Shadow Effect-Triggered\nPhotosensitive Gate of Organic\nPhotoelectrochemical Transistor for Enhanced Biodetection

The\nintegration of a photosensitive gate into an organic\nelectrochemical\ntransistor has currently emerged as a promising route for biological\nsensing. However, the modification of the photosensitive gate always\ninvolves complex processes, and the degradation of sensitivity of\nthe functional materials under illumination will significantly decrease\nthe stability of the devices. Herein, we designed an organic photoelectrochemical\ntransistor (OPECT) biosensor employing horseradish peroxidase (HRP)@glucose\noxidase (GOx)/Pt/n-Si as the photosensitive gate based on the “shadow\neffect”. The glucose-dependent hydrogen peroxide with HRP/GOx\nwas modified on the gate electrode, triggering a biocatalytic precipitation\nreaction, which induces the illumination contrast, resulting in a\nbiologically gating effect on the corresponding channel current response.\nThus, high sensitivity and selectivity in glucose detection of the\nOPECT devices will be realized. Given the easy fabrication and high\nstability of the Pt/n-Si electrode, it has great potential to become\na superior selectivity as an OPECT gate electrode. This work provides\nconceptual validation for the study of the interaction between the\nphotosensitive gate based on the “shadow effect” and\nbiomolecular sensing, which can further expand the application of\nthe OPECT biosensors under interior lighting and shadow surroundings.