Dual-mode luminescent sensors with integrated spectral logic capabilities

This work presents a dual-mode optical sensor based on core-shell silica particles functionalized with two organic dyes, Rhodamine B and fluorescein isothiocyanate, designed to operate in aqueous environments. The particles were synthesized via modified Stöber method, forming a solid silica core with a mesoporous shell to spatially separate the dyes. The photoluminescent response of the system was analyzed under changing temperature and pH conditions. For thermal sensing, both conventional single-parameter ratiometric analysis and a novel multiparametric approach based on multiple linear regression were applied to the same dataset. The multiparametric method led to a nearly 2-fold increase in relative thermal sensitivity and a roughly 3-fold decrease in temperature uncertainty compared to the single-parameter ratiometric approach. In addition, pH sensing capabilities were analyzed using a single ratiometric parameter yielding outstanding performances regarding relative pH sensitivity and uncertainty. With our finding we characterize the system by adequately binarizing the spectra and finding characteristic Boolean operations introducing in this way novel representative optic logical gates. • Core-shell silica: RhB in pores, FITC on surface • FITC pH-sensitive; RhB temperature-responsive. • 2× thermal sensitivity, 3× less uncertainty. • Novel optical logic gate demonstrated.