Spectroscopic and luminescence properties of (CH ₃)₄NMnCl₃: a sensitive Mn ²⁺-based pressure gauge

Abstract

This work investigates the Mn ²⁺ electronic structure and photoluminescence (PL) in [(CH ₃)₄N]MnCl ₃ (TMMC) and their variation with pressure by time-resolved excitation and emission measurements in the 0–15 GPa range. We show that both the crystal-field excitation and the corresponding PL bands experience large pressure redshifts, which are associated with the anisotropic crystal compressibility providing large axial ligand fields at the Mn ²⁺ site in TMMC. These variations are very large for the emission band, which shifts with pressure at a rate of 21 nm/GPa (50 meV/GPa), making TMMC suitable for using as a pressure gauge. We show that TMMC provides precise pressure determinations in low pressure ranges (MPa–GPa), since it has the capability to detect pressure variations of 10 MPa.

Keywords:

• Mn ²⁺
• TMMC
• pressure gauge
• sensors
• photoluminescence
• time-resolved spectroscopy

Acknowledgements

Financial support from the Spanish MEC (Project No. MAT2008-06873-C02-01/MAT) and MALTA INGENIO-CONSOLIDER 2010 (Ref. CDS2007-0045) are acknowledged. L.N. thanks financial support from a Postdoctoral fellowship from the University of Cantabria.