Enhancement of light harvesting efficiency of perovskite solar cells by using one-dimensional photonic crystals.

We present methyl-ammonium lead iodide perovskite solar cells coupled with one-dimensional photonic crystals (PCs) to achieve enhancement in light harvesting and photocurrent efficiencies. The introduction of PCs as a light reflection layer in the solar cells attributes to the increase in light harvesting efficiency and photocurrent density, which can be tuned by controlling the PC parameters such as the number of layers and layer thickness. Another important feature of the design is the introduction of a thin Au/Ag layer on top, which lets through more than 70% sunlight incident on it into the device, protects the hole transporting layer, and also helps in containing the light reflected from the PC layer into the device for further harvesting. The effects of layer thickness of the perovskite, hole transporting, and metallic contact layers on solar absorption enhancement and photocurrent density are also studied to achieve high power conversion efficiencies. We propose the optimum structural parameters of the considered solar cell structures, which provide the required guidance and also give further opportunities in the design of organo-metal halide perovskite solar cells coupled with PC structures.