A Facile Surface Passivation Enables Thermally Stable and Efficient Planar Perovskite Solar Cells Using a Novel IDTT‐Based Small Molecule Additive

Abstract

Although perovskite solar cells (PSCs) have attracted enormous attention owing to their fascinating optoelectronic properties and solution processability, defects in PSCs, which adversely affect efficiency and stability, are still not completely resolved. Herein, a novel indacenodithieno[3,2‐b]thiophene‐based small molecule (SM) additive (IDTT‐ThCz), capable of interacting with perovskite layers, is developed. In particular, the IDTT‐ThCz, which can perform a surface passivation, is introduced into the perovskite layer to significantly suppress perovskite defects via antisolvent treatment. Furthermore, this facile surface passivation not only significantly improves the charge extraction capability, but also prevents perovskite degradation. The IDTT‐ThCz‐treated PSCs exhibits a power conversion efficiency (PCE) of 22.5% and retains 95% of its initial PCE after 500 h storage under thermal condition (85 °C), representing the most remarkable efficiency as well as stability among the SM additives reported to date.

Unraveling Passivation Mechanism of Imidazolium-Based Ionic Liquids on Inorganic Perovskite to Achieve Near-Record-Efficiency CsPbI2Br Solar Cells

“…Recently, common surface passivators including Lewis bases/acids, organic halide salts, polymers, fullerenes, and their derivatives have been used to passivate the defects of perovskite film [ 11 – 15 ]. Among them, most Lewis bases/acids, organic halide salts and polymers possess insulating properties and could hinder efficient carrier extraction at the interface owing to their poor conductivity, and negatively affect the reproducibility of PSCs due to a distribution in molecular weights [ 16 ]. The fullerenes and their derivatives such as PCBM require many steps for synthesis, are expensive, and exhibit low yields [ 17 , 18 ].…”

“…Lewis bases/acids, organic halide salts and polymers possess insulating properties and could hinder efficient carrier extraction at the interface owing to their poor conductivity, and negatively affect the reproducibility of PSCs due to a distribution in molecular weights [16]. The fullerenes and their derivatives such as PCBM require many steps for synthesis, are expensive, and exhibit low yields [17,18].…”

Roles and Impacts of Ancillary Materials for Multi‐Component Blend Organic Photovoltaics towards High Efficiency and Stability

“…Meanwhile, indaceno [1,2-b : 5,6-b']dithiophene (IDT)-based polymers have planar and rigid structures, which enable strong intermolecular interactions between polymer chains. [105] IDT-based polymers retain their morphology at high temperatures [106] and are strong candidates for polymer additives. Yang et al employed an IDTbased polymer (1 wt % PZ1) in the PM6 : BTTT-2Cl blend and observed the suppressed crystallization of BTTT-2Cl by GIWAXS analysis (i. e., no crystallite peak in BTTT-2Cl film treated for 24 h at 150°C).…”

Methylthiophene terminated D–π–D molecular semiconductors as multifunctional interfacial materials for high performance perovskite solar cells

“…21,35 Therefore, much effort has been devoted to developing interfacial materials with semiconducting properties that can simultaneously passivate defects and improve interfacial hole extraction. [36][37][38][39] For instance, Li et al reported a pyrene based two-dimensional molecule SMe-TATPyr incorporating thiophene and methylthio functionalized triphenylamine as a bifunctional interfacial material to address the above mentioned issues, achieving a PCE of 22.3%. 40 Recently, a dithienopyrrolobenzothiadiazole (DTPBT) based hole transporting interfacial layer was employed by Wang et al to passivate defects via Pb-N/S interactions and slow down the generation of the d phase.…”