Abstract

We describe the expedient synthesis of regioregular thiophene hexadecamers head-to-head (hh) substituted with hexyl and hexylthio grous. The synthesis was carried out by means of a sequence of ultrasound-assisted selective monobrominations and microwave-assisted Suzuki reactions using 4,4,5,5-tetramethyl-1,3,2-dioxaborolane in THF:water. The hexadecamers, which are very soluble in organic solvents, were investigated in solution and thin film by a variety of techniques (UV, PL, CV, X-ray diffraction, FET charge mobility, SKFM) with the aim of elucidating the effect of the sulfur spacer on morphology and functional properties. We show that the sulfur spacer compensates for the decrease in pi-pi conjugation caused by the hh regiochemistry and that the lambda(max) value and redox potentials of the S-alkyl-substituted hexadecamer are similar to those of head-to-tail substituted poly(3-hexylthiophene). Measurements in field effect transistor devices showed that the alkylthio-substituted hexadecamer is a p-type semiconductor while the alkyl-substituted counterpart in the same conditions is not electroactive. Scanning Kelvin force microscopy measurements showed that a blend of the alkylthio-substituted hexadecamer with PCBM displays photovoltaic behavior under illumination. In agreement with this, a bulk heterojunction cell fabricated employing the same blend displayed near 1.5% conversion efficiency without addition of additives or device optimization.

Autore Pugliese

• Rizzo Aurora

Tutti gli autori

• F. Di Maria; M. Gazzano; A. Zanelli; G. Gigli; A. Loiudice; A. Rizzo; M. Biasiucci; E. Salatelli; P. D' Angelo; G. Barbarella

Titolo volume/Rivista

Macromolecules

Anno di pubblicazione

2012

ISSN

0024-9297

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

Ultimo Aggiornamento Citazioni

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Numero di citazioni Scopus

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Ultimo Aggiornamento Citazioni

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Settori ERC

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Codici ASJC

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