Enhanced piezoelectric performance and orange-red emission of Sm3+ doped (Na1/2Bi1/2)TiO3 based lead-free ceramics

Abstract In this work, a novel lead-free multifunctional material, 0.94(Na 1/2 Bi 1/2 )TiO 3 -0.06BaTiO 3 - x Sm 3+ (NBBT- x Sm), was synthesized by a conventional solid-state reaction method. The crystal structure, electrical and photoluminescence properties of the samples were systematically investigated. It was found that doping Sm 3+ into NBBT induced a transition from the rhombohedral and tetragonal phases coexistence to a pseudocubic phase. The sample with x =0.003 displayed a relatively large piezoelectric constant ( d 33 ~202 pC/N), indicating that a small amount of Sm 3+ doping significantly improved the piezoelectric performances for NBBT ceramics. Furthermore, the obtained Sm 3+ doped NBBT ceramics exhibited the strongest absorption peak located at 407 nm, which matches well with the emission wavelength of the commercial near-ultraviolet LED chips. Under the excitation of 407 nm n-UV light, the ceramics presented characteristic emission of Sm 3+ ions with the dominate orange-red emission peak at 598 nm. Particularly, the quantum yield as high as 44% was achieved in the NBBT-0.006Sm specimen, which is higher than that of the most of currently reported rare earth doped ferro/piezoelectric ceramics. In addition, the thermal stability of photoluminescence for the sample was studied in detail and the value of the thermal quenching active energy was calculated to be 0.5543 eV. These results showed that NBBT- x Sm materials have promising potential in white light emitting diodes (WLEDs) or advanced multifunctional devices.