Abstract
This work investigates the Mn2+ electronic structure and photoluminescence (PL) in [(CH3)4N]2MnCl4 and [(CH3)4N]2MnBr4 and their variation with pressure by time-resolved excitation and emission spectra in the 0–10 GPa range. We show that both the crystal-field excitation and corresponding PL bands experience large-pressure redshifts (about 5 nm/GPa), which are associated with the high crystal compressibility and the interaction between organic/inorganic ([CH3]4N−/MnX) tetrahedra. The energy variation as a function of pressure is explained in terms of the isolated Td MnX
in the respective crystals through crystal-field models. One salient feature is the reduction of the PL Stokes shift with pressure in both crystals as−1.0 and−1.7 nm/GPa for chloride and bromide, respectively.
†This paper was presented at the XLVIth European High Pressure Research Group (EHPRG 46) Meeting, Valencia (Spain), 7–12 September, 2008.
Acknowledgements
Financial support from the Spanish MEC (Project No. MAT2005-00099) and MALTA INGENIO-CONSOLIDER 2010 (Ref. CDS2007-0045) are acknowledged. Y. Rodríguez-Lazcano and L. Nataf thank financial support from the Mobility Program (Ref. SB2005-0201) and Postdoctoral fellowship from the University of Cantabria, respectively.
Notes
†This paper was presented at the XLVIth European High Pressure Research Group (EHPRG 46) Meeting, Valencia (Spain), 7–12 September, 2008.