Grain Boundary Perfection Enabled by Pyridinic Nitrogen Doped Graphdiyne in Hybrid Perovskite

The solution processing in hybrid perovskite films inevitably results in the formation of detrimental defects at grain boundaries (GBs) that deteriorate the optoelectronic properties and bring about severe hysteresis as well as operational instability. Here, an effective scenario to alleviate the imperfection issue at perovskite GBs via incorporating pyridinic nitrogen-doped graphdiyne (N-GDY) is proposed. Taking full advantage of periodic acetylenic linkages and introduced pyridinic N atoms, the deep-level trap states like Pb-I antisite defects and under-coordinated Pb atoms are considerably passivated, thus diminishing the undesired non-radiative recombination. Additionally, the spatial confinement coupling with electrostatic repulsion effect originated from the intrinsic 2D structure of N-GDY, has been identified to deal with the halide ion migration behavior. Such contributions are further theoretically evidenced with the charge density delocalization as well as the ion migration energy barrier elevation. The authors unprecedentedly verified the superiorities based on the flexible chemical-tailorability of atomic crystal GDY materials toward polycrystalline perovskite related energy conversion devices.

Automated summary

This study proposes an effective solution to alleviate defects at grain boundaries in hybrid perovskite films by incorporating pyridinic nitrogen-doped graphdiyne (N-GDY), which passivates deep-level trap states and reduces non-radiative recombination. The 2D structure of N-GDY also helps to address halide ion migration behavior, leading to improved performance of energy conversion devices related to polycrystalline perovskite materials.