상세정보
학술지
Enhanced Photo-Conversion Efficiency of CdSe-ZnS Core-Shell Quantum Dots with Au Nanoparticles on TiO2 Electrodes
- 발행일
- 201102
- 출처
- Journal of Materials Chemistry, v.21 no.8, pp.2694-2700
- ISSN
- 0959-9428
- 출판사
- Royal Society of Chemistry (RSC)
- 협약과제
- 10MB4300, 투명전도성 기판 대체구조 태양전지 개발, 강만구
- 초록
- This study demonstrates that configurations that include gold nanoparticles (Au NPs) as the primary layer attached to a TiO2 electrode with quantum dots (QDs) as the secondary layer have superior photoelectrochemical properties. We found that all Au-QD nanoparticle hybrid systems reveal enhanced photocurrent generation as compared to only a QD-nanoparticle interface. The enhanced Jsc is attributed to sensitization that results indirectly from quantum dots becoming attached to Au NPs by intramolecular charge transfers. As a result of the improved performance, the overall energy conversion efficiency was increased by 100% as compared to that of a reference cell without Au NPs at 100 mW cm-2. When (CdSe)ZnS is prepared from Au-coated TiO2, incident photon-to-current efficiency values approaching 20% can be achieved by (CdSe)ZnS devices. In the electrochemical impedance spectroscopy results, the intermediate frequency region of the Au-QD cells was more significantly reduced compared to that in bare QD cells due to the enhanced charge separation that occurs in the Au-QD structure. Mott-Schottky (C-2-) analysis shows that the lowest acceptor and donor densities having a positive effect on the efficiency could be found in (CdSe)ZnS-Au/TiO2 cells. Therefore, (CdSe)ZnS-Au/TiO2 has a very thin depletion layer that is restricted to the surface of Au/TiO 2. Consequently, this system can be employed to enhance the effective efficiency in the design of the QD-sensitized solar cells. © 2011 The Royal Society of Chemistry.
- KSP 제안 키워드
- Au nanoparticles(Au-NPs), Au/TiO 2, CdSe-ZnS, Charge transfer, Conversion efficiency(C.E.), Core-shell quantum dots, Depletion Layer, Effective efficiency, Impedance spectroscopy(IS), Intermediate frequency, Mott-Schottky