Ratiometric Boltzmann thermometry with Cr³⁺ in strong ligand fields: Efficient nonradiative coupling for record dynamic working ranges.

ABSTRACT: A new ratiometric Boltzmann thermometry approach is presented for the narrow-line red-emitting bright phosphor Al_0.993Cr_0.007B₄O₆N. It relies on thermalization between the two excited states ²E_g(²G) and ²T_1g(²G) of Cr³⁺ with an energy gap of 620 cm^-1 for optimized thermometry at room temperature. It is shown that nonradiative coupling between these excited states is very fast, with rates in the order of several µs^-1. Due to the comparably slow radiative decay (k_r = 0.033 ms^-1) of the lowest excited ²E_g(²G) state, the dynamic working range of this Boltzmann thermometer for the deep red

SUBMITTER: Kinik G 

PROVIDER: S-EPMC12645019 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature