All-organic thin-film transistors made of poly(3-butylthiophene) semiconducting and various polymeric insulating layers

Abstract

We have fabricated fully patterned all-organic thin-film transistors with a variety of organic polymer insulators. Poly(3-butylthiophene) deposited by spin coating was used as the active organic layer. We have built top-gate structures with gates printed on top of the gate dielectric layer. The field enhanced current is weak with poly(4-vinyl phenol), but much stronger with polyvinyl alcohol and cyanoethylpullulan. Carrier mobilities as large as 0.04 cm2/V s were measured in the case of cyanoethylpullulan. A strong correlation is found between the solvents used for the dielectrics, dielectric constant of the insulator, and the field-effect mobility.

Gate Dielectrics for Organic Field‐Effect Transistors: New Opportunities for Organic Electronics

“…In contrast, Parashkov et al reported an opposite mobility trend when fabricating top-gate TFTs of poly(3-butylthiophene) (P3BT) as the semiconductor. [49] PEDOT:PSS source-drain contacts were defined on polyimide substrates on which a solution of the semiconductor was spin-coated. Subsequently, the gate dielectric was deposited by spin-coating and the device completed by screen-printing PEDOT:PSS gate lines.…”

Current Status and Opportunities of Organic Thin-Film Transistor Technologies

“…A promising solution is to reduce the subgap DOS at the channel through solution processed OSCs, and thus, very small gate dielectric capacitance can be used to realize low operation voltage [77], [112]. This approach provides the possibility of using a wide range of low-k polymer dielectric materials in a relatively thick layer to achieve stable low-voltage OTFTs [69], [74], [75], [88].…”

“…However, there are very few choices of suitable polymer dielectrics with high enough k values. Cyanoethylpullulan (CYEPL) [75], ferroelectric polymer poly (vinylidenefluoride-trifluoroethylene) [P(VDF-TrFE)] [76], and relaxor ferroelectric polymer poly(vinylidene fluoridetrifluoroethylene-chlorofloroethylene) [P(VDF-TrFE-CFE)] [77], [78] have been studied for lowvoltage OTFTs. P(VDF-TrFE-CFE) was reported to have a k value above 60 [78].…”

Direct Ink‐Jet Printing of Ag–Cu Nanoparticle and Ag‐Precursor Based Electrodes for OFET Applications

“…The related build-up of negative charge close to the PVA/P3HT interface causes an accumulation of positive counter-charges in the semiconducting layer leading to an enhanced drain current. Such effects are frequently observed with highly polar gate dielectrics [6,[39][40][41][42] and have to be avoided by applying a different dielectric material or purification procedures. [43] Despite the unstable device characteristics, however, Figure 6 clearly reveals the potential of silver-copper nanoparticle based inkjet printed source, drain and gate electrodes to be applied in allliquid processed OFETs.…”