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Synthesis of CuInS2 quantum dots using polyetheramine as solvent.

Shei SC, Chiang WJ, Chang SJ - Nanoscale Res Lett (2015)

Bottom Line: An excess of group VI elements facilitated precipitation, whereas an excess of group I elements resulted in CuInS2 QDs with high photoluminescence quantum yield.Our results demonstrate that the band gap of the CuInS2 QDs is tunable with size as well as the composition of the reactant.We also determined some important physical parameters such as the band gaps and energy levels of this system, which are crucial for the application of CuInS2 nanocrystals.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical Engineering, National University of Tainan, Tainan, 70005 Taiwan.

ABSTRACT
This paper presents a facile solvothermal method of synthesizing copper indium sulfide (CuInS2) quantum dots (QDs) via a non-coordinated system using polyetheramine as a solvent. The structural and optical properties of the resulting CuInS2 QDs were investigated using composition analysis, absorption spectroscopy, and emission spectroscopy. We employed molar ratios of I, III, and VI group elements to control the structure of CuInS2 QDs. An excess of group VI elements facilitated precipitation, whereas an excess of group I elements resulted in CuInS2 QDs with high photoluminescence quantum yield. The emission wavelength and photoluminescence quantum yield could also be modulated by controlling the composition ratio of Cu and In in the injection stock solution. An increase in the portion of S shifted the emission wavelength of the QDs to a shorter wavelength and increased the photoluminescence quantum yield. Our results demonstrate that the band gap of the CuInS2 QDs is tunable with size as well as the composition of the reactant. The photoluminescence quantum yield of the CuInS2 QDs ranged between 0.7% and 8.8% at 250°C. We also determined some important physical parameters such as the band gaps and energy levels of this system, which are crucial for the application of CuInS2 nanocrystals.

No MeSH data available.


Absorption spectra (a) and photoluminescence spectra (b) of the CIS QDs.
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Fig1: Absorption spectra (a) and photoluminescence spectra (b) of the CIS QDs.

Mentions: CuInS2 QDs were synthesized using CuCl2 · 2H2O, InCl3 · 3H2O, and sulfur powder as precursors. Figure 1a presents the absorption spectra of CIS QDs with different solvothermal growth temperatures of 150°C, 200°C, and 250°C. The QDs grown at 250°C exhibited absorption at longer wavelengths, which are different from those grown at 150°C due to a reduction in the quantum confinement effect associated with QDs of larger size. CIS QDs grown at 150°C presented a blue shift in the absorption spectra of the resulting CIS QDs, as shown in Figure 1b. After increasing the growth temperature, the absorption features of CIS QDs became less pronounced; however, we observed a shift in the onset of absorption by CIS QDs to a longer wavelength. It should be noted that the optical band gaps of CIS QDs grown at 150°C, 200°C, and 250°C were estimated at 2.19, 1.82, and 1.65 eV, respectively. A similar narrowing in the band gap of CIS QDs with increased temperature has been attributed to an increase in the effective size of the QD core [9,11]. The emission QY values, calculated at an excitation wavelength of 450 nm, were as follows: 150°C-CIS QDs (3.7%), 200°C-CIS QDs (5.0%), and 250°C-CIS QDs (8.8%). As expected, the enhanced photoluminescence peaks appeared following an increase in the growth temperature from 150°C to 250°C. No changes were observed below 150°C. Furthermore, the full width at half maximum (FWHM) of emissions dropped was slightly from 120 to 105 nm. From our measurements, the growth temperature of 250°C is best for PL intensity.Figure 1


Synthesis of CuInS2 quantum dots using polyetheramine as solvent.

Shei SC, Chiang WJ, Chang SJ - Nanoscale Res Lett (2015)

Absorption spectra (a) and photoluminescence spectra (b) of the CIS QDs.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385220&req=5

Fig1: Absorption spectra (a) and photoluminescence spectra (b) of the CIS QDs.
Mentions: CuInS2 QDs were synthesized using CuCl2 · 2H2O, InCl3 · 3H2O, and sulfur powder as precursors. Figure 1a presents the absorption spectra of CIS QDs with different solvothermal growth temperatures of 150°C, 200°C, and 250°C. The QDs grown at 250°C exhibited absorption at longer wavelengths, which are different from those grown at 150°C due to a reduction in the quantum confinement effect associated with QDs of larger size. CIS QDs grown at 150°C presented a blue shift in the absorption spectra of the resulting CIS QDs, as shown in Figure 1b. After increasing the growth temperature, the absorption features of CIS QDs became less pronounced; however, we observed a shift in the onset of absorption by CIS QDs to a longer wavelength. It should be noted that the optical band gaps of CIS QDs grown at 150°C, 200°C, and 250°C were estimated at 2.19, 1.82, and 1.65 eV, respectively. A similar narrowing in the band gap of CIS QDs with increased temperature has been attributed to an increase in the effective size of the QD core [9,11]. The emission QY values, calculated at an excitation wavelength of 450 nm, were as follows: 150°C-CIS QDs (3.7%), 200°C-CIS QDs (5.0%), and 250°C-CIS QDs (8.8%). As expected, the enhanced photoluminescence peaks appeared following an increase in the growth temperature from 150°C to 250°C. No changes were observed below 150°C. Furthermore, the full width at half maximum (FWHM) of emissions dropped was slightly from 120 to 105 nm. From our measurements, the growth temperature of 250°C is best for PL intensity.Figure 1

Bottom Line: An excess of group VI elements facilitated precipitation, whereas an excess of group I elements resulted in CuInS2 QDs with high photoluminescence quantum yield.Our results demonstrate that the band gap of the CuInS2 QDs is tunable with size as well as the composition of the reactant.We also determined some important physical parameters such as the band gaps and energy levels of this system, which are crucial for the application of CuInS2 nanocrystals.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical Engineering, National University of Tainan, Tainan, 70005 Taiwan.

ABSTRACT
This paper presents a facile solvothermal method of synthesizing copper indium sulfide (CuInS2) quantum dots (QDs) via a non-coordinated system using polyetheramine as a solvent. The structural and optical properties of the resulting CuInS2 QDs were investigated using composition analysis, absorption spectroscopy, and emission spectroscopy. We employed molar ratios of I, III, and VI group elements to control the structure of CuInS2 QDs. An excess of group VI elements facilitated precipitation, whereas an excess of group I elements resulted in CuInS2 QDs with high photoluminescence quantum yield. The emission wavelength and photoluminescence quantum yield could also be modulated by controlling the composition ratio of Cu and In in the injection stock solution. An increase in the portion of S shifted the emission wavelength of the QDs to a shorter wavelength and increased the photoluminescence quantum yield. Our results demonstrate that the band gap of the CuInS2 QDs is tunable with size as well as the composition of the reactant. The photoluminescence quantum yield of the CuInS2 QDs ranged between 0.7% and 8.8% at 250°C. We also determined some important physical parameters such as the band gaps and energy levels of this system, which are crucial for the application of CuInS2 nanocrystals.

No MeSH data available.