As is always accompanying temperature in
physics fundamental principles, Boltzmann constant k B
can be used to verify the accuracy of a thermometer. This
paper presents a photoluminescent method to measure k B
via temperature dependent fluorescence of phosphors.
Diagram of a phosphor’s energy levels was simplified to
illustrate the principle of measurement. The relationship
between k B and h*c (Planck constant h multiplying light
speed in vacuum c) was experimentally derived. Finally,
the determined k B was 1.38065
10 –23 J/K. The
determination could give a value of (1.380.1)
10 –23
J/K even when the in-use spectrometer was with a poor
resolution as about 2 nm. At the end, optimization of
measuring conditions for the determination process was
suggested.

• Boltzmann constant determined by fluorescent spectroscopy for verifying thermometers