ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStereocontrolled synthesis of polyfunctionalized trans-hydrindan systems: a model study toward anisatinHaruki Niwa, Tatsuya Mori, Takashi Hasegawa, and Kiyoyuki YamadaCite this: J. Org. Chem. 1986, 51, 7, 1015–1018Publication Date (Print):April 1, 1986Publication History Published online1 May 2002Published inissue 1 April 1986https://doi.org/10.1021/jo00357a013RIGHTS & PERMISSIONSArticle Views633Altmetric-Citations16LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (543 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts
Semiconductor nanocrystals smaller than 10 nm, known as quantum dots (QDs), exhibit optoelectronic properties that are dependent on their size due to the quantum size effect. Recently, QDs made of I-III-VI group multinary semiconductors, such as CuInS 2 and AgInS 2 , have attracted significant attention for their potential in highly efficient solar energy conversion systems. This is because these QDs were composed of less toxic elements and their optical properties were broadly tuned in the visible and near-IR wavelength regions through chemical composition. It was reported in our previous papers (1,2) that solid solution QDs composed of Zn-Ag-In-S and Zn-Ag-In-Se exhibited the photocatalytic activity for H 2 evolution, which varied according to their size and composition. In this study, we introduce the solution-phase synthesis of less-toxic QDs composed of AgIn (1-x) Ga x S 2 (AIGS) and CuIn (1-x) Ga x S 2 (CIGS). The photocatalytic activity for H 2 evolution was investigated for AIGS QDs under visible light irradiation. The photoluminescence (PL) properties of CIGS QDs were improved for the application to QD-based light-emitting diodes (QD-LEDs). AIGS QDs with different In/(In+Ga) ratios were synthesized by thermal decomposition of corresponding metal complexes and S powders in an oleylamine-dodecanethiol solution.(3) The energy gap ( E g ) of AIGS QDs was increased from 2.07 to 2.54 eV with a decrease in the In fraction in the QDs from 1.0 to 0.20. After the surface coating with GaS x shell, the resulting AIGS@GaS x QDs exhibited sharp band-edge PL peak, the wavelength of which was tunable from 610 to 500 nm with an increase in the E g . The photocatalytic activity of AIGS QDs was imoroved by the modification with ZnS shell of 2 nm in thickness. The resulting AIGS@ZnS QDs were dispersed in the aqueous solution containing Na 2 S as a hole scavenger. Visible light irradiation (λ> 350 nm) to the dispersion caused the H 2 evolution, the amount of which linearly increased with the elapse of the irradiation time. The H 2 evolution rate was remarkably dependent on the composition of AIGS core. A volcano-type dependence was observed between the photocatalytic activity rate and the In fraction. The highest photocatalytic activity was obtained for AIGS@ZnS QDs with In/(In+Ga)=0.4. This result can be explained by the changes of the conduction band level of AIGS cores and the amount of photon absorbed by the photocatalysts. CIGS QDs were prepared in a similar way.(4) The E g of CIGS QDs also increased from 1.74 eV to 2.77 eV with a decrease in In/(In+Ga) ratio from 1.0 to 0. The GaS x coating on CIGS QD surface enlarged the intensity of PL peak without changing its peak width: CIGS@GaS x QDs exhibited a narrow PL peak (FWHM: 0.20 eV) at 671 nm, being comparable to the PL peak of CIGS QDs (the peak wavelength of 675 nm and the FWHM of 0.23 eV). The PL QY was also increased to 27% from 8% by the GaS x coating on CIGS QDs. QD-LEDs fabricated with CIGS@GaS x QDs showed a red color with a narrow emision peak at 688 nm with a fwhm of 0.24 eV. In cnclusion, the tunabilities of optical properties and energy structure of I-III-VI-based QDs are useful for constructing efficient light energy conversion systems and luminescent devices. References T. Kameyama, et al. , J. Phys. Chem. C , 2015 , 119 , 24740-24749. P. Y. Hsieh, et al. , J. Mater. Chem. A 2020 , 8, 13142-13149. T. Kameyama, et al. , ACS Applied. Mater. Interfaces 2018 , 10 , 42844-42855. C. Jiang, et al., J. Chem. Phys. 2023, 158, 164708.
The integration of high-speed light emitters on silicon chips is an important issue that must be resolved in order to realize on-chip or interchip optical interconnects. Here, we demonstrate the first electrically driven ultrafast carbon nanotube (CNT) light emitter based on blackbody radiation with a response speed (1-10 Gbps) that is more than 10(6) times higher than that of conventional incandescent emitters and is either higher than or comparable to that of light-emitting diodes or laser diodes. This high-speed response is explained by the extremely fast temperature response of the CNT film, which is dominated by the small heat capacity of the CNT film and its high heat dissipation to the substrate. Moreover, we experimentally demonstrate 140 ps width pulsed light generation and real-time optical communication. This CNT-based emitter with the advantages of ultrafast response speeds, a small footprint, and integration on silicon can enable novel architectures for optical interconnects, photonic, and optoelectronic integrated circuits.
Electrically driven high-speed light emitters based on compound semiconductors are widely used in the areas of optical communication, time-resolved spectroscopy, etc. However, because of their large footprints, the low crystal-linity of the compound semiconductors grown directly on Si wafers, these emitters face significant challenges with respect to their integration with silicon-based electronics, photonics and micromechanical platforms. Single-walled carbon nanotubes (CNTs) are an attractive material for optical and optoelectronic applications, such as optically and electrically excited light sources. Electrically driven CNT emitters, which can be based on electron-hole recombination or blackbody radiation, have several advantages: (i) a small footprint emitter can easily be obtained due to its simple fabrication process, (ii) CNTs can be prepared directly on a Si wafer, unlike compound semiconductor-based light emitters. These advantages could open new routes to photonics or optoelectronics integrated with silicon-based electronics. However, for such applications, the question remains as to whether an electrically driven CNT emitter can be modulated at high frequency as well as compound-semiconductor LEDs and LDs, which have modulation speeds on the order of MHz to GHz. In this study, we report the first electrically driven, ultra-high-speed CNT light emitter based on blackbody emission. Although these emission properties have been studied under steady-state conditions, the transient properties of these emitters have not been reported to date.
While the range of accessible borylenes has significantly broadened over the last decade, applications remain limited. Herein, we present tricoordinate oxy-borylenes as potent photoreductants that can be readily activated by visible light. Facile oxidation of CAAC stabilized oxy-borylenes (CAAC)(IPr
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
