A facile one-step method to fabricate multi-scaled solar selective absorber with nano-composite and controllable micro-porous texture

A multi-scaled structured solar selective absorber (SSA), combining micro-porous texture and ternary nano-composite (carbon-dielectric-metal), was prepared by a facile one-step method in the frame work of sol-gel process. The textured surface has a crater-like pattern ranging from 0.2 to 2μm, in which carbon-dielectric nano-composite serves as the thermal stable skeleton material to protect Cu and Cu2O particles embedded inside the matrix. Complementary structure has been demonstrated by theoretical modeling and optical characterization to enhance the optical absorptance of SSA coating. The results indicated that the one-layer SSA with a pore size of around 1.1µm presents an absorptance of about 0.8 and an emittance of about 0.08. Furthermore, the little deterioration after aging test for 50h (at 100°C in water vapor atmosphere and 500°C in vacuum) highlights an outstanding durability, implying that such multi-scaled structured film is low cost, easy to large-area product, and capable of being an excellent SSA for the low-middle temperature applications.