Interfacial Bridge Using a cis‐Fulleropyrrolidine for Efficient Planar Perovskite Solar Cells with Enhanced Stability

Abstract

Fullerene derivatives, especially after purposely functionalization, have potential to efficiently passivate interfacial defects between perovskites and electron transport layers. In this work, a fullerene derivative with amine functional group, 2,5‐diphenyl C60 fulleropyrrolidine (DPC60), is synthesized and employed as an interfacial layer between a perovskite and SnO2 in planar perovskite solar cells (PSCs). The cis‐configuration and the specific amine group of DPC60 effectively enhance the chemical interaction between the perovskite and DPC60, promoting the passivation of perovskite defects at the interface. The suitable energy level of DPC60 and the improved conductivity of the SnO2/DPC60 film facilitate the electron extraction from the perovskite layer. As a result, PSCs incorporated with DPC60 reach a PCE of 20.4% with high reproducibility, which is much higher than that of the bare SnO2 based devices (18.8%). Furthermore, the hydrophobic DPC60 layer suppresses heterogeneous nucleation and improves the crystallinity of the perovskite film, resulting in better device stability, retaining 82% of its initial efficiency after 200 h of 1 sun continuous irradiation and thermal ageing (55 ± 5 °C).

Tin Oxide Electron‐Selective Layers for Efficient, Stable, and Scalable Perovskite Solar Cells

“…Image for “DPC 60 ”: Reproduced with permission. [ 261 ] Copyright 2019, Wiley‐VCH. Image for “Polystyrene”: Reproduced with permission.…”

Applications of Self‐Assembled Monolayers for Perovskite Solar Cells Interface Engineering to Address Efficiency and Stability

“…[121] They discovered imbalance charge transfer at perovskite interfaces, which caused hysteresis, and reported C 60 -SAM modified interfaces with reduced hysteresis (from 13.54% to 4.6%) and additional PCE improvement of 20.54%. Functionalized fullerenes based on 2,5-diphenyl C60 fulleropyrrolidine (DPC60) have also been employed by Tian et al [125] to passivate defects by chemical interaction with the perovskite. This improves the device performance from 18.8% to 20.4% and stabilized 82% of its efficiency for 2 h under 1 sun irradiation at 55 °C.…”

“…Functionalized fullerenes based on 2,5‐diphenyl C60 fulleropyrrolidine (DPC60) have also been employed by Tian et al. [ 125 ] to passivate defects by chemical interaction with the perovskite. This improves the device performance from 18.8% to 20.4% and stabilized 82% of its efficiency for 2 h under 1 sun irradiation at 55 °C.…”

Perovskite Passivation Strategies for Efficient and Stable Solar Cells

“…[ 51 ] Energy‐level matching with organic molecules is important in the passivation of perovskite GBs. [ 137,138 ] Once organic molecules are doped into perovskite, the P/N junction is formed and the energy offset between the molecules and perovskite crystal plays a substantial role in trap‐state passivation and intergrain carrier transport. Organic molecule and halide ions in perovskite can be combined to form the Lewis adducts [ 139–141 ] or halide‐fullerene radical [ 142 ] to passivate Pb‐I antibit defect.…”

“…[51] Energy-level matching with organic molecules is important in the passivation of perovskite GBs. [137,138] Once organic molecules are doped into perovskite, the P/N junction [97] FACl FAPbI 3 1.04 18.9 68 13.37 N/A 2015 [119] FACl FAPbI 3 1.01 22.3 77.4 17.4 N/A 2017 [105] MACl MAPbI 3 1.06 21.87 75 17.22 N/A 2016 [120] MACl FAPbI 3 1.08 23.13 77 19.16 92% of initial PCE after 1000 h stored in nitrogen-filled glove box 2017 [121] EAI 2019 [158] PEA 2018 [160] MDACl [153] is formed and the energy offset between the molecules and perovskite crystal plays a substantial role in trap-state passivation and intergrain carrier transport. Organic molecule and halide ions in perovskite can be combined to form the Lewis adducts [139][140][141] or halide-fullerene radical [142] to passivate Pb-I antibit defect.…”