Synergistical Dipole–Dipole Interaction Induced Self‐Assembly of Phenoxazine‐Based Hole‐Transporting Materials for Efficient and Stable Inverted Perovskite Solar Cells

Abstract

Delicately designed dopant-free hole-transporting materials (HTMs) with ordered structure have become one of the major strategies to achieve high-performance perovskite solar cells (PSCs). In this work, we report two donor-p linkerdonor (D-p-D) HTMs, N01 and N02,which consist of facilely synthesized 4,8-di(n-hexyloxy)-benzo[1,2-b:4,5-b']dithiophene as a p linker,w ith 10-bromohexyl-10H-phenoxazine and 10-hexyl-10H-phenoxazine as donors,r espectively.T he N01 molecules form at wo-dimensional conjugated network governed by C À H•••O and C À H•••Br interaction between phenoxazine donors,a nd synchronously construct at hreedimension lamellar structure with the aid of interlaminar p-p interaction. Consequently, N01 as ad opant-free small-molecule HTM exhibits ah igher intrinsic hole mobility and more favorable interfacial properties for hole transport, hole extraction and perovskite growth, enabling an inverted PSC to achieve av ery impressive power conversion efficiency of 21.85 %.

Multifunctional anchoring of O‐ligands for high‐performance and stable inverted perovskite solar cells

“…16 In a study on the degradation of perovskite under the action of amide, Jeffrey et al demonstrated that the reduction of Pb 2+ was coordinated with amine first, and the oxidation-reduction process required the degradation of alkyl amine β-C-H bonds, revealing the interaction mechanism between amide and Pb 2+ from the chemical state. 17 The above work not only confirmed the feasibility of amide as an additive to assist in the deposition of highquality perovskite films but also revealed the significant contribution of amide additives to improve device stability. Additionally, due to the relative volatility of MA + (MA = methylammonium) cation, PSCs with MA + cation suffer from intrinsic instability at elevated temperature.…”

“…As a result, the device with 11MA delivered a champion PCE of 23.34% with outstanding ambient stability 16 . In a study on the degradation of perovskite under the action of amide, Jeffrey et al demonstrated that the reduction of Pb 2+ was coordinated with amine first, and the oxidation–reduction process required the degradation of alkyl amine β‐C‐H bonds, revealing the interaction mechanism between amide and Pb 2+ from the chemical state 17 . The above work not only confirmed the feasibility of amide as an additive to assist in the deposition of high‐quality perovskite films but also revealed the significant contribution of amide additives to improve device stability.…”

Compact Hole‐Selective Self‐Assembled Monolayers Enabled by Disassembling Micelles in Solution for Efficient Perovskite Solar Cells

“…[11][12] Recently, self-assembled monolayers (SAMs) have been applied as very effective HSLs to replace conventional organic holetransporting materials such as PTAA and PEDOT:PSS, as SAMs benefit from their easily tuned energy level alignment with perovskite, minimized parasitic absorption, sufficient stability, and facile processibility that is compatible with low-cost and scalable production. [13][14] These SAM molecules usually consist of an anchor group that can bind with the substrates, a flexible spacer to provide sufficient rotational freedom for selfassembly, and a functional head group to facilitate efficient hole extraction. [15] Through rational molecular design, an ultra-thin and efficient HSL can be robustly formed on the ITO anode in inverted PSCs.…”

Defect‐Passivating and Stable Benzothiophene‐Based Self‐Assembled Monolayer for High‐Performance Inverted Perovskite Solar Cells

“…[10][11] Recently, self-assembled monolayers (SAMs) have emerged as a class of highly effective HSLs in inverted PSCs, outperforming conventional hole-transporting materials (HTM) such as organic polymers like PTAA, PEDOT:PSS, and inorganic metal oxides like NiO x . [12][13] These SAM molecules usually consist of an anchor group, a spacer, and a head group. The anchor group of phosphonic acid or carboxylic acid can react with the hydroxy groups on the indium-tin oxide (ITO) surface to form an ultra-thin monolayer at the anode.…”