In printed electronics, the drying semiconductor solution undergoes a solution-to-solid phase transformation that must yield optimal microstructure and performance. In small-molecule organic ...fieldeffect transistors (OFETs), it is crucial to yield films with large area lamellar coverage with excellent inplane p-stacking. Aram Amassian and co-workers present new methodology and insight, which help to ensure that the drying solution crystallizes in optimal ways to promote carrier transport in OFETs.
The cycloaromatization of acyclic enediynes typically requires very high temperatures (>160 °C) and dilute conditions to proceed in a synthetically useful yield. These conditions hinder reaction ...throughput, inhibiting the use of this reaction for the large-scale production of materials. The reaction of sodium telluride with acyclic arenediynes yields the corresponding tellurepine, which under gentle heating extrudes Te° to yield the cycloaromatization product. We have developed conditions that form sodium telluride from inexpensive tellurium metal in situ, and that also perform the desilylation of silylated arenediynes in the same process. Under our conditions, we are able to perform desilylation and cycloaromatization at temperatures as low as 40 °C and on a scale as large as 5 g in standard laboratory glassware.
Abstract
Triplet population dynamics of solution cast films of isolated polymorphs of 6,13‐bis(triisopropylsilylethynyl) pentacene (TIPS‐Pn) provide quantitative experimental evidence that triplet ...excitation energy transfer is the dominant mechanism for correlated triplet pair (CTP) separation during singlet fission. Variations in CTP separation rates are compared for polymorphs of TIPS‐Pn with their triplet diffusion characteristics that are controlled by their crystal structures. Since triplet energy transfer is a spin‐forbidden process requiring direct wavefunction overlap, simple calculations of electron and hole transfer integrals are used to predict how molecular packing arrangements would influence triplet transfer rates. The transfer integrals reveal how differences in the packing arrangements affect electronic interactions between pairs of TIPS‐Pn molecules, which are correlated with the relative rates of CTP separation in the polymorphs. These findings suggest that relatively simple computations in conjunction with measurements of molecular packing structures may be used as screening tools to predict a priori whether new types of singlet fission sensitizers have the potential to undergo fast separation of CTP states to form multiplied triplets.
Metal contacts are known to impact the crystallization behavior of solution‐processed organic semiconductors (OSCs) with important implications for the performance of thin film transistors. Now, A. ...Amassian and co‐workers show on page 2371 that migrating to blade‐coating drama tically changes the crystallization behavior of OSCs and OSC:polymer blends as compared with spin‐coating, indicating that different crystallization behaviors may be operant in these solution‐coating methods.
Correction for 'Large-area printed low-voltage organic thin film transistors
via
minimal-solution bar-coating' by Sujin Sung
et al.
,
J. Mater. Chem. C
, 2020,
8
, 15112-15118, DOI:
...10.1039/D0TC03089A
.
Herein, we report on the fabrication of large-area printed low-voltage organic thin film transistor arrays
via
minimal-solution bar-coating. We established the bar-coating of the chemically ...cross-linked polymer dielectric based on poly(4-vinylphenol) and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride by investigating the effects of composition, reaction and printing conditions on film thickness, cross-linking efficacy, and dielectric properties. Subsequently, we elucidated various aspects of large-area (up to 4-inch wafer) bar-coated cross-linked polymeric dielectric prepared from minimal solution (∼100 μL, ∼1.2 μL cm
−2
) by addressing film uniformity, thickness control, capacitance variation, underlying step coverage, patternability,
etc.
The resultant polymeric dielectric exhibited good insulating properties as exemplified by a low leakage current density of ∼10
−8
A cm
−2
(at 1 MV cm
−1
) and a high areal capacitance of 42.6 nF cm
−2
. Finally, a highly-crystallized organic semiconductor layer based on 2,8-difluorinated 5,11-bis(triethylsilylethynyl)anthradithiophene was deposited on the bar-coated cross-linked polymeric dielectric
via
bar-coating, leading to the realization of printed low-voltage organic transistor arrays with minimum ink solution wasted.
Large-area printed low-voltage organic thin film transistors are fabricated with the bar-coating of minimal solutions of cross-linked dielectric and organic semiconductor.
We present the device parameters for organic field-effect transistors fabricated from solution-deposited films of functionalized pentacene and anthradithiophenes. These materials are easily prepared ...in one or two steps from commercially available starting materials and are purified by simple recrystallization. For a solution-deposited film of functionalized pentacene, hole mobility of 0.17 cm2/V·s was measured. The functionalized anthradithiophenes showed behavior strongly dependent on the substituents, with hole mobilities as high as 1.0 cm2/V·s.
Halogen–halogen and halogen–sulphur interactions at the interface between a semiconductor and self‐assembled monolayer‐treated contacts can mediate film crystallization in organic thinfilm ...transistors. On page 5052, A. Amassian, O. D. Jurchescu, and co‐workers explain how highly ordered films form when such interactions are allowed by the structure and orientation of the consituent molecules during the heterogenous nucleation at the solution–solid interface.
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