We report a detailed study of ultrafast exciton dephasing processes in semiconducting single-walled carbon nanotubes employing a sample highly enriched in a single tube species, the (6,5) tube. Systematic measurements of femtosecond pump-probe, two-pulse photon echo, and three-pulse photon echo peak shift over a broad range of excitation intensities and lattice temperature (from 4.4 to 292 K) e...

Random walk simulations of exciton trapping and annihilation on binary and ternary lattices are presented. Single walker visitation efficiencies for ordered and random binary lattices are compared. Interacting multiple random walkers on binary and ternary random lattices are presented in terms of trapping and annihilation efficiencies that are related to experimental observables. A master equat...

We report on shakeup processes in the luminescence spectra of a negatively charged exciton (X) at moderate magnetic fields. These processes manifest themselves as a series of low-energy satellite peaks emerging from the negatively charged exciton line. We analyze the dependence of the X energy on magnetic field. We conclude that at magnetic fields above ;1 T the X structure can be viewed as an ...

It is suggested that an exciton in the engineered vacuum of a photonic-band-gap-quantum-well heterostructure exhibits electromagnetically induced anomalous quantum dynamics. The exciton is dressed by coherent emission and reabsorption of virtual photons near the photonic band edge and captured in momentum space, lowering its energy by 1-10 meV and lowering its effective mass by 4-5 orders of ma...

Nardeep Kumar,1 Qiannan Cui,1 Frank Ceballos,1 Dawei He,2 Yongsheng Wang,2,* and Hui Zhao1,† 1Department of Physics and Astronomy, The University of Kansas, Lawrence, Kansas 66045, USA 2Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044, China (Received 4 October 2013; revised manuscr...

Excitons are pairs of electrons and holes bound together by the Coulomb interaction. At low temperatures, excitons can form a Bose-Einstein condensate (BEC), enabling macroscopic phase coherence and superfluidity1,2. An electronic double layer (EDL), in which two parallel conducting layers are separated by an insulator, is an ideal platform to realize a stable exciton BEC. In an EDL under stron...

Organic solar cells have the potential to become a low-cost sustainable energy source. Understanding the photoconversion mechanism is key to the design of efficient organic solar cells. In this review, we discuss the processes involved in the photo-electron conversion mechanism, which may be subdivided into exciton harvesting, exciton transport, exciton dissociation, charge transport and extrac...

Through an investigation of photoemission properties of highly photoexcited single-walled carbon nanotubes, we demonstrate that there is an upper limit on the achievable excitonic density. As the intensity of optical excitation increases, all photoluminescence emission peaks arising from different chirality singlewalled carbon nanotubes showed clear saturation in intensity. Each peak exhibited ...