The kinetics of luminescence of sol-gel synthesized terbium doped Y (2)SiO(5) (YSO) phosphor particles is investigated in detail with reference to Tb concentration in the 0.001%-10% range. By increasing the dopant concentration, the luminescence profile changes from a blue to a green peaked emission spectrum because of the energy transfer among centers. The inter-center energy transfer mechanism is well accounted for by the Inokuti-Hirayama (IH) kinetic model which is based on a statistical average of inter-center distance dependent decay modes of the donor luminescence. The distribution of the decay modes is implemented from the Förster-Dexter resonance theory of energy transfer by assuming a rate constant for the energy transfer by multipolar interactions between donors and acceptors. However, the experimental results recorded in the low concentration limit show the presence of green emission contributions in the luminescence spectrum which cannot be related to the Tb concentration; for this reason an additional internal energy transfer mechanism, occurring among levels of the same center, is proposed to account for the recorded emission properties. Thus, a new and more exhaustive model which includes both the internal and external energy transfer processes is considered; the proposed model allows a better explanation of the spectroscopic features of Tb related centers in YSO crystals and discloses the critical concentration and the quantum yields of the different energy transfer mechanisms.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1088/0953-8984/24/29/295401 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Modulation of interface structure on titanium-based metal-organic frameworks heterojunctions for boosting photocatalytic carbon dioxide reduction.
J Colloid Interface Sci
January 2025
College of Materials Science and Engineering, Beijing University of Technology, Beijing 100124, China. Electronic address:
Rational regulation of interface structure in photocatalysts is a promising strategy to improve the photocatalytic performance of carbon dioxide (CO) reduction. However, it remains a challenge to modulate the interface structure of multi-component heterojunctions. Herein, a strategy integrating heterojunction with facet engineering is developed to modulate the interface structure of metal-organic frameworks (MOF)-based heterojunctions.
View Article and Find Full Text PDFCharacterisation and anaerobic digestion of fat, oil and grease (FOG) waste from wastewater treatment plants.
J Environ Manage
January 2025
Department of Civil, Environmental and Architectural Engineering, University of Padova, Via Marzolo 9, 35131, Padova, Italy.
The materials removed in the oil separation units of wastewater treatment plants can be referred to as fat, oil and grease (FOG) waste. FOG waste accumulation in treatment plants can cause clogging of pipes, production of excessive scums and foams, and negatively affect air/liquid oxygen transfer. While conventional disposal routes of this material can be limited by its water and organic content, FOG can represent a source of bio-energy other than bio-diesel production.
View Article and Find Full Text PDFResidence time of particles in indoor surface networks.
J Hazard Mater
January 2025
Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, PR China; Faculty of Architecture, The University of Hong Kong, Hong Kong, PR China. Electronic address:
Infectious microbes can spread rapidly from fomites (contaminated surfaces) via hand touch, with prolonged residence time on surfaces increasing transmission risk by extending exposure periods and/or involving more susceptible individuals. Existing studies have focused on decreasing microbial contamination, but not on the need for rapid removal from surface systems. This study introduces residence time as the time that a microbe spends within the surface system.
View Article and Find Full Text PDFCoupling Bifunctional Scaffolds with Slow Photon Effect for Synergistically Enhanced Photoassisted Lithium-Sulfur Battery Properties.
ACS Nano
January 2025
Institute of Flexible Electronics, Xi'an Key Laboratory of Flexible Electronics, Northwestern Polytechnical University, Xi'an 710072, China.
Photoassisted lithium-sulfur (Li-S) batteries offer a promising approach to enhance the catalytic transformation kinetics of polysulfide. However, the development is greatly hindered by inadequate photo absorption and severe photoexcited carriers recombination. Herein, a photonic crystal sulfide heterojunction structure is designed as a bifunctional electrode scaffold for photoassisted Li-S batteries.
View Article and Find Full Text PDFEnhancing Activation Energy Predictions under Data Constraints Using Graph Neural Networks.
J Chem Inf Model
January 2025
Department of Chemical Engineering, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan.
Accurately predicting activation energies is crucial for understanding chemical reactions and modeling complex reaction systems. However, the high computational cost of quantum chemistry methods often limits the feasibility of large-scale studies, leading to a scarcity of high-quality activation energy data. In this work, we explore and compare three innovative approaches (transfer learning, delta learning, and feature engineering) to enhance the accuracy of activation energy predictions using graph neural networks, specifically focusing on methods that incorporate low-cost, low-level computational data.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!