BiVO₄/C₃N₄ heterojunction-gated organic photoelectrochemical transistor for sensitive detection of neurotransmitter

Developing advanced signal amplification strategies is essential for improving performance of state-of-the-art photoelectrochemical (PEC) analysis and integrated organic electrochemical transistor (OECT) devices. This study introduces a novel approach by integrating a BiVO₄/C₃N₄ heterojunction photoanode with organic photoelectrochemical transistor (OPECT) devices to achieve efficient signal modulation. The BiVO₄/C₃N₄ heterojunction is designed to promote effective charge separation and enhance the photoelectrochemical effect, introducing an efficient dual electrochemical signal amplification strategy. Dopamine (DA), a key neurotransmitter, is used as the target analyte as a proof-of-concept study. It acts as an effective electron donor, directly participating in redox reactions to amplify the channel signal and indirectly modulating the channel response through the BiVO₄/C₃N₄ electrode. The signal amplification results in the signal enhancement of three orders of magnitude. The developed bioanalytical method enables sensitive detection of DA with a good linear range from 10^-7 to 10^-4 M. Importantly, this dual amplification mechanism is independent of interactions between biological recognition molecules and analytes, providing a universal dual electrochemical signal amplification OPECT sensing platform. These findings indicate the potential this device has for the real-time monitoring of neurotransmitter levels, important for neurological disease monitoring.