Lanthanide complexes dispersed in enamel: a promising new material for photonic devices

A lanthanide-thin-film based dosimeter with high sensitivity and selectivit y to UV cumulative measurements was developed. The dosimeter is based on ni trocellulose-enamel and has been designed in order to present useful respon ses covering the three main UV regions related to skin damage effects: UV-A (365 nm), UV-B (315 nm), UV-C (290 nm). The active part of the system is a thin layer of commercial nitrocellulose enamel ultrasound-mixed with lanth anide complex powder. We have monitored the Eu (III) emission (D-5(0)--> F- 7(2)) and the Tb (III) emission (D-5(4)--> F-7(5)) as a function of UV expo sure time and a luminescence decrease of the Eu (III) emission was observed . Since this effect is irreversible, a memory effect is associated to the s ystem allowing dosimetry measurements. For the red (600 nm), green (540 nm) and blue (430 nm) excitation the luminescence remained the same, which rei nforces the UV selectivity of the dosimeter proposed. We may also adjust th e dosimeter sensitivity by controlling the amount of powder mixed with the enamel. (C) 2001 Elsevier Science B.V. All rights reserved.