Facile synthesis of monoclinic CsPbBr3 - for promising photovoltaic characteristics

In the work presented here, we optimize the synthesis condition to obtain monoclinic CsPbBr3 which is challenging and exhibit promising photovoltaic characteristics. Monoclinic CsPbBr3 was obtained successfully using simple and low cost precursors digested at 150°C for different duration of time in a hydrothermal synthesis process. X-ray diffraction studies showed that the tetragonal phase CsPb2Br5 was more stable for up to 8 h with only minor amount of monoclinic phase. However, for a duration of 10 h had monoclinic CsPbBr3 as a major phase along with tetragonal CsPb2Br5. Further, absorption spectrum recorded for up to 8h sample showed a strong peak at 286 nm which is due to CsPb2Br5. Whereas, the 10 h sample shows a distinctive absorption around 337 nm. Further, under UV illumination, the sample emitted a bright green radiation which is in clear correlation with previous literature reports. Also the absorption spectrum recorded for both the Ultraviolet illuminated and un-illuminated sample showed no change in the absorption wavelength which lies around 337±5 nm proving stability of the sample.