Implication of device functioning due to back reaction of electrons via the conducting glass substrate in dye sensitized solar cells

Enhanced efficiency of dye sensitized solar cells requires minimization of all electron losses in the device. In addition to the loss via the nanoparticles of TiO2, the loss via the surface of the conducting glass substrate (TCO) needs to be contained. This additional electron recombination pathway at the TCO becomes increasingly pronounced at low light intensities. Hence, the determination of the lifetime of electrons within the nanoparticles of TiO2 requires a resistive layer at the surface of the TCO. Lowering the electron loss at the TCO/electrolyte interface increases the shunt resistance, thereby increasing the fill factor by over 10%.