导电高分子Conductive polymer

共轭主链中 π 轨道重叠形成能带，但由于派尔斯畸变，单双键交替使能隙约 1–3 eV，未掺杂时是绝缘体或半导体。用碘、AsF₅ 等氧化（p 型掺杂）或用碱金属还原（n 型掺杂）后，链上产生可移动的电荷载体——孤子、极化子和双极化子，电导率可提高 10 个数量级以上。掺杂伴随对离子进入，是可逆的化学过程。

Overlapping π orbitals along a conjugated backbone form bands, but Peierls distortion makes single and double bonds alternate, leaving a gap of about 1–3 eV, so undoped polymers are insulators or semiconductors. Oxidising with iodine or AsF₅ (p-doping) or reducing with alkali metals (n-doping) creates mobile charge carriers, solitons, polarons and bipolarons, and raises conductivity by more than ten orders of magnitude. Doping brings in counter-ions and is a reversible chemical process.

1967 年前后，白川英树实验室的一名访问学者在合成聚乙炔时误将齐格勒-纳塔催化剂加多约一千倍，得到银色光泽的聚乙炔薄膜。1976–1977 年白川英树与麦克迪尔米德、黑格合作，发现碘掺杂使聚乙炔电导率提高约 10⁹ 倍。三人因此获得 2000 年诺贝尔化学奖。

Around 1967 a visiting researcher in Hideki Shirakawa's laboratory added roughly a thousand times too much Ziegler–Natta catalyst while making polyacetylene and obtained silvery films. In 1976–77 Shirakawa, working with MacDiarmid and Heeger, found that iodine doping raised polyacetylene's conductivity about a billionfold. The three shared the 2000 Nobel Prize in Chemistry.

PEDOT:PSS 用作透明导电涂层、抗静电材料和有机发光二极管（OLED）的空穴注入层；聚苯胺用于防腐涂料和传感器；共轭聚合物还用于有机太阳能电池、有机场效应晶体管、电致变色窗、柔性电子和生物电极。聚乙炔本身在空气中不稳定，实际应用较少。

PEDOT:PSS serves as transparent conductive coating, antistatic material and hole-injection layer in organic light-emitting diodes (OLEDs); polyaniline goes into anticorrosion coatings and sensors; conjugated polymers are used in organic solar cells, organic field-effect transistors, electrochromic windows, flexible electronics and bioelectrodes. Polyacetylene itself is unstable in air and little used.