Elucidating the temperature-dependent structural and optoelectronic properties of Ag4V2O7 microhexagons

• Silver pyrovanadate (Ag 4 V 2 O 7 ) has temperature-dependent structural and optoelectronic behavior. • Ag 4 V 2 O 7 is stable at low-temperatures, but undergoes phase transformation at high-temperatures. • An irreversible phase transition from Ag 4 V 2 O 7 to β -AgVO 3 is induced at high laser excitation power. • Anisotropic characteristics in Ag 4 V 2 O 7 enable thermo-responsive optical modulation and directional electronic transport. Silver pyrovanadate (Ag 4 V 2 O 7 ) microhexagons were synthesized by coprecipitation and characterized to investigate their temperature-dependent structural and optoelectronic properties. The information framework was obtained by powder X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, UV-visible spectroscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy, and is discussed in detail throughout this article. In summary, the data indicated that the orthorhombic phase ( Pbca space group) of Ag 4 V 2 O 7 with microhexagonal morphology and 2.15 eV band-gap was produced, maintaining the synthesis conditions at 298 K. The Ag 4 V 2 O 7 phase undergoes a complete and irreversible phase transition to the monoclinic β -AgVO 3 phase when exposed to laser excitation power ≥ 6.16 m W. Additionally, two exothermic events were identified at 543 and 658 K, corresponding to the parallel formation of vanadium oxide and the subsequent melting of this material, respectively. In contrast, the material demonstrated good structural stability at low temperatures (135 - 300 K). Upon cooling back to room temperature (298 K), the sample recrystallized as a mixture of Ag 4 V 2 O 7 and vanadium oxide. Furthermore, the structural robustness and thermal responsiveness exhibited by Ag 4 V 2 O 7 microhexagons complement the database on this ceramic material with innovative insights, in addition to making it a strong candidate for advanced optoelectronic devices.