Silver antimony sulfide-selenide for thin film solar cells

Thin films of AgSbS2 (150 nm) are prepared (75 min at 40 °C) via chemical deposition using a solution mixture containing SbCl3, Na2S2O3 and AgNO3. As-deposited films are amorphous. When they are heated in nitrogen at 180-320 °C, crystalline cubic-AgSbS2 films are formed. They show an optical band gap 1.89 eV and photoconductivity 1.8x10-5 Ω-1cm-1. Silver antimony sulfide-selenide film, AgSb(SxSe1-x)2, is produced from the initial amorphous film when it is heated in presence of Se-vapor. XRD analysis confirms the formation of solid solution AgSbS1.25Se0.75 or AgSbSe2 depending on the extent of Se-vapor available during heating. SnO2:F/CdS/AgSbS2/C solar cell shows Voc 610 mV, Jsc 0.88 mA/cm2,FF 0.53 and η 0.28%. In SnO2:F/CdS/Sb2S3/AgSb(SxSe1-x)2/C solar cell, Voc is 582 mV, Jsc 0.99 mA/cm2, FF 0.51 and η 0.29%.

A SYNCHROTRON RADIATION STUDY OF THE FORMATION OF CuxSey AND NaxCuySez THIN FILMS ON Cu SUBSTRATES: Cl2-INDUCED OUT-DIFFUSION OF Na

In this paper we study the growth of Cu x Se y and Na x Cu y Se z thin films on polycrystalline Cu substrates. The investigation took place in situ by means of photoemission spectroscopy with synchrotron radiation, in UHV. Deposition of elemental Se with a dense flux on a polycrystalline Cu substrate at RT and subsequent heating to 100°C causes the formation of a thick Cu 2-x Se film (with x equal or very close to zero). A phase transition of this copper selenide occurs by annealing at 200°C. Deposited Na on the Cu 2-x Se film is diffused into the bulk, resulting in the formation of a Na x Cu y Se z compound. Exposure to Cl 2 at 120°C causes the out-diffusion of Na to the surface, where NaCl is formed. The Na diffusion in and out of the copper selenide film is analogous to alkali intercalation–deintercalation from TX 2 layer compounds.