Biradicaloid compounds with an open-shell ground state have been the subject of intense research in the past decade. Although diindenoacenes are one of the most developed families, only few examples have been reported as active layer in organic field-effect transistors (OFETs) with charge mobility of around 10−3 cm2 V−1 s−1 due to a steric disadvantage of the mesityl group to kinetically stabilize compounds. Herein, we disclose our efforts to improve the charge transport of the diindenoacene family based on hexahydro-diindenopyrene (HDIP) derivatives with different annelation modes for which the most reactive position has been functionalized with (triisopropylsilyl)ethynyl (TIPS) groups. All the HDIP derivatives show remarkably higher stability than that of TIPS-pentacene, enduring for 2 days to more than 30 days, which depends on the oxidation potential, the contribution of the singlet biradical form in the ground state and the annelation mode. The annelation mode affects not only the band gap and the biradical character (y0) but also the value of singlet-triplet energy gap (ΔES-T) that does not follow the reverse trend of the y0. A method based on comparison between experimental and theoretical bond lengths has been disclosed to estimate the y0 and shows that the y0 computed at projected unrestricted Hartree-Fock (PUHF) is most relevant among all other methods. Thanks to the high stability, thin-film OFETs were successfully fabricated. Well balanced ambipolar transport was obtained in the order of 10−3 cm2 V−1 s−1 in the bottom-gate/top-contact configuration, and unipolar transport in top-gate/bottom-contact configuration was obtained in the order of 10−1 cm2 V−1 s−1 which is the highest value obtained for biradical compounds with a diindenoacene skeleton.

中文翻译：

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调节双自由基六氢二茚并芘衍生物 OFET 中的基态、稳定性和电荷传输以及估计双自由基特性的建议方法

具有开壳基态的双自由基化合物在过去十年中一直是深入研究的主题。尽管二茚并苯是最发达的家族之一，但由于其空间缺陷，只有少数例子被报道为有机场效应晶体管（OFET）中的有源层，其电荷迁移率约为 10−3 cm2 V−1 s−1异丙叉基团可对化合物进行动力学稳定。在此，我们公开了我们在改善基于六氢二茚并芘（HDIP）衍生物的二茚并苯家族的电荷传输方面所做的努力，该衍生物具有不同的退火模式，其中最具反应性的位置已被（三异丙基甲硅烷基）乙炔基（TIPS）基团官能化。所有HDIP衍生物都表现出比TIPS-并五苯更高的稳定性，持续2天到30天以上，这取决于氧化电位、基态单线态双自由基形式的贡献和退火模式。退火模式不仅影响带隙和双自由基特征（y0），而且影响不遵循y0相反趋势的单重态-三重态能隙（ΔES-T）的值。已经公开了一种基于实验键长和理论键长之间的比较的方法来估计 y0，并且表明在投影无限制 Hartree-Fock (PUHF) 下计算的 y0 在所有其他方法中是最相关的。由于稳定性高，薄膜 OFET 得以成功制造。在底栅/顶部接触配置中获得了大约 10−3 cm2 V−1 s−1 的平衡良好的双极传输，在顶栅极/底部接触配置中获得了大约 10 的单极传输−1 cm2 V−1 s−1 这是具有二茚并苯骨架的双自由基化合物获得的最高值。