Photoelectrical properties of In(OH)xSy/PbS(O) structures deposited by SILAR on TiO2

Photoelectrical properties of uncoated In(OH)xSy and PbS(O) layers deposited by SILAR (successive ion layer adsorption reaction) and of TiO2/In(OH)xSy/PbS(O)/PEDOT:PSS solar cell structures were investigated by spectral surface photovoltage, Kelvin-probe, current–voltage and quantum efficiency analysis. By changing the annealing temperature of In(OH)xSy in air between 50 and 350 °C, the band gap of In(OH)xSy was tuned between 2.6 and 2 eV while the band gap of PbS(O) remained unchanged at about 0.7 eV. The open circuit voltage of the solar cell structures correlated well with the band gap and the workfunction of the In(OH)xSy. Surprisingly, excess charge carriers generated in the PbS(O) layer do not contribute significantly to the short circuit current. A short circuit current of more than 10 mA cm−2 was reached by modifying TiO2 with Nb. Possible ways of optimization are discussed.