Optoelectronic Studies of Solar Cells

Abstract

Solar cells are a most promising candidate to supply future energy needs in a sustainable and renewable way. Currently, solar cell devices based on semiconductor materials achieve the highest power conversion efficiencies. A typical solar cell consists of a semiconductor pn-junction where the semiconductor band gap is in the range between 1 and 2 eV, well adapted to absorb a large part of the solar spectrum. Issues as band alignment and spatial homogeneity of the materials are essential in providing the optimum achievable efficiencies. Kelvin probe force microscopy has been applied to a wide range of solar cell materials and devices, ranging from crystalline and amorphous silicon to polycrystalline CdTe and Cu(In,Ga)(S,Se)2 to organic semiconductors and molecules. On these systems, KPFM has been applied in different ways, from surface characterization to effects of illumination to cross-sectional studies. From many of these local work function measurements, understanding of functional principles and limiting factors has been gained. This chapter reviews the results that have been obtained by Kelvin probe force microscopy on solar cell devices and materials and describes how the gained understanding promotes the improvement of solar cell devices for renewable energy conversion.KeywordsSolar CellWork FunctionOrganic Solar CellThin Film Solar CellSolar Cell DeviceThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.