Flexible Solar on Fibers as substrates coated with Molybdenum and CZTS

Photovoltaic cell or commonly known as solar cell is an electrical device used to convert energy from light directly into electricity using the photovoltaic effect. Solar cells are categorized into many types. Thin film solar cells from the second generation are mostly used and have gained enormous interest among the research community. Thin film solar cells have a few common layers that deposit on substrate. The layers are known as back contact, absorUer layer (p type), window layer (n-type), and front contact layer. Cadmium, Indium, Gallium, and Selenium (CIGS) used as the absorber layer in the solar cell have been proven to achieve high efficiency. However, it is a well- known fact that indium and selenide in the stated compound are rare earth (RE) matenals, expensive, and toxic. Therefore, it is a requirement to identify an alternate type of material to use for the aUsorber layer that outains high efficiency as well. In view of this, significant research has been reported with Copper, Zinc, Tin, and Sulphur (CZTS) used as the absorber layer. This material can be easily obtained and is low cost due to the abundant materials on earth and has a bandgap of 1.5 eV and absorption coefficient of >10⁴. Commonly, the CZTS based thin film researches have been conducted on a rigid substrate such as soda lime glass and the layer will be deposited by a vacuum based process such as sputtering and evaporation. In view of identifying a new application of solar cell, in this study, a non-vacuum process was utilized to deposit the CZTS precursors on a flexible substrate. Fiber was used as a substrate for this study to develop the solar cell due to its flexibility which can be bent and rolled into a bulk that is able to reduce the usage of surface area and thus reduce the cost as well. The coated layers were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM) to study the layer surface morphologies, grain sizes, and the roughness of the coated layer.