Now showing items 1-3 of 3

    • Anomalous phosphorescence from an organometallic white-light phosphor 

      Paul, Lopa; Chakrabarti, Swapan; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-09-25)
      We report theoretical results on the possible violation of Kasha’s rule in the phosphorescence process of (acetylacetonato)bis(1-methyl-2-phenylimidazole)iridium(III), and show that the anomalous emission from both the T1 and T2 states is key to its white-light phosphorescence. This analysis is supported by the calculated Boltzmann-averaged phosphorescence lifetime of 2.21 μs, estimated including ...
    • Origin of Dual-Peak Phosphorescence and Ultralong Lifetime of 4,6-Diethoxy-2-carbazolyl-1,3,5-triazine 

      Paul, Lopa; Chakrabarti, Swapan; Ruud, Kenneth (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-03-02)
      Recently, ultralong phosphorescence lifetime has been observed in 4,6-diethoxy-2-carbazolyl-1,3,5-triazine, and H-aggregation induced stabilization of the T1 state was suggested as its source. The response theory calculations demonstrate that the Davydov stabilization of the T1 state of the dimer is marginal with respect to the monomer and the corresponding transition moments are virtually the same. ...
    • Unraveling the Microscopic Origin of Triplet Lasing from Organic Solids 

      Paul, Lopa; Banerjee, Ambar; Paul, Ankan; Ruud, Kenneth; Chakrabarti, Swapan (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-07-16)
      We present a heuristic mechanism for the origin of the unusual triplet lasing from (E)-3-(((4-nitrophenyl)imino)methyl)-2H-thiochroman-4-olate·BF<sub>2</sub>. We demonstrate that whereas the moderate lifetime (1.03 μs) of the first triplet state (T<sub>1</sub>) prohibits triplet–triplet annihilation, the relatively faster S<sub>1</sub> → T<sub>1</sub> intersystem crossing and the 10<sup>4</sup> times ...