Science and Technology



Fabrication of dye-sensitized solar cells using natural dyes extracted from Brazilian plants

Marcelo Alatzatianou Rodrigues

Download PDF


Dye-sensitized solar cell (DSSC) is one of the emerging thin-film photovoltaic technologies. Advantages come from the low cost and easier fabrication process. The realistic overall conversion efficiency already made the commercial availability a reality. It is possible the use of natural dyes extracted from plants in DSSC fabrication to substitute synthetic dyes, which requires complex fabrication processes and the use of toxic and scarce materials, like ruthenium. Natural dye-sensitized solar cells (NDSSC) are still in an early stage, with many research groups working hard to overcome efficiency and stability issues. Natural dyes are cheap, highly available, environmentally safe and easy to extract. Nature has so much to offer to humankind, each plant is unique, with characteristics developed during million of years of evolution. Each biome has an enormous number of species readily available for study. Among them, Brazilian forests are in an outstanding position, with a gigantic quantity of species with hidden opportunities. This work aims to inspire other researchers to explore this field and find in nature new answers for a clean energy demanding world. It is shown the basic aspects of NDSSC study and practical research, from laboratory construction to cells fabrication. After a brief introduction about PV technologies, DSSC is deeper discussed based on a literature review. Physical and electrochemical aspects are presented in details. Natural dyes specificities and application in DSSC are then discussed also based on other researchers findings. With a well-established theoretical basis, this work focus then on the development of a NDSSC fabrication protocol, presenting the most important tests and results achieved. A special highlight is given to the design and fabrication of a solar simulator from scratch. Having the infrastructure, equipments and protocol defined, the fabrication of NDSSC based on Brazilian plants was possible, including plants naturally originated in the country: blackberry, quaresmeira and embaúba-vermelha, and two other non-native species due to their economically important role, of which Brazil is currently the world leader producer, they are: arabica coffee and sugarcane. The found cells efficiencies for all studied plants dyes are in the range of other important research publications, even for the simplified and low cost proposed protocol, which validates the solutions and techniques used. Coffea arabica (arabica coffee) provided the best performance, reaching 0.44% overall conversion efficiency, with no special commonly used chemical treatment, co-adsorbent or purification, such as: TiCl4, organic acids, chromatography and lyophilization. It is hoped this work contribute for the development of an even greener energy generation from sunlight.


Lifelike Pedagogy

Marcelo Alatzatianou Rodrigues


Download PDF




What will children educated through life be capable of in the future?

Only an educational approach based on real experiences, when the students decide and learn through the achievement of their own enterprises, prepares them for the challenges brought by the future.

It must be taught not only basic school content, but also how to deal with the life challenges and opportunities, preparing real independent, creative, self-confident and happy people.

Pedagogia Vivencionista

Marcelo Alatzatianou Rodrigues


Download PDF




Do que serão capazes, no futuro, as crianças educadas através da vida? Apenas uma educação voltada para a vivência de experiências reais, em que o aluno decide e aprende através da realização de seus próprios empreendimentos, prepara a criança para os desafios que o futuro lhe trará, ensinando não apenas o elenco básico de disciplinas escolares, mas também os conhecimentos que somente a experiência de vida lhes trará, favorecendo ainda o desenvolvimento de habilidades fundamentais para a formação de um ser humano mais independente, criativo, autoconfiante e feliz. Pedagogia, vivencionista, vivencionismo, abordagem, educacional, educação, ensino, crianças.