The design and preparation of metal‐free organic materials that exhibit room‐temperature phosphorescence (RTP) is a very attractive topic owing to potential applications in organic optoelectronic ...devices. Herein, we present a facile approach to efficient and long‐lived organic RTP involving the doping of N‐phenylnaphthalen‐2‐amine (PNA) or its derivatives into a crystalline 4,4′‐dibromobiphenyl (DBBP) matrix. The resulting materials showed strong and persistent RTP emission with a quantum efficiency of approximately 20 % and a lifetime of a few to more than 100 milliseconds. Bright white dual emission containing blue fluorescence and yellowish‐green RTP from the PNA‐doped DBBP crystals was also confirmed by Commission Internationale de l'Eclairage (CIE) coordinates of (x=0.29–0.31, y=0.38–0.41).
Doping‐enhanced performance: Strong room‐temperature phosphorescence (RTP) of pure organic compounds was induced by doping PNA and its derivatives into a DBBP crystalline matrix. The PNA/DBBP crystal system emitted efficient, stable, and long‐lived RTP under ambient conditions (see picture).
In this review, we survey several recent developments in printing of nanomaterials for contacts, transistors, sensors of various kinds, light-emitting diodes, solar cells, memory devices, and bone ...and organ implants. The commonly used nanomaterials are classified according to whether they are conductive, semiconducting/insulating or biological in nature. While many printing processes are covered, special attention is paid to inkjet printing and roll-to-roll printing in light of their complexity and popularity. In conclusion, we present our view of the future development of this field.
In this review article, we survey the current state of art of printed nanomaterial systems and their future prospects.
Crystalline samples of 3(5)-(9-anthryl)pyrazole and its one derivative exhibit interesting piezochromic behaviors with the emission colors differently changing from blue to green and from green to ...blue, respectively, upon grinding.
Thermally driven reversible emission switching between different colors and solid‐phase transformation are investigated for two aromatic‐amine compounds bearing trifluoromethyl (CF3) groups. The ...phase‐dependent emission properties are attributed to the different molecular packing properties and changeable molecular geometry for different solid phases (see figure).
The development of non‐fullerene‐based electron acceptors (especially organic molecules with sufficient absorption property within the solar spectrum region) for bulk‐heterojunction (BHJ) organic ...solar cells (OSCs) is an important issue for the achievement of high photoconversion efficiency. In this contribution, a new class of organic acceptors di‐cyan substituted quinacridone derivatives (DCN‐nCQA, n = 4, 6 and 8) for BHJ solar cells was designed and synthesized. DCN‐nCQA molecules possess facile synthesis, solution processability, visible and near‐IR light absorption and relatively stable characteristics. The DCN‐8CQA molecule exhibited a proper LUMO energy level (–4.1 eV), small bandgap (1.8 eV) and moderate electron mobility (10−4 cm2 V−1 S−1), suggesting that this molecule is an ideal acceptor material for the classical donor material regio‐regular poly (3‐hexylthiophene) (P3HT). A photovoltaic device with a structure of ITO/PEDOT:PSS/P3HT:DCN‐8CQA/LiF/Al displayed a power conversion efficiency of 1.57% and a fill factor of 57% under 100 mW cm−2 AM 1.5G simulated solar illumination. The DCN‐nCQA molecules showed remarkable absorption in the region from 650 to 700 nm, where P3HT has a weak absorption promoting overlap with the solar spectrum and potentially improving the performance of the solar cell.
A novel light‐absorbing DCN‐nCQA compound that can be used as the acceptor in BHJ solar cells is reported. By introducing DCN‐nCQA, the range of absorption of sunlight is expanded to 700 nm (see image), suggesting the possibility of achieving efficient solar cells by using co‐absorbed donor and acceptor materials.
This paper presents a versatile method to fabricate ultrathin nanofibrillated cellulose (NFC) films as thin as 800 nm by blade coating, which is compatible with a roll-to-roll process on a large ...scale. Our approach allows obtaining a dried nanocellulose film within a span of 1 h subsequent to 2,2,6,6-tetramethylpiperidine-1-oxyl radical-assisted oxidation and homogenization procedures. One of the thinnest freestanding NFC films with a thickness of 800 nm is achieved using a blade coating of nanocellulose after 72 h of oxidation followed by homogenization with a channel size of 65 μm. Incorporating water-soluble CdTe core-type quantum dots into the nanocellulose film led to a uniform emission under 385 nm UV irradiation, indicating excellent material compatibility. We anticipate nanocellulose developed in our study to be beneficial in biomimicry flying objects, environmentally friendly encapsulation, color filters, and energy storage device membranes, to name a few.
This work demonstrates a novel method for the synthesis of large pore mesoporous silica nanoparticles (MSNs) with a pore diameter of 10.3 nm and a particle diameter of ∼50 nm based on the ...incorporation of mixed anionic surfactants sodium dodecyl benzene sulfonate (SDBS) and sodium dodecyl sulphate (SDS) as the template in the synthesis process. The dispersity, morphology, pore structure and size of mesoporous nanoparticles were adjusted by changing the molar ratio of two anionic surfactants, the concentration of the co-structure-directing agent (3-aminopropyltrimethoxysilane) and the reaction temperature. The results of synthesis experiments suggested that the formation of large pore MSNs involved a nucleation and growth process. MSNs were post-grafted with a Schiff base moiety for fluorescence sensing of Fe3+ in water. The applicability of functionalized MSNs was demonstrated by selective fluorescence detection of Fe3+ in aqueous media.
The diversity of hydrogen and ionic bond interactions in 2,6-biphenyl-4-pyrone-acid (BPP–acid) supramolecular systems and the acid-induced luminescence character of BPP was reported. On the basis of ...X-ray single crystal structure analysis and theoretical calculation, the strong luminescence of BPP–HCl and BPP–TFA (TFA = trifluoroacetic acid) crystals was attributed to the protonation or strong hydrogen bond interactions between the carbonyl group of BPP and the proton of HCl or TFA. Notably, in BPP–TFA crystal the interaction between BPP and TFA displayed a “mixed bond” feature; namely, the bond between carbonyl of BPP and hydroxyl of TFA possesses partial hydrogen bond and partial ionic bond nature. The acid stimuli-luminescence properties of BPP film may offer a potential application in chemical sensors.
A new series of acceptor–donor–acceptor (A–D–A) type quinoacridine derivatives (1–3) with aggregation-induced red emission properties were designed and synthesized. In these compounds, the ...electron-withdrawing 2-(3,5-bis(trifluoromethyl)phenyl)acetonitrile groups act as electron-accepting units, while the alkyl-substituted conjugated core acts as electron-donating units. The restriction of intramolecular rotation was responsible for the AIE behavior of compounds 1–3. All compounds were employed as building blocks to fabricate one-dimensional (1-D) organic luminescent nano- or microwires based on reprecipitation or slow evaporation approaches. Morphological transition from zero-dimensional (0-D) hollow nanospheres to 1-D nanotubes has been observed by recording SEM and TEM images of aggregated sates of compound 2 in THF/H2O mixtures at different aging time. It was demonstrated that the synthesized compounds with different lengths of alkyl chains displayed different wire formation properties. The single-crystal X-ray analysis of compound 2 provided reasonable explanation for the formation of 1-D nano- or microstructures.
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