arXiv subjects

Vitor Santaella Zanuto

Publications and source records attributed to Vitor Santaella Zanuto.

4 recordsLinked to original sources

arXiv2026

Upcycling solar glass into Ce-doped oxyfluorides: spectroscopic and crystallization properties

Oxyfluorides containing up to 80 wt% recycled glass from end-of-life solar panels have been investigated. Reduced processing temperature and high transparency have shown that the material has potential for optical applications. In this work, cerium-doped samples were investigated. Spectroscopic study reveals the presence of Ce$^{3+}$, and luminescence from these ions and oxygen-deficient centers was detected. Raman demonstrated that cerium affects the glass network by promoting polymerization. In turn, thermal analysis indicated some changes in the crystallization events between 500-800 $^o$ C, which were confirmed by in situ X-ray powder diffraction measurements. Crystallization of fluorite, xonotlite, and combeite was confirmed, while other phases give minor contributions to the XRD patterns. Cerium addition reduced the formation of xonotlite, mainly above 700 $^o$ C. The potential applications of the material and the further studies required are discussed.

cond-mat.mtrl-sci↗

arXiv2025

Oxyfluoride glasses obtained through incorporation of CaF$_2$ into photovoltaic cover glass melts

The glass industry has limited options to mitigate its environmental footprint, and the demand for cover glass to produce photovoltaic panels is increasing. Currently, the majority of this special type of glass is not being recycled, and in this work, we propose to reuse it as raw material to obtain oxyfluoride glasses. The incorporation of CaF$_2$ and the increasing Na$_2$CO$_3$ content resulted in a melting temperature of about 1200$^o$C, significantly lower than in soda-lime glasses, which adds up to the environmental benefits of reusing end-of-life cover glass. The obtained samples show high transparency and thermal stability, allowing the cover glass to make up to 80\% of its weight. XRF analysis was employed to determine the elemental composition of the samples, while XRD and Raman indicated that by adding CaF$_2$, the glass network was depolymerized. In situ XRD as a function of temperature showed the formation of a few crystalline phases in these oxyfluoride samples, evidencing that it can be explored as a matrix to obtain different glass-ceramics. The combination of the glass properties indicates that this method and the resulting material can contribute to reducing the environmental impact of the glass industry, by creating new glass or glass-ceramic materials that can be obtained at a reduced temperature compared to the soda-lime glass, while cover glass being the primary raw material could reduce the need to extract minerals from nature.

cond-mat.mtrl-sci↗

arXiv2023

Glassy materials for Silicon-based solar panels: present and future

Glass provides mechanical, chemical, and UV protection to solar panels, enabling these devices to withstand weathering for several decades. The increasing demand for solar electricity and the need to reduce anthropogenic carbon emissions require researchers to develop new materials and processes to make solar even more sustainable. Here, we review the current research to create environmentally friendly glasses and to add new features to the cover glass used in silicon solar panels, such as anti-reflection, self-cleaning, and spectral conversion properties. While several studies have proposed spectral converter designs and reported information regarding their light-conversion efficiency, there is still a need for a standardized protocol to investigate and compare the impact of these modified materials on the electrical output of photovoltaic systems. In light of these issues, we propose a framework for quantifying parameters that can serve as benchmarks for comparing different cover glasses, which is especially important in the search for a viable spectral converter.

cond-mat.mtrl-sci↗

arXiv2020

Glass engineering to enhance Si solar cells: a case study of Pr$^{3+}$-Yb$^{3+}$ codoped tellurite-tungstate as spectral converter

Spectral converters are known to increase photovoltaic energy conversion by minimizing losses due to fundamental non-absorption and thermalization processes, and have been suggested to surpass the Shockley-Queisser efficiency limit in single junction solar cells. Here we present a detailed spectroscopic study of photoluminescence in tellurite-tungstate glasses doped and codoped with $Pr^{3+}-Yb^{3+}$ and $Ag$ nanoparticles. The energy transfer mechanisms between $Pr^{3+}$ and $Yb^{3+}$ are discussed based on the near infrared emission under excitation at $442$ nm and on the upconversion emission under excitation at $980$ nm. Fluorescence quenching of $^2 F_{5/2}$ level of $Yb^{3+}$ is observed by increasing the concentration of $Pr^{3+}$, as well as by the addition of $Ag$ nanoparticles. In addition, a discussion on the potential of this glass to increase energy production in spectral converters is presented. The results suggest that the few undesirable energy transfer processes occurring in this material are difficult to be controlled or eliminated properly, resulting in intrinsic losses. This discussion is extended to the potential of glass science to enhance energy production in solar cells, showing that newer designs such as bifacial cells may facilitate the exploration of glasses other than soda-lime for mass production of solar cells. The focus on extending the lifespan by reducing UV induced degradation seems to be a more effective approach than the development of spectral converters for Si solar cells.

cond-mat.mtrl-sci↗