Title:	ZnO Nanorods as Tunable Light Management Structures in Silicon Thin-Film Solar Cells
Author(s):	R.-E. Nowak, M. Kellermann, O. Sergeev, M. Vehse, K. von Maydell, C. Agert
Keywords:	Anti-Reflection Coating, Electrodeposition, Light Trapping, a-Si:H, TCO Transparent Conducting Oxides
Topic:	MATERIAL STUDIES, NEW CONCEPTS, ULTRA-HIGH EFFICIENCY AND SPACE TECHNOLOGY
Subtopic:	New Materials and Concepts for Cells
Event:	28th European Photovoltaic Solar Energy Conference and Exhibition
Session:	1AV.2.16
Pages:	303 - 308
ISBN:	3-936338-33-7
Paper DOI:	10.4229/28thEUPVSEC2013-1AV.2.16
Price:	0,00 EUR
Document(s):	paper

Abstract/Summary:

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Electrochemical deposition is a cost-effective and versatile technique to grow nanostructured zinc oxide films for the application as transparent electrodes in photovoltaic devices. In this work, we performed a systematic study about the influence of the electrochemical deposition parameters (deposition time, potential, ZnCl2 and KCl concentration) on the morphology of ZnO nanorod arrays and their optical properties as well as on the performance of amorphous silicon thin-film solar cells. Our results showed that long deposition times (>3600s) and medium potentials (from -0.8V to -0.9V) favor morphologies with a high roughness. Furthermore, we observed a supplement structure of micrometer sized disks which are formed at high ZnCl2 concentrations (≥0.01M), especially in combination with a high KCl concentration. For the arrays with high overall roughness, we found both a low reflection and high transmission haze, resulting in significantly enhanced short circuit current densities if applied as a transparent electrode in amorphous silicon thin-film solar cells, with a maximum increase of 42% in the short circuit current density compared to a flat reference cell. However, as the rough structures lead to electrical losses in the cells, we achieved the best cell efficiencies for nanorod arrays with medium roughness.