The optimization of solar cells properties with thermal criteria gives the possibility to achieve higher conversion efficiency in outdoor conditions. An innovative setup that allows the control of the surroundings of a solar cell is described. Under such specific conditions, the cell temperature can be stabilized and measured. The variation of the cell temperature with the applied bias is experimentally observed and quantified. Between short circuit current density (J(sc)) and open circuit voltage (V-oc), a slight difference of temperature is observed, revealing a variation of the thermal equilibrium between these two points. The resistivity of the absorber and the input power density are found to influence this temperature shift. From the experimental results, it appears that the emissivity of the solar cell increases with the applied voltage due to an increase in the excess carrier concentration. Consequently, the operating temperature at open-circuit is lower than at short-circuit.