Controlling exciton lifetimes

Exciton coherence lifetimes from electronic structure.

We model the coherent energy transfer of an electronic excitation within covalently linked aromatic homodimers from first-principles. Our results shed light on whether commonly used models of the bath calculated via detailed electronic structure calculations can reproduce the key dynamics. For the systems we model, the time scales of coherent transport are experimentally known from time-depende...

Exciton radiative lifetimes in two-dimensional transition metal dichalcogenides.

Light emission in two-dimensional (2D) transition metal dichalcogenides (TMDs) changes significantly with the number of layers and stacking sequence. While the electronic structure and optical absorption are well understood in 2D-TMDs, much less is known about exciton dynamics and radiative recombination. Here, we show first-principles calculations of intrinsic exciton radiative lifetimes at lo...

Controlling adsorbate vibrational lifetimes using superlattices

We propose using short-period superlattices as substrates to control the vibrational relaxation dynamics of adsorbate overlayers. The mass modulation of superlattices creates both band gaps and large spectral enhancements in the phonon density of states. These modifications can dramatically alter the coupling between vibrational modes of the adsorbate overlayer and the substrate lattice, thereb...

Spatial mapping of exciton lifetimes in single ZnO nanowires

Long exciton lifetimes in stacking-fault-free wurtzite GaAs nanowires