Selective manipulation of electronically excited states through strong light–matter interactions

• Published in: Nature communications Vol. 9; no. 1; pp. 2273 - 7
• Main Authors: Stranius, Kati, Hertzog, Manuel, Börjesson, Karl
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 11.06.2018; Nature Publishing Group; Nature Portfolio
• Subjects: 140/125; 639/301/923/3931; 639/638/440/527/1819; 639/638/440/949; Atomic energy levels; Atomic structure; Chemical Sciences; Coupling (molecular); Decay rate; delayed fluorescence materials; emission; Energy; Energy gap; Energy levels; Excitation; field; Heavy metals; Humanities and Social Sciences; Kemi; Molecular chains; Molecular structure; molecules; multidisciplinary; Organic light emitting diodes; organic microcavities; room-temperature; Science; Science & Technology - Other Topics; Science (multidisciplinary); strong-coupling regime; surface-plasmon polaritons; Triplet state; vacuum
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-018-04736-1

Strong coupling between light and matter leads to the spontaneous formation of hybrid light–matter states, having different energies than the uncoupled states. This opens up for new ways of modifying the energy landscape of molecules without changing their atoms or structure. Heavy metal-free organic light emitting diodes (OLED) use reversed intersystem crossing (RISC) to harvest light from excited triplet states. This is a slow process, thus increasing the rate of RISC could potentially enhance OLED performance. Here we demonstrate selective coupling of the excited singlet state of Erythrosine B without perturbing the energy level of a nearby triplet state. The coupling reduces the triplet–singlet energy gap, leading to a four-time enhancement of the triplet decay rate, most likely due to an enhanced rate of RISC. Furthermore, we anticipate that strong coupling can be used to create energy-inverted molecular systems having a singlet ground and lowest excited state. Manipulating energy levels in molecules could allow applications such as improving organic LEDs. Here, the authors show evidence that reversed intersystem crossing can be enhanced in Erythrosine B coupled to a cavity by selectively manipulating the energy of the singlet state.