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The organic insulator–metal interface is the most important junction in flexible electronics. The strong band offset of organic insulators over the Fermi level of electrodes should theoretically impart a sufficient impediment for charge injection known as the Schottky barrier. However, defect formation through Anderson localization due to topological disorder in polymers leads to reduced barriers and hence cumbersome devices. A facile nanocoating comprising hundreds of highly oriented organic/inorganic alternating nanolayers is self‐coassembled on the surface of polymer films to revive the Schottky barrier. Carrier injection over the enhanced barrier is further shunted by anisotropic 2D conduction. This new interface engineering strategy allows a significant elevation of the operating field for organic insulators by 45% and a 7× improvement in discharge efficiency for Kapton at 150 °C. This superior 2D nanocoating thus provides a defect‐tolerant approach for effective reviving of the Schottky barrier, one century after its discovery, broadly applicable for flexible electronics.

Amelioration of the mobility and, in particular, the thermal stability of a hole-transporting molecular semiconductor is a practicable strategy to attain the enhancement of both power conversion efficiency (PCE) and operational durability of perovskite solar cells (PSCs). Here a cost-effective double-[4]helicene-based molecular semiconductor (DBC-OMeDPA) is synthesized for a solution-deposited thin film, exhibiting an improved hole mobility in comparison with state-of-the-art spiro-OMeTAD control. X-ray crystallographic analysis and theoretical calculation reveal the three-dimensional molecular stacking and multidirectional hole-transporting property of DBC-OMeDPA, clarifying the microscopic mechanism of the hole-transport process. A better PCE of 22% at the AM 1.5G conditions is achieved for PSCs with DBC-OMeDPA as the hole-transporter. Moreover, PSCs using DBC-OMeDPA characteristic of an elevated intrinsic glass transition temperature of 154 °C maintain a stable PCE output for hundreds of hours at 60 °C under equivalent full sunglight soaking.

Clarifying the structural basis and microscopic mechanism lying behind electronic properties of molecular semiconductors is of paramount importance in further material design to enhance the performance of perovskite solar cells. In this paper, three conjugated quasilinear segments of 9,9-dimethyl-9H-fluorene, 9,9-dimethyl-2,7-diphenyl-9H-fluorene, and 2,6-diphenyldithieno­[3,2-b:2′,3′-d]­thiophene are end-capped with two bis­(4-methoxyphenyl)­amino groups for structurally simple molecular semiconductors Z1, Z2, and Z3, which crystallize in the monoclinic P 21/n, triclinic P1̅, and monoclinic C 2/ c space groups, respectively. The modes and energies of intermolecular noncovalent interactions in various closely packed dimers extracted from single crystals are computed based on the quantum theory of atoms in molecules and energy decomposition analysis. Transfer integrals, reorganization energies, and center-of-mass distances in these dimers as well as band structures of single crystals are also calculated to define the theoretical limit of hole transport and microscopic transport pictures. Joint X-ray diffraction and space-charge-limiting current measurements on solution-deposited films suggest the dominant role of crystallinity in thin-film hole mobility. Photoelectron spectroscopy and photoluminescence measurements show that an enhanced interfacial interaction between the perovskite and Z3 could attenuate the adverse impact of reducing the energetic driving force of hole extraction. Our comparative studies show that the molecular semiconductor Z3 with a properly aligned highest occupied molecular orbital energy level and a high thin-film mobility can be employed for efficient perovskite solar cells, achieving a good power conversion efficiency of 20.84%, which is even higher than that of 20.42% for the spiro-OMeTAD control.

Ionic organic-inorganic hybrid lead halide perovskites are prone to degrade at elevated temperatures, especially in the presence of water moisture. This grand challenge heavily impedes the outdoor application of high-efficiency...

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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.