Publications (2)0 Total impact
Conference Proceeding: Influence of Cbd-Deposited CdS on the Carrier Collection in Cigs-Based Solar Cells[show abstract] [hide abstract]
ABSTRACT: CdS films were deposited with chemical bath deposition (CBD) onto Cu(In,Ga)Se<sub>2</sub>/Mo/soda-lime glass structures. The basic ingredients for the CBD were ammonia (NH<sub>4</sub>OH), cadmium acetate (CdAc), and thiourea CS(NH<sub>2</sub>)<sub>2</sub>. Two recipes with very low thiourea concentration were compared to the baseline recipe. From quantum efficiency measurements we observe an increased carrier collection for longer wavelengths for the modified buffer recipes as compared to baseline. The higher carrier collection is explained by an increase in the depletion region width. A lower bandgap is observed for the modified buffer. The solar cells with modified buffer layers have lower voltages and fill factors than the solar cells with our baseline buffer, leading to a lower efficiency for the modified cell structures in spite of slightly higher current densities. A tentative explanation is given assuming an inverted CIGS layer at the CIGS/buffer interface, possibly with Cd as a donor elementPhotovoltaic Energy Conversion, Conference Record of the 2006 IEEE 4th World Conference on; 06/2006
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ABSTRACT: ABSTRACT Three independent European CIS manufacturers of different countries, a big player in glass coating industry, three universities and three research institutes work together in the EU project LARCIS in order to advance CIS manufacturing at high yields on glass substrates. The two main approaches for the realisation of enhanced module efficiencies at reduced costs are inline co evaporation of Cu In,Ga Se2 and electrodeposition of the CuInSe2 CIS precursor. Alternative back contacts such as ZrN and TiN with high optical reflection have been tested and molybdenum layers with enhanced conductivity for homogeneous electrodeposition on 30 x 30 cm2 have been DC sputtered. A chemical bath deposited Cd free ZnS based buffer has been applied on both CIS types resulting in high photocurrents and efficiencies which are at least as high as reference cells with CdS buffers. In parallel, an In2S3 buffer has been evaporated ex situ from powder with a certified maximum efficiency of 14.16 . Solar cells of up to 17.8 efficiency certified, with ARC were fabricated by using co evaporated multi stage CIGS from an inline reactor. CuIn Se,S 2 was electrodeposited homogeneously on substrate areas of 30 x 30 cm2. The mean efficiency of test cells distributed on this area was lt;8 gt;.