The Effect of Multi‐Fields Synergy from Electric/Light/Thermal/Force Technologies on Photovoltaic Performance of Ba0.06Bi0.47Na0.47TiO3 Ferroelectric Ceramics via the Mg/Co Substitution at A/B Sites

Abstract Currently, it is widely reported that the photovoltaic effect in ferroelectric materials can be promoted by the application of a piezoelectric force, an external electric field, and intense light illumination. Here, a semiconducting ferroelectric composition is introduced, (1− x ) Ba 0.06 Bi 0.47 Na 0.47 TiO 3 ‐ x MgCoO 3 (abbreviated as x MgCo, where x = 0.02–0.08), synthesized through Mg/Co ions codoping. This process effectively narrows the optical bandgaps to a spectrum of 1.38–3.06 eV. Notably, the system exhibits a substantial increase in short‐circuit photocurrent density ( J sc ), by the synergy of the electric, light, and thermal fields. The J sc can still be further enhanced by the extra introduction of a force field. Additionally, the J sc also shows an obvious increase after the high field pre‐poling. The generation of a considerable number of oxygen vacancies due to the Co 2+ /Co 3+ mixed valence state (in a 1:3 ratio) contributes to the reduced optimal bandgap. The integration of Mg 2+ ion at the A‐site restrains the loss and sustains robust ferroelectricity ( P r = 24.1 µC cm −2 ), high polarizability under an electric field, and a significant piezoelectric coefficient ( d 33 = 102 pC N −1 ). This study provides a novel perspective on the physical phenomena arising from the synergy of multiple fields in ferroelectric photovoltaic materials.