Revealing the impact of buried interfacial nanostructure in perovskite solar cells

The buried interfacial that usually accompanied by nanoscale void defects has recently been addressed due to its adverse effect on the efficiency and lifetime of perovskite solar cells (PSCs). However, the in-depth understanding of its impact on the fundamental optoelectronic characteristics remains unexplored, especially for the quantitative analysis of efficiency reduction in terms of structural or physical parameter factors, which are challenging for experiment study. Herein, an electro-optical simulation model is established to investigate the effect of buried interfacial nanostructures on device photovoltaic performance. The energy dissipation processes related to photovoltaic parameters were quantitatively identified, in which the optical loss and charge transport loss dominate the drop in short-circuit current and fill factor, respectively, and result in performance degradation. The device optoelectronic performance is further discussed with various factors, including structural (interfacial void size and geometrical shape) and physical (carrier mobility and trap density) factors. We found that the geometrical shape rather than the size of void determines the energy dissipation mechanism, of which specific nanostructures, such as narrow ones, could normally trade off light absorption, carrier transport route, and defect density, being relatively benign to the device performance. Finally, a dielectric filling strategy is proposed to suppress the negative impact of these imperfect nanostructures, which may provide new insights towards device construction engineering for achieving efficient PSCs.