Print Email Facebook Twitter Photoluminescence and excited states dynamics of Tm2+-doped CsCa(Cl/Br)3 and CsCa(Br/I)3 perovskites Title Photoluminescence and excited states dynamics of Tm2+-doped CsCa(Cl/Br)3 and CsCa(Br/I)3 perovskites Author Plokker, M.P. (TU Delft RST/Luminescence Materials) Biner, D. A. (University of Bern) Dusoswa, N. (TU Delft ChemE/O&O groep) Dorenbos, P. (TU Delft RST/Luminescence Materials) Krämer, K. W. (University of Bern) van der Kolk, E. (TU Delft RST/Luminescence Materials) Date 2021 Abstract In this study, we systematically vary the Cl/Br and Br/I ratios in CsCaX3:Tm2+ (X = Cl, Br, I) and hereby gradually shift the positions of the Tm2+ 4f125d1-levels as relative to the two 4f13 levels. At low temperatures up to five distinct Tm2+ 4f125d1→4f13 emissions and the 4f13→4f13 emission can be observed. As the temperature increases, most of the 4f125d1→4f13 emissions undergo quenching via multi-phonon relaxation (MPR) and at room temperature only the lowest energy 4f125d1→4f13 and the 4f13→4f13 emission remains. For all compositions a 4f13→4f13 risetime phenomenon is then observed whose duration matches the 4f125d1→4f13 decay time. It shows the feeding of the 4f13 state after 4f125d1 excitation. Surprisingly, the feeding time becomes longer from Cl→Br→I, while the related 4f125d1-4f13 energy gap becomes smaller. The temperature dependence of the 4f125d1→4f13 and 4f13→4f13 emission intensity shows a anticorrelation as earlier observed in other systems and confirms that the feeding process is thermally stimulated. However, the thermally stimulated activation energies that control the feeding process, increase from Cl→Br→I despite our observation that the 4f125d1-4f13 energy gap becomes smaller. An analysis reveals that the unexpected behaviour in risetime and activation energy, as a function of composition, cannot be explained by 4f125d1→4f13 feeding via interband crossing, but more likely via MPR where the electron–phonon coupling strength decreases from Cl→Br→I. No strong relation was found between composition and the quantum efficiency (QE) of the 4f13→4f13 emission, due to the presence of fluctuations that are likely caused by intrinsic differences in sample quality. Nevertheless, a 4f13→4f13 QE of up to 70% has been observed and the materials can therefore be used in luminescence solar concentrators. Subject CsCaBr3:TmCsCaCl3:TmCsCaI3:TmHalide solid solutions with TmPhotoluminescenceTm doped halidesTm excited states dynamicsOA-Fund TU Delft To reference this document use: http://resolver.tudelft.nl/uuid:8e1c11fc-1eba-4c57-a4d7-3af2a633a35a DOI https://doi.org/10.1088/2515-7639/ac24ed Source JPhys Materials, 4 (4) Part of collection Institutional Repository Document type journal article Rights © 2021 M.P. Plokker, D. A. Biner, N. Dusoswa, P. Dorenbos, K. W. Krämer, E. van der Kolk Files PDF Plokker_2021_J._Phys._Mat ... 045004.pdf 3.53 MB Close viewer /islandora/object/uuid:8e1c11fc-1eba-4c57-a4d7-3af2a633a35a/datastream/OBJ/view