Investigation of the photoluminescence spectra of rare-earth elements in pores of an opal matrix

Abstract

The main idea of this paper is researching the light emission of Eu³⁺ and Dy³⁺ in an opal matrix. The opal synthesis was carried out using Stöber method. The size of globules calculated from the transmission spectrum of prepared samples is equal to 231 nm. The samples were infiltrated with rare-earth element oxides in concentrated solution of nitric HNO₃ and perchloric HCl acids in the ratio 3:1. Next, the samples were heated to 100°C to reduce the relative content of water. The spectra of photoluminescence in the range 420-640 nm were excited by a semiconductor laser with λ=405 nm at the radiation registration along the direction of growth [111]. In the spectrum of the sample infiltrated by europium, there are distinctive europium lines at 580, 593 and 618 nm, which correspond to the typical transitions of this rare-earth element, such as ⁵D₀→⁷F₀, ⁵D₀→⁷F₁ and ⁵D₀→⁷F₂. Distinctive spectral lines of dysprosium luminescence are at wavelengths of 480 and 572 nm. The maxima of these wavelengths correspond to the typical lines of luminescence of trivalent dysprosium – specifically, transitions ⁴D_9/2→⁶H_13/2 and ⁴D_9/2→⁶H_11/2. The influence of photonic crystalline effects on the photoluminescence spectra of the obtained samples is studied.