Synthesis and Characterization of Chemical Spray Pyrolysed CZTS Thin Films for Solar Cell Applications

Abstract

In present work, thin films of CZTS have been prepared by chemical spray pyrolysis (CSP) by spraying precursor solution directly onto the soda lime glass (SLG) substrates by varying sulphur molar concentration. Copper chloride [CuCl2.2H2O], zinc chloride [ZnCl2.2H2O], tin chloride [SnCl4.5H2O] and thiourea [(NH2)2CS] were used as precursor materials to deposit CZTS thin films by using home-built chemical spray pyrolysis system. Influence of sulphur variation on structural, optical, morphology and electrical properties of CZTS films have been investigated by using variety techniques such as low angle x-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), UV-Visible spectroscopy, four probe method, etc. The formation of CZTS has been confirmed by low angle XRD and Raman spectroscopy. The structural analysis reveals formation of kesterite tetragonal phase with preferential orientation along (112) direction. The band gap values of CZTS thin films have been calculated and found in the range 2 -2.25 eV over the entire range of sulphur variation studied. The change in band gap may be due to quantum confinement effects at nanoscale. The morphological studies show formation of islands of nanoscale particulate clusters which constitute the films in most of the samples. The films exhibit higher resistivity values (in KΩ) which may be due to presence of the strain in the films.

Structure, morphology and optical parameters of spray deposited CZTS thin films for solar cell applications

“…XRD spectra of CZTS thin film lattice planes respectively. Similar structure have been reported byDiwate, K et al(2017) …”

“…The full width at half maximum (FWHM) was obtained from Lorentzian fit of (112) preferential peak. The crystallite size (D) was calculated using following Sucherrer relation (15) and displayed in Table 1.…”

Synthesis and Post-Annealing of Cu2ZnSnS4 Absorber Layers Based on Oleylamine/1-dodecanethiol

“…Peaks at 288 cm −1 are attributed to the vibration of the Zn atoms and S atoms with some contribution from the Cu atoms in CZTS lattice [24]. The secondary phase Cu 2 S, observed in the XRD pattern (Figure 2) is not observed in the Raman spectra, a feature made evident by the absence of peaks at 475 cm −1 [25]. This suggests that Cu 2 S could be in the bulk of the film, seen by XRD, but not easily reached by Raman.…”

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

“…The effect of sulfur concentration on the film properties was studied by Kiran Diwate et al in 2017. The molar concentration of the precursors for Cu, Zn, and Sn were kept constant at 0.04, 0.02, and 0.02 M, respectively, changing the thiourea concentration alone from 0.12 to 0.18 M. The substrate temperature was fixed at 598 K. As S concentration was increased from 0.012 to 0.16 M, the thickness of the film decreased from 505 to 392 nm and again increased for 0.018 M indicating the complex process of formation of the quaternary compound.…”