近日，英国剑桥大学的Richard H. Friend及其研究小组与英国斯旺西大学的Emrys W.Evans等人合作并取得一项新进展。经过不懈努力，他们研究了发光有机自由基中的可逆自旋光界面。相关成果已于2023年8月16日在国际权威学术期刊《自然》上发表。

该研究团队报道了自旋多重性S大于1的有机分子具有高效的发光和接近1的激发态产率。这是通过在三(2,4,6-三氯苯基)甲基咔唑自由基和蒽的共价偶联上设计发射二重态和三重态能级之间的能量共振来实现的。研究人员观察到，在1.8电子伏特附近，二重态光激发在几皮秒内离域到链接的并苯上，并随后演化为纯高自旋态（单基时的四重态，双基时的五重态）的混合自由基-三重态特征。这些高自旋态即使在295开尔文时也可以用微波相干寻址，通过反向系统间交叉到发射态实现光学读出。

此外，对于双基，在返回基态时，先前不相关的基团自旋在蒽的两侧显示出很强的自旋关联性。这一研究方法在室温下同时支持高效率的初始化、自旋操纵和基于光的读出。将发光和高自旋态相结合，为新兴量子技术创造了一个有机材料平台。

据悉，分子为量子信息科学提供了一个通用的平台，是传感和计算应用的候选者。鲁棒的自旋光学界面是利用材料量子资源的关键。到目前为止，碳基的候选材料是不发光的，这阻碍了通过发射来进行光学读出。

附：英文原文

Title: Reversible spin-optical interface in luminescent organic radicals

Author: Gorgon, Sebastian, Lv, Kuo, Grne, Jeannine, Drummond, Bluebell H., Myers, William K., Londi, Giacomo, Ricci, Gaetano, Valverde, Danillo, Tonnel, Claire, Murto, Petri, Romanov, Alexander S., Casanova, David, Dyakonov, Vladimir, Sperlich, Andreas, Beljonne, David, Olivier, Yoann, Li, Feng, Friend, Richard H., Evans, Emrys W.

Issue&Volume: 2023-08-16

Abstract: Molecules present a versatile platform for quantum information science and are candidates for sensing and computation applications. Robust spin-optical interfaces are key to harnessing the quantum resources of materials. To date, carbon-based candidates have been non-luminescent, which prevents optical readout via emission. Here we report organic molecules showing both efficient luminescence and near-unity generation yield of excited states with spin multiplicity S > 1. This was achieved by designing an energy resonance between emissive doublet and triplet levels, here on covalently coupled tris(2,4,6-trichlorophenyl) methyl-carbazole radicals and anthracene. We observed that the doublet photoexcitation delocalized onto the linked acene within a few picoseconds and subsequently evolved to a pure high-spin state (quartet for monoradical, quintet for biradical) of mixed radical–triplet character near 1.8 eV. These high-spin states are coherently addressable with microwaves even at 295K, with optical readout enabled by reverse intersystem crossing to emissive states. Furthermore, for the biradical, on return to the ground state the previously uncorrelated radical spins either side of the anthracene shows strong spin correlation. Our approach simultaneously supports a high efficiency of initialization, spin manipulations and light-based readout at room temperature. The integration of luminescence and high-spin states creates an organic materials platform for emerging quantum technologies.

DOI: 10.1038/s41586-023-06222-1

Source: https://www.nature.com/articles/s41586-023-06222-1