Shadow Effect-Triggered Photosensitive Gate of Organic Photoelectrochemical Transistor for Enhanced Biodetection

The integration of a photosensitive gate into an organic electrochemical transistor has currently emerged as a promising route for biological sensing. However, the modification of the photosensitive gate always involves complex processes, and the degradation of sensitivity of the functional materials under illumination will significantly decrease the stability of the devices. Herein, we designed an organic photoelectrochemical transistor (OPECT) biosensor employing horseradish peroxidase (HRP)@glucose oxidase (GOx)/Pt/n-Si as the photosensitive gate based on the "shadow effect". The glucose-dependent hydrogen peroxide with HRP/GOx was modified on the gate electrode, triggering a biocatalytic precipitation reaction, which induces the illumination contrast, resulting in a biologically gating effect on the corresponding channel current response. Thus, high sensitivity and selectivity in glucose detection of the OPECT devices will be realized. Given the easy fabrication and high stability of the Pt/n-Si electrode, it has great potential to become a superior selectivity as an OPECT gate electrode. This work provides conceptual validation for the study of the interaction between the photosensitive gate based on the "shadow effect" and biomolecular sensing, which can further expand the application of the OPECT biosensors under interior lighting and shadow surroundings.