Simulation based Investigation of Inverted Planar Perovskite Solar Cell with All Metal Oxide Inorganic Transport Layers

Due to simpler fabrication process and low temperature processability beneficial for flexible and tandem structures, planar architectures (n-i-p and p-i-n) are gaining popularity in organic-inorganic lead halide perovskite solar cell (PSC) research fields. For p-i-n or inverted planar cells, mostly studied charge transport materials are organic, which suffer from poor conductivity, poor chemical stability and higher processing cost. This is leading towards growing interest of using solution processed inorganic metal oxide transport layers which can easily overcome the shortcomings of organic counterparts upto certain extent. In this work, a simple but comprehensive ID simulation based study of inverted planar PSC is presented using all-metal oxide transport layers. Three different electron transport materials (ETM), TiO2 (most popular for mesoscopic and n-i-p structures), ZnO and SnO2 are comparatively studied for the same hole transport material (HTM), NiOx in Methyl Ammonium Lead Iodide, CH3NH3PbI3 based PSC structure. Detailed analysis are performed for open circuit voltage (Voc), short circuit current (JSC), fill factor (FF) and power conversion efficiency (PCE) considering the variation of perovskite layer thickness, bulk defect densities and ETM-perovskite interface states. It is found that, cells with ZnO show better PCE and Jsc for almost all situations because of having higher carrier mobility and optical absorption, whereas owing to better band alignment, SnO2 based cells provide enhanced Voc, FF and more robustness to the interface state variations. Thus this work provides a thorough investigation of the interfacial layer properties on the performance of inverted planar PSC in all metal oxide inorganic transport layer environment.