Optimization the Sensing Performance of BaTiO3/P(VDF-TrFE) via Proton Irradiation

Abstract

The pyroelectric-piezoelectric dual-mode sensor simultaneously decodes temperature and strain, serving as a core component for health monitoring, human-machine interfaces, and bionic skin applications. To achieve high fidelity, self-powering, and long-term endurance, the sensing materials must balance sensitivity, stability, and multi-physics field coordination across multiple scales. This study employs a synergistic strategy combining barium titanate (BaTiO₃) doping with proton irradiation to regulate polyvinylidene fluoride-trifluoroethylene copolymer (P(VDF-TrFE)). By enhancing crystallinity and β-phase content of P(VDF-TrFE) while introducing oxygen vacancies and lattice distortions within the BaTiO₃ lattice, the strategy significantly strengthens interfacial polarization coupling and charge transport efficiency. As a result, doping with 2wt% BaTiO₃ increases pyroelectric coefficient (p) to 66.1 μC/m²•K. Although piezoelectric coefficient (d₃₃) slightly decreases from 22.0 pC/N to 20.1 pC/N, its variation range (standard deviation) narrows from 3.9 to 3.1. Subsequent proton irradiation at 1×10¹⁰ p/cm² further increases p to 86.6 μC/m²•K, accompanied by a slight decrease in d₃₃. At 5×10¹⁰ p/cm² fluence, p maintains a 6.8% increase compare to pre-irradiation levels, and d₃₃ recovers to 20.0 pC/N with a standard deviation reduced to 2.4, effectively balancing piezoelectric uniformity and stability with high pyroelectric sensitivity. The composite film exhibits a linear sensitivity of 1.2 V/K over a temperature range of 0.1-12.2 K, with no degradation observed after 10³ thermal cycles. It conformally adheres to the human body and enables real-time analysis of respiration, pulse, and touch signals, offering a novel approach for high-sensitivity, high-reliability dual-mode sensing in wearable electronics and bionic skin applications.