Marcelo Alatzatianou Rodrigues
April 2024 | Departamento de Pesquisa, União Max de Ensino e Pesquisa, Rua Francisco de Vitória, São Paulo, Brasil
Figure 1: Construction diagram and working principle of a DSSC
Abstract
Dye-sensitized solar cells (DSSC) are an emerging thin-film photovoltaic technology with advantages such as low cost and easy fabrication. But the use of synthetic dyes requires complex fabrication processes and toxic and scarce materials, like ruthenium. Natural dye-sensitized solar cells (NDSSC) use dyes found in plants and can become an environment friendly alternative. The use of plants already commercially produced can offer synergy and an alternative use of the crops produced. Extracts from Rubus spp (blackberry), Coffea arabica (arabica coffee) and Saccharum officinarum (sugarcane) were used to produce NDSSC. The cells were fabricated using a simple and cheap protocol based on thin film deposition of TiO2 and Pt over conductive glass using screen printed and sintered pastes. Liquid electrolyte is sealed between electrodes using Parafilm®. Detailed fabrication and characterization protocols with lists of materials and equipments can be found in the appendix. Characterization was made by electrical parameters and absorption spectra. Power conversion efficiencies were compared and Coffea arabica (arabica coffee) achieved the best performance of the three species: 0.44%.
Keywords: dye-sensitized solar cell, DSSC, natural dye, plants, arabica coffee, photovoltaic
Introduction
Photovoltaic (PV) technology is not restricted to panels made of crystalline silicon solar cells. In an effort to achieve further costs reduction, increasing efficiency and finding new utilization possibilities, researchers all around the world have dedicated efforts to find new ways to generate electricity from sunlight and have created several PV technologies based on different materials with creative structures and clever working principles.
Figure 7: Absorption spectra
Absorption spectra (Figure 7) offer some interesting observations. At the first glance, the negative values in the range 700-850 nm catches one’s attention.
… Stellarnet® Black-Comet-C-SR 200-1080 nm spectrometer for irradiance and dye absorption spectrum (also used for films thickness measurement) …
