Effect of Er³⁺ ion incorporation on the structural, photoluminescence, and ferroelectric properties of K_0.5Na_0.5NbO₃ ceramic for optoelectronic applications

The lead-free ceramics K_0.5Na_0.5NbO₃: x wt% Er³⁺ (x = 0, 1, 2, 3 and 4) were produced via solid-state method. The ceramic was sintered at 1100 °C to produce a pure-phase perovskite with an orthorhombic structure. No extra phases in the XRD spectra demonstrate that all the Er³⁺ ions have dispersed into the host lattice. At room temperature, PL emission spectra were examined under the wavelengths 488 and 980 nm. In both emission spectra, green emission bands (528 and 549 nm) and slightly faint red emission bands (662 nm) were found. Observing the effect of pump power revealed that two photons are involved in the emission process. The time decay profile indicates an average lifetime of Er³⁺ ions is 25.05 μs. The ferroelectric hysteresis loop at room temperature showed decent shapes with good remnant. Thus, by combining the optical and ferroelectric properties, KNN may have potential applications to be employed in optoelectronic devices.