Energy-Recording Spectrofluorimeter*

Abstract

The design and application of an instrument for the measurement of excitation, fluorescence, and reflectance spectra of luminescent powders is described. Both excitation and fluorescence spectra are recorded on an absolute energy scale that is independent of wavelength. This is accomplished by internal standardization against the output of a thermocouple detector. The excitation and emission monochromators scan the wavelength region 200–700 mμ; the spectra are displayed as continuous curves on a strip-chart recorder. The use of the thermocouple detector as a reference for the calibration of both excitation and fluorescence spectra is described. Photometric accuracy better than five percent has been achieved. Typical spectra obtained for a luminescent silicate, and sulfide are shown. An application involving an electroluminescent sample is shown. The instrument is also useful as a reflectometer, since reflectance may be measured without interference from fluorescence. Improvements are discussed that would permit the instrument to record in terms of quantum yield rather than energy. In addition, the instrument may be extended farther into the red by different detectors.