A novel TiO2 nanostructure as photoanode for highly efficient CdSe quantum dot-sensitized solar cells

Abstract

For sensitized solar cells, photoanodes combining the advantages of TiO₂ nanoparticles (high specific surface area) and one-dimensional (1D) nanostructures (fast transport channels) are ideal for obtaining highly efficient sensitized solar cells. In this paper, 1D connected TiO₂ nanoparticles (1D CTNPs) were synthesized by a simple one-pot solvothermal reaction and utilized to fabricate CdSe quantum dot-sensitized solar cells (QDSSCs). To evaluate the effects of the 1D CTNPs on the performance of CdSe QDSSCs, another CdSe QDSSC was fabricated based on conventional TiO₂ nanoparticles (TNPs), which were synthesized via a similar solvothermal route with a different reaction time. The 1D CTNP-based CdSe QDSSC showed an impressive light-to-electricity conversion efficiency of 5.45% accompanying an open-circuit voltage of 596 mV, a fill factor of 0.52, and a short-circuit current density of 17.48 mA cm⁻². This efficiency is much higher than that of the TNP-based cell (4.00%). The significant enhancements in the open-circuit voltage, short-circuit current, and power conversion efficiency of the 1D CTNP-based CdSe QDSSC compared to the TNP-based cell are explained as follows. The 1D CTNP photoanode has large pores and a relatively high specific surface area, facilitating the loading of CdSe QDs and, most importantly, providing an efficient electron transport pathway, which effectively facilitates electron transport and prolongs electron lifetime. The excellent properties of the 1D CTNPs make them an optimal candidate as a photoanode material for highly efficient QDSSCs.