NIR emission in Ba2SiO4:Eu2+, Nd3+ phosphors with near UV/violet excitation

New results on NIR emission in Ba2SiO4:Eu2+, Nd3+ phosphors are reported. Though excitation for Eu2+ emission is in predominantly near UV (nUV) region, that for the Nd3+ emission around 1067 nm extends into visible region covering violet and blue part of the spectrum. These results are highly significant for applications where NIR emission with nUV/blue excitation is required, e.g. for improving efficiency of c-Si solar cell, for designing NIR sources using efficient blue LEDs, etc. Energy transfer efficiencies for Eu2+→ Nd3+ energy transfer are estimated by measuring reduction of Eu2+ emission lifetime, and are close to 80%. Possible mechanisms for Eu2+→ Nd3+ energy transfer are suggested. These involve down shifting or quantum cutting.