Skin Thermal Management for Subcutaneous Photoelectric Conversion Reaching 500 mW

Despite possessing higher tissue transmittance and maximum permissible exposure power density for skin relative to other electromagnetic waves, second near-infrared light (1000-1350 nm) is scarcely applicable to subcutaneous photoelectric conversion, owing to the companion photothermal effect. Here, skin thermal management is conceived to utmostly utilize the photothermal effect of a photovoltaic cell, which not only improves the photoelectric conversion efficiency but also eliminates skin hyperthermia. In vivo, the output power can be higher than 500 mW with a photoelectric conversion efficiency of 9.4%. This output power is promising to recharge all the clinically applied implantable devices via wireless power transmission, that is, clinical pacemakers (6-200 µW), drug pumps (0.5-2 mW), cochlear (5-40 mW), and wireless endo-photo cameras (≈100 mW).