Photoinduced degradation of thermally stable Cs2AgBiBr6 double perovskites by micro-Raman studies

The thermal stability of lead-free double perovskite Cs2AgBiBr6 for stable optoelectronic and photovoltaic devices is essential. There are contradicting reports, with some claiming stability from 300 to 400 degrees C based on X-ray diffraction and thermogravimetry studies and others up to 250 degrees C from Raman studies for Cs2AgBiBr6. We perform thermogravimetry analysis and temperature-dependent Raman studies with different laser intensities and show that Cs2AgBiBr6 is thermally stable up to similar to 410 degrees C. A low power (3.68 mW) laser excitation source does not induce any structural changes at all temperatures. On the contrary, higher power laser light (7.15 mW) decomposes Cs2AgBiBr6 to Cs3Bi2Br9 at temperatures beyond 180 degrees C. Meticulous thermogravimetry, Raman, and X-ray diffraction studies confirm that Cs2AgBiBr6 is structurally stable up to 410 degrees C, whereas its stability decreases under light exposure beyond a certain critical intensity. This study brings out the importance of light and thermal stability of Cs2AgBiBr6, which is crucial for designing various optoelectronic devices.

Automated summary

This study investigates the thermal stability of lead-free double perovskite Cs2AgBiBr6 for optoelectronic and photovoltaic devices. It confirms that Cs2AgBiBr6 is thermally stable up to 410 degrees C, but its stability decreases under light exposure beyond a certain critical intensity.