Charge transfer and optical properties of wurtzite-type ZnS/(CdS/ZnS)  (n= 2, 4, 8) superlattices

Zeng, Xianghua; Zhang, Wei; Cui, Jieya; Zhou, Min; Chen, Haitao

doi:10.1016/j.materresbull.2013.11.010

Cited by 9 publications

(3 citation statements)

References 35 publications

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“…38 Then, the effect of the inner structure on the carrier relaxation dynamics of Cd 1Àx Zn x S QDs has also been discussed. 39 Due to the shell effect of ZnS with a reduced lattice mismatch, as-prepared G-Cd 1Àx Zn x S QDs possess higher PLQYs and longer lifetimes than not only bare CdS QDs but also any other types of Cd 1Àx Zn x S QDs.…”

Section: Introductionmentioning

confidence: 99%

Facile synthesis of composition-gradient Cd_1−xZn_xS quantum dots by cation exchange for controlled optical properties

et al. 2015

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Three different types of water-soluble Cd 1Àx Zn x S quantum dots (QDs) having nearly identical sizes and compositions have been synthesized via simple and low-cost methods to understand the effect of internal structures on the optical properties of QDs. Compared with the other two types, CdS@ZnS core-shell Cd 1Àx Zn x S QDs and alloy Cd 1Àx Zn x S QDs, composition-gradient CdS@ZnS core-shell Cd 1Àx Zn x S (G-Cd 1Àx Zn x S) QDs, which have been prepared by exchanging the Cd 2+ ions of CdS QDs partially with Zn 2+ ions conserving the shapes and sizes, have shown the longest lifetime and the highest quantum yield of photoluminescence due to the smallest nonradiative and the largest radiative decay constants of photogenerated charge carriers. The composition-gradient ZnS shells, which passivate the CdS cores optimally alleviating the lattice strain caused by the lattice mismatches between the CdS cores and the ZnS shells, have been considered to be the main reason for the enhanced optical properties of G-Cd 1Àx Zn x S QDs. Among our prepared G-Cd 1Àx Zn x S QDs, the quantum yield and the lifetime of photoluminescence are the highest (22%) and the longest (290 ns), respectively, due to the smallest nonradiative decay constant when about half of the Cd 2+ ions in CdS QDs are replaced by Zn 2+ ions with composition gradients from their surfaces, suggesting that internal structures play an important role in the relaxation dynamics of photoexcited charge carriers.

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Section: Introductionmentioning

confidence: 99%

Facile synthesis of composition-gradient Cd_1−xZn_xS quantum dots by cation exchange for controlled optical properties

et al. 2015

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“…Recently, a new type of superlattices (SLs) composed of different allotropes such as using Zinc‐Blende (ZB) and Wurtzite (WZ) phases of the same chemical elements has been extensively studied . These SLs (e. g. GaN, GaAs, InP, InAs, CdTe, ZnS, etc.…”

Section: Introductionmentioning

confidence: 99%

Structural Engineering of Zinc‐Blend/Wurtzite BN Superlattices

et al. 2018

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By constructing Zinc-Blende (ZB)/Wurtzite (WZ) boron nitride (BN) (ZB 1-x /WZ x -BN) superlattices (SLs), their electronic structure and mechanical properties were investigated by first-principles techniques based on density functional theory. It is found that the band structure is significantly modulated by the ratio of WZ phase in ZB/WZ-BN SLs. With the increase of WZ ratio, the band gap of SLs decreases and then increases dramatically. More importantly, transformation from type-I to type-II band alignment between ZB and WZ can be tuned by adjusting the ratio of WZ to be > 0.6. In addition, a universal expression of the band gap is proposed to reveal a nonlinear dependence of the band gap within the structure of SLs as induced by from the interface effect achieved via structural transformation. The elastic constants results revealed that the change of ZB/WZ ratio poses no significant effect on the mechanical properties. The effect of structure modulation on band structure and mechanical properties is significantly important for future engineering of novel semiconductor SLs.

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“…Multilayer structure attracts much attention recently, since the optical properties can be enhanced and charge transfer characteristics in the surface and interface regions of hetero-structure can also be improved [9]. Therefore, we designed a novel composite window structure for CdTe thin film solar cells.…”

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confidence: 99%

Preparation and characterization of pulsed laser deposited a novel CdS/CdSe composite window layer for CdTe thin film solar cell

Yang

Liu

et al. 2016

Applied Surface Science

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A novel CdS/CdSe composite window structure was designed and then the corresponding films were prepared by pulsed laser deposition as an improved window layer for CdTe-based solar cells. Two types of this composite window structure with 5 cycles and 10 cycles CdS/CdSe respectively both combined with CdS layers were prepared at 200 compared with pure CdS window layer and finally were applied into CdTe thin film solar cells. The cross section and surface morphology of the two composite window layers were monitored by using scanning electron microscopy and the result shows that the pulsed laser deposited composite window layers with good crystallinity are stacking together as the design. The devices based on CdS/CdSe composite window layers have demonstrated the enhanced photocurrent collection from both short and long wavelength regions compared to CdS/CdTe solar cell. The efficiency of the best reference CdS/CdTe solar cell was10.72%. And the device with 5 cycles CdS/CdSe composite window showed efficiency of 12.61% with V OC of 772.92 mV, J SC of 25.11 mA/cm 2 and FF of 64.95%. In addition, there are some differences which exists within the optical transmittance spectra and QE curves between the two CdS/CdSe composite window samples, indicating that the volume proportion of CdSe may influence the performance of CdTe thin film solar cell.

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Charge transfer and optical properties of wurtzite-type ZnS/(CdS/ZnS) (n= 2, 4, 8) superlattices

Cited by 9 publications

References 35 publications

Facile synthesis of composition-gradient Cd_1−xZn_xS quantum dots by cation exchange for controlled optical properties

Facile synthesis of composition-gradient Cd_1−xZn_xS quantum dots by cation exchange for controlled optical properties

Structural Engineering of Zinc‐Blend/Wurtzite BN Superlattices

Preparation and characterization of pulsed laser deposited a novel CdS/CdSe composite window layer for CdTe thin film solar cell

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Charge transfer and optical properties of wurtzite-type ZnS/(CdS/ZnS) (n= 2, 4, 8) superlattices

Cited by 9 publications

References 35 publications

Facile synthesis of composition-gradient Cd1−xZnxS quantum dots by cation exchange for controlled optical properties

Facile synthesis of composition-gradient Cd1−xZnxS quantum dots by cation exchange for controlled optical properties

Structural Engineering of Zinc‐Blend/Wurtzite BN Superlattices

Preparation and characterization of pulsed laser deposited a novel CdS/CdSe composite window layer for CdTe thin film solar cell

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Facile synthesis of composition-gradient Cd_1−xZn_xS quantum dots by cation exchange for controlled optical properties

Facile synthesis of composition-gradient Cd_1−xZn_xS quantum dots by cation exchange for controlled optical properties