Topic
Exciton
About: Exciton is a research topic. Over the lifetime, 31603 publications have been published within this topic receiving 810642 citations.
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TL;DR: In this paper, an inverted organic solar cell based on poly(3-hexylthiophene) (P3HT) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 (PCBM) was fabricated with an ultrathin Ca electron-transporting layer and MoO3 hole-transport layer.
Abstract: An inverted organic solar cell based on poly(3-hexylthiophene) (P3HT) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 (PCBM) was fabricated with an ultrathin Ca electron-transporting layer and MoO3 hole-transporting layer. The 1 nm Ca on indium tin oxide (ITO) electrode modifies the work function of ITO suitable for electron extraction. An appropriate thickness of MoO3 hole extraction layer is also essential to effectively prevent exciton quenching at the Ag anode, yet not introduce much voltage loss and series resistance. The optical field distribution across the active layer was also simulated to discuss the effect of MoO3 thickness on the photocurrent. The maximum power conversion efficiency obtained was 3.55% under simulated 100 mW/cm2 (AM 1.5G) solar irradiation.
170 citations
TL;DR: In this paper, the compositional dependence of the band gap energy was determined and the free and bound exciton lines for x = 0 and 1 and only broadened bound excititon peaks for other compositions were quantitatively explained based on compositional fluctuations of the cations.
Abstract: Photoluminescence (PL) experiments were carried out at 300 and 12 K to investigate the electro‐optical properties of Cd1−xZnxTe grown by molecular beam epitaxy on GaAs substrates. The compositional dependence of the band‐gap energy was determined. It has a quadratic dependence on x. The near band edge PL spectra at 12 K show free and bound exciton lines for x=0 and 1 and only broadened bound exciton peaks for other compositions. The bound exciton broadenings are quantitatively explained based on the compositional fluctuations of the cations. The PL line shapes give indications of the high quality of the layers.
170 citations
TL;DR: Sub-wavelength-thick, one-dimensional photonic crystals are demonstrated as a designable, compact, and practical platform for strong coupling with atomically thin van der Waals crystals.
Abstract: Semiconductor microcavity polaritons, formed via strong exciton-photon coupling, provide a quantum many-body system on a chip, featuring rich physics phenomena for better photonic technology. However, conventional polariton cavities are bulky, difficult to integrate, and inflexible for mode control, especially for room-temperature materials. Here we demonstrate sub-wavelength-thick, one-dimensional photonic crystals as a designable, compact, and practical platform for strong coupling with atomically thin van der Waals crystals. Polariton dispersions and mode anti-crossings are measured up to room temperature. Non-radiative decay to dark excitons is suppressed due to polariton enhancement of the radiative decay. Unusual features, including highly anisotropic dispersions and adjustable Fano resonances in reflectance, may facilitate high temperature polariton condensation in variable dimensions. Combining slab photonic crystals and van der Waals crystals in the strong coupling regime allows unprecedented engineering flexibility for exploring novel polariton phenomena and device concepts.
169 citations
TL;DR: This work studies the effect of an external biaxial stress on the light emission of single InGaAs/GaAs(001) quantum dots placed onto piezoelectric actuators to provide a robust method to achieve color coincidence in the emission of X and XX, which is a prerequisite for the possible generation of entangled photon pairs via the recently proposed "time reordering" scheme.
Abstract: We study the effect of an external biaxial stress on the light emission of single InGaAs/GaAs(001) quantum dots placed onto piezoelectric actuators. With increasing compression, the emission blueshifts and the binding energies of the positive trion (X+) and biexciton (XX) relative to the neutral exciton (X) show a monotonic increase. This phenomenon is mainly ascribed to changes in electron and hole localization and it provides a robust method to achieve color coincidence in the emission of X and XX, which is a prerequisite for the possible generation of entangled photon pairs via the recently proposed “time reordering” scheme.
169 citations
TL;DR: The influence of an Al(2)O(3) shell on the photoluminescence emission of ZnO nanowires is reported and a model explaining the spectral changes is proposed.
Abstract: We report the influence of an Al2O3 shell on the photoluminescence emission of ZnO nanowires. At room temperature, the spectrum of the core?shell nanowires shows a strong reduction of the relative intensity of the green defect emission with respect to the near-band-edge emission. At 5?K an increase of the relative intensity of the surface exciton band with respect to the donor-bound exciton emission is observed. Annealing the core?shell nanowires at 500??C does not increase the green defect luminescence at 5?K. We propose a model explaining the spectral changes.
169 citations