SeongYeon Kim

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.

Ge-alloyed CZTSe thin film solar cell using molecular precursor adopting spray pyrolysis approach

We report a promising fabrication approach for the synthesis of Ge-alloyed Cu2Zn(GexSn1−x)Se4 (CZGTSe) thin films using molecular precursors by spray pyrolysis to obtain band gap tuned kesterite solar cells. A stable and well dissolved precursor solution of CZTS/CZGTS with the desired elemental composition is prepared in DMSO solvent, sprayed on a Mo substrate and subsequently selenized under ambient selenium at high temperature to obtain well-crystallized absorber layers. The Ge-alloyed CZTSe thin films had improved surface morphology, grain size and crystal quality, which led to power conversion efficiencies as high as 4.72%. The growth properties and device analysis suggest that enhancement of the device performance can be achieved by further optimization of the absorber and interface layers with mitigation of defect activities.