Dark And Photoconductivity Behavior of CH3NH3PbI3 Thin Films Depending On Atmospheric Conditions

Methylammonium lead iodide (MAPbI3) (CH3NH3PbI3) has great potential for several fields, especially for photovoltaic applications. Unfortunately, MAPbI3 can seriously suffer from degradation. Hence, the degradation problem limits the photovoltaic and other potential applications of this material. In order to produce a stable photovoltaic material, the degradation mechanism and electronic defect profile of MAPbI3 should be understood carefully, especially regarding its conductivity. In this study, electronic defect changes due to stress factors were evaluated. MAPbI3 films were deposited using thermal chemical vapor deposition (Thermal CVD) and spin coating techniques. Morphological differences due to deposition temperatures were defined by using scanning electron microscopy (SEM). Elemental analysis and structural analysis were conducted by energy-dispersive X-ray spectroscopy (EDS) and X- ray diffraction (XRD), respectively. Deposited MAPbI3 films were exposed to in-situ stress factors such as vacuum atmosphere, deionized water vapor (DIWV) atmosphere, and UV light soaking at constant temperature (300 K) in order to define degradation and electronic defect changes. The electronic changes in the samples were investigated by time-dependent dark conductivity, temperature-dependent dark conductivity, and flux-dependent photoconductivity. This study provides an in-depth understanding of the degradation mechanism and electronic defect profile of MAPbI3 regarding its conductivity.