Dye-sensitized solar cells with thin film TiO2 electrodes were fabricated. The TiO2 films were prepared on conducting and non-conducting glass substrates. A high-intensity laser was shining on the dye/TiO2 electrodes to excite the dyes and inject electrons to the conduction band of the TiO2 electrode. The dye degradation rate showed much difference for the dyes adsorbed on the TiO2 films on conducting and non-conducting glass substrates. On non-conducting glass substrate the injected electrons gathered near where they were injected. This increased the local Fermi level of the TiO2 conduction band and consequently the electron injection efficiency was decreased, leading to a relatively high degradation rate for the dyes when they were radiated by a high-intensity laser. The experimental results showed that dye stability is sensitive to the local electro-chemical environment.