Structure, Luminescence and Temperature Detection Capability of [C(NH(2))(3)]M(HCOO)(3) (M = Mg(2+), Mn(2+), Zn(2+)) Hybrid Organic–Inorganic Formate Perovskites Containing Cr(3+) Ions

Metal-organic frameworks are of great interest to scientists from various fields. This group also includes organic–inorganic hybrids with a perovskite structure. Recently their structural, phonon, and luminescent properties have been paid much attention. However, a new way of characterization of these materials has become luminescence thermometry. Herein, we report the structure, luminescence, and temperature detection ability of formate organic–inorganic perovskite [C(NH(2))(3)]M(HCOO)(3) (Mg(2+), Mn(2+), Zn(2+)) doped with Cr(3+) ions. Crystal field strength (Dq/B) and Racah parameters were determined based on diffuse reflectance spectra. It was shown that Cr(3+) ions are positioned in the intermediate crystal field or close to it with a Dq/B range of 2.29–2.41. The co-existence of the spin-forbidden and spin-allowed transitions of Cr(3+) ions enable the proposal of an approach for remote readout of the temperature. The relative sensitivity (S(r)) can be easily modified by sample composition and Cr(3+) ions concentration. The luminescent thermometer based on the (2)E/(4)T(2g) transitions has the relative sensitivity S(r) of 2.08%K(−1) at 90 K for [C(NH(2))(3)]Mg(HCOO)(3): 1% Cr(3+) and decrease to 1.20%K(−1) at 100 K and 1.08%K(−1) at 90 K for Mn(2+) and Zn(2+) analogs, respectively.