Polymer-like Photochromic Tungsten Oxide Sub-1 nm Nanowires

Photochromic materials are promising in optical information storage, nonlinear optics, nonemissive displays, smart windows, etc. Photochromic transition metal oxides have significant advantages in stability and cost but are limited by poor processability. Herein, tungsten oxide sub-1 nm nanowires (TOSNWs) with a diameter of 0.8 nm and a length of several microns are synthesized by a solvothermal method. The extremely high aspect ratio endows them with polymer-analogous properties and good processability. The as-prepared TOSNWs exhibit a transmittance >95% in the visible light region, a rapid photochromic response within 15 s, and show broad near-infrared absorption after photochromic transformation, which are potential candidates as light-triggered transparent heat ray shielding materials.