Defect-free Naphthalene Diimide Bithiophene Copolymers with Controlled Molar Mass and High Performance via Direct Arylation Polycondensation

Matsidik, Rukiya; Komber, Hartmut; Luzio, Alessandro; Caironi, Mario; Sommer, Michael

doi:10.1021/jacs.5b03355

Cited by 251 publications

(344 citation statements)

References 50 publications

Supporting

Mentioning

327

Contrasting

Unclassified

Order By: Relevance

“…Amongst the candidate conjugated n-type polymers for OTFTs, naphthalenediimide (NDI) containing copolymers have shown impressive performance to date. [30][31][32][33][34][35] For example the copolymer with bithiophene, poly{[N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-dithiophene)} (P(NDI2OD-T2)) was one of the first high performance n-type polymers. 30,36 Further improvements in performance have come from tuning the co-monomer utilised.…”

Section: Introductionmentioning

confidence: 99%

Anion-induced N-doping of naphthalenediimide polymer semiconductor in organic thin-film transistors

et al. 2018

View full text Add to dashboard Cite

Molecular doping is an important strategy to improve the charge transport properties of organic semiconductors in various electronic devices. Compared to p-type dopants, the development of n-type dopants is especially challenging due to poor dopant stability against atmospheric conditions. In this article, we report the n-doping of the milestone naphthalenediimide-based conjugated polymer P(NDI2OD-T2) in organic thin film transistor devices by soluble anion dopants. The addition of the dopants resulted in the formation of stable radical anions in thin films, as confirmed by EPR spectroscopy. By tuning the dopant concentration via simple solution mixing, the transistor parameters could be readily controlled. Hence the contact resistance between the electrodes and the semiconducting polymer could be significantly reduced, which resulted in the transistor behaviour approaching the desirable gate voltage-independent model. Reduced hysteresis was also observed, thanks to the trap filling by the dopant. Under optimal doping concentrations the channel on-current was increased several fold whilst the on/off ratio was simultaneously increased by around one order of magnitude. Hence doping with soluble organic salts appears to be a promising route to improve the charge transport properties of n-type organic semiconductors.

show abstract

Section: Introductionmentioning

confidence: 99%

Anion-induced N-doping of naphthalenediimide polymer semiconductor in organic thin-film transistors

et al. 2018

View full text Add to dashboard Cite

show abstract

“…[14][15][16][17] Our recent accomplishment of establishing a very simple and highly efficient DAP protocol for NDI-based copolymers in aromatic solvents successfully addressed the hitherto unsolved issue associated with the copolymerization of the NDI unit and suitable C-H monomers. 13,18 Indeed, commonly used Stille polycondensation protocols entail environmental and safety issues, and the fewreported DAP protocols for the synthesis of NDI-based copolymers were either inefficient, led to low molecular weight (MW) or did not allow for structural versatility. 16,[19][20][21] Another intriguing feature of the recently established DAP protocol involves MW control through the in situ C-H activation of aromatic solvents, which clearly increases the degree of synthetic control and thus brings DAP to the forefront of synthetic methods also for this class of materials.…”

Section: Introductionmentioning

confidence: 99%

“…16,[19][20][21] Another intriguing feature of the recently established DAP protocol involves MW control through the in situ C-H activation of aromatic solvents, which clearly increases the degree of synthetic control and thus brings DAP to the forefront of synthetic methods also for this class of materials. 13,18 However, although aromatic solvents are best suited to overcome limited solubilities of conjugated polymers, to control MW and are less toxic than the often used dimethylacetamide (DMAc) in DAP, 7 they are neither ideal considering the principles of green chemistry. 22 Tetrahydofuran (THF) is another frequently used solvent in DAP.…”

Section: Introductionmentioning

confidence: 99%

Effects of PNDIT2 end groups on aggregation, thin film structure, alignment and electron transport in field-effect transistors

et al. 2016

Self Cite

View full text Add to dashboard Cite

To develop greener protocols toward the sustainable production of conjugated polymers, we combine the advantages of atom-economic direct arylation polycondensation (DAP) with those of the green solvent 2-methyltetrahydrofuran (MeTHF). The n-type copolymer PNDIT2 is synthesized from unsubstituted bithiophene (T2) and 2,6-dibromonapthalene diimide (NDIBr 2 ) under simple DAP conditions in MeTHF.Extensive optimization is required to suppress nucleophilic substitution of NDIBr end groups, which severely limits molar mass. Different carboxylic acids, bases, palladium precursors and ligands are successfully screened to enable quantitative yield and satisfyingly high molar masses up to M n,SEC B 20 kDa. In contrast to PNDIT2 made via DAP in toluene with tolyl-chain termini, nucleophilic substitution of NDIBr chain ends in MeTHF finally leads to NDI-OH termination. The influence of different chain termini on the optical, thermal, structural and electronic properties of PNDIT2 is investigated. For samples with identical molecular weight, OH-termination leads to slightly reduced aggregation in solution and bulk crystallinity, a decreased degree of alignment in directionally deposited films, and a consequently reduced, but not compromised, electron mobility with promising values still close to 0.9 cm 2 V À1 s À1.

show abstract

“…[2][3][4][5][6][7][8][9][10][11][12] Therefore by scaling the channel length down to 10-1 μm, in principle OTFTs should be able to operate at relatively high (1-10 MHz) frequencies at reasonable (<10 V) applied voltages. [ 13 ] In practice, apart from some reports, [13][14][15][16][17][18][19][20][21][22] this is often not easy to achieve because of injection issues: [ 23,24 ] contact resistances tend to become dominant over the channel resistance in short channel transistors reducing the expected improvement of device performances.…”

mentioning

confidence: 99%

Injection Length in Staggered Organic Thin Film Transistors: Assessment and Implications for Device Downscaling

Natali

Chen

Maddalena

et al. 2016

Adv Elect Materials

Self Cite

View full text Add to dashboard Cite

of organic semiconductors show carrier mobility in excess of 5 cm 2 V −1 s −1 when employed as active materials in long (>10 μm) channel organic thin fi lm transistors (OTFT). [2][3][4][5][6][7][8][9][10][11][12] Therefore by scaling the channel length down to 10-1 μm, in principle OTFTs should be able to operate at relatively high (1-10 MHz) frequencies at reasonable (<10 V) applied voltages. [ 13 ] In practice, apart from some reports, [13][14][15][16][17][18][19][20][21][22] this is often not easy to achieve because of injection issues: [ 23,24 ] contact resistances tend to become dominant over the channel resistance in short channel transistors reducing the expected improvement of device performances. [ 25 ] This situation is severely limiting the range of applications for OTFTs. [ 26 ] Indeed contact resistances arise from contact/semiconductor interface properties hence they are not expected to scale with the transistor channel length. To address this issue not only suitable modifi cations of the contact/semiconductor interface aimed at enhancing the contact injecting properties have to be implemented, [ 27 ] but also the device topology has to be considered. Staggered OTFTs, where the contacts and the transistor channel do not lie in the same plane, are usually characterized by lower contact resistances than coplanar ones: [ 28 ] while in these latter the injection area is limited by the accumulated channel depth (few nanometers), in the former the overlap between gate and source/drain contacts (many micrometers or even tens of micrometers) can be exploited, as shown in Figure 1 . The gate/contact overlapping length has to be suitably engineered: on the one hand it should be large enough to accommodate the injected current and to minimize contact resistances; but on the other hand it should not be too large because overlapping areas not effectively involved in injection solely result in additional parasitic capacitances that deteriorate the device speed. [ 13,29 ] It is therefore important to quantify the injection length, which is the length over which sizeable carrier injection occurs. [ 30,31 ] Despite the large number of studies on contact effects in OTFTs, [ 24,32 ] few of them discuss the effect of the gate to contact overlap: Xu et al. found a relationship between the optimal contact length and the semiconductor thickness in staggered OTFT. [ 33 ] Park et al. found that threshold voltage, fi eld effect mobility and contact resistances are affected by the contact length in staggered OTFT; [ 34 ] Wang et al. simulated the effect of contact length scaling. [ 35 ] Ante et al. studied the effect of contact In staggered thin fi lm transistors, the injection length is the fraction of the gate to contact overlap that is effectively involved in current injection. Its assessment is important to properly downscale device dimensions. In fact, in order to increase transistor operation speed, the whole device footprint should be downscaled, which means both the gate to contact overlap and the channel length, as ...

show abstract

Defect-free Naphthalene Diimide Bithiophene Copolymers with Controlled Molar Mass and High Performance via Direct Arylation Polycondensation

Cited by 251 publications

References 50 publications

Anion-induced N-doping of naphthalenediimide polymer semiconductor in organic thin-film transistors

Anion-induced N-doping of naphthalenediimide polymer semiconductor in organic thin-film transistors

Effects of PNDIT2 end groups on aggregation, thin film structure, alignment and electron transport in field-effect transistors

Injection Length in Staggered Organic Thin Film Transistors: Assessment and Implications for Device Downscaling

Contact Info

Product

Resources

About