Exciton Dynamics and Spectra of Organic Semiconductors
Jianshu Cao, MIT
(I) Calculations of coherent quantum transport in disordered systems reveal an optimal diffusion constant at an intermediate level of noise and temperature and predict charge mobility close to experimental values. [1] Further, we have explored the dependence on the dimensionality and shape and demonstrated the universal scaling of the 1D-2D transition in the diffusion of nanotubes [2]. Though transport is suppressed by disorder, trapping or dissociation can be enhanced by disorder. [3]
(II) Spectroscopic measurements of nanotubes and 2D systems allow us to classify the structure of dipolar lattices beyond the simple rule of H and J aggregates. [4] Further, we have obtained the universal scaling laws of the anisotropic dispersion and the density of states (unpublished) and predicted subsequent spectroscopic signatures including the spectral shift, splitting, and width, and related them to the structure of molecular aggregates. [4,5]
(1) “Coherent quantum transport in disordered systems (III): A unified polaron treatment of hopping and band-like transport” Lee, Moix, Cao, JCP 142, 164103 (2015)
(2) “Quantum diffusion on molecular tubes: Universal scaling of the 1D to 2D transition”. Chuang, Lee, Moix, Knoester, and Cao, Phys. Rev. Lett. 116, 196803 (2016)
(3) “Generic mechanism of optimal energy transfer efficiency: A scaling theory of the mean firstpassage time in exciton systems” Wu, Silbey, Cao, Phys. Rev. Lett 110 (20), 200402 (2013)
(4) “Generalized Kasha's Scheme for Classifying Two-Dimensional Excitonic Molecular Aggregates: Temperature Dependent Absorption Peak Frequency Shift” Chuang, Bennett, Caram, Aspuru-Guzik, Bawendi, J Cao, accepted by CHEM. 5, p3135 (2019)
(5) “Construction of multichromophoric spectra from monomer data: Applications to resonant energy transfer”. Chenu and Cao, Phys. Rev. Lett. 118, 013001 (2017)