13·9%‐efficient CdTe polycrystalline thin‐film solar cells with an infrared transmission of ∼50%

To fabricate a high-efficiency polycrystalline thin-film tandem cell, the most critical work is to make a high-efficiency top cell ( > 15%) with high bandgap (Eg = 1·5–1·8 eV) and high transmission (T > 70%) in the near-infrared (NIR) wavelength region. The CdTe cell is one of the candidates for the top cell, because CdTe state-of-the-art single-junction devices with efficiencies of more than 16% are available, although its bandgap (1·48 eV) is slightly lower for a top cell in a current-matched dual-junction device. In this paper, we focus on the development of a: (1) thin, low-bandgap CuxTe transparent back-contact; and (2) modified CdTe device structure, including three novel materials: cadmium stannate transparent conducting oxide (TCO), ZnSnOx buffer layer, and nanocrystalline CdS:O window layer developed at NREL, as well as the high-quality CdTe film, to improve transmission in the NIR region while maintaining high device efficiency. We have achieved an NREL-confirmed 13·9%-efficient CdTe transparent solar cell with an infrared transmission of ∼50% and a CdTe/CIS polycrystalline mechanically stacked thin-film tandem cell with an NREL-confirmed efficiency of 15·3%. Copyright © 2005 John Wiley & Sons, Ltd.

[1]  Xuanzhi Wu,et al.  High-efficiency polycrystalline CdTe thin-film solar cells , 2004 .

[2]  C. DeHart,et al.  High-efficiency polycrystalline CdTe thin-film solar cells with an oxygenated amorphous cds (a-CdS:O) window layer , 2002, Conference Record of the Twenty-Ninth IEEE Photovoltaic Specialists Conference, 2002..

[3]  H. Zogg,et al.  CdTe solar cell in a novel configuration , 2004 .

[4]  Martha Symko-Davies.  Progress in High-Performance PV: Polycrystalline Thin-Film Tandem Cells , 2004 .

[5]  S. Hegedus,et al.  Correlation of surface phases with electrical behavior in thin-film CdTe devices , 2003 .

[6]  R. Klenk,et al.  Improved performance of thin film solar cells based on Cu(In,Ga)S2 , 2002 .

[7]  Reiner Klenk,et al.  Efficient CuInS2 solar cells from a rapid thermal process (RTP) , 2001 .

[8]  W. Shafarman,et al.  Five-source PVD for the deposition of Cu(In1−xGax)(Se1−ySy)2 absorber layers , 2005 .

[9]  D. Aspnes,et al.  Nondestructive analysis of Hg1−xCdxTe (x=0.00, 0.20, 0.29, and 1.00) by spectroscopic ellipsometry. I. Chemical oxidation and etching , 1984 .

[10]  C. Ferekides,et al.  RF sputtered back contacts for CdTe/CdS thin film solar cells , 1997, Conference Record of the Twenty Sixth IEEE Photovoltaic Specialists Conference - 1997.

[11]  T. Minemoto,et al.  Material and device characterization of thin film Cu(InAl)Se/sub 2/ solar cells , 2002, Conference Record of the Twenty-Ninth IEEE Photovoltaic Specialists Conference, 2002..

[12]  S. Hegedus,et al.  Transparent ZnTe:Cu contacts for bifacial characterization of CdTe solar cells , 2005 .

[13]  Rommel Noufi,et al.  Critical issues in the design of polycrystalline, thin‐film tandem solar cells , 2003 .

[14]  Dean H. Levi,et al.  Interdiffusion of CdS and Zn2SnO4 layers and its application in CdS/CdTe polycrystalline thin-film solar cells , 2001 .

[15]  Jie Zhou,et al.  Nanostructured CdS:O film: preparation, properties, and application , 2004 .