Formation of 2D-Layered (CH3NH3)3Sb2I9 Lead-Free Perovskite Phase from CH3NH3I and SbSI: Photodetection Activity in Carbon Based Lateral Devices

The reaction between methylammonium iodide ( $${\text{MAI}}$$ $$({\text{MA}} = {\text{CH}}_{3} {\text{NH}}_{3}^{ + } )$$ ) and antimony sulfoiodide ( $${\text{SbSI}}$$ ) in reflux conditions results in the formation of a 2D-layered perovskite phase, methylammonium antimony iodide ( $${\text{MA}}_{3} {\text{Sb}}_{2} I_{9}$$ ). X-ray diffraction $$\left( {{\text{XRD}}} \right)$$ and $${\text{UV}} - {\text{Vis}}$$ spectroscopy confirm that in reflux conditions, the reaction between $${\text{MAI}}$$ and $${\text{SbSI}}$$ in a 2:7 molar ratio (MR(2:7)) obtains the $$2D$$ -layered $${\text{MA}}_{3} {\text{Sb}}_{2} I_{9}$$ lead-free perovskite phase as the main product. The MR(2:7) $${\text{~MAI}}$$ - $${\text{SbSI}}$$ reaction product in a carbon matrix in lateral electrode configuration exhibits a relatively high difference between light and dark current $$\left( {I_{{{\text{light}}}} - I_{{{\text{dark}}}} } \right)$$ of ~ 55 µA at 1 V applied bias voltage. The better photoresponse for the MR(2:7) $${\text{MAI}}$$ - $${\text{SbSI}}$$ reaction product in the presented device configuration indicates that the lead-free 2D-layered perovskite structure ( $${\text{MA}}_{3} {\text{Sb}}_{2} I_{9}$$ ) found assistance from the carbon materials for improved photogenerated charge carrier harvesting.