Excitonic fine structure in emission of linear carbon chains

• Main Authors: Kutrovskaya, Stella, Osipov, Anton, Baryshev, Stepan, Zasedatelev, Anton, Samyshkin, Vladislav, Demirchyan, Sevak, Pulci, Olivia, Grassano, Davide, Gontrani, Lorenzo, Hartmann, Richard Rudolph, Portnoi, Mikhail E., Kucherik, Alexey, Lagoudakis, Pavlos G., Kavokin, Alexey
• Format: text
• Published: Animo Repository 2020
• Subjects: Carbon; Exciton theory; Luminescence spectroscopy; Chemical Engineering
• Online Access: https://animorepository.dlsu.edu.ph/faculty_research/2479; https://animorepository.dlsu.edu.ph/context/faculty_research/article/3478/type/native/viewcontent
• Institution: De La Salle University

We studied monatomic linear carbon chains stabilized by gold nanoparticles attached to their ends and deposited on a solid substrate. We observe spectral features of straight chains containing from 8 to 24 atoms. Low-temperature PL spectra reveal characteristic triplet fine structures that repeat themselves for carbon chains of different lengths. The triplet is invariably composed of a sharp intense peak accompanied by two broader satellites situated 15 and 40 meV below the main peak. We interpret these resonances as an edge-state neutral exciton and positively and negatively charged trions, respectively. The time-resolved PL shows that the radiative lifetime of the observed quasiparticles is about 1 ns, and it increases with the increase of the length of the chain. At high temperatures a nonradiative exciton decay channel appears due to the thermal hopping of carriers between parallel carbon chains. Excitons in carbon chains possess large oscillator strengths and extremely low inhomogeneous broadenings.