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

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 ultra thin 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 mu M from the transient photocurrent response method (linear range: 0.1-0.8 mM) and 12.6 mu 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. (C) 2016 Elsevier B.V. All rights reserved.