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 [email protected] [email protected] quantum dots ( [email protected] QDs)-decorated TiO 2 nanotubes (TiO 2 NTs). [email protected] QDs were prepared by the combination of CdTe and CdS with a proper lattice mismatch. Due to their large band offsets, [email protected] QDs can reduce undesirable carrier recombination, significantly improving their charge separation efficiency. Then the synthesized [email protected] QDs were modified on TiO 2 NTs ( [email protected] QDs/TiO 2 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.