The structural, phonon and optical properties of [CH₃NH₃]M_0.5Cr_xAl_0.5−x(HCOO)₃ (M = Na, K; x = 0, 0.025, 0.5) metal–organic framework perovskites for luminescence thermometry

Abstract

We report the structural, phonon and optical properties of perovskite-type heterometallic formates templated by methylammonium cations.

Layered Lead Iodide of [Methylhydrazinium]2PbI4 with a Reduced Band Gap: Thermochromic Luminescence and Switchable Dielectric Properties Triggered by Structural Phase Transitions

“…It is worth adding that significant changes of the temperature-dependent emission intensity indicate that this perovskite has high potential for noncontact temperature sensing. The potential of the metal-organic frameworks with perovskite-type architecture for noncontact thermometry has been recently reported by Ptak et al for formate-based materials …”

Power of Infrared and Raman Spectroscopies to Characterize Metal-Organic Frameworks and Investigate Their Interaction with Guest Molecules

“…Recently, a group of [A + ]­[M 1 M 2 (HCOO) x ] MOFs (where A + is ammonium, organic ammonium or other N-based cation) have attracted interest because of the order-disorder phase transition and multiferroic properties at low temperature. In general, these MOFs can be divided into five sub-groups: [A + ]­[M II (HCOO) 3 ] (M II = Mg, Mn, Fe, Co, Ni, Cu, Zn, Cd) exhibiting an order-disorder phase transition and multiferroic properties; ,− [A + ]­[M I 0.5 M III 0.5 (HCOO) 3 ] (M I = Na, K; M III = Fe, Cr) showing ferroelastic, ferroelectric, luminescent properties and pronounced dielectric relaxation; ,− [A + ]­[M III M II (HCOO) 6 ], where coexistence of antiferroelectric and magnetic orders has been reported for the Fe III Fe II compounds; ,− [A + ]­[Ln III (HCOO) 4 ] (Ln III = Eu, Gd, Tb, Dy, Er, Y) exhibiting luminescence and magnetic properties; ,, Other MOFs with formula [A + ]­[M 1 M 2 (HCOO) x ]. …”

“…[A + ]­[M I 0.5 M III 0.5 (HCOO) 3 ] (M I = Na, K; M III = Fe, Cr) showing ferroelastic, ferroelectric, luminescent properties and pronounced dielectric relaxation; ,− …”

“…The vibrational bands of simple molecules can be calculated by the so-called normal coordinate analysis that provides harmonic vibrational frequency . The spectra of crystals are more complicated and have been analyzed using site-group and factor-group methods. , However, such analysis has hardly been applied to MOFs . The assignment of the spectral bands of MOFs and their guest molecules is a difficult task.…”

Deep-Tissue Temperature Sensing Realized in BaY2O4:Yb3+/Er3+ with Ultrahigh Sensitivity and Extremely Intense Red Upconversion Luminescence

“…Therefore, rapid and accurate thermometry is essential in practical application. Nevertheless, conventional contact thermometry, such as thermometers and thermocouples, which are based on liquid or metal expansion, are unsuitable to be utilized in some harsh and extreme environments, such as high voltage conditions, strong corrosive environments, subcutaneous circumstances, and so on. − Up to now, numerous efforts have been made to develop new kinds of noncontact optical temperature sensing techniques for the aim of solving this problem. − Generally speaking, fluorescence lifetime, fluorescence intensity, and fluorescence intensity ratio (FIR) are all highly sensitive to temperature, making them fit for optical thermometry . However, utilizing fluorescence lifetime or intensity to determine temperature is strongly dependent on excitation source, optoelectronic system, background noise, and other factors, resulting in difficulties to guarantee precision and repeatability for temperature measurement.…”