AgSb(SxSe1−x)2 thin films for solar cell applications

Silver antimony sulfoselenide (AgSb(SxSe1−x)2) thin films were prepared by heating glass/Sb2S3/Ag layers after selenization using sodium selenosulphate solution. First, Sb2S3 thin films were deposited on glass substrates from a chemical bath containing SbCl3 and Na2S2O3. Then Ag thin films were thermally evaporated onto glass/Sb2S3, followed by selenization by dipping in an acidic solution of Na2SeSO3. The duration of selenium dipping was varied as 30 min and 2 h. The heating condition was at 350 °C for 1 h in vacuum. Analysis of X-ray diffraction pattern of the thin films formed after heating showed the formation of AgSb(SxSe1−x)2. Morphology and elemental analysis were done by scanning electron microscopy and energy dispersive X-ray detection. Depth profile of composition of the thin films was performed by X-ray Photoelectron Spectroscopy. The spectral study showed the presence of Ag, Sb, S, and Se, and the corresponding binding energy analysis confirmed the formation of AgSb(SxSe1−x)2. Photovoltaic structures (PV) were prepared using AgSb(SxSe1−x)2 thin films as absorber and CdS thin films as window layers on FTO coated glass substrates. The PV structures were heated at 60–80 °C in air for 1 h to improve ohmic contact. Analysis of J–V characteristics of the PV structures showed Voc from 230 to 490 mV and Jsc 0.28 to 5.70 mA/cm2, under illumination of AM1.5 radiation using a solar simulator.

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► AgSb(SxSe1−x)2 thin films were formed by heating Na2SeSO3 dipped Sb2S3/Ag layers.
► S/Se ratio was varied by changing the dipping time in Na2SeSO3 solution.
► Characterized the films using XRD, XPS, SEM, Optical and electrical measurements.
► Band gap engineering of 1−1.1 eV for x = 0.51 and 0.52 respectively.
► PV Glass/FTO/CdS/AgSb(SxSe1−x)2/C were prepared showing Voc = 410 mV, Jsc = 5.7 mA/cm2.