1. Otto Schott Institute of Materials Research University of Jena Jena 07743 Germany
2. Centre for Energy and Environmental Chemistry (CEEC) University of Jena Jena 07743 Germany
3. Department of Biochemistry and Food Chemistry University of Turku 20014 Turku Finland
4. Department of Physics University La Laguna 38206 La Laguna Tenerife Spain
5. State Key Laboratory of Luminescent Materials and Devices Institute of Optical Communication Materials South China University of Technology Guangzhou 510640 P.R. China