Development of dual-emitting Sb3+/Eu3+ codoped CaTiO3 phosphors for energy-efficient white LEDs

Dual-emitting phosphors have emerged as a promising class of materials due to their ability to produce multiple emissions from a single host, offering enhanced efficiency and reducing the potential of compatibility problems with different color combination materials. Considering this, CaTiO₃ powders doped with Sb³⁺ and Sb³⁺/ Eu³⁺ were synthesized by high temperature solid state reaction method and subjected to various characterization studies such as X-ray diffraction, FTIR, SEM, EDX, UV–Vis DRS and PL. Diffraction patterns confirmed the orthorhombic nature of all the samples without any significant impact due to doping. FTIR studies showed dominant Ca–O and Ti–O vibrations whereas DRS spectra revealed the absorption nature of corresponding dopant ions. Bandgap values, estimated from the absorption spectra match well with the standard energy gap of the host matrix. SEM coupled with EDX showed near spherical particles with all the chemical elements distributed uniformly. From the emission studies, we determined the optimum Sb³⁺ concentration to be 2% for blue emitting Sb³⁺ doped CaTiO₃ whereas for codoped, optimum Eu³⁺ concentration was found to be 4% with the maximum red emission. Under UV excitation of 252 nm, codoped samples had a dual emission in blue and red wavelength regions corresponding to both the dopant ions (Sb³⁺, Eu³⁺). Eu³⁺ emission is enhanced with the addition of sensitizer Sb³⁺ ions due to the energy transfer between Sb³⁺ and Eu³⁺. CIE chromaticity and CCT parameters for the codoped phosphors revealed the white color emission from the prepared powders, making them suitable candidate for white light emitting diodes (WLEDs).