Evolution of Photovoltaic Performance in Fully Printable Mesoscopic Carbon-Based Perovskite Solar Cells

Hole-conductor-free carbon-based perovskite solar cells (C-PSCs) are a promising candidate for commercialization due to low cost, simple, and industry applicable fabrication methods. However, when measuring the photovoltaic parameters of these cells, they do not achieve their maximal performance immediately following their fabrication, but rather require a certain maturation period. Herein, the natural and induced changes that occur in C-PSCs are studied after their fabrication is complete. It is observed that the current density increases by natural maturation, and the open-circuit voltage increases by light-soaking treatment. Using charge extraction, intensity-modulated photovoltage spectroscopy, and voltage decay measurements during the three steps of maturation, it is possible to observe some changes in crystallization and surface traps, which are the cause for the evolution in the photovoltaic parameters. Moreover, in the case of two-step deposition, the cells achieve their final performance already as fresh cells in contrast to the case of one-step deposition cells. The conclusions offer practical information regarding the preparation and optimal measurement conditions of C-PSCs as well as possible prospects for the improvement and optimization of this cell type.