Improved Performance in n-Type Organic Field-Effect Transistors via Polyelectrolyte-Mediated Interfacial Doping
발표자
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초록
내용
A series of nonconjugated polyelectrolyte (NPE) based on an ethoxylated polyethylenimine backbone with various counterions, including Cl−, Br−, and I−, improve electron mobilities up to ≈10−2 cm2 V−1 s−1 and yield on–off ratios of 105 in PCBM OFETs. UPS reveals that all of the NPEs lead to reduced electron injection barriers at the NPE/metal interface which is consistent with dipole formation or n-type doping at the electrode interface. Absorption measurements of PCBM films treated with NPEs are consistent with n-doping of the PCBM. Regardless of the type of anion, thick NPE layers lead to high conductivity in the films independent of gate bias, whereas thin NPE layers lead to dramatically improved electron injection and performance. These results demonstrate that thin polyelectrolyte layers can be used to achieve controlled interfacial doping in organic semiconductors.