Conversion of broadband UV-visible to near infrared emission by LaMgAl11O19: Cr3+, Yb3+ phosphors

•Energy transfers from Cr3+ single ions and Cr3+-Cr3+ ion pairs to Yb3+ ions are both witnessed in LaMgAl11O19: Cr3+,Yb3+.•Phonon-assisted energy transfer mechanism is verified based on doping concentration and temperature dependent luminescence behaviors.•The phosphor is possible to convert light in region of 250–650 nm into 980 nm light to enhance solar cell efficiency. The Cr3+, Yb3+ co-doped LaMgAl11O19 spectral conversion materials have been synthesized by solid-state reaction method. The phosphor can absorb photons in UV–vis spectral region and then give intense near-infrared emission around 980 nm originated from Yb3+: 2F5/2 → 2F7/2 transition. Phonon-assisted energy transfers from Cr3+ ions and Cr3+-Cr3+ ion pairs to Yb3+ ions are both witnessed in LaMgAl11O19 host. The doping concentration and temperature dependent luminescence properties have been investigated. It is believed that Cr3+, Yb3+ co-doped LaMgAl11O19 phosphor might potentially act as spectral convertor for silicon-based solar cells to enhance the photovoltaic conversion efficiency.