Enhanced photoelectrochemical detection of l-cysteine based on the ultrathin polythiophene layer sensitized anatase TiO2 on F-doped tin oxide substrates

By Wang, Yuqiao; Wang, Wei; Wang, Shasha; Chu, Wenjing; Wei, Tao; Tao, Haijun; Zhang, Chuanxiang; Sun, Yueming
Published in Sensors and Actuators B: Chemical NULL 2016

Abstract

Abstract An effective photoelectrochemical (PEC) detection methodology was established and used to determine l-cysteine based on the ultrathin polythiophene layer sensitized anatase TiO2 on F-doped tin oxide substrates (PTh/TiO2/FTO). The PTh/TiO2 core-shell composites were synthesized by in situ polymerization of thiophene on TiO2 nanoparticle surfaces, resulting in a 1-nm-thick {PTh} layer decorated TiO2. The ultrathin layer could improve the electronic conductivity and enhance the light absorption, indicating that the PTh/TiO2/FTO electrode might strengthen a weak electrical signal response in detecting the low concentration of l-cysteine. Under Xe light of 25 mW cm?2, the {PEC} detection limit of l-cysteine was 12.8 ?M from the transient photocurrent response method (linear range: 0.1-0.8 mM) and 12.6 ?M the amperometric response method (linear range: 0.06-0.5 mM), respectively. Moreover, the results also indicated an acceptable accuracy and excellent anti-interference in practical application, providing a rapid and sensitive {PEC} detection.

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