We report on the magneto-optical study of the spatially separated electron and hole layers in GaAs/AlxGa12xAs coupled quantum wells at low temperatures T>50 mK and high magnetic fields B <16 T. At high magnetic fields cusps are observed in the energy and intensity of the indirect ~interwell! exciton photoluminescence. We tentatively attribute these to the commensurability effects of the magneto...

The optical Stark effect is a coherent light-matter interaction describing the modification of quantum states by non-resonant light illumination in atoms, solids and nanostructures. Researchers have strived to utilize this effect to control exciton states, aiming to realize ultra-high-speed optical switches and modulators. However, most studies have focused on the optical Stark effect of only t...

We study theoretically two electron-hole pair states (biexcitons) in core/shell hetero-nanocrystals with type II alignment of energy states, which promotes spatial separation of electrons and holes. To describe Coulomb interactions in these structures, we apply first-order perturbation theory, in which we use an explicit form of the Coulomb-coupling operator that takes into account interface-po...

Carrier multiplication (CM) is a process in which absorption of a single photon produces not just one but multiple electron-hole pairs (excitons). This effect is a potential enabler of next-generation, high-efficiency photovoltaic and photocatalytic systems. On the basis of energy conservation, the minimal photon energy required to activate CM is two energy gaps (2Eg). Here, we analyze CM onset...

: We investigate the effects of coupling between a molecular exciton, which consists of an electron and a hole in a molecule, and a surface plasmon (exciton-plasmon coupling) on the electron transitions of the molecule using nonequilibrium Green's function method. Due to the exciton-plasmon coupling, excitation channels of the molecule arise in the energy range lower than the electronic excitat...

The exciton relaxation process of CsPbI3 perovskite nanocrystals (NCs) has been investigated by using transient absorption (TA) spectroscopy. The hot exciton relaxation process is confirmed to exist in the CsPbI3 NCs, through comparing the TA data of CsPbI3 NCs in low and high energy excitonic states. In addition, the Auger recombination and intrinsic decay paths also participate in the relaxat...

Metal halide perovskites have emerged as versatile photonic device materials because of their outstanding optical properties. Here, we report the two-photon absorption (TPA) spectra for $\mathrm{C}{\mathrm{H}}_{3}\mathrm{N}{\mathrm{H}}_{3}\mathrm{Pb}{\mathrm{Br}}_{3}$ perovskite single crystals under linearly and circularly polarized laser pulses. We experimentally determined spin-orbit splitti...

  Objective(s): A fast and reliable evaluation of the binding energy from a single conformation of a molecular complex is an important practical task. Artificial neural networks (ANNs) are strong tools for predicting nonlinear functions which are used in this paper to predict binding energy. We proposed a structure that obtains binding energy using physicochemical molecular descripti...

Nanocomposites of colloidal quantum dots (QDs) integrated into conjugated polymers (CPs) are key to hybrid optoelectronics, where engineering the excitonic interactions at the nanoscale is crucial. For such excitonic operation, it was believed that exciton diffusion is essential to realize nonradiative energy transfer from CPs to QDs. In this study, contrary to the previous literature, efficien...

Coherent coupling between excitons is at the heart of many-body interactions with transition metal dichalcogenide (TMD) heterostructures as an emergent platform for investigation these interactions. We employ multi-dimensional coherent spectroscopy on monolayer MoSe\textsubscript{2}/WSe\textsubscript{2} and observe spatially localized in MoSe$_2$ WSe$_2$. Through spectroscopy, we further absorp...