"

Cookies ussage consent

Our site saves small pieces of text information (cookies) on your device in order to deliver better content and for statistical purposes. You can disable the usage of cookies by changing the settings of your browser. By browsing our site without changing the browser settings you grant us permission to store that information on your device.

I agree, do not show this message again.

Development of highly stabilized efficiency micromorph tandem solar cells

Y. LIU1, J. K. RATH1,* , R. E. I. SCHROPP1

Affiliation

  1. Utrecht University, Faculty of Sciences, SID-Physics of Devices, P.O.Box 80.000, 3508TA Utrecht, The Netherlands

Abstract

Micromorph silicon (a-Si:H/μc-Si:H) tandem solar cells on Asahi U-type substrates have been fabricated by very high frequency (VHF) PECVD in a high vacuum multichamber system called ASTER. The microcrystalline silicon (μc-Si) intrinsic layer (i-layer) was deposited using a shower head cathode at high pressures and under silane depletion conditions, at a high deposition rate of about 0.5 nm/s. The best optoelectronic quality μc-Si i-layer was found at the transition phase from amorphous to crystalline. An initial efficiency of 9.9% for a single junction μc-Si cell in a p-i-n configuration on texture-etched ZnO:Al was achieved. We measured a stabilized efficiency of 10% (Voc = 0.52V, FF = 0.74) after light soaking. The best tandem efficiency based on this single cell was achieved with 12% initial and 11.4% stabilized values. To fully exploit the benefit of the high stability of the μc-Si single junction cell, we made micromorph cells with a bottom cell limited structure. These tandem cells delivered an initial efficiency of 10.3% (Voc = 1.32V, FF = 0.69). To further study the independent influences of light illumination and thermal heating, annealing treatment was carried out for such μc-Si:H single junction cells and tandem cells. It was found that light soaking does not increase recombination in the μc-Si:H i-layer, and annealing treatment can improve the cell contact..

Keywords

Microcrystalline silicon, Solar cells, Micromorph, Tandem cells, Light soaking, Annealing.

Submitted at: Nov. 28, 2006
Accepted at: Feb. 15, 2007

Citation

Y. LIU, J. K. RATH, R. E. I. SCHROPP, Development of highly stabilized efficiency micromorph tandem solar cells, Journal of Optoelectronics and Advanced Materials Vol. 9, Iss. 2, pp. 363-366 (2007)