Photometric study on excitation tailored cyan to white color conversion in SrCeO3: Dy3+ for wLEDs, latent fingerprint, and security ink applications

The current research focuses on the excitation-dependent dual light-emission of SrCeO3: Dy3+ perovskite synthesized via fuel excess gel combustion method, for enhanced optical and security applications. By tailoring the excitation wavelength, it is for the first-time reporting that the emission color can be tuned from cyan to white. The powder XRD results confirm an orthorhombic crystal structure with the space group Pnma and crystallographic parameters in the nano regime. The broad UV–visible absorption spectra indicate the effective energy transfer from Ce4+ → Dy3+ ions. The elemental purity, uniform distribution, and lattice vibrations were verified through EDS analysis, Elemental mapping, and Raman microscopy respectively. The PL emission under UV excitation shows concentration quenching after 2 wt% Dy3+, attributed to dipole-dipole interactions. Monitored under 270 nm, the SrCe0.98Dy0.02O3 gives out a cyan color whereas, with 350 nm it tunes to white light. The CIE profile further verified the authentic emission of SrCe0.98Dy0.02O3 phosphor obtained from PL analysis. The optimal sample exhibited an average grain size of 0.496 µm, average decay time of 25.6 ms, and possessed an internal quantum efficiency of 31.21%. Digital photographs under 350 nm excitation, demonstrate near-ideal white light (x = 0.3061, y = 0.3433), making them suitable for white LEDs. Additionally, owing to its adaptable color properties under two different excitations, integrating the cyan-emission makes these materials potential for latent fingerprint and security applications, reducing the risk associated with security breaches and duplication. Moreover, the study highlights a cost-effective and user-friendly approach, reducing chemical usage to transform the commercial application of simple perovskites in optical, forensic, and security ink applications, to enhance affordability in utilizing these materials, replacing complex perovskites.