Project Title:             Transition Metal Assisted UP Conversion in Lanthanide doped (nano)particles: Resolving the                                              mechanisms in spectral and temporal domains

Project Code:            PN-III-P4-ID-PCE-2020-1553

Contract Nr. :            62/2021

Project Funded by:  UEFISCDI, Ministry of Education, Research, Youth and Sport, Romania 

Period:                       2021 - 2023

Project Leader:        Carmen TISEANU

Contract Value:        1 198 032 RON


Project Summary  

       Our primary goal is to develop a unitary description of transition metal (TM: Mo anion, bivalent Mn) assisted lanthanide (Ln: Yb/Er, Yb/Tm, Gd) upconversion (UPC) emission in both spectral and temporal domains. Three relevant classes of materials are selected: rare-earth based oxides, where Mo is employed as both dopant and host cation (I), and Rare-Earth fluorides with hexagonal/cubic (II) and tetragonal (III) lattice structures, where Mn is employed as dopant. The questions we address in this proposal are: How the low solubility and heterovalency of transition metals impact on the local structure, and hence d-d (Mn) and f-f absorption/emission transitions of Ln? How does spectral selective and time-resolved/gated excitation influences the different roles (sensitizer, activator, mediator) played by TM/Ln in UPC processes with impact on the emission colour, intensity and dynamics? To what extent the complex picture of UPC processes includes (if at all) the Yb – Mo/Mn dimer mechanism? We seek answers to all these questions using a battery of spectral and temporal resolved luminescence approaches: investigation and analysis of site selective, time-resolved emission and excitation spectra monitoring all key absorption/emission levels involved in UPC, emission decays and energy density dependencies by using unique configuration based on tunable pulsed excitation laser with controlled beam profile.


Project Objectives:

    Our primary goal is to develop a unitary description of transition metal (TM: Mo anion, bivalent Mn) assisted lanthanide (Ln: Yb/Er, Yb/Tm, Gd) upconversion (UPC) emission in both spectral and temporal domains. Three relevant classes of materials are selected: rare-earth based oxides, where Mo is employed as both dopant and host cation (I), and Rare-Earth fluorides with hexagonal/cubic (II) and tetragonal (III) lattice structures, where Mn is employed as dopant.


Project Team:


International Conferences

 1. D. Avram, C. Colbea, C. Tiseanu “Local symmetry effects on the upconversion emission intensity, shape and mechanisms under pulsed excitation” UPCONline 2021, 09 – 09 april 2021, Online Conference. (Oral presentation)




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