**1.2 Photovoltaic cell**

Photovoltaic device generates electrical power by converting sunlight into electricity in the presence of semiconducting materials using the phenomenon, the so-called photovoltaic effect. At first, French scientist Alexandre Becquerel in 1839 discovered photovoltaic effect [2]. After that more than 100 years later, Reynolds et al. in 1954 developed silicon solar cell that was primarily used in space applications until about the mid-1970s [3]. Recently, various kinds of photovoltaic devices are being developed, including silicon solar cells (Si-SCs), dye-sensitized solar cells (DSSCs), quantum dot-sensitized solar cells (QD-DSSCs), organic photovoltaic cells (OPVs), perovskite solar cells (PSCs), etc. Presently, solar cell devices are being used in customer electronics, small-scale remote residential power systems, communications, and signaling applications.
