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

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.