1. Physics Department and CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193Aveiro, Portugal
2. Department of Chemistry and Physics, Federal University of Paraíba, 58397-000Areia, Brazil
3. Department of Chemistry, Southern Methodist University, Dallas, Texas75275-0314, United States
4. Department of Fundamental Chemistry, Federal University of Pernambuco, 50740-560Recife, Brazil
5. Dipartimento Politecnico di Ingegneria e Architettura, Laboratorio di Tecnologie Chimiche, University of Udine, 33100Udine, Italy
6. Luminescent Materials Laboratory, Department of Biotechnology, University of Verona and INSTM, UdR Verona, 37134Verona, Italy