A chemical deposition process for low-cost CZTS solar cell on flexible substrates

Abstract

Cu 2 ZnSnS 4 (CZTS) thin films and solar cells were successfully prepared using a new process based on spray pyrolysis technique. The main advantage of the proposed process is the avoiding of sulphurisation process at high temperature and in toxic gases like H 2 S. X-ray diffraction studies and Raman spectroscopy confirmed the formation of good-quality microcrystalline CZTS films in a tetragonal structure. Optical measurements showed that CZTS films have a direct band gap and high absorption coefficient (4 × 10 4 cm −1 ) as requested for solar cell application. CZTS solar cell prototypes deposited on low-cost flexible plastic substrates were prepared and tested.

A review on growth optimization of spray pyrolyzed Cu 2 ZnSnS 4 chalcogenide absorber thin film

“…Boshta et al had dissolved the acetate form of copper and zinc salts, thiourea in water, and tin chloride in ethanol to produce a precursor solution which was sprayed on a Mo‐coated flexible polyimide substrate in the temperature range of 498 to 673 K varied in steps of 25 K. The film deposited below 523 K showed peak for excess sulfur, and all the other films above 523 K showed similar CZTS peak with calculated crystallite size as 2 nm, but some fractures and delamination of the film were observed at higher substrate temperatures. The grain size increased to 15 nm as the FWHM of the peak increased due to annealing at 673 K for 1 hour as expected with some sulfur peaks.…”

“…Boshta et al annealed the films at 673 K, the maximum temperature supported by a polyimide substrate in the argon atmosphere for 1 hour. As expected the peak intensity in the XRD pattern got increased with decrease in the FWHM value indicating the improvement in crystallinity after annealing.…”

“…Boshta et al deposited CZTS absorber film on polyimide substrate keeping annealing time as 1 hour at 673 K in argon atmosphere. Thirty‐minute annealing time was fixed by Courel et al, and they employed a temperature of 853 K in a mixed vapor of sulfur and tin to produce CZTS thin films with better values of carrier concentration.…”

CZTSe solar cells developed on polymer substrates: Effects of low‐temperature processing

“…Only a very scarce number of publications report kesterite solar cells fabricated on PI substrates. By using spray pyrolysis deposition, a CZTS device with a modest 0.15% was fabricated on PI . A 0.49% CZTS solar cell was also achieved using PI as a substrate by screen printing .…”

“…By using spray pyrolysis deposition, a CZTS device with a modest 0.15% was fabricated on PI. 21 A 0.49% CZTS solar cell was also achieved using PI as a substrate by screen printing. 22 Finally, CZTS was successfully synthesized on PI by sulfurization of sputtered metallic precursors, but no working devices were reported.…”