All solution processed superstrate type Cu2ZnSnS4 (CZTS) thin film solar cell: Effect of absorber layer thickness

• Published in: Journal of alloys and compounds 2019-04, Vol.781, p.280-288
• Main Authors: Tumbul, Ahmet, Aslan, Ferhat, Göktaş, Abdullah, Mutlu, I.H.
• Format: Article
• Language: English
• Subjects: Absorber thickness; Absorbers; Argon; Complex systems; Copper zinc tin sulfide; Cracks; Crystallization; CZTS solar cell; Dip coatings; Energy gap; Glass substrates; Immersion coating; Photovoltaic cells; Soda-lime glass; Solar cells; Solution process; Superstrate type solar cell; Thickness; Thin films; Titanium dioxide; X ray photoelectron spectroscopy
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2018.12.012

In this study, superstrate-type ITO/TiO2/In2S3/C2ZnSnS4 thin film solar cells were investigated. We obtained thin film solar cells by using the facile, vacuum-free solution process which has no require complex system. The C2ZnSnS4(CZTS) thin film was produced by solution process and dip-coating technique on the glass substrate and annealed at 515 °C for 30 min under argon condition. The CZTS thin film was characterized by means of XRD, micro-Raman, XPS, SEM-EDX, AFM and UV–Visible Spectrometer tools. The XRD result showed that the CZTS quaternary semiconductor crystallized in the kesterite phase formation. The Raman and X-ray photo-electron studies were conducted to support the formation of crystalline structure. The SEM and AFM images showed that the surfaces of substrate were covered with sub-micron sized CZTS absorber without any cracks. The optical study revealed that the CZTS has a suitable band gap energy about ∼1.65 eV for solar cell applications. All the layers of the CZTS solar cells including the transparent conductive oxide (TCO) ITO, TiO2/In2S3 buffers and CZTS absorber layers were also coated on the soda-lime glass by the solution process, respectively. The ITO/TiO2/In2S3/CZTS device exhibited the solar conversion efficiency of 0.7% which was the first device that all layers including TCO obtained by means of the non-vacuum processed solution method. [Display omitted] •Superstrate-type ITO/TiO2/In2S3/C2ZnSnS4 thin film solar cell was developed.•Transparent conductive-oxide layer ITO was obtained by the non-vacuum processing.•From back to top contacts, all layers were prepared by using the solution processes.•Cd-free CZTS thin film solar cell was fabricated with the conversion efficiency of 0.7%.