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[Display omitted] • A moderate amount of Dy3+ doping can enhance the ferroelectricity of the NBT host. • The NBT: x Dy3+ specimens exhibit intense prominent orange-yellow emission with optimal performance for x = 0.012. • The NBT: 0.012Dy3+ ceramic could be applied to optical temperature sensing. A series of Dy3+ doped Na 0.5 Bi 0.5 TiO 3 (NBT: x Dy3+, x = 0.003–0.018) lead-free ferroelectric ceramics were successfully prepared by a solid-state reaction method. The Dy3+ ions composition dependent photoluminescence properties were systematically studied. All the samples display intense characteristic emission of Dy3+ under an excitation wavelength of 454 nm, which are attributed to the transitions of 4F 9/2 → 6H J /2 (J = 13, 11 and 9). All the samples show strong orange-yellow emission, which could be applied to warm white light hopefully. When the content of Dy3+ is equal to 0.012, the ceramic has the optimal luminous performance. Remarkable thermal quenching of the luminous intensity ceramic occurs as the temperature is higher than initial temperature 293 K. Furthermore, Dy3+ activated photoluminescence performance combined with the presence of ferroelectricity in the NBT host can be applied to developing non-contact optical temperature sensitive materials and other future novel optoelectronic devices. [ABSTRACT FROM AUTHOR]

Luminescent ions doped lead free ferroelectric ceramics are the potential candidates to the widespread application of optoelectronic devices due to the coupling between their unique photoluminescence and inherent ferroelectric performance. In this work, the tunable photoluminescence response is successfully achieved in (1- x)Na 0·5 Bi 0·5 TiO 3 - x CaTiO 3 : Eu3+ (NBT- x CT: Eu3+, x =0.07, 0.1) via electric field poling. It is found that the enhancement of photoluminescence intensity became apparent for polarized NBT-0.07CT: Eu3+, wherein x =0.07 is near the morphotropic phase boundary region. However, for NBT-0.1CT: Eu3+ ceramic with a morphotropic phase boundary, the variation trend of the emission intensity after electric field poling is opposite. These results are ascribed to the lattice distortion and phase transition induced by an external field poling, which originates from ferroelectric and structural instability near and in the morphotropic phase boundary of NBT- x CT: Eu3+ (x =0.07, 0.1) ceramics. • The NBT- x CT: Eu3+ specimens exhibit strong prominent red emission. • The lattice distortion and phase transition are induced by an external field poling. • Electric-field-induced photoluminescence modulation is successfully achieved. • NBT-0.07CT: Eu3+ possesses more superior performance than NBT-0.1CT: Eu3+. [ABSTRACT FROM AUTHOR]

A series of Sm3+ doped 0.92(Na 0.5 Bi 0.5)TiO 3 -0.08(Ba 0.90 Ca 0.10)(Ti 0.92 Sn 0.08)O 3 (NBT-8BCTS: x Sm3+, x = 0–0.025) lead-free piezoelectric ceramics are fabricated via a conventional solid-state reaction method, and their phase structure, photoluminescence properties and temperature dependent of luminescence spectra are studied in detail. The emission spectra with dominant orange-red emission consist of four emission peaks at 542 nm, 598 nm, 644 nm and 709 nm, which are ascribed to the 4G 5/2 → 6H J/2 (J = 5, 7, 9, 11) transition of Sm3+ ions, respectively. Furthermore, the optical temperature sensing properties of the NBT-8BCTS: 0.01Sm3+ ceramic in the temperature range between 313 K and 533 K are analyzed with a maximum relative sensitivity 1.29%K−1 at T = 463 K. Besides, the phosphors exhibit excellent stable temperature sensing performance under repeated heat-cooling cycles. These results suggest that the Sm3+ doped NBT-8BCTS ceramics may have potential applications in multifunctional sensing devices by integrating its optical temperature sensing and intrinsic ferroelectric property. [Display omitted] • Ferroelectricity and photoluminescence emissions coexist in NBT-BCTS: x Sm3+. • A maximum relative sensitivity of 1.29% K−1 at 463 K is obtained. • Sm doped NBT-BCTS ceramics have potential for developing multifunctional optical-electric devices. [ABSTRACT FROM AUTHOR]