Perylene Diimide Moieties Research Articles

Highly photostable N-annulated perylene-diimide-based dimeric acceptors: Synthesis and role of linking core

Two N-annulated perylene diimide (PDI) dimers, termed as, TVT-(PPDI-B)2 and TYT-(PPDI-B)2, selecting (E)-1,2-di(thien-2-yl)ethylene (TVT) and 1,2-di(thien-2-yl)acetylene (TYT) as the middle linkers, N-butyl-[1,12-b,c,d]pyrrole-N,Nʹ-bis(2-hexyldecyl)perylene diimide (PPDI-B) fused aromatic moiety as two wings, were developed to investigate the influence of linking core. It was exhibited that the improved absorption, 0.05 eV up-shifted ELUMO, drastically reduced twisting angle from 68.0o to 27.9o between two N-annulated PDI moieties and enhanced molecular aggregation were found after substituting TVT linking core with TYT. Accordingly, under the best processing condition, TVT-(PPDI-B)2-based device gained the VOC of 0.92, JSC of 3.61 mA‧cm−2, FF of 30.3% and consequently PCE of 1.02% when blending with PTB7-Th. In contrast, TYT-(PPDI-B)2-based device afforded 4.35% increased VOC of 0.96 V, 86.98% enhanced JSC of 6.75 mA‧cm−2 and 55.45% raised FF of 47.1%, collectively contributed to a 211% raised PCE as high as 3.17%. This efficiency enhancement was mainly attributed to improved absorption, raised ELUMO, more efficient exciton dissociation and electron mobility, weakened charge recombination, and more suitable morphology. Interestingly, 0.12⁓0.16 V up-shifted VOC was achieved after applying N-annulation strategy at the bay-position of PDI building block. This indicates that precisely tuning the linking core in the N-annulated PDI-based dimers can effectively affect optoelectronic property, molecular geometry and morphology, and thus further boost the corresponding device efficiency.

Effect of Hyperconjugation on Photovoltaic Performance in Pseduo‐2D Perylene Diimide Derivatives†

Comprehensive SummaryThe π‐π interaction is acknowledged as the predominant factor to determine the molecular packing in organic photovoltaic materials, while other non‐covalent intermolecular interactions especially the σ‐π hyperconjugation are often ignored. Herein, a perylene diimide (PDI) derivative named FIDT‐PDI is designed and synthesized to shed light into the effect of hyperconjugation on the molecular packing and further the photovoltaic performance. Dynamic NMR and 2D NOE NMR demonstrate the formation of intermolecular σ‐π hyperconjugation between the C—H bond of the PDI moiety in one molecule and the phenyl sidechain in another molecule of FIDT‐PDI. Benefiting from the σ‐π hyperconjugation, FIDT‐PDI with twisted backbone reversely exhibits more ordered packing and stronger crystallinity compared with another PDI derivative FIDTT‐PDI which has better planarity, consequently achieving superior PCE and higher carrier mobility. This contribution is the first paradigm to unravel the structure‐property relationship between σ‐π hyperconjugation of conjugated materials and corresponding photovoltaic performance.

Designed and synthesized de novo ANTPABA-PDI nanomaterial as an acceptor in inverted solar cell at ambient atmosphere

In this work, a novel soluble and air-stable electron acceptor containing perylenediimide moiety named ANTPABA-PDI was designed and synthesized with band gap 1.78eV and that was used as non-fullerene acceptor material. ANTPABA-PDI possess not only good solubility but also much lower LUMO (lowest unoccupied molecular orbital) energy level. Furthermore, its excellent electron acceptor capability also supported by density functional theory calculation which validates the experimental observations. Inverted organic solar cell has been fabricated using ANTPABA-PDI along with P3HT as standard donor material in ambient atmosphere. The device, after characterization in open air, exhibited a power conversion efficiency of 1.70%. This is the first ever PDI based organic solar cell that has been fabricated completely in ambient atmosphere. The characterizations of the device have also been performed in ambient atmosphere. This kind of stable organic material can easily be used in fabricating organic solar cell and therefore it can be used as the best alternative as non-fullerene acceptor materials.

Ultrafast Dynamics of Photoinduced Electron Transfer in Bay-Aryl-Substituted Perylene Diimide Derivatives.

Blends of donors and acceptors have been widely used in bulk-heterojunction solar cells to have exciton formation and charge separation by photoinduced electron transfer (PET). In this work, we have synthesized perylene diimide (PDI)-based materials having different aryl substituents at the bay positions (4-Anisyl-PDI, CBZ-N-Ph-PDI, and 4-Pyridyl-PDI) to understand the excited-state dynamics of electron transfer. The detailed photophysics was studied using steady-state as well as ultrafast dynamics of the excited states in different solvents. CBZ-N-Ph-PDI showed tremendous effects of the solvent on the electronic properties compared with the other two derivatives. The emission quantum yield of CBZ-N-Ph-PDI decreases drastically in dichloromethane and other polar solvents, indicating strong electron transfer. DFT calculations showed that in CBZ-N-Ph-PDI the HOMO is centered mostly on the N-phenylcarbazole and the LUMO is on the electron-poor PDI moieties. In addition, the energy levels of the HOMO and HOMO-1 in CBZ-N-Ph-PDI are estimated to be identical. The free energy change for charge separation (ΔGCS) was calculated using electrochemical and photophysical data and found to be negative for CBZ-N-Ph-PDI. The ground- and excited-state dipole moment ratios suggest that the excited state of 4-Pyridyl-PDI (1.90) is less polar than that of 4-Anisyl-PDI (3.67), which provides an idea of the lower possibility of charge separation in 4-Anisyl-PDI and 4-Pyridyl-PDI. Ultrafast photodynamics studies of 4-Anisyl-PDI, CBZ-N-Ph-PDI, and 4-Pyridyl-PDI showed fast electron transfer only in CBZ-N-Ph-PDI and not in the other PDI derivatives. It was also observed that electron transfer is faster in DCM and THF than in toluene. Ultrafast dynamics studies showed the presence of an equilibrium between electron transfer and decay from the singlet excited state. Ultrafast studies also showed the features of the N-phenylcarbazole cation and PDI anion, further confirming the intramolecular electron transfer in CBZ-N-Ph-PDI.

From Monolayer to Multilayer: Perylenediimide Diazonium Derivative Acting Either as a Growth Inhibitor or a Growth Enhancer.

Fine control of electrografting kinetics of diazonium salts is of paramount importance, particularly when considering the application of diazoniums for the fabrication of 2D nanomaterials. In this work, we develop controlled grafting of a perylenediimide (PDI) moiety separated with a 12-carbon aliphatic chain from aryldiazonium. The particular design of the diazonium cation synthesized for this study allows for fine tuning of the surface coverage by simple adjustment of the applied potential. Indeed, according to the potential imposed at the working electrode, the PDI moiety can either enhance the charge propagation within the growing layer or consume the diazonium salt in the bulk solution via redox cross-reaction. With this approach, the surface functionalization can be restricted to a monolayer or a multilayer in a robust and elegant manner, obeying Langmuir or first-order kinetics of electrografting, respectively. The experimental observations are supported with in situ spectroelectrochemical investigations aimed to differentiate the reduction of PDI moieties in the deposited layer and the bulk solution. A tentative mechanistic scheme is proposed, and numerical simulations are undertaken to rationalize the data.

Imide modification coupling with NH2-MIL-53(Fe) boosts the photocatalytic performance of graphitic carbon nitride for efficient water remediation

Graphite carbon nitride (g-C3N4) is a significant non-metal photocatalyst, but still challenging for photocatalytic degradation of pollutants because of its poor visible light utilization, easy recombination of photo-generated carriers and low surface reactive reaction sites. In this paper, perylene diimide (PDI), an electron-deficient building block for constructing n-type organic semiconductors, was introduced into the framework of g-C3N4 (PDI-g-C3N4) to build polymer with donor–acceptor structure for energy band amelioration, achieving the most expanded visible light response up to date. Besides, a large dihedral angle (90°) induced by PDI moiety in PDI-g-C3N4 changes the molecular aggregation behavior according to calculations, which is advantageous to increase surface area for the reactive site exposure. The most promising functional photocatalyst PDI-g-C3N4/MIL is constructed by in-situ generation of NH2-MIL-53(Fe) on the surface of PDI-g-C3N4 to further facilitate the separation and transfer of interfacial photo-induced carriers. Through a finely adjusting ratio of PDI-g-C3N4 in heterojunction, the target material of PDI-g-C3N4/MIL exhibits superior activity for the photodegradation of organic pollutants in the presence of H2O2 and visible light illumination, providing potential direction in practical application for wastewater treatment.

New 4,5-diaza-9,9'-spirobifluorene derivative – promising electron acceptor for nonfullerene polymer solar cells

New 4,5-diaza-9,9'-spirobifluorene derivative 8 with two electron-accepting perylene diimide moieties has been prepared. The compound 8 was characterized by NMR spectroscopy, elemental analysis, UV-spectroscopy and cyclic voltammetry. Energies of HOMO/LUMO levels are of -5.81 eV/-3.89 eV; Egopt and Egech values are of 1.75 eV and 1.92 eV, respectively. Low-lying energy levels and strong absorption in the visible region of UV- spectrum indicate the potential use of the compound 8 as a new promising electron acceptor in nonfullerene polymer solar cells.

Covalently Linked Perylene Diimide-Polydiacetylene Nanofibers Display Enhanced Stability and Photocurrent with Reversible FRET Phenomenon.

Because of their unique structural and optical properties, 1D perylene diimide (PDI) derivatives have gained attention for use in optoelectronic devices. However, PDI-containing self-assembled supramolecular systems often are of limited use because they have supramolecular architectures that are held together by weak noncovalent π-π stacking, hydrogen bonding, and hydrophobic interactions. As a result, they are intrinsically unstable under solution-processing conditions. To overcome this limitation, a polydiacetylene (PDA)-based strategy is developed to construct a solvent-resistant and stable PDI assembly. For this purpose, first the monomer PDI-BisDA is generated, in which two polymerizable diacetylene (DA) units are covalently linked to a PDI core. Importantly, 254 nm UV irradiation of self-assembled PDI-BisDA nanofibers forms solvent-resistant and stable PDI-PDA fibers. Owing to the presence of PDA, the generated polymer fibers display an increased photocurrent. In addition, the existence of PDA and PDI moieties in the fiber leads to the occurrence of switchable on-off fluorescence resonance energy transfer (FRET) between the PDI and reversibly thermochromic PDA chromophores.

Synthesis and Characterization of Poly(3-hexylthiophene)-<i>block</i>-poly(styrene) Containing Perylene Diimide Moiety at Junction

Synthesis and Characterization of Poly(3-hexylthiophene)-<i>block</i>-poly(styrene) Containing Perylene Diimide Moiety at Junction

Impact of alkyl chain branching positions on molecular packing and electron transport of dimeric perylenediimide derivatives

Abstract Side chains play a critical role in tuning intermolecular interaction and charge transport in organic semiconductors. Here, we have systematically investigated the impact of branching positions of the alkyl side chains on the molecular packing and electron transport properties of a series of bay-linked dimeric perylenediimide (PDI) derivatives by atomistic molecular dynamics simulations in combination with charge transfer rate theory and kinetic Monte Carlo simulations. The results show that despite of different branching positions of the alkyl chains, π–π stacking is effectively inhibited for all the dimeric PDI derivatives. As the branching position moves away from the PDI backbone, the appearance of the alkyl atoms around the PDI backbone will first decrease and then increase. Correspondingly, the short contacts between the PDI moieties are first enhanced and then reduced. In particular, when the branching position is at the third carbon atom, the intermolecular connectivity becomes the most effective and the electron mobility is significantly increased by 2 times.

Rationalizing device performance of perylenediimide derivatives as acceptors for bulk-heterojunction organic solar cells

Abstract This study examines the correlation between the structure of four perylenediimide (PDI) derivatives and their optoelectronic behaviors. Three of them with one, two or four PDI moieties conjugated peripherally to porphyrin core by phenylene linker, denoted as nPDI-ZnP (n = 1,2,4), are investigated as acceptors on the charge transport property and device performance in non-fullerene (NF) bulk-heterojunction (BHJ) organic photovoltaic cells with a commercial polymer PTB7-Th as the donor material. Besides, the parent PDI molecule is studied as a control. Detailed charge carrier transport analysis is carried out on these PTB7-Th:Acceptor BHJs. Among all acceptor molecules, PTB7-Th:4PDI-ZnP film possesses the most desirable transport properties among the NF BHJs, and the best device performance with a power conversion efficiency (PCE) of 8.35%. To quantify the transport behaviors, the charge imbalance factor Δ is introduced to describe the global electron and hole balance in different electric fields. We discover that PTB7-Th:4PDI-ZnP has the least Δ and thereby gives rise to a BHJ cells with the highest fill factor and PCE.

9,9'-Bifluorenylidene-Core Perylene Diimide Acceptors for As-Cast Non-Fullerene Organic Solar Cells: The Isomeric Effect on Optoelectronic Properties.

Two different non-fullerene small-molecule acceptors, m-PIB and p-PIB, based on 9,9'-bifluorenylidene (BF) and perylene diimide (PDI) were designed and synthesized. Four β-substituted PDIs were linked to BF in different positions. Based on DFT analysis, derivative p-PIB exhibited reduced intramolecular twisting between the PDI moieties, more delocalized wave function, and sufficiently wider π-electron delocalization than that of m-PIB. The absorption ability of p-PIB was enhanced due to increased intermolecular interactions. By blending p-PIB with poly{4,8-bis[5-(2ethylhexyl)thiophen-2-yl]benzo[1,2-b:4,5-b']dithiophene-co-3-fluorothieno[3,4-b]-thiophene-2-carboxylate} (PTB7-Th), organic solar cells (OSCs) based on p-PIB obtained a maximum power conversion efficiency of 5.95 % without any treatments. Due to the improved and balanced hole and electron mobilities, the short-circuit current and fill factor of OSCs based on PTB7-Th and p-PIB were significantly increased. The AFM and TEM results revealed that the PTB7-Th:p-PIB film had favorable nanoscale phase separation and formed a bicontinuous interpenetrating network.

Controlled Self-Assembly of Photofunctional Supramolecular Nanotubes.

Designing supramolecular nanotubes (SNTs) with distinct dimensions and properties is highly desirable, yet challenging, since structural control strategies are lacking. Furthermore, relatively complex building blocks are often employed in SNT self-assembly. Here, we demonstrate that symmetric bolaamphiphiles having a hydrophobic core comprised of two perylene diimide moieties connected via a bipyridine linker and bearing polyethylene glycol (PEG) side chains can self-assemble into diverse molecular nanotubes. The structure of the nanotubes can be controlled by assembly conditions (solvent composition and temperature) and a PEG chain length. The resulting nanotubes differ both in diameter and cross section geometry, having widths of 3 nm (triangular-like cross-section), 4 nm (rectangular), and 5 nm (hexagonal). Molecular dynamics simulations provide insights into the stability of the tubular superstructures and their initial stages of self-assembly, revealing a key role of oligomerization via side-by-side aromatic interactions between bis-aromatic cores. Probing electronic and photonic properties of the nanotubes revealed extended electron delocalization and photoinduced charge separation that proceeds via symmetry breaking, a photofunction distinctly different from that of the fibers assembled from the same molecules. A high degree of structural control and insights into SNT self-assembly advance design approaches toward functional organic nanomaterials.

Design of perylene-diimides-based small-molecules semiconductors for organic solar cells

ABSTRACTA series of perylene-diimide-based small molecules have been designed to explore their optical, electronic and charge transport properties as organic solar cell materials. The frontier molecular orbitals analysis has turned out that the vertical electronic transitions of absorption are characterised as intramolecular charge transfer between perylene diimide moieties and substituent aromatic groups. Our results suggest that the optical and electronic properties and reorganisation energies are affected by the introduction of different aromatic groups to these molecules. The calculation results showed that the designed molecules own the large longest wavelength of absorption spectrum, the oscillator strength and absorption region values. On the basis of the investigated results, the designed molecules could be used as solar cell material with intense broad absorption spectra. Furthermore, they are expected to be the promising candidates for hole and/or electron transport materials.

High‐Performance n‐Type Electrical Memory and Morphology‐Induced Memory‐Mode Tuning of a Well‐Defined Brush Polymer Bearing Perylene Diimide Moieties

Poly(N‐(1‐hexylheptyl)‐N′‐(12‐oxydodecyl)perylene‐3,4,9,10‐tetracarboxyldiimide acrylate) (PAcPDI), a perylene diimide (PDI) containing brush polymer, is synthesized, revealing good solubility in organic solvents, excellent thermal stability up to around 340 °C, and two melting transitions over 130−220 °C. The self‐assembly and n‐type memory characteristics of PAcPDI in nanoscale thin films are quantitatively investigated. As‐cast films of PAcPDI are completely amorphous and the PDI units nevertheless formed π–π stacks favorably. However, the PAcPDI molecules can self‐assemble via thermal annealing, developing a well‐ordered horizontal lamellar structure with monomorphic or polymorphic monoclinic PDI crystals. The formation of monomorphic or polymorphic monoclinic crystals is attributed to various π–π stack modes of the PDI units, and is shown to be dependent on the film thickness. The differences in the thin film morphologies are directly reflected into the electrical memory behavior. The thermally annealed films demonstrate high‐performance n‐type unipolar volatile memory behavior within the thickness range of 12−31 nm. The as‐cast films show n‐type unipolar nonvolatile or volatile memory behavior in the range of 12−53 nm. The memory mode of PAcPDI films can be tuned by changing either the morphology or the film thickness.

Amphiphilic Perylene–Calix[4]arene Hybrids: Synthesis and Tunable Self-Assembly

The first highly water-soluble perylene-calix[4]arene hybrid with the calixarene scaffold acting as a structure-determining central platform is presented. In this tetrahedrally shaped amphiphilic architecture the hydrophilic and hydrophobic subunits are oriented at the opposite side of the calixarene platform. The hydrophobic part contains the two perylene diimide moieties, which enable strong π-π interactions in self-assembly processes. Two hydrophilic Newkome-type dendrons provide sufficient water solubility at slightly basic conditions. The tetrahedrally shaped amphiphile displays an unprecedented aggregation behavior down to concentrations as low as 10(-7) mol L(-1). The intriguing self-assembly process of the compound in water as well as under changed polarity conditions, achieved by addition of THF, could be monitored by the complemented use of cryogenic transmission electron microscopy (cryo-TEM), UV-vis spectroscopy, and fluorescence spectroscopy. Molecular-dynamics and molecular modeling simulations helped in understanding the interplay of supramolecular and optical behavior.

The effect of the linking topology on the electrochemical and spectroelectrochemical properties of carbazolyl substituted perylene bisimides

We report on electrochemical and spectroelectrochemical characteristics of two isomeric, carbazolyl substituted perylene bisimides and their polymers. Investigations were carried out in order to determine the effect of the linking topology on their properties.Cyclic voltammetry (CV) measurements of the investigated monomers showed typical two-step reduction of the perylene diimide moiety. The electrochemical oxidation of the studied compounds gave the corresponding polymer, which was deposited on the electrode. The resulting films were also examined by cyclic voltammetry. Investigation indicated both: n-type and p-type doping of polymers. Analysis of redox process of the monomers and polymers was carried out using UV-Vis and EPR spectroscopy. Our studies point to differences in the kinetics of the reduction process, depending on the substitution of the carbazole moiety. Although both monomers easily undergo of electrochemical polymerization, an effect of the linking topology of carbazolyl substituted perylene bisimides on the polymerization process was evidently noticed. Monomer PE2 as well as PE3 led to stable polymers, but polymer based on PE3 displays the conjugation in a longer extend than that based on PE2, where carabazole is linked to perylene diimide at less favorable position 2.

Synthesis and photophysical properties of novel phthalocyanine–perylenediimide–phthalocyanine triad and phthalocyanine–perylenediimide dyads

Three novel multi-component chromophores based on phthalocyanine and perylenediimide moieties were synthesized by one condensation reaction.

Donor–spacer–acceptor monodisperse conjugated co-oligomers for efficient single-molecule photovoltaic cells based on non-fullerene acceptors

The current challenges for efficient bulk heterojunction (BHJ) organic photovoltaics (OPVs) based on organic/polymeric (non-fullerene) acceptors involve difficult control of neat phase separation in the nanoscale, severe geminate charge recombination, etc. Herein, a new molecular design concept, that is to construct donor–spacer–acceptor (D–S–A) co-oligomers with self-assembly properties, is proposed in order to realize ideal film morphology and manipulate the exciton dissociation and geminate charge recombination processes simultaneously. Three D–S–A co-oligomers, i.e.F5T8P-C2, F5T8P-C4 and F5T8P-C6 with oligo(fluorene-alt-bithiophene), perylene diimide (PDI) and alkyl as D-, A- and S-segments, respectively, were synthesized. All three D–S–A co-oligomers can form D–A alternating lamellar nanostructures with periods of ∼15 nm, an ideal nanostructure for BHJ OPVs. Compared to D–A co-oligomer F5T8-epP in which the D- and A-segments are directly connected without the alkyl spacer, the D–S–A co-oligomers not only show higher electron mobilities due to closer packing of PDI moieties, but also exhibit longer lifetimes of the charge-transfer states that can potentially restrain the geminate charge recombination and improve the charge generation efficiency. Accordingly, the single-molecule photovoltaic cells based on the D–S–A co-oligomers exhibit an improved fill factor of 0.47 and a high open-circuit voltage of 1.04 V. In particular, an external quantum efficiency of ∼65%, which is the highest for BHJ OPVs based on non-fullerene acceptor materials, has been demonstrated. By further extending the absorption onset of D–S–A co-oligomers to ∼600 nm, a single-molecule photovoltaic device with a power conversion efficiency of 2.70% has been fabricated. These results prove that high-efficiency BHJ OPVs based on non-fullerene acceptors are achievable if both the film morphology of the D–A blend and D–A interfaces are suitably manipulated.

Photomodulated Self-Assembly of Hydrophobic Thiol Monolayer-Protected Gold Nanorods and Their Alignment in Thermotropic Liquid Crystal

Three terminal thiols possessing azobenzene and perylene diimide (PDI) segments covalently linked by alkylene spacers of different lengths (PnSH, n = 4, 6, and 8) were synthesized to stabilize and functionalize gold nanorods (GNRs) via strong covalent Au–S bonds onto the gold surface. The resulting hydrophobic thiol monolayer-protected GNRs (PnGNRs) were stable in both organic solvent and the solid state and exhibited fascinating photoresponsive self-assembly behavior. The PDI moieties provided π–π interactions to promote GNR self-assemblies while the photoresponsive azobenzene moieties offered a way to phototune the assemblies in a reversible manner. Interestingly, when PnGNRs were mixed with a structurally similar room-temperature thermotropic liquid-crystal perylene diimide (LCP), the UV-irradiated PnGNRs showed more compatibility with the LCP host than their corresponding unirradiated ones. Furthermore, the PnGNRs with varied alkylene chain lengths showed different dispersion abilities in LCP. The UV-irradiated P4GNRs did not disperse well in LCP, whereas the UV-irradiated P6GNRs and P8GNRs dispersed well in LCP and were further aligned upon mechanical shearing. In addition, preliminary molecular simulation was performed to explain this interesting photomodulated self-assembly of the GNRs.