Quantum efficiency measurements are among the fundamental characterization techniques for solar cells; probably the most important after current-voltage analysis of the diode characteristics. Through spectrally resolving the current yield of a photovoltaic device, quantum efficiency gives a closer view on the short-circuit current – one of the basic parameters of a solar cell – and loss mechanisms restricting it. It helps understanding the physics of current generation, recombination and carrier diffusion mechanisms. Hence, quantum efficiency is a valuable tool for scientists in this field. In the scope of this report, a quantum efficiency system was drafted and set up at the Université de Nantes to complement the characterizational possibilities of the research groups in Cu(In,Ga)Se2 thin-film photovoltaics and electrochemical dye-sensitized solar cells. Fundamentals on Cu(In,Ga)Se2 solar cells and their characterization, as well as details on the system setup and an evaluation of its performance are presented. An application of the system in a study on the correlation of Cu(In,Ga)Se2 absorber morphology and device performance resulting from varied duration of the Cu-rich interval during isothermal three-stage co-evaporation of the absorber exemplifies the application of this measurement setup.