From Linear to Angular Isomers: Achieving Tunable Charge Transport in Single‐Crystal Indolocarbazoles Through Delicate Synergetic CH/NH⋅⋅⋅π Interactions

Abstract

Weak intermolecular interaction in organic semiconducting molecular crystals plays an important role in molecular packing and electronic properties. Here, four five-ring-fused isomers were rationally designed and synthesized to investigate the isomeric influence of linear and angular shapes in affecting their molecular packing and resultant electronic properties. Single-crystal field-effect transistors showed mobility order of 5,7-ICZ (3.61 cm V s ) >5,11-ICZ (0.55 cm V s ) >11,12-ICZ (ca. 10 cm V s ) and 5,12-ICZ (ca. 10 cm V s ). Theoretical calculations based on density functional theory (DFT) and polaron transport model revealed that 5,7-ICZ can reach higher mobilities than the others thanks to relatively higher hole transfer integral that links to stronger intermolecular interaction due to the presence of multiple NH⋅⋅⋅π and CH⋅⋅⋅π(py) interactions with energy close to common NH⋅⋅⋅N hydrogen bonds, as well as overall lower hole-vibrational coupling owing to the absence of coupling of holes to low frequency modes due to better π conjugation.

Organic‐Inorganic Hybrid Perovskite Single Crystals: Crystallization, Molecular Structures, and Bandgap Engineering

“…Because single crystals have nearly perfect structures and minimum concentration of structure imperfections (i. e., grain boundaries) and impurities, which decrease the charge trapping and scattering and improve the intrinsic properties. [35][36] Recent studies indicate that organicinorganic hybrid perovskites single crystals, compared with its polycrystalline films, possess much better optoelectrical properties. [12,37] This is because that the long carrier diffusion length allows the photogenerated charge carriers to be completely extracted from perovskite single crystals with an active layer thickness much larger than thin-film analogs, which is very desirable for both photovoltaic and photodetection applications.…”

Strong Enhancement of π‐Electron Donor/Acceptor Ability by Complementary DD/AA Hydrogen Bonding

“…To examine the electrical properties of the complexes, we fabricated bottom‐gate bottom‐contact OFETs by laminating single co‐crystals on n ‐octyltrichlorosilane‐modified Si/SiO 2 (500 nm) substrates with pre‐patterned Au electrodes of channel lengths 5 and 20 μm (Figure S24). Surprisingly, with no homogenous hole transport channel (that is, no continuous π‐overlap of the donor), IC–AceNap exhibited a typical p ‐type field‐effect behavior with a hole mobility μ + up to 0.002 cm 2 V −1 s (on/off ratio ≈10 3 , Figures a and S25), which is two orders of magnitude higher than that of the single crystal OFET of IC itself (μ + ≈10 −5 cm 2 V −1 s) . The observed charge transport in mixed‐stack crystals can likely be attributed to the superexchange mechanism .…”

Patterning 2D Organic Crystalline Semiconductors via Thermally Induced Self‐Assembly

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] To date, 2DOCS-based field-effect transistors (FETs) have experienced impressive mobility enhancement; [17][18][19] the charge-carrier-transport and injection physics have also been explicitly elucidated. [20][21][22] These fascinating breakthroughs have thus greatly motivated performance optimization of tremendous organic functional devices, including transistor memories, [23,24] photodetectors, [25,26] light-emitting diodes, [27] and biosensors. [28,29] To further expand the practical application of available 2DOCSs to cost-effective, high-throughput manufacturing functional devices and integrated circuits, patterning of 2DOCSs, which has never been experimentally demonstrated, is undoubtedly an essential prerequisite.…”