Synthesis and photophysical characterization of isoindigo building blocks as molecular acceptors for organic photovoltaics

Five isoindigo-based donor-acceptor-donor (D-A-D) type small molecules have been synthesized in order to investigate their intramolecular charge transfer characteristics. UV-vis absorption of these dyes exhibits a wide absorption band ranging from 300 to 650 nm with two distinct bands, giving the narrow bandgaps between 1.72 and 1.85 eV. Taking into account their HOMO-LUMO energy levels and bandgaps, isoindigo dyes have been used in the active layer of organic solar cell (OSC) devices. When these small molecule semiconductors were used as acceptors with the donor poly(3-hexylthiophene-2,5-diyl (P3HT) polymer in the inverted OSC devices, the highest power conversion efficiency (PCE) was obtained as 0.10% for pyrene-substituted isoindigo derivative.

Direct (Hetero)Arylation for the Synthesis of Molecular Materials: Coupling Thieno[3,4-c]pyrrole-4,6-dione with Perylene Diimide to Yield Novel Non-Fullerene Acceptors for Organic Solar Cells

Herein we report on the synthesis of an N-annulated perylene diimide (PDI) disubstituted thieno[3,4-c]pyrrole-4,6-dione (TPD) molecular acceptor (PDI–TPD–PDI) by direct heteroarylation (DHA) methods. Three sets of DHA conditions that explore the effects of solvent, temperature, and catalyst were employed to find the optimal conditions for the synthesis of two PDI–TPD–PDI derivatives. We then selected one PDI–TPD–PDI for use as a non-fullerene acceptor in organic solar cell devices with the donor polymer PBDB-T. Active layer bulk-heterojunction blends were modified using several post-deposition treatments, including thermal annealing, solvent vapour annealing, and high boiling solvent additives. It was found that active layers cast from o-dichlorobenzene with a 3% v/v diphenylether additive yielded films with adequate phase separation, and subsequently gave the best organic solar cell performance, with power conversion efficiencies greater than 3%.

Exploiting direct heteroarylation polymerization homocoupling defects for the synthesis of a molecular dimer

Molecular dimerization: an effective design strategy for spectral engineering.

Fullerene-free polymer solar cells processed from non-halogenated solvents in air with PCE of 4.8%

Progress towards practical organic solar cells amenable to large scale production is reported.

Synthesis and characterization of acceptor–donor–acceptor-based low band gap small molecules containing benzoselenadiazole

Acceptor–donor–acceptor-type compounds 5′,5″-(benzo[c][1,2,5]selenadiazole-4,7-diyl)bis(3′-dodecyl-2,2′-bithiophene-5-carbonitrile) (9) and 4,4′-(5,5′-(benzo[c][1,2,5]selenadiazole-4,7-diyl)bis(3-dodecylthiophene-5,2-diyl))dibenzonitrile (10) were designed and synthesized. These compounds differ in terminal positions, compound 9 with a thiophene-containing nitrile group and compound 10 with a phenyl-containing nitrile group. Both compounds have shown good thermal stability and low band gap. The band gaps of compounds 9 and 10 were 1.74 and 1.83 eV, respectively. These results indicate that they are promising materials for use in optoelectronics.

Modulation of band gap and p- versus n-semiconductor character of ADA dyes by core and acceptor group variation

By variation of donor and acceptor building blocks in acceptor–donor–acceptor dyes a transition from p- to n-type semiconductor has been achieved.

Structure–properties relationship in diketopyrrolopyrrole based small molecules using functional terminal side chains via direct arylation: a joint experimental and theoretical study

The role of terminal side chains in diketopyrrolopyrrole based small molecules has been analyzed, demonstrating how their optoelectronic properties vary.

Understanding the morphology of solution processed fullerene-free small molecule bulk heterojunction blends

The impact of processing conditions on the morphological characteristics of bulk-heterojunction molecular blends prepared from small molecules based on diketopyrrolopyrrole (DPP) and perylene-diimide (PDI) chromophores have been investigated.

Synthesis and structure–property relationships of phthalimide and naphthalimide based organic π-conjugated small molecules

Six organic π-conjugated small molecules with a bithiophene core and aryl imide terminal units are reported. The impact of alky side chain length and topology, and aryl imide size on materials properties in solution and as thin-films was investigated.

Fine chemical syntheses under flow using SiliaCat catalysts

After reviewing selected recent applications from diverse laboratories, we show how mesoporous organosilica-entrapped catalysts of the SiliaCat series have been successfully used for clean manufacturing of APIs in a number of different reactions carried out under laminar flow in microreactors.

Utility of a heterogeneous palladium catalyst for the synthesis of a molecular semiconductor via Stille, Suzuki, and direct heteroarylation cross-coupling reactions

Demonstration of the utility of a commercially available heterogeneous palladium catalyst in the synthesis of a relevant high performance molecular semiconductor.

The structural evolution of an isoindigo-based non-fullerene acceptor for use in organic photovoltaics

The structural evolution of an isoindigo molecule acceptor.

Synthesis and photovoltaic properties of A–D–A type non-fullerene acceptors containing isoindigo terminal units

Four solution-processable acceptor–donor–acceptor structured organic molecules with isoindigo as terminal acceptor units and different aromatic rigid planar cores as donor units were designed and synthesized as the acceptor materials in organic solar cells (OSCs).

A narrow band gap isoindigo based molecular donor for solution processed organic solar cells

Organic photovoltaics devices with 3.2% PCE were demonstrated using an isoindigo small molecule donor: fullerene acceptor active layer.

Facile synthesis of unsymmetrical and π-extended furan-diketopyrrolopyrrole derivatives through C–H direct (hetero)arylation using a heterogeneous catalyst system

We report a synthetic method that enables efficient and rapid access to a family of narrow band gap DPP materials.