Synthesis, characterization and its photoluminescence properties of group I-III-VI2 CuInS2 nanocrystals

We report the synthesis, characterization, and photoluminescence (PL) properties of colloidal I-III-VI2 CuInS2 and CuInS2/ZnS nanocrystals (NCs). Absorption shoulder and PL bands of the NCs are located at higher energy than those of band gap energy of bulk crystals due to a quantum-confinement effect. The PL band has a relatively large Stokes-shift, broad linewidth, and long decay-time, which suggests that the PL originates from a recombination of confined-excitions associated with donor(s) and/or acceptor(s). We found that quantum yield of the PL depends strongly on the photon-energy of excitation light and that it is up to 40-50% in resonant excitation at the energy positions corresponding to the absorption shoulder. Detailed properties and possible dynamics will be described. We also present preliminary results of PL properties focused on single NCs. There exist highluminescent NCs exhibiting so-called PL blinking as similar with II-VI NCs, while the others are dark NCs. 73.21.La, 78.47.jd, 78.67.Bf, 78.67.H

Room-Temperature Fluorescence Lifetime of Pseudoisocyanine (PIC) J Excitons with Various Aggregate Morphologies in Relation to Microcavity Polariton Formation

The results of room-temperature fluorescence lifetime measurements are reported for the excitation of J aggregates (Js) of pseudoisocyanine chloride (PIC-Cl) prepared in potassium polyvinyl sulfate (PVS) polymer thin films, their aqueous solutions, and NaCl aqueous solutions. Variations of the microscopic morphologies of the aggregates were investigated. The results show that fluorescence decay features correlated to the morphology change. The observed fluorescence lifetime and quantum efficiency of PIC J aggregates (PIC-Js) in a NaCl aqueous solution were 310 ps and 28%, respectively. The lifetime of the fibril-shaped macroaggregates prepared in PVS thin films was below the instrumental time resolution of 5 ps, and the efficiency decreased to below 3%. The results indicate that PIC-Js prepared with PVS polymers have an increased nonradiative contribution to the excitation deactivation process. In particular, macro-Js with isolated fibril-shaped structures revealed nonradiative pathway(s) that are closely associated to the specific packaging morphology of the constituent meso-Js. The possibility of a destructive effect on the formation of cavity-polaritons is also discussed

Room-temperature strong coupling of hexane-dispersed colloidal CdSe nanoplatelets in a microcavity composed of two Bragg reflectors

CdSe nanoplatelets (NPLs) are suitable for exploring strong light-matter coupling in semiconductor nanocrystal systems due to their giant oscillator strength and large exciton binding energy. Herein, we report on the facile fabrication and optical characterization of a half-wavelength planar microcavity, which consists of two distributed Bragg reflectors with a hexane layer containing concentrated colloidal CdSe NPLs. Using a hexane solution layer instead of the typically used dried active layers makes the layer thin and flat, even under dense NPL conditions, without stressing or charging of the NPLs' surfaces. Reflectance spectra showed that strong light-matter coupling can be realized at room temperature and that the vacuum Rabi splitting energy is 53.5 meV. Intense photoluminescence (PL) emerges at the lower polariton branch where 25.1 meV (longitudinal optical (LO)-phonon energy) below the energy of the polariton dark states, indicating that the relaxation from the dark states occurs efficiently in this microcavity owing to LO-phonon-assisted relaxation. We describe the reflectance and PL properties using the model that a cavity photon couples to a one-exciton state delocalized over nonuniformly orientated NPLs. This model contributes to an intuitive and quantitative understanding of the microcavity containing colloidal NPLs.Comment: 34 pages, 4 figures (6 figures in Supporting Information

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係結については多くの研究がなされているが,違例,破格とされる例の全体像は明らかではない。しかし,係結の本質に迫るためにも,係結の違例の詳細な調査,整理が必要である。本稿は,係結の違例のうち,一つの結びに二つ(以上の)係助詞が係る現象(「二重の係り」と呼ぶ)についてとりあげ,(1)用例は極めて少ないがそれでも中古和文中に異文のない例(またはそれに準ずるもの)も存在すること,(2)「二重の係り」となるのは「-ぞーぞー連体形」「-なむーなむー連体形」「-こそーこそー已然形」のように同じ係助詞どうしに限られること,(3)「二重の係り」の句型は三つのタイプに限られること,などを指摘する

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In the Japanese language, a noun is usually followed by a particle in a sentence. And the particle marks the case. As for the classical Japanese, it is known that a noun is often used without having a particle when the noun is interpreted as either the nominative or the accusative. (I call this type of noun "the noun phrase without a particl" in this paper.) In The Tale of Genji, however, noun phrases without a particle are found which are interpreted as neither the nominative nor the accusative. This paper deals with the various usages of the noun phrases without a particle found in The Tale of Genji and shows that they are classified into the following three types : I, the ones which are taken as the nominative, the accusative, the dative, and other cases, ii. The ones which can function as the conjunctive, and iii. The ones indicating the theme of the sentence

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本稿は,従来実態が調査されていない「係結の流れ」について正面から取り上げ,「成立しない係結び」という裏側から係結についての考察を試みたものである。源氏物語の「係結びの流れ」の調査から,次の諸点が指摘される。(1)流れは「なむ」が最も多い,(2)接続句内の流れは「こそ」は逆接で「なむ」は順接で流れることが多い,(3)「なむ」は流れた後で再度「なむ」の係結によって結ばれる文が多いのに対し,「ぞ」は一文中に一度しか使われないことが多い。これらの実態は,各係助詞の特徴を色濃く反映していると考えられ,この点から,「ぞ」は卓立,「こそ」は対比的強調,「なむ」は文全体の基調に関係するという傾向が指摘される