Structural and Solar Cell Properties of a Ag-Containing Cu₂ZnSnS₄ Thin Film Derived from Spray Pyrolysis

Abstract

A silver (Ag)-incorporated kesterite CuZnSnS (CZTS) thin film was fabricated by a facile spray pyrolysis method. Crystallographic analyses indicated successful incorporation of various amounts of Ag up to a Ag/(Ag + Cu) ratio of ca. 0.1 into the crystal lattice of CZTS in a homogeneous manner without formation of other impurity compounds. From the results of morphological investigations, Ag-incorporated films had larger crystal grains than the CZTS film. The sample with a relatively low Ag content (Ag/(Ag + Cu) of ca. 0.02) had a compact morphology without appreciable voids and pinholes. However, an increase in the Ag content in the CZTS film (Ag/(Ag + Cu) ca. 0.10) induced the formation of a large number of pinholes. As can be expected from these morphological properties, the best sunlight conversion efficiency was obtained by the solar cell based on the film with Ag/(Ag + Cu) of ca. 0.02. Electrostructural analyses of the devices suggested that the Ag-incorporated film in the device achieved reduction in the amounts of unfavorable copper on zinc antisite defects compared to the bare CZTS film. Moreover, the use of a Ag-incorporated film improved band alignment at the CdS(buffer)-CZTS interface. These alterations should also contribute to enhancement of device properties.

Green Atmospheric Aqueous Solution Deposition for High Performance Cu2ZnSn(S,Se)4 Thin Film Solar Cells

“…However, after the selenization process, the metastable wurtzite phase of the as‐prepared CZTS thin film was converted into the thermodynamically stable kesterite structure. The distinct peaks with high intensity at 22.36°, 27.55°, 28.73° 45.69°, 54.21°, and 66.65° were observed and can be indexed to the (110), (112), (103), (204)/(220), (312)/(116), and (400)/(008) planes of kesterite, indicating that the packed grains in the CZTSSe thin films with good crystallinity have been formed (Figure a green and blue lines), which correspond well with those of previously reported results . To further detect the possible impurities of the CZTSSe thin film, Raman spectra with an excitation laser wavelength of 532 nm were collected and shown in Figure b.…”

Doping and alloying of kesterites

“…Similar results are also obtained for CAZTS (Ag/(Ag+Cu) of ca. 0.02) deposited by spray pyrolysis, where the use of an Ag-incorporated film improved the band alignment at the CdS-CZTS interface [73]. In that case the conduction band-offset at the absorber-buffer interface estimated from x-ray photoelectron spectroscopy and EQE measurements was reduced from −0.25 eV for the CdS-CZTS down to -0.17 eV for the CdS-CAZTS heterointerface [73].…”

Preparation of a CuGaSe2single crystal and its photocathodic properties

“…À0.05 V (vs. Ag/AgCl), which is close to the value of several sulfur (S)based p-type chalcopyrite and related compound thin lms applied to solar cells and PEC water splitting. 7,17…”