S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Material Science and Engineering (재료공학부) Theses (Master's Degree_재료공학부)
Hydrothermal Synthesis of Branched ZnO Nanowire Array as an Effective Photoanode for Quantum-Dot-Sensitized Solar Cells
- 공과대학 재료공학부
- Issue Date
- 서울대학교 대학원
- Quantum-dot-sensitized solar cell; Zinc oxide; Nanowire array; Hierarchical structure; Light trapping
- 학위논문 (석사)-- 서울대학교 대학원 : 재료공학부, 2014. 2. 박병우.
- I have focused on the synthesis of branched ZnO nanowires and the understanding of the growth kinetics during my thesis. Furthermore, the branched ZnO nanowire array was introduced as a photoelectrode of a quantum-dot-sensitized solar cell, and the correlation between the nanostructures and solar cell performance was investigated in terms of both optical (light trapping) and electrical (charge recombination) characteristics.
Three-dimensional branched ZnO nanowires were synthesized by a seed-mediated hydrothermal growth. The fast growth-rate of (001) direction was possible due to the anisotropic nature of ZnO and the capping agents blocking a lateral growth of nanowire.
About two-fold enhancement of power conversion efficiency (PCE) was obtained by growing secondary branches, and both short-circuit current and open-circuit voltage were enhanced. Highly increased surface area of photoelectrode, resulting in higher light harvesting from increased quantum-dot loading amount, and the higher diffused reflectance was observed due to enhanced light-scattering of 3D structure. In addition, electrochemical impedance spectroscopy and open-circuit voltage decay revealed the reduced recombination and higher lifetime of branched ZnO nanowires.