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The Eu3+‐doped (1 − x)Na0.5Bi0.5TiO3‐xSrTiO3 (Eu‐NBT‐xSTO) thin films were prepared on Pt/Ti/SiO2/Si substrates. Raman analysis reveals that the phase structure may undergo a phase evolution of rhombohedral → rhombohedral + tetragonal (morphotropic phase boundary) → tetragonal with increasing content of STO. The scanning electron microscopy images show that the uniformity and high density of Eu‐NBT‐xSTO films were increased by adding STO, resulting in a pronounced effect on energy storage properties. The ɛ‐T curves confirm that a high phase transition diffuseness of γ = 2.02 ± 0.03 and 1.98 ± 0.03 was achieved in Eu‐NBT‐0.24STO and Eu‐NBT‐0.3STO films, respectively. Furthermore, a large recoverable energy storage density of 31.5 J cm−3 with an efficiency of 64% was obtained in Eu‐NBT‐0.3STO film, which also exhibited good thermal stability in the temperature range between −60°C and 80°C as well as long‐term stability up to 1 × 108 switching cycles. These results suggest that the Eu‐NBT‐xSTO films may be used in the novel and advanced energy storage capacitors.

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(100)C‐oriented Na0.5Bi0.5‐xSmxTiO3 (NBST) lead‐free ferroelectric thin films were prepared on Pt/Ti/SiO2/Si substrates by chemical solution deposition method, and their microstructural, dielectric, ferroelectric, and photoluminescent properties were studied. X‐ray diffraction and scanning electron microscopy analysis indicated that both the grain size and (100)C orientation degree of NBST thin films were decreased by doping Sm3+ ions. Raman spectra showed that structural symmetry of NBST thin films decreased at low Sm3+ doping concentration and then increased at high doping concentration of Sm3+ ions. An appropriate amount of Sm3+ dopants was confirmed to enhance dielectric and ferroelectric properties of the NBST thin films. Among all the compositions, the Na0.5Bi0.492Sm0.008TiO3 thin film exhibited the largest remnant polarization (2Pr) of 27.3 μC/cm2 and high dielectric constant of 1068, as well as a low dielectric loss of 0.04. Temperature‐ and frequency‐dependent dielectric characteristics illustrated the relaxor ferroelectric behavior of Na0.5Bi0.492Sm0.008TiO3 thin film. Meanwhile, the Na0.5Bi0.492Sm0.008TiO3 thin film also showed optimal orange‐red emission at 600 nm, which is originating from the 4G5/2 → 4H7/2 transition of Sm3+ ions.

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