Combination of co-sensitization and Forster resonance energy transfer in natural-synthetic dye sensitized solar cells

A new approach for performance enhancement of dye sensitized solar cells (DSSC) is presented in this paper using a combination of co-sensitization method and Fo & BULL;rster resonance energy transfer (FRET) from natural pigments to synthetic pigment. Although co-sensitization is the most common method for spectral extension of DSSCs, the loading of pigment on the semiconductor is restricted in this method. To overcome this problem, here, the TiO2 was sensitized directly by an organic synthetic pigment that has suitable anchor groups, while the natural pigments were used as energy-donors without the need for direct bonding to the TiO2. The natural pigments were selected in such a way that satisfies the FRET requirements. Three natural pigments were inex-pensively extracted from plants to prepare a broad absorption spectrum. This issue was evaluated by UV-Visible analyses. It was found that the natural pigments can be more useful in the spectral expansion if applied in the FRET process as energy-donors due to their weaker anchoring groups compared to synthetic pigment. The anchoring groups of the extracted pigments were evaluated by FT-IR analysis. Also, the FRET occurrence be-tween the natural pigments with the synthetic pigment was examined by photoluminescence spectroscopy. The results indicated a proper spectral overlap and emission quenching between these pigments. Finally, the opto-electrical performances of the DSSCs fabricated by the proposed method were investigated by J-V characteris-tics, electrochemical Impedance spectroscopy (EIS), and induced photon conversion efficiency (IPCE) compared with conventional co-sensitization methods (cocktail and sequential methods). The efficiencies obtained for these two conventional methods were 1.8% and 2.2%, respectively, while an efficiency of 2.9%. was provided by the proposed approach.

Automated summary

This paper presents a new approach for enhancing the performance of dye sensitized solar cells (DSSC) by combining co-sensitization and Förster resonance energy transfer (FRET) from natural pigments to synthetic pigment. The results show that natural pigments can be more effective in the FRET process as energy-donors compared to synthetic pigment, and sensitizing TiO2 directly with an organic synthetic pigment improves the loading capacity on the semiconductor.