Co-sensitization aided efficiency enhancement in betanin–chlorophyll solar cell

Abstract

Dye-sensitized solar cells (DSSCs) are a promising third-generation photovoltaic cell technology whose advantages are low-cost fabrication, reduced energy payback time, better performance under diffuse light conditions and flexibility. Typically DSSCs employ toxic dyes such as metal-based porphyrins requiring complex synthesis. In contrast, natural pigments are environmentally and economically superior to synthetic dyes. However, narrow absorption spectra of natural pigments result in low efficiencies of the solar cells. Hence, co-sensitizing pigments with complementary absorption spectra, which increases the absorption band, is an attractive pathway to enhance the efficiency. In this paper, we report the performance of betanin-chlorophyll co-sensitized solar cell using betanin (λ max = 535 nm) and chlorophyll-a (λ max = 435 nm, 668 nm), natural pigments having complementary absorption spectra. Density functional theory simulations were performed to verify that the lowest unoccupied molecular orbital and the highest occupied molecular orbital levels of the dye molecules, are aligned appropriately with that of TiO 2 and the redox electrolyte, respectively, which is necessary for optimal device performance. Electrochemical impedance spectroscopic studies were performed to determine parameters corresponding to the charge transfer processes in the dye solar cells. Individual and co-sensitized solar cells were fabricated and the co-sensitized solar cell demonstrated a higher efficiency of 0.601% compared to efficiencies of 0.562% and 0.047% shown by betanin and chlorophyll solar cells, respectively.

Plasmonic enhancement of betanin-lawsone co-sensitized solar cells via tailored bimodal size distribution of silver nanoparticles

“…Following the optimization, the various solar cell configurations (described subsequently) were prepared and tested: (i) betanin-lawsone solar cell, (ii) betanin-lawsone solar cell with 20 nm AgNPs (iii) betanin-lawsone solar cell with 60 nm AgNPs and (iv) betanin-lawsone solar cell with 20 nm and 60 nm AgNPs. (The performance of solar cells individually sensitized with only betanin and lawsone pigments has been described in our earlier publications 27,72 ) The J-V and P-V curves of the highest performing sample in each type of solar cell are shown in Fig. 7d,e.…”

“…Several groups have worked on various aspects of the design of photoanodes and its constituent materials for developing high-efficiency DSSCs [20][21][22][23][24] . Prior studies have demonstrated the co-sensitization of natural pigments for improved light harvesting and better photoelectric conversion efficiencies [25][26][27][28][29][30][31] . The present study examines the efficiency enhancement of a betanin-lawsone co-sensitized solar cell by the plasmonic route.…”

Semisynthetic Chlorophyll Derivatives Toward Solar Energy Applications

“…The combination of natural chlorophyll‐ a with anthocyanin as a cosensitizer could broaden absorption region and enhance charge extraction ability, which increased the efficiency correspondingly . Sreeja and Pesala used chlorophyll‐ a and betanin as cosensitizers to get a complimentary absorption . In light of the fact that natural green plants utilize chlorophylls‐ a/b simultaneously, we also investigated the effects of mixing different types of semisynthetic chlorophyll derivatives on the final photovoltaic efficiency.…”

Co‐sensitized cells from Antarctic resources using Ag nanoparticles

“…[16][17][18] Natural dyes showed efficiencies values up to 2% with average efficiencies of 0.4% achieved by solar cells using natural photosensitizers. [19][20][21][22][23][24][25][26][27][28][29][30][31][32] Besides, silver nanoparticles (NPs) have been reported as useful to improve the performance with several goals, from biosensing to photovoltaic devices. [33][34][35] In particular, the use of dyes mixed with NPs for sensitization was reported as a successful way to increase DSSC performance.…”

“…The dye finally is restored by the electron donation from the electrolyte 16–18 . Natural dyes showed efficiencies values up to 2% with average efficiencies of 0.4% achieved by solar cells using natural photosensitizers 19–32 …”