University of Electro-Communications

About: University of Electro-Communications is a education organization based out in Tokyo, Japan. It is known for research contribution in the topics: Laser & Robot. The organization has 8041 authors who have published 16950 publications receiving 235832 citations. The organization is also known as: UEC & Denki-Tsūshin Daigaku.

Highly Efficient 17.6% Tin-Lead Mixed Perovskite Solar Cells Realized through Spike Structure.

Abstract: Frequently observed high Voc loss in tin–lead mixed perovskite solar cells is considered to be one of the serious bottle-necks in spite of the high attainable Jsc due to wide wavelength photon harvesting. An amicable solution to minimize the Voc loss up to 0.50 V has been demonstrated by introducing an n-type interface with spike structure between the absorber and electron transport layer inspired by highly efficient Cu(In,Ga)Se2 solar cells. Introduction of a conduction band offset of ∼0.15 eV with a thin phenyl-C61-butyric acid methyl ester layer (∼25 nm) on the top of perovskite absorber resulted into improved Voc of 0.75 V leading to best power conversion efficiency of 17.6%. This enhancement is attributed to the facile charge flow at the interface owing to the reduction of interfacial traps and carrier recombination with spike structure as evidenced by time-resolved photoluminescence, nanosecond transient absorption, and electrochemical impedance spectroscopy measurements.

Chemical Reactivity of Sc3N@C80 and La2@C80

Abstract: Sc3N@C80 has a lower thermal reactivity than La2@C80, although Sc3N@C80 has the same carbon cage (Ih) and oxidation state (C806-) as La2@C80. This result is attributed to the difference in the energy level and distribution of LUMO between Sc3N@C80 and La2@C80.

Determination of two-dimensional phonon dispersion relation of graphite by Raman spectroscopy

Abstract: Phonon dispersion relations of a two-dimensional (2D) graphite are obtained by fitting dispersive Raman modes that originate from nonzone center phonons near the $\ensuremath{\Gamma}$ or K point in the Brillouin zone (BZ). A new set of 12 force constants of 2D graphite up to the fourth neighbor are determined by a self-consistent fitting procedure, combined with double-resonance Raman theory. Analytical expressions for eigenvalues and eigenvectors at high symmetry points of the BZ are presented.

Composite Yb:YAG/Cr 4+ :YAG ceramics picosecond microchip lasers

Abstract: Efficient laser-diode pumped picosecond self-Q-switched all-ceramic composite Yb:YAG/Cr4+:YAG microchip lasers with 0.72 MW peak power has been developed. Lasers with nearly diffraction-limited beam quality (M2 < 1.09), oscillate at stable single- and multi- longitudinal-modes due to the combined etalon effects in the Yb:YAG and Cr4+:YAG parts of its binary structure.