Search for: All records

In this paper, the photoluminescent properties of a lead-free double perovskite Cs 2 NaInCl 6 doped with Sb 3+ are explored. The host crystal structure is a cubic double perovskite with Fm 3̄ m symmetry, a = 10.53344(4) Å, and rock salt ordering of Na + and In 3+ . It is a wide bandgap compound ( E g ≈ 5.1 eV), and substitution with Sb 3+ leads to strong absorption in the UV due to localized 5s 2 → 5s 1 5p 1 transitions on Sb 3+ centers. Radiative relaxation back to the 5s 2 ground state, via a 3 P 1 → 1 S 0 transition, leads to intense blue luminescence, centered at 445 nm, with a photoluminescent quantum yield of 79%. The Stokes shift of 0.94 eV is roughly 33% smaller than it is in the related vacancy ordered double perovskite Cs 2 SnCl 6 . The reduction in Stokes shift is likely due to a change in coordination number of Sb 3+ from 6-coordinate in Cs 2 NaInCl 6 to 5-coordinate in Cs 2 SnCl 6 . In addition to the high quantum yield, Cs 2 NaInCl 6 :Sb 3+ exhibits excellent air/moisture stability and can be prepared from solution; these characteristics make it a promising blue phosphor for applications involving near-UV excitation.