Near-infrared emission of Yb³⁺ sensitized by Mn⁴⁺ in La₂MgTiO₆

Mn⁴⁺/Yb³⁺ co-doped La₂MgTiO₆ near infrared phosphor were prepared by co-precipitation technique. The La₂MgTiO₆: Mn⁴⁺, Yb³⁺ phosphors can convert the short-wavelength sunlight in 250–550 nm spectral region into near infrared emission at 990 nm, which matches well with the high photosensitive region of Si-based solar cells. The mechanisms for the Mn⁴⁺→Yb³⁺ have been discussed based on the Mn⁴⁺ and Yb³⁺ concentration dependent steady-state and transient luminescence properties. The energy transfer efficiency is 31% in the La_1.91MgTi_0.998O₆: 0.002Mn, 0.09Yb sample with the maximal 990 nm emission intensity. It is found that phonon-assisted energy transfer plays an important role in sensitization process from Mn⁴⁺ to Yb³⁺ in the Mn⁴⁺/Yb³⁺ co-doped La₂MgTiO₆.