Proceedings of International Conference on Hybrid and Organic Photovoltaics (HOPV16)
Publication date: 28th March 2016
A single molecular precursor solution is described for the deposition of CuIn(S,Se)2 (CIS) film onto Mo coated glass substrates by spin coating followed by annealing in Se atmosphere. Characterization of the films by X-ray diffraction, Raman spectroscopy and scanning electron microscopy demonstrate the formation of a highly homogenous and compact layer 1.1 μm thick CIS with a MoSe2 under-layer. Atomic force microscopy reveals the presence spherical particles, with a fibrular overgrowth, ranging between 400-450 nm. Composition of films is found to be in close agreement with that of the precursor. Diffuse reflectance spectroscopy of the films indicate a direct band gap of 1.36 eV. The presence of electronic defects in the annealed materials were examined by low temperature photoluminescence spectroscopy. Over 85 solar cell devices with the configuration Mo/CZTS/CdS/i-ZnO/Al:ZnO/Ni-Al and an active area of 0.5 cm2 were fabricated and tested. The champion cell shows a power efficiency of 3.36 % with an open circuit voltage of 520.84 mV and short circuit current of 13.92 mA/cm2 under AM 1.5 illumination. Overall variation in each of solar cell parameters remains below 10% of the average value, demonstrating the remarkable homogeneity of this solution processing method. External quantum efficiencies of above 60 % are observed for all the devices.