Objective: Conduct a bibliometric analysis of articles on the synthesis of graphene and graphene oxide, as well as their applications, from the documents in the last fourteen years. Method: The bibliometric analysis used data from the Scopus database to visualize the main keywords, countries, and journals, addressing the theme of graphene synthesis and its applications over the past 14 years, from 2010 to 2024. Results and Discussion: Using the Bibliometrix software combined with R programming, 1,485 documents published in English were analyzed, which includes articles in review and in their final version. The results demonstrated that despite being a widely explored theme in the scientific community, there is still a growing global relevance. Research Implications: The analysis provided significant data on the development and key trends in academic research. The study revealed a great interest in obtaining reduced graphene oxide and its application in solar cells, as well as the efficiency they produce. Originality/Value: The study aimed to contribute to academic research by demonstrating and analyzing the main trends in graphene synthesis and its applications. Demonstrating its relevance in recent years and the growth in applications in photovoltaic systems.

Semiconductors films have many applications, energy conversion is one of the main ones. Oxides are often the material used to fabricate these films. Electrophoresis technique can deposit oxides semiconductors at different voltages and time. Films of zinc oxide (ZnO) were electrodeposited on conductive glass, adding weight percentage of tin chloride to improve its photo catalytic properties. The films and cells were characterized by X-ray, UV-Vis and EIS. The characterization showed that higher voltage decreased the band gap value from 3.3 to 3.26 eV, below the average for pure zinc oxide, around 3.30. The films acted as photoanodes in solar cells, with maximum current density of 2.88 mA/cm² and open circuit of 0.68 V. The synthesis method was efficient and can be used for further reseach into semiconductors’ films and be applied for membranes, photoanodes and other applications.

Multilayerfilms with kesterite are often used for energy conversion, such as photoanode for hydrogen production and manufacture of photovoltaic solar cells. It is due to the fact that they are efficient and use small amounts of material. Cu₂ZnSnS₄, known as CZTS, is a semiconductor belonging to the kesterite group, which can be obtained in powder or film form. Copper, zinc, tin and sulfide are precursors commonly used in the synthesis of the CZTS. The methodology used to synthesize films is crucial for the success of the final product. It is essential to develop methods which can lower synthesis costs, which can also lower the solar cell costs, for example. Besides the costs, the method must be efficient and increase the efficiency of the devices in which they are employed, and must not be harmful to the environment. This study developed a methodology to synthesize CZTS. It was used in this work dimethyl sulfoxide, copper acetate, tin chloride, zinc chloride and thiourea as precursors. The layers of the film above the glass substrate were characterized with X-ray diffraction, ultraviolet and visible analyses, scanning electron microscopy, fourier transform infrared spectroscopy and X-ray fluorescence spectroscopy. The results absorbance peaks between 300 and 400 nm, in the ultraviolet range, reflectance around 40% in the visible, transmittance reaching above 50% and 50%, and direct band gap about 1.42 ± 0.02 eV associated with the kesterite. The characterization methods proved to be efficient to identify the presence of the kesterite phase at films produced by overlapping layers.

Objective: This paper aims to collaborate to the development of the reverse logistic for solar panels, impulse by the energetic transition into the green hydrogen. Additionally, it intends to map all the logistic activities linked to the green hydrogen production, including the reverse logistic of solar photovoltaic panels, to take advantage of its components. This paper wanted to identify all the photovoltaic solar panels components, for a more broadly comprehension of its structure, and define all the activities related to the post consumption of the panels. Theoretical Framework: The references explore the photovoltaic solar panels characteristics and the necessity to implement the reverse logistic for this energy source, focusing on green hydrogen production. Also, applying the just-in-time tool. Method: The methodology is detailed, with a clear and objective description of all the steps. Including the mapping of the activities through a flowchart, that illustrates the sequence of the steps, with a detailed description of each step. Results and Discussion: The obtained results revealed the necessity of a perspective for the reversed logistic driven from the energetic transition, especially by the green hydrogen. This problem is linked to the increasing environmental awareness and boosting on the solar panels production, which also increased the demand for the discarded components of those panels in a sustainable manner. Thus logistic can be optimized through the just-in-time tool, that allows the reverse mapping of the steps, improving its logistic aspects. Research Implications: The theoretical and practical implications of this research highlight mainly the questions related to sustainability and awareness in short, medium and long term. The search for an energetic vector capable of supplying the energetic necessities in a clean and abundant way is a topic of constant study. However, the answers to these questions and how they are connected can impact directly the energetic research. Therefore, it must be done in an efficient and strategic way. Originality/Value: This study explores the reverse logistics for solar panels, aiming to demonstrate the possibility to produce in a large scale in a sustainable form. This connection is linked to the GH2 energetic vector, since the source for the production of this vector is directly related to renewable energies, such as solar energy. Thus, this study maps in detail this reverse pathway searching for a sustainable reverse logistic.

Semiconductors are often used in the energy conversion field, due to its electronic properties. One of the applications is for photovoltaic solar cells. Doping is a way of altering the properties of a material without significantly causing alterations in the structure of the materials. One of these properties that can be changed is the photon to current efficiency of a semiconductor. Many elements are being used for the doping of semiconductors, such as aluminum, cobalt, indium and lithium. This work doped zinc oxide with tin in the chloride form to try to increase the generated current inside a dye sensitized cell at different dye immersion times. The time used to immerse the film can affect the stability of the cell, and, by consequence, the efficiency of photovoltaic conversion. Ruthenium based dye was tested in this study. The results showed better current and efficiency values for a longer period of time, 3.38 mA/cm² and 0.52%; absorption peaks in the UV region and band gap around 3.0 eV, below the average 3.37 eV found for zinc oxide thin films, and crystalline size of 46.7 nm.