Synthesis of one-dimensional potassium tungsten bronze with excellent near-infrared absorption property

Potassium tungsten oxide nanofibers were successfully synthesized via a facile hydrothermal reaction route in the presence of sulfate. After reduction under a reductive atmosphere of H₂(5 vol %)/N₂, the potassium tungsten oxide transformed to potassium tungsten bronze. Because of the lack of free electrons, the potassium tungsten oxide (K_xWO _3+x/2) showed no NIR shielding performance; however, the potassium tungsten bronze (K_xWO₃) showed promising optical characteristics such as high transmittance for visible light, as well as high shielding performance for near-infrared lights, indicating its potential application as a solar filter. Meanwhile, the potassium tungsten bronze (K _xWO₃) showed strong absorption of near-infrared light and instantaneous conversion of photoenergy to heat.