Synthesis, structural and optical properties of a novel double perovskite for LED applications

Unveiling Local Electronic Structures of Manganese‐Doped Double Perovskites Red Emitters

“…Additionally, three distinct absorption peaks are observed at 358, 408, and 509 nm, which correspond to the transitions ( 4 A 2g → 4 T 1g ), ( 4 A 2g → 2 T 2g ) and ( 4 A 2g → 4 T 2g ) in the Mn 4+ ions, representing spin-allowed and spin-forbidden processes, respectively. The energy band gap (E gap ) of the Mn 4+ ion doped Sr 2 Lu(Nb 1−x Mn x )O 6 (x = 0.005, 0.010, 0.015 and 0.020) double perovskite can be obtained according to the equation (𝛼h𝜈) n ∞(h𝜈-E gap ), [19] where a represents the absorption coefficient, h is Planck's constant, 𝜈 represents the optical frequency, n represents the band gap type, n = 2 or n = 1/2 indicates a direct or indirect band gap in the matrix respectively, and E gap represents the band gap value. The linear relationship between (𝛼h𝜈) n and h𝜈 can be found in Figure S1 (Supporting Information).…”

“…To further clarify the luminescence properties, the decay curves of Sr 2 Lu(Nb 0.990 Mn 0.010 )O 6 double perovskite, monitoring at 688 nm under an excitation wavelength of 350 nm, as shown in Figure 5f. These decay curves can be well approximated by a double exponential function, as described below Equation ( 11): [19] I (t) =I 0 +A 1 exp…”