Chloride Double Perovskites Doped with Sb3+/Er3+ as Stable and Effective Luminescence Materials in the Vis-NIR Region.

Abstract

The luminescence properties of stable halide double perovskites Cs2BIInCl6, where BI - 40% Ag, 60% Na, doped with Sb3+ and Er3+ in the region 250-1600 nm were investigated for the first time and reveal significant potential for advanced application. We employed XPS and TOF-SIMS for chemical analyses, while SEM, XRD, and Raman Spectroscopy provided insights into the morphology, crystal structure, and vibrational characteristics of the samples. The crystal structures of Cs2Ag0.292Na0.708InCl6, Cs2Ag0.285Na0.715In0.971Er0.029Cl6, Cs2Ag0.16Na0.84In0.893Er0.017Sb0.09Cl6 were examined using single-crystal methods. The excited Sb3+ ions emit blue light at 450 nm due to electronic absorption at sub-band gap levels, facilitating energy transfer to Er3+ ions. Notably, the Er3+ emit radiation at 1540 nm, a wavelength particularly advantageous for optical communication applications. Additionally, emissions at 525 nm, 552 nm, 665 nm and 805 nm are observed, corresponding to f-f transitions of Er3+ ions. These compelling results have been supported by calculations based on Modified Crystal Field Theory, elucidating the effects of varying concentrations of Sb3+ and Er3+ on the crystal structure and luminescent properties. Leveraging the synthesized materials, we successfully have developed a LED prototype that utilizes a UV chip  combined with the Cs2Ag0.4Na0.6In0.9Er0.01Sb0.09Cl6 powder as a stable and effective luminophore for optoelectronic applications.