Limits...
Solution-Processed Donor-Acceptor Polymer Nanowire Network Semiconductors For High-Performance Field-Effect Transistors.

Lei Y, Deng P, Li J, Lin M, Zhu F, Ng TW, Lee CS, Ong BS - Sci Rep (2016)

Bottom Line: Organic field-effect transistors (OFETs) represent a low-cost transistor technology for creating next-generation large-area, flexible and ultra-low-cost electronics.Conversely, the readily soluble, low-MW D-A polymers give low mobility.With the help of cooperative shifting motion of polystyrene chain segments, (I) readily self-assembled and crystallized out in the polystyrene matrix as an interpenetrating, nanowire semiconductor network, providing significantly enhanced mobility (over 8 cm(2)V(-1)s(-1)), on/off ratio (10(7)), and other desirable field-effect properties that meet impactful OFET application requirements.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics and Institute of Advanced Materials, Hong Kong Baptist University, Hong Kong SAR, P. R. China.

ABSTRACT
Organic field-effect transistors (OFETs) represent a low-cost transistor technology for creating next-generation large-area, flexible and ultra-low-cost electronics. Conjugated electron donor-acceptor (D-A) polymers have surfaced as ideal channel semiconductor candidates for OFETs. However, high-molecular weight (MW) D-A polymer semiconductors, which offer high field-effect mobility, generally suffer from processing complications due to limited solubility. Conversely, the readily soluble, low-MW D-A polymers give low mobility. We report herein a facile solution process which transformed a lower-MW, low-mobility diketopyrrolopyrrole-dithienylthieno[3,2-b]thiophene (I) into a high crystalline order and high-mobility semiconductor for OFETs applications. The process involved solution fabrication of a channel semiconductor film from a lower-MW (I) and polystyrene blends. With the help of cooperative shifting motion of polystyrene chain segments, (I) readily self-assembled and crystallized out in the polystyrene matrix as an interpenetrating, nanowire semiconductor network, providing significantly enhanced mobility (over 8 cm(2)V(-1)s(-1)), on/off ratio (10(7)), and other desirable field-effect properties that meet impactful OFET application requirements.

No MeSH data available.


Related in: MedlinePlus

AFM topographic images of thermally annealed films of (I) in monodispersed polystyrenes of various MWs.(a) Mw of polystyrene = 2.2 kg mol−1; (b) Mw of polystyrene = 19.7 kg mol−1; (c) Mw of polystyrene = 97.1 kg mol−1; and (d) Mw of polystyrene = 301.6 kg mol−1; (e) Field-effect mobility as a function of Mw of polystyrene, showing inverse exponential dependence of mobility of (I) on Mw of polystyrene.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4835732&req=5

f6: AFM topographic images of thermally annealed films of (I) in monodispersed polystyrenes of various MWs.(a) Mw of polystyrene = 2.2 kg mol−1; (b) Mw of polystyrene = 19.7 kg mol−1; (c) Mw of polystyrene = 97.1 kg mol−1; and (d) Mw of polystyrene = 301.6 kg mol−1; (e) Field-effect mobility as a function of Mw of polystyrene, showing inverse exponential dependence of mobility of (I) on Mw of polystyrene.

Mentions: Further support for polystyrene as a fluid medium for crystallization of (I) came from the dependence of FET mobility of (I)/polystyrene semiconductor on polystyrene MW. The molecular orders of (I) in (I)/polystyrene film and thus the mobility would be expected to decrease as the viscosity of the medium or MW of polystyrene increase since higher viscosity would hamper the movement of (I), thus inhibiting its self-assembly into higher crystalline orders. For our studies, we used monodispersed polystyrenes of Mw ranging from 2.2 to 301.6 kg mol−1 at a polystyrene loading of 60 wt%. AFM topographic images of thermally annealed films of (I)/polystyrene showed presence of nanowire network features in the film with polystyrene Mw of 2.2 kg mol−1 (Fig. 6a). The network features of (I) degraded gradually as the Mw of polystyrene went up, and became non-existent beyond Mw of ~20 kg mol−1, when isolated islands or blocks of (I) appeared within the polystyrene matrix (Fig. 6b–d). These observations were consistent with the impediment of self-assembly of (I) into higher crystalline orders as the viscosity or Mw of polystyrene was increased. Consequently, degradation in field-effect mobility with increasing Mw of polystyrene was also observed (Fig. 6e), suggesting that low-viscosity or low-Mw polystyrene matrix would be most efficient in facilitating achievement of long-range crystalline orders of (I). With the ~300 kg mol−1-polystyrene in the (I)/polystyrene semiconductor composition, the mobility was still much higher than that of neat (I), reflecting the benefits of polystyrene incorporation. It was observed that while phase separation of nanowire domains occurred with high polystyrene MWs (Fig. 6c,d), extensive nanowire domain overlaps or connectivity existed. This may explain for the observed high FET mobility of the (I)/polystyrene semiconductors as compared to neat (I) semiconductor.


Solution-Processed Donor-Acceptor Polymer Nanowire Network Semiconductors For High-Performance Field-Effect Transistors.

Lei Y, Deng P, Li J, Lin M, Zhu F, Ng TW, Lee CS, Ong BS - Sci Rep (2016)

AFM topographic images of thermally annealed films of (I) in monodispersed polystyrenes of various MWs.(a) Mw of polystyrene = 2.2 kg mol−1; (b) Mw of polystyrene = 19.7 kg mol−1; (c) Mw of polystyrene = 97.1 kg mol−1; and (d) Mw of polystyrene = 301.6 kg mol−1; (e) Field-effect mobility as a function of Mw of polystyrene, showing inverse exponential dependence of mobility of (I) on Mw of polystyrene.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835732&req=5

f6: AFM topographic images of thermally annealed films of (I) in monodispersed polystyrenes of various MWs.(a) Mw of polystyrene = 2.2 kg mol−1; (b) Mw of polystyrene = 19.7 kg mol−1; (c) Mw of polystyrene = 97.1 kg mol−1; and (d) Mw of polystyrene = 301.6 kg mol−1; (e) Field-effect mobility as a function of Mw of polystyrene, showing inverse exponential dependence of mobility of (I) on Mw of polystyrene.
Mentions: Further support for polystyrene as a fluid medium for crystallization of (I) came from the dependence of FET mobility of (I)/polystyrene semiconductor on polystyrene MW. The molecular orders of (I) in (I)/polystyrene film and thus the mobility would be expected to decrease as the viscosity of the medium or MW of polystyrene increase since higher viscosity would hamper the movement of (I), thus inhibiting its self-assembly into higher crystalline orders. For our studies, we used monodispersed polystyrenes of Mw ranging from 2.2 to 301.6 kg mol−1 at a polystyrene loading of 60 wt%. AFM topographic images of thermally annealed films of (I)/polystyrene showed presence of nanowire network features in the film with polystyrene Mw of 2.2 kg mol−1 (Fig. 6a). The network features of (I) degraded gradually as the Mw of polystyrene went up, and became non-existent beyond Mw of ~20 kg mol−1, when isolated islands or blocks of (I) appeared within the polystyrene matrix (Fig. 6b–d). These observations were consistent with the impediment of self-assembly of (I) into higher crystalline orders as the viscosity or Mw of polystyrene was increased. Consequently, degradation in field-effect mobility with increasing Mw of polystyrene was also observed (Fig. 6e), suggesting that low-viscosity or low-Mw polystyrene matrix would be most efficient in facilitating achievement of long-range crystalline orders of (I). With the ~300 kg mol−1-polystyrene in the (I)/polystyrene semiconductor composition, the mobility was still much higher than that of neat (I), reflecting the benefits of polystyrene incorporation. It was observed that while phase separation of nanowire domains occurred with high polystyrene MWs (Fig. 6c,d), extensive nanowire domain overlaps or connectivity existed. This may explain for the observed high FET mobility of the (I)/polystyrene semiconductors as compared to neat (I) semiconductor.

Bottom Line: Organic field-effect transistors (OFETs) represent a low-cost transistor technology for creating next-generation large-area, flexible and ultra-low-cost electronics.Conversely, the readily soluble, low-MW D-A polymers give low mobility.With the help of cooperative shifting motion of polystyrene chain segments, (I) readily self-assembled and crystallized out in the polystyrene matrix as an interpenetrating, nanowire semiconductor network, providing significantly enhanced mobility (over 8 cm(2)V(-1)s(-1)), on/off ratio (10(7)), and other desirable field-effect properties that meet impactful OFET application requirements.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics and Institute of Advanced Materials, Hong Kong Baptist University, Hong Kong SAR, P. R. China.

ABSTRACT
Organic field-effect transistors (OFETs) represent a low-cost transistor technology for creating next-generation large-area, flexible and ultra-low-cost electronics. Conjugated electron donor-acceptor (D-A) polymers have surfaced as ideal channel semiconductor candidates for OFETs. However, high-molecular weight (MW) D-A polymer semiconductors, which offer high field-effect mobility, generally suffer from processing complications due to limited solubility. Conversely, the readily soluble, low-MW D-A polymers give low mobility. We report herein a facile solution process which transformed a lower-MW, low-mobility diketopyrrolopyrrole-dithienylthieno[3,2-b]thiophene (I) into a high crystalline order and high-mobility semiconductor for OFETs applications. The process involved solution fabrication of a channel semiconductor film from a lower-MW (I) and polystyrene blends. With the help of cooperative shifting motion of polystyrene chain segments, (I) readily self-assembled and crystallized out in the polystyrene matrix as an interpenetrating, nanowire semiconductor network, providing significantly enhanced mobility (over 8 cm(2)V(-1)s(-1)), on/off ratio (10(7)), and other desirable field-effect properties that meet impactful OFET application requirements.

No MeSH data available.


Related in: MedlinePlus