Synthesis of a Low-Bandgap Fluorinated Donor–Acceptor Copolymer and Its Optoelectronic Application

Abstract

We demonstrate the synthesis of a new copolymer which is composed of dialkyl thienylated benzodithiophene and perfluororalkyl-carbonyl thienothiophene (DTBDT-TTFO) and the characterization of its optoelectronic properties. The introduction of thienyl groups enabled the extended delocalization of π electrons in the DTBDT-TTFO backbone and efficient intermolecular charge transport as proved by the fairly high field effect mobility of 0.02 cm(2)/(V s). The introduction of perfluororalkyl-carbonyl side chains resulted in a significant red-shift of DTBDT-TTFO in the absorption spectra and a decrease in the HOMO and LUMO levels. The resulting energy levels of DTBDT-TTFO were not satisfactory for solar cell applications, especially in terms of charge separation at the polymer/PCBM interfaces. Rather, the DTBDT-TTFO showed better energy level matching with the colloidal nanocrystals (NCs) of CdSe. A photodetector based on the bulkheterojunction of DTBDT-TTFO and CdSe NCs with coplanar device geometry resulted in a high photoconductive gain (responsivity higher than 1A/W under a low operating voltage of 1 V), possibly arising from electron trapping at CdSe NCs such that the hole can travel along the detector and its surrounding circuit. More importantly, the photodetector revealed a time constant of a few hundreds of microseconds, which means that the response speed of the photodetector is fast enough for lag-free imaging applications.

Nicotinonitrile centered luminescent polymeric materials: Structural, optical, electrochemical, and theoretical investigations

“…The reaction pathways followed for the preparation of respective monomers and new polymeric materials [45][46][47][48] The monomer used for the polymerization, viz. 4,6-bis(3 0 -formyl-[1,1 0 -biphenyl]-4-yl)-2-(heptyloxy) nicotinonitrile (7) was obtained in good yield by reacting 3-formylphenyl boronic acid (6) with the aforementioned intermediate, (4). Finally, this monomer was condensed with different difunctional molecules, viz.…”

“…Over the last two decades, π-conjugative polymers possessing excellent optical and electrical properties have engrossed considerable attention due to their attractive benefits of being solution-processable, light-weight, and cost-effective [1][2][3] and further merits like a facile synthesis, tunable bandgap, and good flexibility. [4][5] Indeed, they find their major applications in organic electronics devices, such as organic/polymer light-emitting diodes (PLEDs), organic photovoltaic cells, organic field-effect transistors, sensors, and imaging materials. [6][7][8] Among them, currently, the PLEDs are a rapidly progressing technology owing to their utility in energy-saving solidstate lighting and flat-panel full-color displays with many Naveenchandra Pilicode and Praveen Naik contibuted equally to this study.…”

Fused Thiophenes and Some Oligomers and Polymers Therefrom

“…Thus, reaction of thieno [3,4-b]thiophene-2-carbaldehyde (150) with heptadecafluorooctyl iodide in the presence of methyllithium to form 170 was followed by oxidation with MnO 2 giving ketone 171. Bromination with two equivalents of NBS furnished dibromide 172, and this was Stille cross-coupled with 173 in the presence of Pd 2 (dba) 3 to obtain the copolymer 174 [63].…”

Dithieno[2,3‐d:2',3'‐d']benzo[1,2‐b:4,5‐b']dithiophene (DTBDAT)‐based copolymers for high‐performance organic solar cells

“…DTBDAT can be prepared using a TCNT moiety as an electron acceptor unit, which helps to strengthen the intermolecular interactions between polymer chains, resulting in relatively large charge carrier mobility. Here we investigate the structural properties of P(BDT‐TCNT) and P(DTBDAT‐TCNT) with extended conjugations for applications in organic thin film transistor (TFTs) and organic solar cells (OSCs) …”