Exciton

About: Exciton is a research topic. Over the lifetime, 31603 publications have been published within this topic receiving 810642 citations.

Organic photosensitive optoelectronic device with an exciton blocking layer

Abstract: An organic photosensitive optoelectronic device having a plurality of cells disposed between a first electrode and a second electrode. Each cell includes a photoconductive organic hole transport layer adjacent to a photoconductive organic electron transport layer. A metal or metal substitute is disposed between each of the cells. At least one exciton blocking layer is disposed between the first electrode and the second electrode.

An exciton-polariton laser based on biologically produced fluorescent protein

Abstract: Under adequate conditions, cavity polaritons form a macroscopic coherent quantum state, known as polariton condensate. Compared to Wannier-Mott excitons in inorganic semiconductors, the localized Frenkel excitons in organic emitter materials show weaker interaction with each other but stronger coupling to light, which recently enabled the first realization of a polariton condensate at room temperature. However, this required ultrafast optical pumping, which limits the applications of organic polariton condensates. We demonstrate room temperature polariton condensates of cavity polaritons in simple laminated microcavities filled with biologically produced enhanced green fluorescent protein (eGFP). The unique molecular structure of eGFP prevents exciton annihilation even at high excitation densities, thus facilitating polariton condensation under conventional nanosecond pumping. Condensation is clearly evidenced by a distinct threshold, an interaction-induced blueshift of the condensate, long-range coherence, and the presence of a second threshold at higher excitation density that is associated with the onset of photon lasing.

Large-scale room-temperature synthesis and optical properties of perovskite-related Cs4PbBr6 fluorophores

Abstract: Currently, metal–halide perovskite semiconductors have attracted enormous attention for their excellent optical performance. However, challenging issues, such as the ability to perform large-scale synthesis as well as the thermal/moisture stability, limit their practical applications. Herein, we developed an inhomogeneous interface reaction strategy in a liquid–liquid immiscible two-phase system to realize the large-scale room temperature synthesis of novel perovskite-related Cs4PbBr6 semiconductors. Although the sizes were on the micrometer scale, the Cs4PbBr6 products exhibited bright green luminescence with a narrow line-width originating from exciton recombination confined in PbBr64− octahedra, and the photoluminescence quantum yields reached 40–45% owing to a large exciton binding energy of 222 meV. Furthermore, temperature cycling experiments demonstrated their excellent thermal stability with repeatable and reversible luminescence, and moisture-resistance experiments showed ∼65% of quantum yield loss after exposure to air for one month. Finally, a prototype white light-emitting diode device with a low correlated color temperature of 3675 K and a high color rendering index of 83 was constructed using green emissive Cs4PbBr6 and red emissive Eu2+:CaAlSiN3 phosphors, certainly indicating its promising applications in the optoelectronics field.

Spatial and spectral shape of inhomogeneous nonequilibrium exciton-polariton condensates

Abstract: We develop a mean-field theory of the spatial profile and the spectral properties of polariton condensates in nonresonantly pumped semiconductor microcavities in the strong coupling regime. Specific signatures of the nonequilibrium character of the condensation process are pointed out: a striking sensitivity of the condensate shape on the optical pump spot size is demonstrated by analytical and numerical calculations, in good quantitative agreement with recent experimental observations.