Strong enhancement of band-edge photoluminescence in CdS quantum dots prepared by a reverse-micelle method

Kim, D.; Miyamoto, Masashi; Mishima, T.; Nakayama, Masaaki

doi:10.1063/1.2106008

Cited by 40 publications

(27 citation statements)

References 24 publications

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“…Compared to the PL emissions shown in figure 5 (curves a, b), CdS nanocrystals synthesized by wet chemical co-precipitation in methanol (figure 5(c)) show much more intense ≈ 35 times stronger PL emission. In contrast, Kim et al (2005) reported the activation of CdS nanocrystals originating from reverse micelle method. Hence, we tried such a surface modification to improve the PL properties of CdS quantum dots prepared by wet chemical co-precipitation reaction.…”

Section: Resultsmentioning

confidence: 89%

Effect of solvent-induced structural modifications on optical properties of CdS nanoparticles

et al. 2010

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We have investigated the effects of solvent used during synthesis on structural and optical properties of CdS quantum dots. Different methods of synthesis for the production of CdS quantum dots are presented. These are: (a) wet chemical co-precipitation in non-aqueous medium (i.e. methanol); (b) wet chemical co-precipitation in aqueous medium (deionized water) and (c) solid state reaction. It is demonstrated that the use of methanol as solvent leads to a strong enhancement of PL intensity of CdS quantum dots for use in optoelectronic devices. These products were characterized by X-ray powder diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). The change in bandgap with size-quantization was investigated by UV-VIS absorption spectroscopy. CdS nanocrystals prepared in non-aqueous medium have narrow size distribution than those prepared in aqueous medium and solid state reaction. Phase transformation of CdS nanocrystals from a cubic to hexagonal structure was observed in methanol solution. The formation of CdS/Cd(OH) 2 nanostructure was also confirmed using X-ray diffraction pattern. This suggests that the strong enhancement of the PL intensity may have originated from the remarkable reduction of non-radiative recombination process, due to surface defects of quantum dots. The red shift of the Raman peaks compared to that for bulk CdS may be attributed to optical phonon confinement.

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Section: Resultsmentioning

confidence: 89%

Effect of solvent-induced structural modifications on optical properties of CdS nanoparticles

et al. 2010

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“…[28][29][30][31] In general, there are two different kinds of emission bands for the NCs prepared in colloids.…”

Section: The Influence Of S/cd Ratio On Absorption and Photoluminescementioning

confidence: 99%

Effects of surface modification on photocatalytic activity of CdS nanocrystals studied by photoluminescence spectroscopy

Huang

Yang

Wang

et al. 2013

Phys. Chem. Chem. Phys.

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The surface features of semiconductors play very important roles in photocatalytic processes but they are far from being well understood. In this work, we used CdS nanocrystals (NCs) as a model semiconductor photocatalyst to investigate the influence of surface features on photocatalytic activity.The effects of surface modification on the recombination behavior were studied by photoluminescence (PL) spectroscopy. The surface of CdS NCs was modified by tuning the surface S/Cd ratio or by co-loading with Pt and/or PdS co-catalysts. It was found that the surface modifications significantly affect the emission bands at B540 nm due to shallow traps and B650 nm assigned to S 2À vacancies, and consequently the photocatalytic activities. Without co-catalysts loading, the excited carriers are readily transferred to the shallow traps, while they are readily transferred to the co-catalysts upon co-catalystsloading. These results demonstrate that the surface features are crucial to photocatalytic activity of the CdS NCs. The surface modification is helpful for the excited carriers to transfer to either the shallow trap states or co-catalysts, resulting in higher quantum efficiency of photocatalytic H 2 production.

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“…In contrast, in an aqueous phase, the synthetic reaction, e.g. CdS [19,[23][24][25][26] and CdTe [13,27] occurs under mild conditions, e.g. at ambient temperature and pressure.…”

Section: Introductionmentioning

confidence: 92%

Polyacrylic acid coating of highly luminescent CdS nanocrystals for biological labeling applications

Sato

Tachibana

Hattori

et al. 2008

Journal of Colloid and Interface Science

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Strong enhancement of band-edge photoluminescence in CdS quantum dots prepared by a reverse-micelle method

Cited by 40 publications

References 24 publications

Effect of solvent-induced structural modifications on optical properties of CdS nanoparticles

Effect of solvent-induced structural modifications on optical properties of CdS nanoparticles

Effects of surface modification on photocatalytic activity of CdS nanocrystals studied by photoluminescence spectroscopy

Polyacrylic acid coating of highly luminescent CdS nanocrystals for biological labeling applications

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