High-entropy oxides: exploring structural, thermal and luminescent properties of the (Gd0.2Eu0.2Tb0.2Er0.2Yb0.2)2O3 rare earth oxide

• Grant number: 23/17865-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2024
• End date: November 30, 2024
• Field of knowledge: Engineering - Materials and Metallurgical Engineering
• Principal Investigator: Ricardo Alexandre Galdino da Silva
• Grantee: Mayara Hitomi Rosa Suenaga
• Host Institution: Instituto de Ciências Ambientais, Químicas e Farmacêuticas (ICAQF). Universidade Federal de São Paulo (UNIFESP). Campus Diadema. Diadema , SP, Brazil

Abstract

High-entropy compounds have gained attention in the scientific community in the last decade, like high-entropy alloys and more recently, high-entropy oxides. The growing interest in these materials is related to their unique properties that emerge when compared with traditional materials, such as luminescent, magnetic, electric, and structural properties. This allows application on many fields where the control and precision of these properties are important, like magnetic sensors, piezoelectricity, and photosensors, besides other promising applications in solar cells and energy storage and conversion. Therefore, high-entropy oxides are classified as smart and functional materials with high technological potential. High-entropy compounds are composed of five or more elements that tend to form a solid solution and, therefore, allow a high number of possible configurations. In other words, the configurational entropy is high, thus the term "high-entropy" is used in these materials. Lanthanides are a group of 15 elements from 57La to 71Lu. When 21Sc and 39Y elements are added they are called as rare earths (RE). RE, mainly the trivalent ones, present singular properties due to their electronic configuration involving 4f orbitals allowing good luminescent properties in a large spectrum range. Therefore, R2O3 oxides (R = rare-earth element) are interesting materials to study and the cubic structure in some of them allows the formation of multi-component equiatomic oxides in solid solution, such as the high-entropy oxide (Gd0.2Eu0.2Tb0.2Er0.2Yb0.2)2O3. This project proposes the study of high-entropy oxide (Gd0.2Eu0.2Tb0.2Er0.2Yb0.2)2O3 focusing on its structural, thermic, and luminesce properties. The high-entropy oxide will be progressively formed by adding one element each time to understand the role of each element in the multi-component material regarding its modification in the crystalline lattice and emission spectra.