No abstract

Currently, luminescent sensors for detecting vapors of nitroaromatic compounds and other explosives are being actively developed. In practice, the stability of the luminescence signal of the sensor is of great importance. In this work we study photostability of sensitive luminophore embedded in porous silicon microcavities under exciting at a wavelength of 450 nm. As the sensitive luminophore we used Poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMOPPV). It was found that the rate of photodegradation of MDMO-PPV luminescence depends nonlinearly on the intensity of the exciting radiation. Apparently, the observed effect is related to the limited rate of diffusion of oxygen molecules into the porous silicon. Additionally, similar studies were carried out for MDMO-PPV films on a glass substrate. It is shown that in this case the photostability of the luminophore decreases by several times. Based on the data obtained, the operating modes of the sensor element are analyzed.