Ferroelectric polarization modulation self-powered photoelectrochemical biosensor for sensitive CEA detection based on semiconductor-ferroelectric heterojunction

Abstract

The development of sensitive and anti-interference photoelectrochemical (PEC) biosensors is of great significance in early disease diagnosis, but remains a major challenge. Herein, we constructed a novel self-powered PEC biosensor based on BiVO₄/Bi_0.95Nd_0.05FeO₃ (BVO/BNFO) semiconductor-ferroelectric heterojunction photoelectrode for detecting carcinoembryonic antigen (CEA). Firstly, the doping of rare earth Nd³⁺ effectively suppressed the oxygen vacancy content and Fe³⁺/Fe²⁺ valence state changes, greatly improving the ferroelectric properties of BiFeO₃. Compared with BiVO₄ (BVO) and BiVO₄/BiFeO₃ (BVO/BFO), BVO/BNFO photoelectrodes increased the photocurrent without external bias by 13.15 times and 2.23 times, respectively, through synergistic ferroelectric polarization and built-in electric field. Furthermore, the interfacial energy band bending and charge transfer of BVO/BNFO could be effectively modulated by controlling the polarization state, thereby resulting in a 203.9 % enhancement in photocurrent under positive poling, and maintaining excellent stability under long-term illumination. As a result, the self-powered PEC biosensor demonstrated a wide detection range for CEA with concentrations ranging from 1 pg/mL to 0.1 mg/mL, as well as a low detection limit of 1.91 pg/mL. Benefiting from its excellent stability and high selectivity of constructed PEC biosensors, we believe this innovative amplification strategy employing ferroelectric polarization may offer new opportunities for clinical diagnosis of CEA and other tumor markers.