arXiv subjects

Robson Ferrari Muniz

Publications and source records attributed to Robson Ferrari Muniz.

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

The role of Ce$^{3+}$/Ce$^{4+}$ in the spectroscopic properties of cerium oxide doped zinc-tellurite glasses prepared under air

Emerging technologies are demanding innovative properties of glasses. In this work, Cerium Oxide is used as a dopant in Zinc-Tellurite samples and its effects on the properties of the glass are investigated. Thermal analysis and x-ray diffraction confirmed the amorphous nature of all samples. The bivalent nature of Cerium is investigated spectroscopically and a strong redshift induced by the dopant is attributed to charge transfers O$^{2-}{\rightarrow}$Ce$^{4+}$, while the 4f-5d transition of Ce$^{3+}$ could not be identified in absorption or luminescence measurements. Yellow/red (570/650 nm) emission under 405/450 nm pumping were observed and are originated from Te$^{4+}$ ions, which absorbs light in the UV/blue region of the spectrum. The incorporation of some Cerium Oxide enhanced the visible luminescence, though we found no evidence that Cerium ions play some role in the radiative process. The luminescence is enhanced though due changes in the glass network induced by the dopant.

cond-mat.mtrl-sci↗