Greener One Step Synthesis of Novel In-situ Selenium-Doped Frameworks Photocatalyst by Melem and Perylene Dianhydride for Enhanced Solar Fuel Production from CO2

To minimize the ever-increasing global warming and environmental problems, the conversion of atmospheric CO₂ into value-added solar chemicals/fuels is one of the most challenging tasks. As a means to accomplish this, herein we have synthesized first time novel in situ selenium doped polyimide frameworks (Se-PIFs) photocatalyst via thermal co-polymerization approach between melem (M) and perylene 3, 4, 9, 10- tetracarboxylic dianhydride (PTDA) along with selenium (Se) as a dopant. The Se-PIFs photocatalyst shows outstanding photocatalytic stability and activity for high solar fuel production (HCOOH ~ formic acid) from CO₂ . The solar light active Se-PIFs photocatalyst was demonstrating the ~ 10 fold higher photo-conversion of CO₂ to formic acid with yields of 250. 6 μmol. The current work is providing a facile and scalable avenue as well as sheds light on creating a new route for in-situ judicious design highly efficient Se-PIFs photocatalyst. The outcome are a benchmark instance for the use of selenium doped polyimide frameworks as a highly practical and efficient solar light active photocatalyst for carrying out the selective production of formic acid from environmental CO₂ .

Unraveling the electrochemical and spectroscopic properties of neutral and negatively charged perylene tetraethylesters

A detailed investigation of the energy levels of perylene-3,4,9,10-tetracarboxylic tetraethylester as a representative compound for the whole family of perylene esters was performed. It was revealed via electrochemical measurements that one oxidation and two reductions take place. The bandgaps determined via the electrochemical approach are in good agreement with the optical bandgap obtained from the absorption spectra via a Tauc plot. In addition, absorption spectra in dependence of the electrochemical potential were the basis for extensive quantum-chemical calculations of the neutral, monoanionic, and dianionic molecules. For this purpose, calculations based on density functional theory were compared with post-Hartree–Fock methods and the CAM-B3LYP functional proved to be the most reliable choice for the calculation of absorption spectra. Furthermore, spectral features found experimentally could be reproduced with vibronic calculations and allowed to understand their origins. In particular, the two lowest energy absorption bands of the anion are not caused by absorption of two distinct electronic states, which might have been expected from vertical excitation calculations, but both states exhibit a strong vibronic progression resulting in contributions to both bands.

Columnar Mesomorphism of Board-Shaped Perylene, Diketopyrrolopyrrole, Isoindigo, Indigo, and Quinoxalino-Phenanthrophenazine Dyes

The properties of organic dyes depend as much on their intermolecular interactions as on their molecular structure. While it is generally predictable what supramolecular structure would be ideal for a specific application, the generation of specific supramolecular structures by molecular design and suitable processing methods remains to be a challenge. A versatile approach to different supramolecular structures has been the application of mesomorphism in conjunction with alignment techniques and self-assembly at interfaces. Reviewed here is the columnar mesomorphism of board-shaped dyes perylene, indigo, isoindigo, diketopyrrolopyrrole, and quinoxalinophenanthrophenazine. They generate a larger number of different supramolecular structures than conventional disc-shaped (discotic) mesogens because of their non-circular shape and directional intermolecular interactions. The mesomorphism of all but the perylene derivatives is systematically and comprehensively covered for the first time.

Development of Perylene-Based Non-Fullerene Acceptors through Bay-Functionalization Strategy

Perylene has had a tremendous impact in the history of material research for the molecular semiconductors. Among numerous derivatives of this polyaromatic hydrocarbon, perylene diimide (PDI) represents a promising class of organic materials envisioned as non-fullerene acceptors (NFAs) for the practical organic photovoltaic (OPV) applications due to their enhanced photo- and thermal stability and remarkably high electron affinity, some of which realize band-like transport properties. The present review guides some of the representative achievements in the development of rationally designed PDI systems, highlighting synthetic methodologies based on bay-functionalization strategies for creating well-designed molecular nanostructures and structure-performance relationship of perylene-based small molecular acceptors (SMAs) for the photovoltaic outcomes.

Real roles of perylene diimides for improving photocatalytic activity

Three novel visible-light-driven composite photocatalysts: five-membered O-heterocyclic annulated perylene diimide doped TiO₂ (PDI-1/TiO₂), 1-phenol-N,N′-dicyclohexyl perylene-3,4,9,10-tetracarboxylic diimide doped TiO₂ (PDI-2/TiO₂), and N,N′-dicyclohexyl perylene diimide doped TiO₂ (PDI-3/TiO₂), were synthesized using a hydrothermal synthesis method. The effects of introducing PDIs with different structures into TiO₂ were evaluated by assaying the photodegradation rate of Methylene Blue (MB). The photoactivities of the PDI-1/TiO₂ and PDI-2/TiO₂ catalysts were better than that of PDI-3/TiO₂. This is because the large surface area of PDI-1 nanorods and PDI-2 nanobelts extended the 1D charge carrier channel, which facilitated electron transfer to the TiO₂ surface and improved the photocatalytic activity of the composites. The PDI-1/TiO₂ composite showed the highest photoactivity, and the activity remained at 86.4% after four reuse cycles. The extended π–π stacking of self-assembled PDI-1 and the strong interactions between self-assembled PDI-1 and TiO₂ played significant roles in accelerating charge transfer and decreasing recombination of photogenerated electron–hole pairs. The steric hindrance of the phenoxy substituent at the bay position of PDI-2 prevented the PDI-2 nucleus from contacting TiO₂ and weakened the interaction between PDI-2 and TiO₂, which further resulted in the low photoactivity of PDI-2/TiO₂. This work provides a practical way to improve the performances of traditional organic and inorganic composite photocatalysts.

Three novel visible-light-driven composite photocatalysts were synthesized by hydrothermal method. The effects of introducing PDIs with different structures into TiO₂ were evaluated by assaying the photodegradation rate of methylene blue.

Microwave-Assisted Classic Ullmann C-C Coupling Polymerization for Acceptor-Acceptor Homopolymers

Developing cheap, clean and atomic-efficient synthetic methodologies for conjugated polymers are always critical for the field of organic electronics. Herein, classic Ullmann coupling polymerization is developed to synthesize a series of Acceptor-Acceptor (A-A) type homopolymers with microwave-assistance, which are supported by nuclear magnetic resonance (NMR), matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF), elemental analysis (EA) and gel permeation chromatography (GPC). The physicochemical properties of these polymers are studied by UV-vis spectroscopy, cyclic voltammetry (CV), thermal gravimetric analysis (TGA), and density functional theory (DFT) calculation. Furthermore, these A-A homopolymers are used as acceptors for all-polymer solar cells (All-PSCs), affording a promising efficiency of 3.08%, which is the highest value for A-A-homopolymer-based organic solar cells.

Recent Advances in n-Type Polymers for All-Polymer Solar Cells

All-polymer solar cells (all-PSCs) based on n- and p-type polymers have emerged as promising alternatives to fullerene-based solar cells due to their unique advantages such as good chemical and electronic adjustability, and better thermal and photochemical stabilities. Rapid advances have been made in the development of n-type polymers consisting of various electron acceptor units for all-PSCs. So far, more than 200 n-type polymer acceptors have been reported. In the last seven years, the power conversion efficiency (PCE) of all-PSCs rapidly increased and has now surpassed 10%, meaning they are approaching the performance of state-of-the-art solar cells using fullerene derivatives as acceptors. This review discusses the design criteria, synthesis, and structure-property relationships of n-type polymers that have been used in all-PSCs. Additionally, it highlights the recent progress toward photovoltaic performance enhancement of binary, ternary, and tandem all-PSCs. Finally, the challenges and prospects for further development of all-PSCs are briefly considered.

Tailoring Photophysical Processes of Perylene-Based Light Harvesting Antenna Systems with Molecular Structure and Solvent Polarity

The excited-state dynamics of perylene-based bichromophoric light harvesting antenna systems has been tailored by systematic modification of the molecular structure and by using solvents of increasing polarity in the series toluene, chloroform, and benzonitrile. The antenna systems consist of blue light absorbing naphthalene monoimide (NMI) energy donors (D1, D2, and D3) and the perylene derived green light absorbing energy acceptor moieties, 1,7-perylene-3,4,9,10-tetracarboxylic tetrabutylester (A1), 1,7-perylene-3,4,9,10-tetracarboxylic monoimide dibutylester (A2), and 1,7-perylene-3,4,9,10-tetracarboxylic bisimide (A3). The design of these antenna systems is such that all exhibit ultrafast excitation energy transfer (EET) from the excited donor to the acceptor, due to the effective matching of optical properties of the constituent chromophores. At the same time, electron transfer from the donor to the excited acceptor unit has been limited by the use of a rigid and nonconjugated phenoxy bridge to link the donor and acceptor components. The antenna molecules D1A1, D1A2, and D1A3, which bear the least electron-rich energy donor, isopentylthio-substituted NMI D1, exhibited ultrafast EET (τ_EET ∼ 1 ps) but no charge transfer and, resultantly, emitted a strong yellow-orange acceptor fluorescence upon excitation of the donor. The other antenna molecules D2A2, D2A3, and D3A3, which bear electron-rich energy donors, the amino-substituted NMIs D2 and D3, exhibited ultrafast energy transfer that was followed by a slower (ca. 20-2000 ps) electron transfer from the donor to the excited acceptor. This charge transfer quenched the acceptor fluorescence to an extent determined by molecular structure and solvent polarity. These antenna systems mimic the primary events occurring in the natural photosynthesis, i.e., energy capture, efficient energy funneling toward the central chromophore, and finally charge separation, and are suitable building blocks for achieving artificial photosynthesis, because of their robustness and favorable and tunable photophysical properties.

Highly uniform supramolecular nano-films derived from carbazole-containing perylene diimide via surface-supported self-assembly and their electrically bistable memory behavior

For electrical memory applications, two perylenetetracarboxylic diimide (PDI) derivatives were synthesized and their surface-supported self-assembly behaviors were investigated.

Electroluminescent and Optoelectronic Properties of OLEDs with Bay-Extended, Distorted Perylene Esters as Emitter Materials

Three esters with a perylene, a unilaterally, and a bilaterally extended perylene core, respectively, were used as emitter materials for organic light-emitting diodes. The electroluminescent properties of these devices were studied. Different spectral shifts were found, which can be attributed to the formation of excited dimers (excimers) in the nanofilms of the emitter materials. Thermal treatment of the unilaterally extended derivative resulted in a red-shift of the electroluminescence owing to the formation of a denser nanofilm. The luminance and efficiency of optoelectronic devices employing the extended perylene esters exceed those of devices using an emitter layer comprised of the perylene ester. Different deposition methods, limitations in the deposition process, and the role of hole-transporting materials are compared.

Synthesis and investigation on liquid crystal and optical properties of dyads based on triphenylene and perylene

Mesogenic dyads consisting of a triphenylene (donor) and a perylene (acceptor) showed photoinduced intramolecular charge transfer process and fluorescent quenching.

Bay-Annulated Perylene Tetraesters: A New Class of Discotic Liquid Crystals

Selenium-annulated perylene tetraesters that stabilize the hexagonal columnar phase have been synthesized and characterized, and their thermal and photophysical behavior has been determined. The mesophase range decreased with an increase in chain length. A comparative account of the structure-property relationships of this series of compounds with respect to parent perylene tetraesters, N- and S-annulated perylene tetraesters, in terms of their thermal, photophysical and electrochemical behavior is provided. The bay-annulation of perylene tetraesters is a good option to modify the thermal and photophysical properties of perylene derivatives and it can provide a new avenue for the synthesis of several technologically important self-assembling perylene derivatives.

pH-Sensitive perylene tetra-(alkoxycarbonyl) probes for live cell imaging

A novel perylene pH probe for imaging of living cells in neutral to weak basic pH changes.

Perylo[1,12-b,c,d] Thiophene Tetraesters: A New Class of Luminescent Columnar Liquid Crystals

Perylo[1,12-b,c,d] thiophene tetraesters exhibiting wide-range hexagonal columnar phase have been synthesized. These compounds also exhibit good homeotropic alignment in the liquid-crystalline phase which is very important for the device fabrication. These compounds showed sky-blue luminescence in solution under the long-wavelength UV light. With high solubility and high quantum yield these compounds can serve as standards to measure quantum yields of unknown samples. This new class of materials is promising, considering the emissive nature and stabilization of hexagonal columnar mesophase over a wide thermal range and ease of synthesis.

Self-assembly of luminescent N-annulated perylene tetraesters into fluid columnar phases

A new class of N-annulated perylene tetraesters and their N-alkylated derivatives has been synthesized. N-Annulated perylene tetraesters stabilize a hexagonal columnar phase over a broad temperature range. The hexagonal columnar phase exhibited by these compounds shows good homeotropic alignment with few defects. Annulation in the bay region of the perylene tetraesters enhanced the width of the mesophase compared with the parent tetraesters. N-Alkylation of these compounds perturbed the self-assembly behaviour and the resulting compounds were non-mesomorphic. A bright green luminescence was visible under long wavelength UV light. These properties suggest that these materials may have promising applications in organic electronics.

New advances in non-fullerene acceptor based organic solar cells

Non-fullerene organic molecules are alternative and competitive acceptor materials for high-efficiency organic solar cells.

Low band-gap weak donor–strong acceptor conjugated polymer for organic solar cell

With an additional weak acceptor, the low band-gap donor–acceptor conjugated polymer displayed a remarkable power conversion efficiency of 5.36%.