Suppression of thermal quenching in fast-responding pressure-sensitive paint by restricting lattice relaxation of luminescent molecules

The thermal quenching of fast-responding pressure-sensitive paint (Fast PSP) has been effectively suppressed by restricting the lattice relaxation of luminescent molecules based on Franck-Condon principle. This is significant for reducing the temperature sensitivity while improving the signal level of Fast PSP. This approach used a self-assembled monolayer (SAM) technique to process PSP samples based on anodized aluminum oxide membrane. Due to the aluminum oxide's capability of forming a strong bond with fatty acid, the monomolecular coating formed by SAM on the PSP membrane was highly organized and dense which restricted the lattice relaxation of luminescent molecule. The sensing performance of PSP samples, including temperature sensitivity, pressure sensitivity, signal level, and response time, was evaluated based on static and dynamic calibrations. Significant reduction in temperature sensitivity (up to 95.7% in a temperature range of 273–323 K) was achieved after the samples were coated by SAM. The effects of geometric parameters (of the porous structure) on temperature sensitivity were investigated in detail. The luminescent intensities of the samples with or without SAM coating were also compared, which showed an improvement of up to 3 times after the samples were coated by SAM. In addition, the effect of temperature in SAM process on the reduction of PSP's temperature sensitivity was evaluated to determine the optimal treatment temperature. •Thermal quenching in PSP was suppressed by restricting the lattice relaxation.•A self-assembled monolayer (SAM) technique was used to process PSP samples.•Significant reduction in temperature sensitivity (up to 95.7%) was achieved.•Substantial improvement in luminescent signal (up to 3 times) was achieved as well.