The characterization techniques are important tools to understand and optimize the performance of a solar cell. In this chapter, some of the common techniques used for solar cell characterization are discussed in detail. These techniques include measurements of the solar cell's current–voltage (IV) curve, external quantum efficiency (EQE), capacitance–voltage (CV) curve, and transient photovoltage (TPV) response. IV curves provide information on the solar cell's maximum power output, open-circuit voltage, short-circuit current, and fill factor. EQE measurements reveal the solar cell's spectral response and its ability to convert photons into electrons. CV curves provide information on the solar cell’s doping concentration and depletion region width. TPV measurements are used to study the solar cell's carrier lifetime and mobility. Other techniques used for solar cell characterization include impedance spectroscopy, photoluminescence spectroscopy, and Raman spectroscopy. By using these techniques, researchers can better understand the underlying mechanisms of solar cell operation and identify ways to improve their efficiency.
The third chapter explores the potential of solar cells based on copper indium gallium diselenide (CIGS). Both the benefits and drawbacks of commercializing CIGS solar cells are explored, highlighting the need of their development. It is shown how CIGS solar cells stack up against c-Si solar cells. The positive impacts of the CIGS absorber's graded bandgap and Na distribution are also discussed. Non-vacuum methods, such as co-evaporation and sequential deposition, as well as vacuum deposition approaches are explained for depositing a CIGS layer. Flexible solar cells, the variables that affect cell efficiency and ways in which efficiency may be increased, are all covered.
