A collaboration between researchers from Donghua University in Shanghai, China and Max Planck Institute for Colloids and Interfaces in Potsdam, Germany has developed photovoltaic cells that can be used to recharge batteries in implanted devices by shining a near infrared laser beam through the skin.
They use rare earth upconverting nanophosphors to absorb 980 nm laser light and then emit visible luminescence which can subsequently excite traditional solar cells to produce electricity.
In their work, the research team determined that, under the irradiation of a 980-nm laser with a power of 1W, the visible up-converting luminescence of rare-earth nanophosphors can be efficiently absorbed by the dyes in 980LD-PVCs so that they exhibit a maximal output power of 0.47 mW.
In particular, after being covered with 1 to 6 layers of pig intestines (thickness: ca. 1mm per layer) as a model of biological tissues, 980LD-PVCs still possess a maximal output power of between 0.28 and 0.02 mW, which is efficient enough to drive many kinds of biodevices.
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Abstract in Advanced Functional Materials: 980-nm Laser-Driven Photovoltaic Cells Based on Rare-Earth Up-Converting Phosphors for Biomedical Applications