Eco-friendly small molecule with polyhydroxyl ketone as buried interface chelator for enhanced carrier dynamics toward high-performance perovskite solar cells

Abstract

Buried interface defects pose a significant challenge to achieving high efficiency and stability of n-i-p perovskite solar cells (PSCs). A multifunctional material is essential for passivating interface defects, suppressing non-radiative recombination, and facilitating rapid carrier transfer at these interfaces. Herein, a new multifunctional eco-friendly small molecule, D-fructose, was introduced into the interface as a modification layer, playing a significant role in passivating defects not only among SnO₂ quantum dots (QDs), but also between perovskite and SnO₂ QDs. The coordination bonds of the C=O group with Pb²⁺ and Sn⁴⁺/Sn²⁺, along with the hydrogen bonds of the –OH group with I⁻ in perovskite, contribute to this passivation process. Meanwhile, this multifunctional collaboration at the buried interface not only triggers uniform heterogeneous nucleation across the perovskite precursor film, leading to high-quality perovskite, but also effectively eliminates residual PbI₂ at grain boundaries to suppress perovskite degeneration. Achieving a more suitable energy level alignment between perovskite and SnO₂ QDs can smooth the interface barrier, thereby facilitating the formation of an electron bridge for rapid electron extraction and transfer. Consequently, the D-fructose based PSC has achieved a champion efficiency of 24.91% with negligible J-V hysteresis, along with excellent stability.