Nonfullerene Agent Enables Efficient and Stable Tin‐Based Perovskite Solar Cells

Abstract

Tin‐based perovskites have emerged as the most promising lead‐free perovskite materials due to the characteristics of the environmentally friendly and more suitable bandgap. However, the power conversion efficiency still lags behind the lead perovskite owing to unfavorable defects of the perovskite film and poor interface contact between tin perovskite and electron transporting layers. Herein, an n‐type conjugated nonfullerene molecule, termed IO‐4Cl, is developed for efficient and stable tin perovskite solar cells (TPSCs). The IO‐4Cl possesses electron‐donating functional groups that can enlarge grain size and passivate defect states of perovskite films through Lewis acid–base interactions. Besides, the IO‐4Cl exhibits an appropriate lowest unoccupied molecular orbital level and interface‐modification ability, enabling superior electron extraction and transport ability of TPSCs. More importantly, the hydrophobic characteristic of IO‐4Cl prevents the decomposition of perovskite films under moisture conditions, improving the moisture stability of TPSCs. Consequently, the TPSCs with IO‐4Cl achieve a champion efficiency of 11.49% with an open‐circuit voltage increase of 100 mV, and excellent moisture stability under ambient air condition with 30% relative humidity, without encapsulation. The work provides a new inspiration for the introduction of functional nonfullerene materials to obtain highly efficient and stable TPSCs.

Ligand Engineering in Tin-Based Perovskite Solar Cells

“…Recently, Wu et al introduced a conjugated non-fullerene molecule (IO-4Cl) with n-type semiconductor property into Sn-based perovskites, where the C=O group could establish strong bonds with Sn 2+ to regulate grain growth and passivate defects. Besides, due to the appropriate lowest unoccupied molecular orbital level and interface modification ability, IO-4Cl enabled superior electron extraction and transport ability of Sn-based perovskites [80].…”

Halogen substitution of perinone-based cathode interfacial materials for high-efficiency inverted perovskite solar cells

“…28 Cao et al designed an n-type molecule called IO-Cl for the interface between tin-based PSCs and C 60 , which passivated surface defects and prevented the decomposition of the PSCs due to its hydrophobicity. 29 Although some of them are easily synthesized and some can improve device stability, the device efficiency is still far behind that of devices with fullerene derivatives.…”

Simulation Design of Novel Non-Fluorine Polymers as Electron Transport Layer for Lead-Free Perovskite Solar Cells

“…Designing a non-fullerene-based (NFA) electron transport layer might potentially overcome the drawbacks of the fullerene-based electron transport layer. The stability, tuneability, and optical absorption can all be improved by easily adjusting the chemical molecular structure, highest occupied molecular orbital (HOMO), and lowest unoccupied molecular orbital (LUMO) of a non-fullerene-based electron transport layer over a reasonably wide range [23][24][25]. The design of NFAs that are reported often falls into one of two categories.…”