Visible photoelectrochemical sensing platform by in situ generated CdS quantum dots decorated branched-TiO2 nanorods equipped with Prussian blue electrochromic display.

In this study, based on in situ generation of CdS quantum dots (QDs) on the surface of branched TiO2 (B-TiO2) nanorods, an solar innovative photoelectrochemical (PEC) sensing platform was constructed for real-time, and sensitive detection of cellular H2S. Specifically, B-TiO2 nanorods arrays consisting of TiO2 nanorods directly grown on fluorine-doped tin oxide (FTO) further using TiCl3 mediated surface treatment of TiO2 nanorods are designed and fabricated as a new type of photoelectrode. CdS quantum dots (QDs) was formed on the surface of B-TiO2 nanorods arrays through the reaction between Cd2+ and S2-. And a significant enhancement in the photocurrent was obtained that ascribed to the formation of CdS-B-TiO2 heterostructures, thus leading to sensitive PEC recording of the H2S level in buffer and cellular environments. By using Prussian blue (PB) a electrochromic material to capture the photoelectron generated from the photoelectrode, a new visual system was proposed due to the formation of Prussian white (PW), which could be used to visualize the quantum photoelectric effect. This novel PEC sensing platform not only achieved satisfied analysis results toward S2-, but also showed excellent sensitivity, selectivity, low cost, and portable features. The strategy through the in situ generation of semiconductor nanoparticles on the surface of wide band-gap semiconductor paves the way for the improvements of PEC analytical performance. Meanwhile, the quantitative read-out electrochromic display paves a facile avenue and initiates new opportunities for creation of cheap, miniaturization sensors for other relevant analytes.