Enhancing the performance of lead halide perovskite solar cells and reducing its toxicity using nanostructures

Lead-halide perovskite solar cells (PSCs) have emerged as highly promising solar cells in recent years, due to their unique optical and electrical properties. Contrarily, the use of lead as one of the contents of such cells constitutes a vital problem to the community. In this study, we suggest various nanostructured designs in the absorber layer of such cells to reduce the lead content while enhancing cell performance. Full optical/electrical simulations of the PSCs are performed for the following cases: planar, cones nanostructured, and semi-ellipsoids nanostructured solar cells. The existence of these nanostructures enhances the absorption of light and consequently the short circuit current while using the same amount of lead-halide perovskite material. These nanostructures enhance the light absorption through two ways: increasing the light trapping, due to their geometrical structure, and enhancing the coupling of the incident light to the waveguide modes in the active layer. The findings of our study show that the implementation of nanostructures enables 33% reduction in the environmentally harmful lead content while still achieving a higher short circuit current. Moreover, the incorporation of nanostructures (conical and semi-ellipsoidal) in the PSC results in enhancements of the open circuit voltage, filling factor, and consequently the power conversion efficiency. The conical structures result in 17% efficiency enhancement compared to planar PSC with an absorber thickness of 200 nm. On the other hand, the semi-ellipsoidal structures achieve a remarkable efficiency enhancement of 27% for the same planar thickness.