Synthesis of CuS nanoplate-containing PDMS film with excellent near-infrared shielding properties

Abstract

The selective shielding of solar light has drawn much attention for the application of innovative energy-saving windows, and a prerequisite for development is obtaining cost-efficient optical materials and coatings which can transmit visible light but cut off near-infrared (NIR) light. In the present work, we have developed low-cost CuS nanoplates as a novel kind of NIR shielding material. CuS nanoplates with a size of 150–250 nm and a thickness of about 30 nm are synthesized by a simple hydrothermal route, and they exhibit weak absorption in the visible region but strong absorption in the NIR region due to their localized surface plasmon resonances. Subsequently, CuS nanoplates are further mixed with polydimethylsiloxane (PDMS) to fabricate CuS/PDMS films. These flexible films retain good transparency in the visible region and strong absorption in the NIR region. For example, a 0.8 mm-thick CuS/PDMS film with 0.10 wt% CuS can transmit 63.0% visible light (400–780 nm) but shield 78.1% NIR light (780–2500 nm). With this film-coated glass as a window of the sealed black box, the interior air temperature of the box goes up from room temperature of 23.0 °C to ∼27.7 °C in 1500 s under the irradiation of strong solar light with an intensity of 0.5 W cm⁻², and the temperature elevation (ΔT = 4.7 °C) is much lower compared with that observed with a glass slide (ΔT = 13.7 °C) or ITO glass (ΔT = 9.3 °C) as the window under identical conditions. These facts confirm that the CuS/PDMS film can efficiently prevent the elevation of room temperature, due to its excellent NIR shielding properties. Therefore, CuS nanoplates have great potential as novel NIR shielding materials for the design and development of cost-efficient optical coatings as innovative energy-saving windows in modern buildings and vehicles.