No 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.

The application of exotic conjugated skeletons in organic semiconductors is alluring due to the topology related optoelectronic peculiarity. In this paper we explore the design of molecular semiconductors starting from...

Due to the amorphous nature and overly low carrier density of intrinsic organic semiconductors, doping either by accident or on purpose is a feasible strategy to achieve sufficiently high carrier density as well as charge mobility. We herein design and synthesize a structurally simple dithienopyrrole-based molecular semiconductor. Mixed with the thermally stable acid salt 4-tert-butylpyridinium bis­(trifluoromethanesulfonyl)­imide, the resultant air-doped composite presents a hole density of 2.4 × 1018 cm–3, a hole mobility of 9.3 × 10–4 cm2 V–1 s–1, an electrical conductivity in excess of 100 μS cm–1, and, in particular, a glass transition temperature of 110 °C as well as low gas permeation coefficients. These critical quality factors allow us to fabricate perovskite solar cells with 21.8% efficiency at the AM1.5G conditions, which also maintain 86% of the initial efficiency after 1000 h of aging at 85 °C.

Due to the extremely low intrinsic carrier density and disordered nature of organic semiconductor thin films, unintentional or intentional chemical doping is inevitable for sufficiently high carrier density and charge mobility unless charges are either injected from appropriate electrodes or by photoexcitation. However, doping often results in a reduction in thermal tolerance. The charge transport layers for thermostable perovskite solar cells (PSCs) need to possess a heat‐resistant morphology and to suppress the diffusion of volatile species. Here the authors report a molecular semiconductor with a molecular mass of >2000 Daltons but free of any flexible side chains. Its air‐doped composite with thermally stable acid salt exhibits an electrical conductivity of over 50 μS cm−1 and a glass transition temperature of 142 °C. Molecular dynamics simulations reveal that molecules and ions in this composite do not experience significant translational motion even at 150 °C. These unusual features allow for the fabrication of 21.5%‐efficiency PSCs that can withstand 200 h at 100 °C.