Novel improvements in the sensitizers of dye-sensitized solar cells for enhancement in efficiencya review

In the present review article, we have focused our study on the novel improvements that have been brought about in the molecular design of various sensitizers for application in dye-sensitized solar cells (DSSCs). The sensitizers based on noble metals such as ruthenium, osmium, and rhenium showed high efficiency, but their cost and complicated synthesis restrict their wide applications. Further, to reduce the cost of fabrication of DSSCs, researchers are focusing their interest in organic sensitizers. In this context, organic dyes have offered several possibilities, as by improving their molecular structure brings about improvement in the light harvesting ability of dyes, and with the help of such dyes, optimal DSSCs have been fabricated. Further, to reduce the cost of DSSCs, researchers are also focusing on natural sensitizers such as betacyanin and anthocyanin or chlorophyll, as natural sensitizers are easy to prepare, cost effective, and environmentally friendly. With the help of these natural sensitizers, eco-friendly and more cost-effective DSSCs can be fabricated. Thus, we found from our study that beside metal-based sensitizers, organic and natural sensitizers also offer a vast potential for the optimization of efficiency in DSSCs. Copyright (c) 2015 John Wiley & Sons, Ltd.