In this paper we present the electrical properties of the typical transparent electrodes (ITO, AZO, IZO, FTO, PEDOT:PSS, etc.) prepared by different methods such as: spray pyrolysis, sputtering, sol-gel, thermal oxidation, PLD, etc. The modifications of electrical properties of electrodes during the sun exposure of the devices may explain some of problems arising in the I-V characterization of thirdgeneration solar cells. The electrical resistivity stability of transparent electrode thin films as a function of the temperature is analysed in detail.