Al kα radiation

The optical microscope images were captured by a Nikon (AZ100M) optical microscope equipped with a CCD camera. The photochromic images under daylight and photoluminescence images under the excitation of 365 nm UV lamp were taken by a CCD camera (Nikon D7100, Japan). A mobile phone with a commercial APP official QR code Reader was used for QR code recognition (Supplementary video 1). The transmission spectra of tungsten phosphate glass samples before and after photochromism were measured by the U-4100 spectrophotometer. The luminescence and excitation spectra of tungsten phosphate glass were measured by the HITACHIU-F-7000 spectrophotometer using Xe lamp as the light source. An Edinburgh FLS 980 instrument (Edinburgh Instruments Ltd., Livingston, UK) was used to measure the lifetime decay of the glasses. The chemical states of tungsten phosphate glass were characterized by XPS (200 W) with Al Kα radiation (Thermo Fisher Scientific) under vacuum conditions. For the Raman spectra measurement of the samples, the Argon laser with continuous wave (λ = 514 nm) was used as the excitation source. The Bruker model ELEXSYS-IIE500 spectrometer (Bruker, Switzerland) was used to measure the EPR spectra at room temperature. The element distribution was detected by a Zeiss sigma 300 scanning electron microscope with an energy-dispersive X-ray spectrometer (SmartEDX).

XRD patterns were collected using Bruker D8 advance equipment (Cu K_α radiation). XPS spectra were recorded using Al K_α radiation (Thermo Scientific, USA). TEM and HR-TEM images were collected using JSM-2100 (JEOL, Japan). The ultraviolet–visible (UV–Vis) DRS of powder samples were collected using an Evolution 220 spectrophotometer (Thermo Fisher Scientific, UK). Tauc’s plots were used to determine the materials band gap. Nitrogen adsorption–desorption isotherms were determined using Quantachrome (USA, at 77 K). Pore size distribution (PSD) was determined using the Barrett-Joyner-Halenda (BJH) method.