Numerical simulation and light trapping in perovskite solar cell

A methyl ammonium lead iodide (H3NH3PbI3)-based solar cell can have photovoltaic conversion efficiency of more than 20%, primarily because the material shows lower defect density, high carrier mobility-lifetime, and broader absorption spectra. A further improvement in device efficiency can be obtained using light capture and trapping schemes, with textured front surface and back reflector. In order to understand characteristic performance of the device, we used numerical simulation and observed that more than 20% device efficiency can be obtained if defect density of the photosensitive material remains lower than 4 x 10(14) cm(-3) and thickness 400 nm or more. Investigation of light trapping scheme shows that the current density (J(sc)) can be raised with this scheme, but the most effective increase in the J(sc) can be observed for 97-nm thick active layers. Reverse saturation current density of these cells that may be directly related to recombination loss of photogenerated carriers, remains low, but increases linearly with the defect density. A tandem cell with pyramidally textured front surface was investigated with such a perovskite-based top cell and Si heterojunction bottom cell; it shows an efficiency of as high as 29.5%. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)