Bitam A, Fartas R, Diaf M, Boubekri H, Cheddadi A, Martin I R
University of Tamanghasset, Tamanghasset, Algeria.
Laser Physics, Optical Spectroscopy and Optoelectronics Laboratory, Badji Mokhtar Annaba University, Annaba, Algeria.
Luminescence. 2025 Jan;40(1):e70102. doi: 10.1002/bio.70102.
Er-doped BaF single crystals were investigated with two primary aims: first, to probe the infrared emissions from the I level (around 1.0 μm) under 1500-nm excitation and, second, to use the crystal to enhance the efficiency of silicon-based solar cells through upconversion mechanism. Upon excitation at 1500 nm, the upconversion emission spectrum of the Er-doped BaF single crystals, recorded in the range of 480-1080 nm, exhibited two well-structured visible bands at 538 and 650 nm, along with a strong near infrared emission at 971 nm. This strong 971-nm emission has an emission cross-section of approximately 0.23 × 10 cm. As with any phenomenon inherent to energy transfer by upconversion, the I fluorescence decay exhibits a rise time followed by a long decay of approximately 15 ms and a positive optical gain from the low values of the population inversion coefficient, which could potentially give rise to laser emission from this level. When we place our crystal on a photovoltaic device illuminated by 1500-nm wavelength radiation, we record a photocurrent of 300 μA at an illumination power of 85 mW. This indicates that the Er-doped BaF crystal is highly suitable for significantly enhancing the efficiency of silicon-based solar cells.
