Preparation and characterization of CZTS thin films by vacuum-assisted spray pyrolysis and fabrication of Cd-free heterojunction solar cells

Abstract

The quaternary chalcogenide material Cu2ZnSnS4 (CZTS) has received much attention owing to its excellent photovoltaic conversion properties. We report the deposition of CZTS thin films by vacuum spray pyrolysis and explore the structural, elemental, optical and electrical properties and its use as an absorber layer in the fabrication of a cadmium free solar cell device. The thin films were deposited at various substrate temperatures ranging from 325° C to 400° C using vacuum spray pyrolysis technique. Structural analysis shows crystalline nature with a CZTS kësterite phase formed at 375 °C. FESEM analysis reveals the presence of coral reef like morphology. XPS measurements were carried out to confirm the elemental composition. Uv-vis measurments indicate that the optical band gap of the as-deposited films is 1.5 eV with a high absorption coefficient of 105cm-1, which is close to the ideal value for an absorber layer. Hall effect measurement confirms the p-type nature of the samples. A simple heterojunction is fabricated with a device structure <ITO/Al:ZnO/CZTS/Ag> using CZTS as the absorber layer and Al:ZnO as the window layer. The solar cell parameters estimated are, Voc = 0.85 V, Isc= 16.68 mA, Fill factor = 36.54 % and Efficiency, ɳ = 2.87 %.

Impact of Top Electrodes (Cu, Ag, and Al) on Resistive Switching behaviour of Cu‐rich Cu2ZnSnS4(CZTS) Ideal Kesterite

“…The estimated band gap is 1.50 eV, as marked with the extrapolated linear region using a black line shown in Figure 1(c). [28] The XRD and Raman peak positions [29,36] along with the FTIR reflectance spectra and exact band gap of CZTS film (1.50 eV) substantiate that the CZTS material is crystallizing in the tetragonal Kesterite phase. Atomic Force Microscopy is carried out on 2 mm×2 mm scan area to understand the surface roughness and topography of the CZTS thin film.…”

Recent Progress and Challenges in Controlling Secondary Phases in Kesterite CZT(S/Se) Thin Films: A Critical Review

“…Energies 2024, 17, x FOR PEER REVIEW 5 of 30 Spray pyrolysis stands as a versatile method for CZTS thin film synthesis, offering a multitude of adjustable parameters that influence the resulting film properties. Among these parameters, substrate temperature holds significance, dictating crystallinity and grain size development [24]. Additionally, precursor concentration serves as a critical factor, impacting film thickness and elemental composition [25].…”

Comparative study between CZTS and CZTSe thin layers for photovoltaic applications

“…The quaternary kesterite materials CZTS, CZTSe and CZTSSe have the advantage of being made up of elements abundant on earth, less expensive, respectful of the environment, and also have semi-conducting qualities such as a coefficient of high absorption (of the order of 10 4 cm −1 ), a direct and adjustable band gap (from 1 to 1.5 eV) and are intrinsic p-type semiconductors [3,4]. Their uses in thin-film photovoltaic technology promise much hope although their current electrical conversion power does not exceed 13% .…”