A Thioxanthenothioxanthene-based Hole Transporter with 2D Molecular Stacking for Efficient and Thermostable Perovskite Solar Cells

Abstract

Maintaining persistent thin-film morphology under certain thermal stress is desirable for durable operation of multi-layer organic optoelectronic devices. We herein report a thioxanthenothioxanthene-centered hole-transporter (N 3 ,N 3 ,N 9 ,N 9 -tetrakis(4-methoxyphenyl)thioxantheno[2,1,9,8klmna]thioxanthene-3,9-diamine, TXTX-OMeDPA) characteristic of two-dimensional molecular stacking in a single crystal. TXTX-OMeDPA can be solution-processed into smooth thin films with suitable energy level and good hole mobility, allowing for the fabrication of perovskite solar cells with an impressive power conversion efficiency of 22.2% when measured under illumination of AM 1.5G sunlight. The remarkable morphological stability of TXTX-OMeDPA-based thin film ensures good stability for perovskite solar cells not only stored at 60 °C in the dark but also operated under equivalent full sunlight at 60 °C.

Molecularly Engineered Cyclopenta[2,1-b;3,4-b′]dithiophene-Based Hole-Transporting Materials for High-Performance Perovskite Solar Cells with Efficiency over 19%

“…42 Clearly, the close stacking interactions between the HTMs induced by the additional intermolecular S•••S interactions in the dithiolane-ring-based LYC-1 is responsible for a higher hole mobility than that of CT1. 46,47 The high hole mobility for LYC-1 is expected to promote the performance of PSCs.…”

A Triple Axial Chirality, Racemic Molecular Semiconductor Based on Thiahelicene and Ethylenedioxythiophene for Perovskite Solar Cells: Microscopic Insights on Performance Enhancement

“…[ 17 ] When the temperature is close to T g , the relaxation kinetics will be greatly accelerated, for example, crystallization is prone to occur, resulting in a serious degradation of device performance. [ 18–21 ] Therefore, several methods have been explored to boost the T g of organic semiconductors. [ 22–32 ] Experimental studies have shown that some key structure factors such as molecular weight, main‐chain rigidity, side‐chain architecture, and intermolecular π⋅⋅⋅π interactions can tailor the T g of conjugated polymers, and thus the mechanical robustness.…”

A Pyrrole-Bridged Bis(oxa[5]helicene)-Based Molecular Semiconductor for Efficient and Durable Perovskite Solar Cells: Microscopic Insights

“…For small molecular organic semiconductors, the achievement of thermostable PSCs can be generally ascribed to high T g s of some new materials. 15,19,21 Under thermal stress, the microscopic morphology of a HTL may gradually change. This may bring forth enlarged interfacial contact resistance and hole transport resistance.…”

“…For low-cost, durable PSCs it is imperative to tailor an ideal HTL with combined properties of proper energy level, large conductivity, high glass transition temperature ( T g ), and good solution-processability. The past decade has witnessed an active exploration of various hole transport materials (HTMs) for PSCs, including inorganic semiconductors, − polymeric semiconductors, − and molecular semiconductors, − some of which ,,,, have been demonstrated for over 21%-efficiency PSCs with certain durability at an elevated temperature. For small molecular organic semiconductors, the achievement of thermostable PSCs can be generally ascribed to high T g s of some new materials. ,, Under thermal stress, the microscopic morphology of a HTL may gradually change.…”

“…The past decade has witnessed an active exploration of various hole transport materials (HTMs) for PSCs, including inorganic semiconductors, − polymeric semiconductors, − and molecular semiconductors, − some of which ,,,, have been demonstrated for over 21%-efficiency PSCs with certain durability at an elevated temperature. For small molecular organic semiconductors, the achievement of thermostable PSCs can be generally ascribed to high T g s of some new materials. ,, Under thermal stress, the microscopic morphology of a HTL may gradually change. This may bring forth enlarged interfacial contact resistance and hole transport resistance.…”