Improving efficiency of natural dye sensitized solar cell using FRET mechanism

Abstract

Dye sensitized solar cells (DSSC) despite their unique properties face an enormous task of obtaining a cheap sensitizer to replace the costly ruthenium dyes and obtain commercially viable efficiencies. Inspite of good progress by natural dyes in this regard, most of the dyes alone are insufficient to get competing efficiencies for a solar cell. To improve the efficiency of a liquid electrolyte based DSSC and to improve light absorbance, a hybrid solar cell using two dyes as sensitizers has been studied in this work. Here one dye acts as a donor and transfers its energy non-radiatively to the acceptor dye which acts as the sensitizer in the solar cell. The mechanism involved is called the Fӧrster Resonance energy transfer (FRET). Here Rhodamine B dye has been utilised as an energy donor to the natural dye (chlorophyll) in a dye-dye FRET system for a DSSC. The solar cell characterisations (efficiency) conducted using solar simulator shows that hybrid system performs better than the individual dyes used as sensitizers supporting energy transfer, however the increase is marginal and needs further improvement in device configuration.