A wavelength-resolved ratiometric photoelectrochemical technique: design and sensing applications. Issue 1 (5th November 2015)

• Record Type: Journal Article
• Authors: Hao, Qing; Shan, Xiaonan; Lei, Jianping; Zang, Yang; Yang, Qianhui; Ju, Huangxian
• Is Part Of: Chemical science. Volume 7:Issue 1(2016:Jan.)
• Page Start: 774
• Page End: 780
• Publication Date: 2015-11-05
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c5sc03336e
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : A wavelength-resolved ratiometric photoelectrochemical technique was developed as a novel concept for designing ratiometric photoelectrochemical sensors. Abstract : In this work, a wavelength-resolved ratiometric photoelectrochemical (WR-PEC) technique was investigated and employed to construct a new type of PEC sensor with good sensitivity and anti-interference ability. The WR-PEC hybrid photoelectrodes were stepwise assembled using semiconductor quantum dots (QDs) and photoactive dyes. Under continuous irradiation, the photocurrent–wavelength ( I–λ ) curves reveal the dependence of the photocurrent on the wavelength. By monitoring the ratios of the two different PEC peak values, a wavelength-resolved ratiometric strategy was realized. Using CdS QDs and methylene blue (MB) as photoactive models, a dual-anodic WR-PEC sensor was established for sensitive detection of Cu 2+ . This ratiometric strategy was identified to be based on the quenching effect of Cu 2+ towards CdS QDs and enhancement of the MB photocurrent through catalytic oxidation of leuco-MB. Under continuous illumination from 400 nm to 800 nm at a 0.1 V bias potential, a WR-PEC sensor for Cu 2+ was developed with a wide linear range and a detection limit of 0.37 nM. This WR-PEC had a greatly improved anti-interference ability in a complex environment, and showed acceptable stability. Moreover, using the CdS/magnesium phthalocyanine (MgPc) and CdTe/MgPc as photoelectrodes, anodic–cathodic and dual-cathodic WR-PEC sensors were established, respectively. The WR-PEC technique could serve as a novel concept for designing ratiometric or multi-channel PEC sensors.