Recent Progress in Colloidal Quantum Dot-Sensitized Solar Cells

Abstract

Among the third-generation solar cells based on quantum dots, the quantum dot-sensitized solar cells (QDSSCs) have received substantial attention probably because they are a straightforward extension of the very popular dye-sensitized solar cells. The nature of the quantum dots (QDs) and their mode of attachment to a wide band gap semiconductor (oxide) are important factors determining the efficiency of the corresponding devices. In this respect, the QDSSCs can be classified into two main groups: those prepared by in situ deposition of the QDs on the oxide template and those resulting from the adsorption of pre-formed, colloidal quantum dots on the oxide surface. Most of the studies on these cells appeared in the last few years have focused on the former type, while the effort devoted to colloidal QDSSCs has been comparatively minor. However, the latter allow for a better control of the device structure and for a separate optimization of different aspects. In addition, there are fundamental reasons to believe that colloidal QDSSCs may have advantages over those prepared by in situ QD deposition, particularly in what refers to recombination. In this chapter, we review and discuss the state of the art in colloidal QDSSCs with a focus on the results obtained in our laboratory.