Improvement of Si adhesion and reduction of electron recombination for Si quantum dot-sensitized solar cells

Quantum dots (QDs) based on multiple exciton generation have attracted much attention. They are capable of generating multiple electrons by single-photon absorption. Si is one of the good QD sources and its nontoxicity and abundance are advantageous for photovoltaics. In this work, Si QDs were fabricated by multihollow discharge plasma chemical vapor deposition, and they were applied to Si QD-sensitized solar cells. Their initial performance was poor because of the weak adhesion of Si and charge recombination. In this work, we solved these problems through the functionalization of Si QDs and a ZnO barrier. Functionalized Si QDs were more adsorbed on TiO₂ with strengthened adhesion and the ZnO barrier prevented the contact between TiO₂ and the redox electrolyte. Consequently, the improved adhesion and the reduced electron recombination led to the enhancement of overall photovoltaic characteristics.