Host-guest recognition assisting exciton-plasmon resonance energy transfer-modulated photoelectrochemical solution-gated graphene field-effect transistor for paraquat detection

The photoelectrochemical solution-gated graphene field-effect transistor (PEC-SGGT) is an innovative sensor that integrates a photoelectrochemical (PEC) signal generation mechanism within the gate circuit of solution-gated graphene field-effect transistors (SGGT). In this work, we address the challenge of paraquat (PQ) detection by leveraging its symmetric molecular structure and the host–guest encapsulation effect of cyclodextrins, designing a PEC-SGGT sensor modulated by exciton-plasmon resonance energy transfer (EPRT) interactions. The sensor functions through host–guest recognition between PQ and cyclodextrins, resulting in the formation of the structure CdS-CD@PQ@Au-CD), which enables the EPRT effect. The signal induced by the EPRT effect in the PEC gate electrode will modulate the channel current of the PEC-SGGT device, ultimately generating the detection signal for PQ. The results indicate that the sensor achieves an impressive detection limit of 0.07 pM, demonstrating excellent sensitivity and strong resistance to interference across a linear detection range of 0.1 pM to 0.1 μM. This work not only provides an effective method for PQ detection by but also introduces a novel approach to designing PEC-SGGT sensors and understanding their underlying detection mechanisms.