Imran Muhammad, Wehrmann Caleb M, Chen Mark S
Department of Chemistry , Lehigh University , Bethlehem , Pennsylvania 18015-3102 , United States.
J Am Chem Soc. 2020 Jan 8;142(1):38-43. doi: 10.1021/jacs.9b10677. Epub 2019 Dec 24.
By stabilizing unpaired spin in the ground state, open-shell π-conjugated molecules can achieve optoelectronic properties that are inaccessible to closed-shell compounds. Here, we report the synthesis and characterization of a -substituted, bisphenalenyl π-radical cation [(OTf)] that shows antiambipolar charge transport and fluorescence via anti-Kasha doublet emission. (OTf) produces a red emission (634-659 nm) by radiative decay from β-LUMO to β-SOMO, based on density functional theory and configuration interaction singles calculations, and records one of the highest photostabilities ( = 9.5 × 10 s) among fluorescent radicals. Characterization of (OTf)-based field-effect transistors reveals that the observed electrical conductivity (σ ≤ 1.3 × 10 S/cm) is enabled by hole and electron transport (μ/μ ≤ 5.70 × 10 cm V s) that is most efficient in the absence of gating, which represents the first example of antiambipolarity in a molecular material.
通过稳定基态中的未成对自旋，开壳层π共轭分子可以实现闭壳层化合物无法获得的光电特性。在此，我们报告了一种α-取代的双苯并菲烯基π-自由基阳离子[(OTf)]的合成与表征，该阳离子通过反卡沙双重态发射表现出反双极性电荷传输和荧光。基于密度泛函理论和单组态相互作用计算，(OTf)通过从β-最低未占分子轨道到β-单占据分子轨道的辐射衰变产生红色发射（634 - 659 nm），并记录了荧光自由基中最高的光稳定性之一（= 9.5 × 10 s）。基于(OTf)的场效应晶体管的表征表明，观察到的电导率（σ≤1.3 × 10 S/cm）是由空穴和电子传输（μ/μ≤5.70 × 10 cm V s）实现的，这种传输在没有栅极的情况下最为有效，这代表了分子材料中反双极性的第一个例子。
