The optical properties of π-conjugated organic molecules in their solid state are critically important determining performance efficiencies optoelectronic devices such as light-emitting diodes and thin-film transistors. This Perspective discusses some recent systematic explorations aimed toward arriving at an understanding the role that molecular packing plays these properties.

We have rationally designed a densely packed 1:1 donor-acceptor (D-A) cocrystal system comprising two isometric distyrylbenzene- and dicyanodistyrylbenzene-based molecules, forming regular one-dimensional mixed stacks. The crystal exhibits strongly red-shifted, bright photoluminescence originating from an intermolecular charge-transfer state. peculiar electronic situation gives rise to high ambipolar p-/n-type field-effect mobility up 6.7 × 10(-3) 10(-2) cm(2) V(-1) s(-1), respectively, as...

Materials design has become a vigorous aspect for organic solid‐state lasing, which often lacks fundamental understanding of structure–property relationships. The development such an is undertaken in this progress report, systematically explores the now‐available libraries single crystals exhibiting light amplification under optical pumping. By doing so, intra‐ and intermolecular contributions are disentangled non‐/occurrence, type, threshold, wavelength, polarization processes, opening path...

Abstract Luminescent small, all‐organic molecules are of tremendous interest in materials and life science applications. Nevertheless, targeted design requires a basic understanding the excited state deactivation pathways themselves, modulations processes that occur solid state. This particularly concerns crystalline molecular solids, as here not only solid‐state rigidification contributes to these modulations, but specific intermolecular interactions well. Starting from properties, this...

Solid state luminescence enhancement (SLE) of conjugated organic materials has had a great impact in science, but deep understanding been rather limited to date. Here, we investigate prototype example SLE materials, cyano-substituted distyrylbenzene (DCS), by varying systematically and subtly the substitution pattern (inter alia position cyano-substituent) give largely different photoresponse fluid solid solution as well crystalline state. The combination quantitative (ultra)fast optical...

Differential cross sections for single ionisation of He and D2 by protons have been measured at impact energies 3 6 MeV, proton scattering angles between 0.1 1.0 mrad. A clear shoulder has observed an angle 0.55 This feature in the differential is attributed to binary encounters quasi-free target electrons. The data are good agreement shape magnitude with both a first Born approximation calculation simple Rutherford from free

The synthesis and optical properties of a series alkoxyphenyl-pyridyl butadiene derivatives in solution the solid state are described. All were practically nonfluorescent but showed good fluorescence solid-state. role molecular packing controlling solid-state was investigated by studying X-ray crystal structure these molecules. One derivatives, 4-((1E,3E)-4-(4-butoxyphenyl)buta-1,3-dienyl)pyridine exhibited polymorphism, with different polymorphs exhibiting visually distinguishable...

Solid-state, luminescent, aggregation-induced enhanced emission (AIEE)-active dicyanodistyrylbenzene-based organic π-conjugated materials, i.e. α-MODCS, α-MODBDCS, β-MODCS, and β-MODBDCS, are designed. In virtue of the systematically substituted modular molecular systems combined with thorough structural analyses, photophysical studies, electronic structure calculations, spontaneous stimulated properties quantified rationalized from a perspective well-established structure–property...

J-aggregation has been shown to be beneficial for light amplification in single crystals of π-conjugated organic molecules. In the case H-aggregation, criteria such processes are still under debate. It also that H-aggregate arrangements with considerable π–π overlap detrimental amplification. We show here a proper alignment molecules crystal lattice, which minimizes between adjacent molecules, gives rise (random) stimulated emission from cofacial similar herringbone aggregates.

Multiresponsive luminescence and photochemical activity (<italic>Z</italic>/<italic>E</italic> isomerization and/or photodimerization) in solution the liquid crystal phase are reported with dicyanodistyryl-based molecules.

Phthalocyanines and their main group metal complexes are important classes of organic semiconductor materials but usually highly insoluble so frequently need to be processed by vacuum deposition in devices. We report two soluble silicon phthalocyanine (SiPc) diester compounds demonstrate potential as materials. Near-infrared (λEL = 698–709 nm) solution-processed light-emitting diodes (OLEDs) were fabricated exhibited external quantum efficiencies (EQEs) up 1.4%. Binary bulk heterojunction...

Angular distributions of 3-9-MeV protons scattered in singly and doubly ionizing collisions with He have been measured. A sharp shoulder is seen at 0.55 mrad, a feature attributed to binary encounters between the projectile quasifree target electrons. The ratio double single ionization found be nearly independent scattering angle 0.25 mrad value near 2%, substantially lower than photoionization producing fast ejected electrons same energies.

The solid-state photophysical and photochromic properties the molecular packing in single crystals of a series donor−acceptor-substituted butadiene derivatives with alkoxy groups as donor indane-1,3-dione acceptor are reported. These materials showed significant enhancement red-shift fluorescence solid state compared to that solution. crystal analysis these indicated effects could be attributed both improved intramolecular charge transfer due planarization molecules intermolecular exciton...

Three-in-one: A novel distyrylbenzene-based material forms J-type aggregates in single crystals with highly polarized and bright red emission, giving rise to optical gain narrowing, for which different mechanisms (amplified spontaneous laser emission stimulated resonance Raman scattering) are observed. These correlated the favorable intrinsic macroscopic properties of crystal, particular orientation molecules crystal surface. Detailed facts importance specialist readers published as...

We report on four cationic iridium(III) complexes [Ir(C^N)2(dtBubpy)](PF6) that have sulfur pentafluoride-modified 1-phenylpyrazole and 2-phenylpyridine cyclometalating (C^N) ligands (dtBubpy = 4,4′-di-tert-butyl-2,2′-bipyridyl). Three of the were characterized by single-crystal X-ray structure analysis. In cyclic voltammetry, undergo reversible oxidation irreversible reduction SF5 group. They emit bright green phosphorescence in acetonitrile solution thin films at room temperature, with...

Star-shaped molecules consisting of a 1,3,4-oxadiazole core derivatized with alkoxy-substituted phenyl ethynylenes, FD12 (dodecyl) and FD16 (hexadecyl) were synthesized. These exhibited enantiotropic columnar mesophases over wide temperature range, the liquid crystalline phases exhibiting strong blue fluorescence. On cooling, transformed into transparent glass at room wherein texture was retained. The glassy film remained stable period one year luminescence an absolute quantum yield 26%....

A series of highly luminescent oxadiazole-based stilbene molecules (OXD4, OXD8, OXD10, and OXD12) exhibiting interesting enantiotropic liquid crystalline gelation properties have been synthesized characterized. The possessing longer alkyl substituents, OXD10 OXD12, possess a pseudodisc shape are capable behaving as supergelators in nonpolar solvents, forming self-standing gels with very high thermal mechanical stability. Notably the self-assembly these molecules, which do not any...

Intermolecular interactions are decisive in controlling optoelectronic properties of molecular materials. Polymorphism one and the same material gives a unique opportunity to gain direct insight into intermolecular contributions. Here, stimulated emission two polymorphs dicyanodistyrylbenzene derivative with multiple trifluoromethyl groups terminal rings investigated, correlated arrangement resulting excitonic coupling. The have distinctly different behavior emitting blue, while other emits...

Combined structural, photophysical, and quantum-chemical studies at the quantum mechanics/molecular mechanics (QM/MM) level precisely reveal structure-property relationships in a mixed-stack donor-acceptor cocrystal, which displays vibronically structured fluorescence, strongly red-shifted against spectra of parent donor acceptor, with high yield despite pronounced CT character emitting state. The study elucidates reasons for this unusual combination, quantifies ordering nature collective...

A carboxylic acid appended naphthalene-diimide (NDI) derivative spontaneously aggregates in decane to generate a kinetically controlled product with irregular fibrillar morphology. By fine-tuning the sample preparation conditions, group can be trapped by intra-molecular H-bonds adjacent imide carbonyl, which retards spontaneous aggregation. In presence of catalytic amount non-nucleophilic organic base (DBU or DMAP), meta-stable monomer exhibits supramolecular polymerization through...

Autoionization of He atoms following double excitation by electrons, protons, ${\mathrm{C}}^{\mathit{Q}+}$ (Q=4--6), and ${\mathrm{F}}^{\mathit{Q}+}$ (Q=7--9) ions has been studied. The electron-emission yields from the doubly excited 2${\mathit{s}}^{2}$${(}^{1}$S), 2s2p${(}^{1}$P), 2${\mathit{p}}^{2}$${(}^{1}$P) states were measured at reduced projectile energy 1.5 MeV/nucleon for observation angles between 10\ifmmode^\circ\else\textdegree\fi{} 60\ifmmode^\circ\else\textdegree\fi{}. results...

Abstract The synthesis and study of the liquid crystalline, photophysical, aggregation behavior novel octupolar oxadiazole derivatives are reported. These molecules formed columnar mesophases at elevated temperatures which transformed into a glassy state ambient wherein order was retained. Their spontaneous concentration dependent hierarchical self‐assembly from spheres to fibrous gels has been investigated using TEM, SEM, XRD. Retention hexagonal (Col h ) also observed in aggregates....

The study reports the solid state photophysical properties of a series alkyloxy-substituted oligo(phenyleneethynylene)s, methoxy to hexyloxy, supported by detailed analysis molecular packing obtained from single crystal X-ray diffraction data. While emission peaks are highly red shifted (by as much 114 nm) in state, all molecules exhibit similar absorption and dilute solutions. shift is maximum ethoxy minimum methoxy, while other crystalline films intermediate values. In structures, spacing...

Differential cross sections for the capture of electrons from argon by 6-MeV protons have been measured as a function hydrogen-atom scattering angle between 0.02\ifmmode^\circ\else\textdegree\fi{} and 0.14\ifmmode^\circ\else\textdegree\fi{}. Cross were all shells $K$ shell alone. The differential section $K$-shell does not agree with theoretical results obtained using either Oppenheimer-Brinkman-Kramers approximation or Born calculation which includes contribution core-core interaction.