Boosting Photo-Pyroelectric Effect via Tunable Polarization and Interfacial Defect Engineering

Pyroelectric catalysis has shown promising prospects for sustainable energy generation and medical treatments. However, its potential is limited by intrinsically low pyroelectric coefficients and insufficient interfacial reactivity, resulting in poor reactive oxygen species (ROS) output. In this study, we design Ba(Ti_0.85Zr_0.15)O₃ (BTZ) nanocatalysts, featuring enhanced polarization tunability and oxygen-vacancy-rich interfaces, for efficient NIR-II-driven photo-pyroelectric cancer therapy. Molecular dynamics and phase-field simulations indicate that Zr incorporation maintains strong polarization while facilitating rapid polarization switching via multiscale nanodomain formation. This results in an ultrahigh pyroelectric coefficient (3505 µC m^-2 K^-1), representing a 678% enhancement over pristine BaTiO₃. Interface engineering introduces oxygen vacancies that enhance NIR-II photothermal conversion and serve as reactive sites to facilitate the dissociation of water molecules. Density functional theory calculations reveal that Zr doping narrows the bandgap and redistributes conduction band electrons, while interfacial oxygen vacancies facilitate water adsorption through optimized hydroxyl binding. As a result, synergistic pyrocatalysis and peroxidase-like activity under NIR-II-driven mild thermal cycling enable robust multipath ROS generation. Both in vitro and in vivo studies confirm efficient tumor cell ablation via NIR-II induced pyroelectric therapy. This work presents a co-engineering strategy integrating polarization and interface design to overcome long-standing limitations in pyroelectric catalysis, advancing its application in precision oncology.