Tanka Raj Rana

Silver Nanowires Binding with Sputtered ZnO to Fabricate Highly Conductive and Thermally Stable Transparent Electrode for Solar Cell Applications.

Silver nanowire (AgNW) film has been demonstrated as excellent and low cost transparent electrode in organic solar cells as an alternative to replace scarce and expensive indium tin oxide (ITO). However, the low contact area and weak adhesion with low-lying surface as well as junction resistance between nanowires have limited the applications of AgNW film to thin film solar cells. To resolve this problem, we fabricated AgNW film as transparent conductive electrode (TCE) by binding with a thin layer of sputtered ZnO (40 nm) which not only increased contact area with low-lying surface in thin film solar cell but also improved conductivity by connecting AgNWs at the junction. The TCE thus fabricated exhibited transparency and sheet resistance of 92% and 20Ω/□, respectively. Conductive atomic force microscopy (C-AFM) study revealed the enhancement of current collection vertically and laterally through AgNWs after coating with ZnO thin film. The CuInGaSe2 solar cell with TCE of our AgNW(ZnO) demonstrated the maximum power conversion efficiency of 13.5% with improved parameters in comparison to solar cell fabricated with conventional ITO as TCE.

Wet chemical synthesis of WO3 thin films for supercapacitor application

Tungstic oxide (WO3) thin films have been synthesized by wet chemical method, i.e., successive ionic layer adsorption and reaction (SILAR) method. These films are characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical absorption techniques. The XRD pattern revealed the formation of polycrystalline WO3 films. Scanning electron micrographs demonstrate the three-dimensional aggregated irregular extended rod shaped morphology of WO3 thin films. The WO3 film showed a direct band gap of 2.5 eV. The WO3 film exhibited specific capacitance of 266 F·g−1 in 1 M Na2SO4 electrolyte at the scan rate of 10 mVs−1.