Efficient charge collection of photoanodes and light absorption of photosensitizers: A review

Abstract

During the recent period of time, dye sensitized solar cells (DSSCs) have become an exciting invention to meet our energy demands. Its reasonable cost of production and easy fabrication make it a powerful competent to the conventional solar cells. But non-achievement of expected efficiency is the key challenge faced by the scientific society. To overcome this, boundless research is going on the revamping of DSSC. Among the four chief parts of DSSC, the photoanodes gain more attention due to its dual function. Scilicet, it act as a charge carrier and as a surface for dye adsorption as well. Hence photoanode modification plays a crucial role in enhancing the power conversion efficiencies of DSSCs. It comprises of wide bandgap semiconducting metal oxides, among which TiO2 stands out with higher efficiency. Likewise in the case of photosensitizers, metal complex based dyes (mainly ruthenium based) take the lead in augmented efficiency. This paper critically reviews the work on all the metal oxides used as photoanode materials, comparing their band gap with the best efficiencies reported for each and analyzing their advantages and disadvantages. An overview of the performance of DSSCs based on different metal atom doped metal oxide photoanode, incorporation of various carbonaceous materials and different passivating agents has been included. Also, the modification in the photosensitizer has been discussed, examining the reports on organometallics based dyes and metal free organic dyes.