π‐Extended Spiro Core‐Based Nonfullerene Electron‐Transporting Material for High‐Performance Perovskite Solar Cells

Abstract

Electron transport materials (ETMs) play a significant role in perovskite solar cells (PSCs). However, conventional solution processable organic ETMs are mainly restricted to fullerene derivatives and it is challenging to obtain nonfullerene ETMs with satisfactory properties. In this work, a new organic semiconductor SPS‐4F is synthesized by utilizing the classical spiro[fluorine‐9′9‐thioxanthene] unit to construct a π‐extended core. Although spiro is normally used in hole transport materials, the new spiro derivative SPS‐4F is successfully used as an ETM in inverted PSCs with power conversion efficiency over 20%. In addition, SPS‐4F can strongly coordinate with MAPbI3 perovskite and lead to efficient surface trap passivation. The resultant PSCs exhibit excellent stability in air because of the hydrophobic property of SPS‐4F. This work opens up opportunities to obtain a new family of ETMs based on spiro and paves a way to the fabrication of high‐performance PSCs with low cost.

Strategies for Large‐Scale Fabrication of Perovskite Films for Solar Cells

“…Thus, a passivation layer can be introduced to reduce the surface defects and recombination in the devices. [ 83 ]…”

“…Thus, a passivation layer can be introduced to reduce the surface defects and recombination in the devices. [83] One critical issue hindering the commercialization of PSCs is device stability. Due to the intrinsic instability of normal organic metal halide perovskite materials, the chemical composition of perovskites can be engineered for better resistance to heat and moisture.…”

A perylene diimide dimer-based electron transporting material with an A–D–A structure for efficient inverted perovskite solar cells

“…1–18 According to device architecture, PSCs can be roughly divided into inverted p–i–n and conventional n–i–p types. Generally, some advantages can be observed in inverted PSCs, including better ambient stability, 19–23 a smaller hysteresis effect, 23–26 and so on. In photovoltaic processes, the electron transport layer plays a key role in electron extraction from the perovskite layer and electron injection to the cathode.…”

Solid‐State Ligand‐Capped Metal Oxide Electron‐Transporting Layer for Efficient and Stable Fullerene‐Free Perovskite Solar Cells

“…In such inverted PSCs, the hole-transporting layer (HTL) and electron-transporting layer (ETL) that have been employed most commonly have been NiO x [2][3][4] and fullerene derivatives. [5][6][7] Although [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) is currently the most broadly used material for deposition on the perovskite to form the ETL, it is expensive, has low chemical stability, and readily aggregates under high operating temperatures, [8,9] thereby limiting the stability of PCBM-based PSCs. [10,11] N-type metal oxides (e.g., titanium dioxide [TiO 2 ], [12][13][14] tin oxide [SnO 2 ], [15][16][17] and zinc oxide [ZnO] [18,19] ) have been applied widely as ETLs in regular n-i-p-structured PSCs.…”