Christian-Herbert Fischer

Role of chlorine in In2S3 for band alignment at nanoporous-TiO2/In2S3 interfaces

Coatings of Cl-free and Cl-containing In2S3 (In2S3:Cl) layers were prepared by spray ion layer gas reaction on nanoporous TiO2 (np-TiO2). Charge separation in FTO/np-TiO2/In2S3:Cl, FTO/In2S3:Cl, FTO/np-TiO2/In2S3:acac, and FTO/In2S3:acac systems has been investigated by modulated surface photovoltage spectroscopy (SPV). The exponential defect tails below the band gap of In2S3 were reduced for In2S3:Cl. The analysis of the SPV spectra allowed to distinguish different mechanisms of charge separation and to deduce the conduction band offsets (about 0.3 eV and 0.05 eV for np-TiO2/In2S3:Cl and np-TiO2/In2S3:acac, respectively) in correlation with photoelectron measurements.

Non-vacuum chalcopyrite solar cell absorbers: The Spray-ILGAR approach

In this report, solar cells based on CuInS2 absorber films, which were prepared by the Spray-ILGAR method, are presented for the first time. All solar cells had a glass/Mo/CuInS2/CdS/i-ZnO/n-ZnO/Ni-Al structure. Solar cells were produced from Spray-ILGAR CuInS2 absorber films using various deposition parameters. To date, a maximum efficiency of 4.1 % has been achieved. The CuInS2 absorber films consist of two layers of different crystalline quality. The origin as well as the influence of this structure on the photovoltaic performance is discussed. Therefore, scanning electron microscopy and Raman spectroscopy were applied, in order to characterize the Spray-ILGAR CuInS2 absorber films.