Electrochemical gating of a hydrophobic organic semiconductor with aqueous media

THIN SOLID FILMS

卷:669

Article

Al Baroot, Abbad^1,2  Alshammari, Alhulw^1,3  Grell, Martin¹ 

[1] Univ Sheffield, Dept Phys & Astron, Hicks Bldg,Hounsfield Rd, Sheffield S3 7RH, S Yorkshire, England

[2] Imam Abdulrahman Bin Faisal Univ, Dept Phys, King Faisal Rd, Dammam 34212, Saudi Arabia

[3] Al Jouf Univ, Dept Phys, Airport St 72388, Sakaka, Saudi Arabia

关键词: Picric acid;    Poly [2,5-bis (3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene];    Regioregular poly(3-hexithiophene);    Organic electrochemical transistor;   

DOI  :  10.1016/j.tsf.2018.11.032

来源: Elsevier

【 摘 要 】

We show that even the highly hydrophobic semiconducting polymer poly [2,5-bis(3-tetradecylthiophen-2-yl) thieno[3,2-b]thiophene] (PBTTT) can operate in organic electrochemical transistor (OECT) rather than field effect (OFET) mode when gated with aqueous media. The required bulk penetration of anions into the semiconducting film within the electrochemical window of water is here enabled by the choice of anion, namely, picric acid (PA). OECT mode operation in PBTTT films or its analogues had previously been seen only when gated with solid electrolytes with a larger electrochemical window, or for PBTTT analogues with hydrophilic sidechains. We assign the ability of PA anions to penetrate bulk PBTTT from their similarity to PBTTT solvents (chlorinated benzenes), in the sense that they both display an electron-deficient pi electron system. In control experiments, we confirm that OECT mode is not observed when gating PBTTT with another organic acid (acetic acid) that does not display such pi electron system, and that the gating mechanism indeed is electrochemical doping rather than a charge transfer mechanism. OECT mode is observed only at rather high PA concentrations in an aqueous gate medium (50 mM or more), but when it is, it leads to conductivities of approximate to 80 S/cm, slightly larger than for a PBTTT analogue with hydrophilic side chains gated with chloride anions.

【 授权许可】

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