Interplay of Porosity, Defects, and Europium Doping in PZT Thin Films: Impact on Ferroelectric and Luminescent Behavior

Porous Eu‐doped Pb(Zr,Ti)O 3 (PZT) thin films were prepared by a sol–gel route to investigate the coupled effects of Eu incorporation, surfactant‐induced porosity, and thermal treatment on crystallization and functional properties. Eu incorporation preserved the perovskite phase composition of dense PZT but resulted in pronounced grain refinement and strongly modified the electrical response. In porous Eu‐containing films, thermal history governed the structural evolution: fast annealing promoted formation of a well‐developed perovskite matrix with enlarged columnar grains and residual porosity while retaining ferroelectric functionality, whereas prolonged annealing enhanced Pb loss and suppressed complete perovskite crystallization. The interaction between Eu incorporation and porosity was particularly evident in photoluminescence. In the amorphous state, characteristic Eu 3 + intra‐4f emission was strongly enhanced after formation of the porous structure. Subsequent perovskite crystallization suppressed Eu 3 + emission and produced host/defect‐related bands near 360, 430, and 550 nm. These results demonstrate that Eu incorporation and porosity are coupled through crystallization and defect evolution, providing a route to tailor the structural, optical, and electrical properties of multifunctional PZT thin films.