Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM, USA.
Center for Nonlinear Studies , Los Alamos National Laboratory, Los Alamos, NM, USA.
Nat Chem. 2018 Nov;10(11):1089-1095. doi: 10.1038/s41557-018-0126-4. Epub 2018 Sep 3.
The introduction of sp defects into single-walled carbon nanotubes through covalent functionalization can generate new light-emitting states and thus dramatically expand their optical functionality. This may open up routes to enhanced imaging, photon upconversion, and room-temperature single-photon emission at telecom wavelengths. However, a significant challenge in harnessing this potential is that the nominally simple reaction chemistry of nanotube functionalization introduces a broad diversity of emitting states. Precisely defining a narrow band of emission energies necessitates constraining these states, which requires extreme selectivity in molecular binding configuration on the nanotube surface. We show here that such selectivity can be obtained through aryl functionalization of so-called 'zigzag' nanotube structures to achieve a threefold narrowing in emission bandwidth. Accompanying density functional theory modelling reveals that, because of the associated structural symmetry, the defect states become degenerate, thus limiting emission energies to a single narrow band. We show that this behaviour can only result from a predominant selectivity for ortho binding configurations of the aryl groups on the nanotube lattice.
通过共价功能化将 sp 缺陷引入单壁碳纳米管中可以产生新的发光状态，从而极大地扩展其光学功能。这可能为增强成像、光子上转换以及室温下在电信波长的单光子发射开辟途径。然而，利用这种潜力的一个重大挑战是，纳米管功能化的名义上简单的反应化学引入了广泛的发光状态多样性。精确定义狭窄的发射能带宽需要约束这些状态，这需要在纳米管表面上的分子结合构型上具有极高的选择性。我们在这里表明，通过所谓的“锯齿形”纳米管结构的芳基功能化可以获得发射带宽的三倍变窄，从而可以获得这种选择性。伴随的密度泛函理论建模表明，由于相关的结构对称性，缺陷状态变得简并，从而将发射能限制在单个窄带中。我们表明，这种行为只能源自芳基基团在纳米管晶格上的邻位结合构型的主要选择性。
