Optical Properties of “Liumogen”: A Phosphor for Wavelength Conversion

Abstract

Optical and physical properties of the phosphor 2,2′-dihydroxy-1,1′ napthaldiazine (“liumogen”) have been investigated. Emission, absorption, and excitation spectra have been measured, as well as dependence of the emission upon the excitation wavelength and the temperature. Methods of sample preparation have been tested. The compound appears to have some notable advantages as a wavelength conversion detector. The material may be sublimed in vacuum without decomposition, and thus may be used in the form of thin transparent films. These films show a reasonable stability. The absorption edge occurs at ~4600 Å; the main emission is in the yellow-green spectral region. The luminescence quantum yield of the phosphor is nearly independent of the excitation wavelength from 4600 Å to at least 900 Å. The efficiency increases by a factor of ~2 upon cooling to 80°K.