Design an efficient photoelectrochemical aptasensor for PCB72 based on CdTe@CdS core@shell quantum dots-decorated TiO2 nanotubes

In this work, an efficient and novel photoelectrochemical (PEC) aptasensor for 2,3′,5,5′-tetrachlorobiphenyl (PCB72) was constructed based on CdTe@CdS core@shell quantum dots (CdTe@CdS QDs)-decorated TiO2 nanotubes (TiO2 NTs). CdTe@CdS QDs were prepared by the combination of CdTe and CdS with a proper lattice mismatch. Due to their large band offsets, core@shell QDs can reduce undesirable carrier recombination, significantly improving their charge separation efficiency. Then the synthesized CdTe@CdS QDs were modified on TiO2 NTs (CdTe@CdS QDs/TiO2 NTs) through electrostatic adsorption method. The as-prepared composites exhibit a wide visible light absorption range, good PEC activity and high photoelectric conversion efficiency. Also, the PEC aptasensor prepared via the immobilization of anti-PCB72 aptamer on the composites exhibits outstanding analytical performance with high sensitivity and specificity for PCB72 under visible-light irradiation, achieving a detection limit as low as 0.03 ng/L. It was also applied to detect PCB72 in four different real environmental samples with satisfactory results. [Display omitted] •The synthesized CdTe@CdS QDs/TiO2 NTs was first explored to develop a PEC sensor.•The PEC aptasensor exhibites outstanding performance for detection of PCB72.•The detection mechanism of the PEC sensor for PCB72 was described in detailed.•This method are easier, faster and less costly compared to instrumental techniques.