Rutile versus anatase for quantum dot sensitized solar cell

In this paper, we report comparative studies of CdS/CdSe quantum dot sensitized solar cell (QDSSC) using the phase pure anatase and rutile TiO2 nanocrystals as the photoanode materials, which were prepared through a controlled hydrolysis route. Photovoltaic performance investigations demonstrate that the QDSSC made from rutile TiO2 (R-QDSSC) achieved higher shot-circuit photocurrent density (Jsc) and open-circuit photovoltage (Voc), which leads to a higher power conversion efficiency compared to the cell made from anatase TiO2 (A-QDSSC). Our systematic studies have shown that the use of rutile TiO2 to fabricate QDSSC offers two advantages over anatase TiO2: (1) rutile is more favorable for the growth of CdS/CdSe QDs that leads to the enhancement of light harvesting. (2) rutile is of advantage to inhibit the charge recombination and improve electron injection from QDs to TiO2, ascribable to its superior ability to lower the surface/interface defects in photoanode film together with the larger conduction band offset between QD and rutile TiO2. (c) 2018 Elsevier Ltd. All rights reserved.