4 research outputs found
Conjugated Random Donor–Acceptor Copolymers of [1]Benzothieno[3,2‑<i>b</i>]benzothiophene and Diketopyrrolopyrrole Units for High Performance Polymeric Semiconductor Applications
Three-component
random copolymers having different ratios of [1]ÂbenzothienoÂ[3,2-<i>b</i>]Âbenzothiophene (BTBT) and diketopyrrolopyrrole (DPP) units
were synthesized, and their application in organic field effect transistors
(OFET) has been discussed. These low band gap polymers exhibit p-type
semiconducting properties, and it has been observed that increase
in the percentage composition of the fused chalcogenophene (BTBT)
in the polymer backbone significantly improves the charge carrier
mobility (μ<sub>h</sub>) up to 2.47 cm<sup>2</sup> V<sup>–1</sup> s<sup>–1</sup>. The GIXRD technique and AFM have been used
to explain the influence of BTBT on the nature of molecular packing
in the polymer thin films. These results unveil the role of the effective
conjugation length as well as the intermolecular ordering of the polymer
chains on the charge carrier transport in OFET
Tuning the Semiconducting Behaviors of New Alternating Dithienyldiketopyrrolopyrrole–Azulene Conjugated Polymers by Varying the Linking Positions of Azulene
Three
new conjugated polymers <b>DPPA1</b>, <b>DPPA2</b>, and <b>DPPA3</b> with dithienyldiketopyrrolopyrrole (DPP) and azulene
moieties were synthesized and characterized. The five-membered rings
of azulene are connected with DPP in <b>DPPA1</b> and <b>DPPA2</b>, whereas the seven-membered ring of azulene is incorporated
into the backbone of <b>DPPA3</b>. The LUMO energy of <b>DPPA3</b>, which was determined on the basis of the respective
cyclic voltammograms and absorption spectra, is lower than those of <b>DPPA1</b> and <b>DPPA2</b>. OFETs were successfully fabricated
with thin films of <b>DPPA1</b>, <b>DPPA2</b>, and <b>DPPA3</b>. Thin films of <b>DPPA1</b> and <b>DPPA2</b> exhibit p-type semiconducting properties with hole mobilities up
to 0.97 cm<sup>2</sup> V<sup>–1</sup> s<sup>–1</sup>, whereas typical ambipolar behavior is found for thin film of <b>DPPA3</b> with hole and electron mobilities reaching 0.062 cm<sup>2</sup> V<sup>–1</sup> s<sup>–1</sup> and 0.021 cm<sup>2</sup> V<sup>–1</sup> s<sup>–1</sup>, respectively.
The results reveal that semiconducting properties of <b>DPPA1</b>, <b>DPPA2</b>, and <b>DPPA3</b> can be tuned by varying
the linkage positions of azulene with DPP moieties. Furthermore, <b>DPPA1</b>, <b>DPPA2</b>, and <b>DPPA3</b> were tested
preliminarily as photovoltaic materials. The power conversion efficiency
(PCE) reaches 2.04% for the blending thin film <b>DPPA1</b> with
PC<sub>71</sub>BM
New Donor–Acceptor–Donor Molecules with Pechmann Dye as the Core Moiety for Solution-Processed Good-Performance Organic Field-Effect Transistors
In this paper, we report the synthesis and characterization
of
two new D-A-D molecules (<i>E</i>)-5,5′-bisÂ(5-(benzoÂ[<i>b</i>]Âthiophen-2-yl)Âthiophen-2-yl)-1,1′-bisÂ(2-ethyl-
hexyl)-[3,3′-bipyrrolylidene]-2,2′(1<i>H</i>,1′<i>H</i>)-dione (<b>BTBPD</b>) and (<i>E</i>)-5,5′-bis- (5-(benzoÂ[<i>b</i>]Âfuran-2-yl)Âthiophen-2-yl)-1,1′-bisÂ(2-ethylhexyl)-[3,3′-bipyrrolylidene]-2,2′(1<i>H</i>,1′<i>H</i>)-dione (<b>BFBPD</b>). They entail bipyrrolylidene-2,2′(1<i>H</i>,1′<i>H</i>)-dione (<b>BPD</b>, known as Pechmann dye) as the
electron-accepting core that is flanked by two benzoÂ[<i>b</i>]Âthiophene moieties and two benzoÂ[<i>b</i>]Âfuran moieties,
respectively. Crystal structures of <b>BTBPD</b> and <b>BFBPD</b> provide solid evidence for the intermolecular donor–acceptor
(D-A) interactions, which are favorable for improving charge transport
performance. Organic field-effect transistors (OFETs) were prepared
based on thin films of <b>BTBPD</b> and <b>BFBPD</b> through
solution-processed technique. OFETs of <b>BTBPD</b> exhibit
relatively high hole mobility up to 1.4 cm<sup>2</sup> V<sup>–1</sup> s<sup>–1</sup> with high on/off ratio up to 10<sup>6</sup>. In comparison, the hole mobility of OFETs with <b>BFBPD</b> (0.14 cm<sup>2</sup> V<sup>–1</sup> s<sup>–1</sup>) is relatively low, because of the poor thin-film morphology and
low molecular ordering, even after annealing. Thin-film morphological
and XRD studies were carried out to understand the variation of hole
mobilities after annealing at different temperatures. The present
studies clearly demonstrate the potentials of <b>BPD</b> that
is planar and polar as the electron-acceptor moiety to build D-A molecules
for organic semiconductors with good performance
New Donor–Acceptor–Donor Molecules with Pechmann Dye as the Core Moiety for Solution-Processed Good-Performance Organic Field-Effect Transistors
In this paper, we report the synthesis and characterization
of
two new D-A-D molecules (<i>E</i>)-5,5′-bisÂ(5-(benzoÂ[<i>b</i>]Âthiophen-2-yl)Âthiophen-2-yl)-1,1′-bisÂ(2-ethyl-
hexyl)-[3,3′-bipyrrolylidene]-2,2′(1<i>H</i>,1′<i>H</i>)-dione (<b>BTBPD</b>) and (<i>E</i>)-5,5′-bis- (5-(benzoÂ[<i>b</i>]Âfuran-2-yl)Âthiophen-2-yl)-1,1′-bisÂ(2-ethylhexyl)-[3,3′-bipyrrolylidene]-2,2′(1<i>H</i>,1′<i>H</i>)-dione (<b>BFBPD</b>). They entail bipyrrolylidene-2,2′(1<i>H</i>,1′<i>H</i>)-dione (<b>BPD</b>, known as Pechmann dye) as the
electron-accepting core that is flanked by two benzoÂ[<i>b</i>]Âthiophene moieties and two benzoÂ[<i>b</i>]Âfuran moieties,
respectively. Crystal structures of <b>BTBPD</b> and <b>BFBPD</b> provide solid evidence for the intermolecular donor–acceptor
(D-A) interactions, which are favorable for improving charge transport
performance. Organic field-effect transistors (OFETs) were prepared
based on thin films of <b>BTBPD</b> and <b>BFBPD</b> through
solution-processed technique. OFETs of <b>BTBPD</b> exhibit
relatively high hole mobility up to 1.4 cm<sup>2</sup> V<sup>–1</sup> s<sup>–1</sup> with high on/off ratio up to 10<sup>6</sup>. In comparison, the hole mobility of OFETs with <b>BFBPD</b> (0.14 cm<sup>2</sup> V<sup>–1</sup> s<sup>–1</sup>) is relatively low, because of the poor thin-film morphology and
low molecular ordering, even after annealing. Thin-film morphological
and XRD studies were carried out to understand the variation of hole
mobilities after annealing at different temperatures. The present
studies clearly demonstrate the potentials of <b>BPD</b> that
is planar and polar as the electron-acceptor moiety to build D-A molecules
for organic semiconductors with good performance