Photothermal-Thermoelectric Cooperative Effects Mediating Zero-Bias Microscale Current Amplification in Organic Photoelectrochemical Transistors

Light-driven organic photoelectrochemical transistors (OPECTs) in bioanalytical contexts show significant potential, yet they often demand a considerable current for photoelectrode-driven redox processes. Here, a robust near-infrared excited photothermal-thermoelectric-driven OPECT sensing platform has been meticulously crafted to facilitate minute current amplification with precision. To attain this objective, the initial step involves harnessing energy via photothermal-thermoelectric-based electrodes. Upon exposure to near-infrared radiation, the photothermal active matrix of MXene and the conformative effector of Bi₂Te₃, endowed with thermoelectric attributes, oscillated between thermal and thermoelectric field oscillations, thereby facilitating the diffusion of charge carriers responsive to near-infrared stimuli and modulating the doping state of the channel film to propel the operation of OPECTs. At the interface between Bi₂Te₃/MXene and the liquid medium, a sophisticated biosensing mechanism was integrated, involving immune competitive enzyme biocatalytic precipitation, which orchestrated target-dependent alterations in the channel current signal, thereby facilitating the detection of marine algal toxin okadaic acid with precision. This study provides near-infrared-stimulated photothermal- thermoelectric-driven OPECT devices, capable of amplifying microcurrents, and delineates novel operational frameworks and perspectives for optoelectronic interfacing with biological entities.