3+ Doping
Wavelength-Tunable Band-Edge Photoluminescence of Nonstoichiometric Ag-In-S Nanoparticles via Ga3+ Doping
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DOI：
10.1021/acsami.8b15222
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发表时间：
2018-12-12
影响因子：
9.5
通讯作者：
Torimoto, Tsukasa
中科院分区：
文献类型：
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作者：
Kameyama, Tatsuya;Kishi, Marino;Torimoto, Tsukasa
半导体I - III - VI族半导体纳米粒子的非化学计量比，特别是I族与III族元素的比例，已被用于控制其物理化学性质。我们报道了非化学计量比的Ag - In - S和Ag - In - Ga - S纳米粒子的溶液相合成，以及对其与化学成分相关的光致发光（PL）性质的研究结果。虽然化学计量比的AgInS₂纳米粒子仅呈现出源自粒子缺陷位点的宽PL谱带，但在非化学计量比的Ag - In - S纳米粒子中，随着Ag含量的降低，出现了一个新的窄带边PL峰。该带边发射相对于缺陷位点发射的相对PL强度在Ag/(Ag + In)值约为0.4时达到最佳。由于能隙增大，通过向Ag - In - S纳米粒子中增加Ga³⁺掺杂，带边发射的峰值波长可从610 nm调谐到500 nm。此外，用GaSₓ壳层对Ga³⁺掺杂的Ag - In - S纳米粒子（即Ag - In - Ga - S纳米粒子）进行表面包覆，极大且有选择性地抑制了宽的缺陷位点PL峰，同时提高了带边发射峰的PL量子产率（QY）。对于Ag - In - Ga - S@GaSₓ核 - 壳粒子，最佳PL量子产率为28%，其在530 nm处有绿色带边发射，半峰全宽为181 meV（41 nm）。所观察到的带边PL峰的波长可调性将有助于这些无有毒元素的基于I - III - VI族的纳米粒子在广泛的应用领域中得到可能的应用。
The nonstoichiometry of semiconductor I-III-VI semiconductor nanoparticles, especially the ratio of group Ito group III elements, has been utilized to control their physicochemical properties. We report the solution-phase synthesis of non-stoichiometric Ag-In-S and Ag-In-Ga-S nanoparticles and results of the investigation of their photoluminescence (PL) properties in relation to their chemical compositions. While stoichiometric AgInS2 nanoparticles simply exhibited only a broad PL band originating from defect sites in the particles, a narrow band edge PL peak newly appeared with a decrease in the Ag fraction in the nonstoichiometric Ag-In-S nano-particles. The relative PL intensity of this band edge emission with respect to the defect-site emission was optimal at a Ag/(Ag + In) value of ca. 0.4. The peak wavelength of the band edge emission was tunable from 610 to 500 nm by increased doping with Ga3+ into Ag-In-S nanoparticles due to an increase of the energy gap. Furthermore, surface coating of Ga3+-doped Ag-In-S nanoparticles, that is, Ag-In-Ga-S nanoparticles, with a GaSx shell drastically and selectively suppressed the broad defect-site PL peak and, at the same time, led to an increase in the PL quantum yield (QY) of the band edge emission peak. The optimal PL QY was 28% for Ag-In-Ga-S@GaSx core-shell particles, with green band-edge emission at 530 nm and a full width at half-maximum of 181 meV (41 nm). The observed wavelength tunability of the band-edge PL peak will facilitate possible use of these toxic-element-free I-III-VI-based nanoparticles in a wide area of applications.