A kinetic model of thin-film fluorescent sensors for strategies to enhance chemical selectivity

Abstract

An analytical model was developed for thin film chemical sensors which provides insight into the sensor dynamics and potential strategies to develop chemical recognition.

Thermal Desorption of Explosives Vapour from Organic Fluorescent Sensors

“…Excitation of the films was performed using 405 nm continuous wave laser light from a diode laser (Photonic Solutions) after attenuation of the power to 16 µW. Photoluminescence from the sensors was measured using a fibre-coupled CCD spectrometer, taking a measurement every 3 s for 300 s. Explosives vapours were generated using the setup as shown in [21] and nitrogen was used as the carrier gas, and at a flow rate of 6 mL/min. To check for fluorescence recovery, nitrogen gas was used to flush the analyte-exposed sensors, or the sensors heated to 90 • C, followed by a flow of nitrogen gas to flush out the desorbed analytes from the chamber.…”

“…An investigation of the complex processes during the temperature ramp is in progress. Although the source of the DNT vapour was turned off and the system flushed with clean nitrogen, the fluorescence continued to decrease, suggesting that there was a continuing diffusion of DNT vapour into the film [14,21] and that there was a strong binding interaction between the DNT molecules and the SY film [17]. An increase in temperature can weaken the binding strength and release the DNT molecules from the thin film.…”

Thermal control of organic semiconductors for trace detection of explosives

“…The responses from the various array elements give a fingerprint unique to a particular analyte. 12,13 Recently, Campbell and Turnbull 14 presented some computational and experimental results studying the interactions of explosives molecules with fluorescent films of various thicknesses. They suggested that analysis should make use of fluorescence recovery after a chemical incident instead of fluorescent quenching because this could give better information about the sensor(s)/analyte(s) interactions, thereby discriminating between analytes.…”

“…The irreversible interaction has been attributed to a strong binding interaction between the thin film of the sensors and the analytes. 14,15…”

Optimizing the Properties of La0.8Sr0.2CrO3 Thin Films through Post-Annealing for High-Temperature Sensing

“…Meanwhile, for xLSCO, wider applications in the energy and sensor fields of the present materials in the thin films field have also been reported in recent years. They are suitable for interconnect materials in solid oxide fuel cells [23][24][25], transparent electrolytes and electrodes of batteries and generators [26][27][28][29][30], thin-film fluorescent sensors, and high-temperature sensing [17,18,31,32], with their high melting point of 2490 • C, good conductivity, and high Seebeck coefficient. From our previous work [17], a screen-printed thick-film thermocouple fabricated by LaCrO 3 (LCO) and La 0.8 Sr 0.2 CrO 3 can be used to measure a temperature of 1550 • C for 10 h in air, which has inspired the fabrication of TFTCs by using xLSCO electrodes.…”