A5066436510- Luminescence Properties of Advanced Materials
- Glass properties and applications
- Radiation Detection and Scintillator Technologies
- Luminescence and Fluorescent Materials
- Nuclear materials and radiation effects
- Inorganic Fluorides and Related Compounds
- Perovskite Materials and Applications
- Lanthanide and Transition Metal Complexes
- X-ray Diffraction in Crystallography
- Crystal Structures and Properties
- Solid State Laser Technologies
- Microwave Dielectric Ceramics Synthesis
- Crystallization and Solubility Studies
- Semiconductor materials and devices
- Inorganic Chemistry and Materials
- Photochromic and Fluorescence Chemistry
- Catalytic Processes in Materials Science
- Solid-state spectroscopy and crystallography
- Advanced Photocatalysis Techniques
- Photorefractive and Nonlinear Optics
- Polyoxometalates: Synthesis and Applications
- Pigment Synthesis and Properties
- Advanced Condensed Matter Physics
- Catalysis and Oxidation Reactions
- Electronic and Structural Properties of Oxides
University of Turku
2016-2025
Turku University of Applied Sciences
2016-2020
Tampere University of Applied Sciences
2020
Tampere University
2020
Turku Centre for Computer Science
2009-2018
Finland University
2014
University of Helsinki
2006
Thermoluminescence properties of the Eu2+-, R3+-doped calcium aluminate materials, CaAl2O4:Eu2+,R3+, were studied above room temperature. The trap depths estimated with aid preheating and initial rise methods. seemingly simple glow curve CaAl2O4:Eu2+ peaking at ca. 80 degrees C was found to correspond several traps. Nd3+ Tm3+ ions, which enhance most intensity high-temperature TL peaks, form suitable traps for intense long-lasting persistent luminescence, too. location 4f 5d ground levels...
The present status and future progress of the mechanisms persistent luminescence are critically treated with knowledge. advantages to be achieved by a further need as well pitfalls excessive use imagination shown. As usual, in beginning era since mid 1990s, played more important role than sparse solid experimental data chemical common sense knowledge was largely ignored. Since some five years, mechanistic studies seem have reached maturity – perhaps deceivingly it seems that there only...
The persistent luminescence of CdSiO3:Tb3+ was investigated with photoluminescence, thermoluminescence (TL), synchrotron radiation X-ray absorption (XANES and EXAFS) UV-VUV spectroscopies. Only the typical intraconfigurational 4f8–4f8 transitions Tb3+ ion were observed no traces band emission in either conventional UV excited or spectra. trap structure from TL three traps 0.65 to 0.85 eV is ideal for room-temperature similar to, e.g., Sr2MgSi2O7:Eu2+,R3+. Despite rather low gap energy, 5.28...
The disintegration of hexagonal NaYF4:Yb3+,Er3+ upconverting nanoparticles (UCNP) was studied by incubating various nanoparticle concentrations in aqueous suspensions over time while monitoring the upconversion emission intensity and measuring dissolved particle-constituting ion concentrations. results revealed that ions into water resulting apparently anisotropic structural UCNPs as observed with transmission electron microscopy. UCNP caused partial loss active Yb3+ Er3+ from host matrix...
Photovoltaics (PV) is the leading renewable energy harvesting technology. Thus, there a remarkable strive to enhance light capability of state-of-the-art solar cells. The major issue common all cell types that they utilize only limited portion spectrum, mostly in visible range, as active semiconductor materials suffer from intrinsic absorption thresholds. As result, photons below and above these threshold values do not contribute electricity generation. A plausible solution performance...
Parent, hierarchical, and metal-modified hierarchical zeolite Y were investigated as heterogeneous catalysts in the R-(+)-limonene epoxidation, a catalytic route for synthesizing precursors of bio-polycarbonates, an alternative to isocyanate polyurethanes. The fresh underwent detailed characterization using XRD, N2 physisorption, TEM, SEM-EDX, pyridine-FTIR, NH3-TPD, CO2-TPD, UV–Vis-DRS, solid-state NMR. Spent materials by TPO-MS TGA, confirming low coke formation on surface. most active...
ConspectusWhile photochromic natural sodalites, an aluminosilicate mineral, were originally considered as curiosities, articles published in the past ten years have radically changed this perspective. It has been proven that their artificial synthesis was easy and allowed compositional tuning. Combined with simulations, it shown a wide range of properties achievable for synthetic sodalites (color, activation energy, reversibility, etc.), making them interesting alternatives to organic...
Luminescence from trivalent rare earth (R3+: La3+–Lu3+, excluding Pm3+) ions was studied in the CdSiO3 host. The positions of R2+/3+ energy levels band structure suggest that doping with R2+ is difficult if not impossible. Red, pink, blue, green and close to white persistent luminescence colours were obtained by Pr3+, Sm3+, Gd3+, Tb3+ Dy3+, respectively. efficiency defect R3+ transfer determines arises 4f–4f, or a combination these two emissions. In contrast what observed for Pr3+ Tb3+, did...
Persistent luminescence (PeL) materials are used in everyday glow‐in‐the‐dark applications and they show high potential for, e.g., medical imaging, night‐vision surveillance, enhancement of solar cells. However, the best performing contain rare earths and/or other heavy metal expensive elements such as Ga Ge, increasing production costs. Here, (Li,Na) 8 Al 6 Si O 24 (Cl,S) 2 :Ti, a heavy‐metal‐ rare‐earth‐free low‐cost material is presented. It can give white PeL that stays 7 h above 0.3 mcd...
Photon-upconversion materials are capable of converting low energy infrared light into higher visible or ultraviolet light.
Abstract Photochromic sodalites are considered for a plethora of possible applications, such as UV indexing and X‐ray imaging, but many these the materials yet to be optimized. can improved through incremental adjustment activation energy coloration from 300 410 nm replacement sulfur with selenium. By combining this other methods tuning presented in literature, excitation threshold photochromism color tuned independently one another. The range absorption maxima is expanded 420–680 nm, or...
Non-doped as well titanium and lutetium doped zirconia (ZrO 2 ) materials were synthesized via the sol-gel method structurally characterized with X-ray powder diffraction.The addition of Ti in lattice does not change crystalline structure whilst Lu doping introduces a small fraction tetragonal phase.The UV excitation results bright white-blue luminescence at ca. 500 nm for all which emission could be assigned to 3+ e g t 2g transition.The persistent originates from same center.The...
In this work, the persistent luminescence mechanisms of Tb3+ (in CdSiO3) and Eu2+ BaAl2O4) based on solid experimental data are compared. The photoluminescence spectroscopy shows different nature inter- intraconfigurational transitions for Tb3+, respectively. electron is charge carrier in both mechanisms, implying presence acceptor defects. preliminary structural analysis a free space CdSiO3 able to accommodate interstitial oxide ions needed by compensation during initial preparation....