Conjugated polymers based on benzodithiophene and arylene imides: Extended absorptions and tunable electrochemical properties

Synthesis of Core-Functionalised Naphthalenediimides from Naphthalenetetracarboxylic Dianhydride using a Vibratory Ball Mill: Bromination, Imidization and Heck-Type Reactions

The synthesis of 9 core-functionalised naphthalene diimide (c-NDI) residues is reported via a 3-step synthesis from naphthalenetetracarboxylic dianhydride using only mechanochemical activation. Selective dibromination and subsequent diimidization were achieved for the first time in a vibratory ball mill, resulting in the key structural intermediate, 2,6-dibromonaphthalenediimide (DBND), which is the basis for elaboration into a multitude of organic electronic materials. Our new synthesis of DBND is achieved in just 5 hours reaction time over two steps compared to typical solution state times of 24 hours. Subsequent Heck-type cross coupling reactions, with a range of styrene residues, produced a series of c-NDIs in good yields. The Heck-type reactions are rapid (1.5 hours), require no additional heating or solvent and are tolerant of atmospheric moisture and air.

Tubular Perylene Bisimide Macrocycles for the Recognition of Geometrical Isomers of Azobenzenes

Perylene bisimide-based materials are good candidates for photosensitive applications. Herein, we report synthesis, characterization, and complexation studies of perylene bisimide macrocycles obtained through bayside coupling. The isomeric macrocycles incorporated with interesting optical properties and tubular-shaped cavities are able to recognize geometric isomers of azobenzenes and aromatic amines. Such selective recognition is useful toward developing potential sensors for interesting isomeric pairs in the future.

Recent progress in wide bandgap conjugated polymer donors for high-performance nonfullerene organic photovoltaics

This feature article summarizes our recent achievements in the development of wide bandgap polymer donors as high-performance organic photovoltaics.

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.

Novel benzodithiophene-based polymer acceptors for efficient organic solar cells

Novel polymer acceptors (P2 and P5) exhibiting high light-absorbing capacity, exciton separation ability, and electron mobility have been designed for OSCs.

Low-Band-Gap BODIPY Conjugated Copolymers for Sensing Volatile Organic Compounds

Conjugated polymers with strong photophysical properties are used in many applications. A homopolymer (P1) and five new low band gap copolymers based on 4,4'-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) and acceptors 3,6-dithienyldiketopyrrolopyrrole (P2), phthalimide (P3), benzotriazole (P4), 4,7-dithienyl[1,2,3]triazolo[4,5g]quinoxaline (P5), and 2,5-dithienylthieno[3,4-b]pyrazine (P6) were prepared by means of Sonogashira polymerization. The characterization of polymers by using (1) H NMR, absorption, and emission spectroscopy is discussed. All polymers with high molecular weights (Mn ) of 16 000 to 89 000 g mol(-1) showed absorption maxima in the deep-red region (λ=630-760 nm) in solution and exhibited significant redshifts (up to 70 nm) in thin films. Polymers P2, P5, and P6 showed narrow optical band gaps of 1.38, 1.35, and 1.38 eV, respectively, which are significantly lower than that of P1 (1.63 eV). The HOMO and LUMO energy levels of the polymers were calculated by using cyclic voltammetry measurements. The LUMO energy levels of BODIPY-based alternating copolymers were independent of the acceptors; this suggests that the major factor that tunes the LUMO energy levels of the polymers could be the BODIPY core. All polymers showed selective and reproducible detection of volatile organic solvents, such as toluene and benzene, which could be used for developing sensors.

Synthesis, spectra, and electron-transfer reaction of aspartic acid-functionalized water-soluble perylene bisimide in aqueous solution

An aspartic acid-functionalized water-soluble perylene bisimide, N,N'-di(2-succinic acid)-perylene-3,4,9,10-tetracarboxylic bisimide (PASP) was synthesized and characterized. It has absorbance maximum A(0-0) and A(0-1) at 527 and 498 nm (ε ≈ 1.7 × 10(4) L cm(-1) mol(-1)) respectively in pH 7.20 HEPES buffer. Two quasi-reversible redox processes with E1/2 at -0.17 and -0.71 V (vs Ag/AgCl) respectively in pH 7-12.5 aqueous solutions. PASP can react with Na2S in pure aqueous solution to form monoanion radical and dianion species consecutively. PASP(-•) has EPR signal with g = 1.998 in aqueous solution, whereas PASP(2-) is EPR silent. The monoanion radical formation is a first-order reaction with k = 8.9 × 10(-2) s(-1). Dianion species formation is a zero-order reaction and the rate constant is 4.3 × 10(-8) mol L(-1) s(-1). The presence of H2O2 greatly increases the radical formation rate constant. PASP as a two-electron transfer reagent is expected to be used in the water photolysis.