AgSbSe 2 and AgSb(S,Se) 2 thin films for photovoltaic applications

Abstract

Silver antimony selenide (AgSbSe 2) thin films were prepared by heating sequentially deposited multilayers of antimony sulphide (Sb 2S 3), silver selenide (Ag 2Se), selenium (Se) and silver (Ag). Sb 2S 3 thin film was prepared from a chemical bath containing SbCl 3 and Na 2S 2O 3, Ag 2Se from a solution containing AgNO 3 and Na 2SeSO 3 and Se thin films from an acidified solution of Na 2SeSO 3, at room temperature on glass substrates. Ag thin film was deposited by thermal evaporation. The annealing temperature was 350 °C in vacuum (10 −3 Torr) for 1 h. X-ray diffraction analysis showed that the thin films formed were polycrystalline AgSbSe 2 or AgSb(S,Se) 2 depending on selenium content in the precursor films. Morphology and elemental analysis of these films were done using scanning electron microscopy and energy dispersive X-ray spectroscopy. Optical band gap was evaluated from the UV–visible absorption spectra of these films. Electrical characterizations were done using Hall effect and photocurrent measurements. A photovoltaic structure: glass/ITO/CdS/AgSbSe 2/Al was formed, in which CdS was deposited by chemical bath deposition. J– V characteristics of this structure showed V oc = 435 mV and J sc = 0.08 mA/cm 2 under illumination using a tungsten halogen lamp. Preparation of a photovoltaic structure using AgSbSe 2 as an absorber material by a non-toxic selenization process is achieved.