BARRIER LOWERING IN DYE-SENSITIZED POROUS-TIO2 SOLAR-CELLS

The current-voltage characteristics of dye-sensitized porous-TiO2 (por -TiO2) solar cells are investigated in the dark and under illumination at light intensities up to 1500 W/m(2) and temperatures between -5 an d 80 degrees C. In the dark, the barrier height and the ideality facto r of the por-TiO2/electrolyte contact are 0.67 eV and 1.05, respective ly. The very low effective Richardson constant indicates the importanc e of diffusion for transport. A current-dependent effective barrier he ight has been established under illumination of dye-sensitized por-TiO 2 solar cells. The barrier lowering effect should be caused by the low neutralization rate of the positively charged dye radicals in the ele ctrolyte. (C) 1998 American Institute of Physics. [S0003-6951(98)02337 -7].