Ultrablack, Harsh‐Condition‐Resistant Micro‐Pyramid Graphite Array for Solar Energy Harvesting and Conversion

ABSTRACT Efficient solar energy utilization demands high‐absorption materials that are low‐cost, easy to fabricate, and harsh‐condition‐resistant. Herein, the micro‐pyramid graphite array (GA) is fabricated by nanosecond laser etching followed by surface modification with the antireflection layer. The optimized GA exhibits a high solar absorbance of 99.3% and good omnidirectional broadband absorption. The superblackness is ascribed to several combined effects, including: the light‐trapping effect of micro‐pyramid cones, the enhancement of localized electric field around submicron/nano‐wrinkles, as well as the reduced interfacial reflection via a low‐refractive‐index polymer coating. With its superior thermal stability, the GA can convert the high‐irradiance light into heat, reaching the surface equilibrium temperature of 300°C under 10‐sun irradiation. The GA‐enhanced thermoelectric generator significantly increases the output power density to 20 mW cm ⁻² under 10‐sun irradiation, which outperforms the reported organic ultrablack materials. The GA may be a promising photothermal converter under harsh operation conditions.