Henan University

About: Henan University is a education organization based out in Kaifeng, China. It is known for research contribution in the topics: Catalysis & Population. The organization has 22749 authors who have published 19444 publications receiving 234466 citations. The organization is also known as: Hénán Dàxué.

Localized exciton emission in CsPbBr3 nanocrystals synthesized with excess bromide ions

Abstract: All-inorganic perovskite nanocrystals (NCs) have recently emerged as a new class of materials due to their tunable bandgaps and high photoluminescence quantum yields (PLQYs). The origin of the enhancement of PLQY of CsPbBr3 NCs is usually attributed to the efficient passivation of the surface halide vacancies creating nonradiative recombination sites. In this work, Br-rich CsPbBr3 NCs with a PLQY of 97% were prepared using an extreme excess of Br source with Br/Pb of 4.5/1 from the ligand itself at room temperature. Br-rich CsPbBr3 NC based light-emitting devices were fabricated under ambient conditions, exhibiting the maximum current efficiency of 1 cd A−1 at the luminance of 750 cd m−2. First principles calculations indicate that Br interstitials can form the strong localized states. Such localized effect can prevent photogenerated carriers from defusing to non-radiative recombination centers, thus being responsible for the high emission efficiency.

Understanding the Factors Influencing the Leisure Tourism Behavior of Visually Impaired Travelers: An Empirical Study in China

Abstract: This study looks at the real-world problems which vision impaired individuals face when they travel. More specifically, this study aims to explore the main factors influencing the leisure tourism behavior of visually impaired individuals. Based on in-depth semi-structured interviews with 26 visually impaired respondents, this study identifies six main factors impacting on the leisure tourism behavior of visually impaired individuals including: tourism products and services, personal psychological factors, social support, community support, personal socio-economic factors, and barrier-free environments. Findings show that visually impaired travelers have strong requirements for auditory, tactile, and physical participation. Support factors such as travel companions/escorts, tour organizers specifically targeting their experiential offerings at the visually impaired, and an accessible environment are important considerations for visually impaired travelers. Findings also show that visually impaired individuals participate in leisure tourism to enhance their own abilities, relieve pressures on their families, break stereotypes associated with the visually impaired, and promote the need for greater tourism development specifically targeting visually impaired travelers. This study also proposes a theoretical model outlining the factors influencing leisure tourism of visually impaired people.

Resonances X (4140 ), X (4160 ) , and P c s (4459 ) in the decay of Λ b →J /ψ Λ ϕ

Abstract: We study the decay of ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}J/\ensuremath{\psi}\mathrm{\ensuremath{\Lambda}}\ensuremath{\phi}$ by taking into account the intermediate resonances $X(4140)$, $X(4160)$, and ${P}_{cs}(4459)$. In addition to the peak of the $X(4140)$, we also find a bump structure around 4160 MeV followed by a cusp structure around ${D}_{s}^{*}{\overline{D}}_{s}^{*}$ threshold in the $J/\ensuremath{\psi}\ensuremath{\phi}$ invariant mass distribution of the ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}J/\ensuremath{\psi}\mathrm{\ensuremath{\Lambda}}\ensuremath{\phi}$ process, which can be associated to the ${D}_{s}^{*}{\overline{D}}_{s}^{*}$ molecular state $X(4160)$. We also show that this reaction can also be used to confirm the existence of the hidden-charm pentaquark ${P}_{cs}(4459)$ with strangeness. We predict an enhancement structure close to the threshold in the ${D}_{s}^{*}{\overline{D}}_{s}^{*}$ invariant mass distribution of the ${\mathrm{\ensuremath{\Lambda}}}_{b}\ensuremath{\rightarrow}{D}_{s}^{*}{\overline{D}}_{s}^{*}\mathrm{\ensuremath{\Lambda}}$ process, which is the reflection of the $X(4160)$ and should not be misidentified with a new resonance. We strongly suggest experimentalists to further measure these processes, which can be useful to clarify the nature of $X(4140)$ and $X(4160)$ resonances, and to confirm the existence of the ${P}_{cs}(4459)$.

Preparation, Characterization, and Photoelectric Properties of Langmuir-Blodgett Films of Some Europium-Substituted Polyoxometalates and 2-Aminofluorene with Tunable Emission Color

Abstract: A new series of organic/inorganic composite Langmuir–Blodgett (LB) films consisting of 2-aminofluorene (Fl–NH2) as the π-conjugated organic molecule, an europium-substituted polyoxometalate (POM, POM = Na9EuW10O36, K13[Eu(SiW11O39)2] and K5[Eu(SiW11O39)(H2O)2], which are denoted by EuW10, EuW22 and EuW11, respectively) as the inorganic component, were prepared. Structural and photophysical characterization of these LB films were achieved by π–A isotherms, UV–Vis absorption and photoluminescence spectra, atomic force microscopy imaging, scanning tunneling microscopy, and surface photovoltage spectroscopy. Our experimental results indicate that stable Langmuir and LB films are formed in pure water and POM sub-phases. Luminescence spectra of the prepared hybrid LB films show that tunable emission color can be obtained due to the dual-emissive nature of the mixed Fl–NH2/POM blends. These 2-aminofluorene-based LB films displayed interesting electrical conductivity behavior. Among them, Fl–NH2/EuW11 3-layer films showed a good electrical response with the a tunneling current up to ± 100 nA when the voltage was monitored at −0.8 to 1.5 V. These LB composites show good photovoltage responses and a photovoltage of 2.7 μV can be obtained for the Fl–NH2/EuW22 system when it is excited by light.