Improvement of Quantum Dot-Sensitized Solar Cells based on Cds and CdSe Quantum Dots

We fabricated Quantum Dot-Sensitized Solar Cells (QDSSCs) using CdS and CdSe Quantum Dots (QDs) onto mesoporous titanium oxide (TiO₂). The CdS and CdSe QDs used as light absorbing materials are prepared over mesoporous TiO₂ electrode by Successive Ionic Layer Adsorption and Reaction (SILAR) process. The growth of the QDs was monitored by UV-visible absorption spectroscopy and the increase of absorption increasing the SILAR cycle numbers was verified. We prepared TiO₂/CdS/CdSe solar cells to introduce a cascade of QD band gaps to facilitate the dissociation of photo-generated excitons in CdSe QDs. We changed platinum counter electrode to gold counter electrode to have the better stability and conductivity with polysulfide electrolyte. Also titanium(IV) isopropoxide (TIP) layer was introduced under mesoporous TiO₂ film as a blocking layer for improving the performance of the cell, especially, photocurrent and open-circuit voltage.