Enantiopure distorted ribbon-shaped nanographene combining two-photon absorption- based upconversion and circularly polarized luminescence?

基于雙光子吸收的對映純失真帶狀納米石墨的上轉換和圓偏振發光

https://pubs.rsc.org/en/content/articlelanding/2018/sc/c8sc00427g#!divAbstract

Herein we describe a distorted ribbon-shaped nanographene exhibiting unprecedented combination of optical properties in graphene-related materials, namely upconversion based on two-photon absorption (TPA-UC) together with circularly polarized luminescence (CPL). The compound is a graphene molecule of ca. 2 nm length and 1 nm width with edge defects that promote the distortion of the otherwise planar lattice. The edge defects are an aromatic saddle-shaped ketone unit and a [5]carbohelicene moiety. This system is shown to combine two-photon absorption and circularly polarized luminescence and a remarkably long emission lifetime of 21.5 ns. The [5]helicene is responsible for the chiroptical activity while the push–pull geometry and the extended network of sp2 carbons are factors favoring the nonlinear absorption. Electronic structure theoretical calculations support the interpretation of the results.

在本文中，我們描述了扭曲的帶狀納米石墨烯，其在石墨烯相關材料中展現出前所未有的光學性質組合，即基于雙光子吸收的上轉換（TPA-UC）以及圓偏振發光（CPL）。 該化合物是約的石墨烯分子。 2nm長度和1nm寬度具有邊緣缺陷，其促進平面晶格的變形。 邊緣缺陷是芳香族馬鞍形酮單元和[5]碳硼烷部分。 該系統顯示出雙光子吸收和圓偏振發光以及21.5ns的非常長的發射壽命。 [5]螺旋烯負責手性活動，而推拉幾何和sp2碳的擴展網絡是有利于非線性吸收的因素。 電子結構理論計算支持結果的解釋。