Perovskite‐Graphene Heterostructure Biosensor Integrated with Biotunable Nanoplasmonic Ternary Logic Gate for Ultrasensitive Cytokine Detection

Abstract The integration of 2D‐materials and optoelectronic devices has attracted great attention for advanced applications. We propose the first perovskite/graphene heterostructure‐based FET biosensor with uniquely biotunable ternary logic gating functionality. The biosensor integrates a lateral perovskite‐on‐graphene heterostructure phototransistor with a vertical bio‐nano‐photonic filter, with a decoupled construction inset. In the phototransistor, photoactive perovskite quantum dots (PQDs) serve as sensitizers to absorb light while a high mobility single‐layer graphene (SLG) acts as an expressway for carrier transport. In the bio‐nano‐photonic filter, a localized surface plasmon resonance (LSPR) is induced by gold nanoparticles (AuNPs) in conjunction with antigen‐antibody binding, tuning the delivery of light passing through the filter and facilitating biotunable functionality with ternary modes. The biosensor is set up to detect human interleukin‐6 (IL6) in order to determine and achieve ultrahigh sensitivity with a limit of detection (LOD) of 0.9 fg mL ⁻¹ (43 aM), which is 4 orders of magnitude greater than graphene‐FET biosensors. This ultrahigh sensitivity is achieved due to the synergistic effect of PQDs/SLG heterostructure, exhibiting superior electrical, optical, and physicochemical properties, consequently providing significantly high performance of the biosensor in terms of label‐free, ultrahigh sensitivity (attomolar level), rapid responsivity (5 min), excellent stability, and selectivity. This heterostructure‐based biotunable configuration could open a new avenue for 2D materials in the realm of next‐generation bio‐nano‐photonic platforms for applications in healthcare, early diagnosis, and rapid detection.