Henan Normal University

About: Henan Normal University is a education organization based out in Xinxiang, China. It is known for research contribution in the topics: Catalysis & Ionic liquid. The organization has 10863 authors who have published 11077 publications receiving 166773 citations.

High-performance large-area quasi-2D perovskite light-emitting diodes.

Abstract: Serious performance decline arose for perovskite light-emitting diodes (PeLEDs) once the active area was enlarged. Here we investigate the failure mechanism of the widespread active film fabrication method; and ascribe severe phase-segregation to be the reason. We thereby introduce L-Norvaline to construct a COO−-coordinated intermediate phase with low formation enthalpy. The new intermediate phase changes the crystallization pathway, thereby suppressing the phase-segregation. Accordingly, high-quality large-area quasi-2D films with desirable properties are obtained. Based on this, we further rationally adjusted films’ recombination kinetics. We reported a series of highly-efficient green quasi-2D PeLEDs with active areas of 9.0 cm2. The peak EQE of 16.4% is achieved in = 3, represent the most efficient large-area PeLEDs yet. Meanwhile, high brightness device with luminance up to 9.1 × 104 cd m−2 has achieved in = 10 film. Performance of perovskite LED tends to decline as the active area increases, thus understanding the failure mechanism is paramount to surmount this limitation. Here, the authors report severe phase-segregation to be the cause, and introduce L-Norvaline to overcome it, as the result, highly-efficient 9.0 cm2 green PeLED is realised.

Study of e(+)e(-) -> omega chi(cJ) at Center of Mass Energies from 4.21 to 4.42 GeV

Abstract: Based on data samples collected with the BESIII detector at the BEPCII collider at nine center of mass energies from 4.21 to 4.42 GeV, we search for the production of e(+)e(-) -> omega chi(cJ) (J = 0, 1, 2). The process e(+)e(-) -> omega chi(c0) is observed for the first time, and the Born cross sections at root s = 4.23 and 4.26 GeV are measured to be (55.4 +/- 6.0 +/- 5.9) and (23.7 +/- 5.3 +/- 3.5) pb, respectively, where the first uncertainties are statistical and the second are systematic. The omega chi(c0) signals at the other seven energies and the e(+)e(-) -> omega chi(c1) and omega chi(c2) signals are not significant, and the upper limits on the cross sections are determined. By examining the omega chi(c0) cross section as a function of center of mass energy, we find that it is inconsistent with the line shape of the Y(4260) observed in e(+)e(-) -> pi(+)pi(-) J/psi Assuming the omega chi(c0) signals come from a single resonance, we extract the mass and width of the resonance to be (4230 +/- 8 +/- 6) MeV/c(2) and (38 +/- 12 +/- 2) MeV, respectively, and the statistical significance is more than 9 sigma.

Planar perovskite solar cells with 15.75% power conversion efficiency by cathode and anode interfacial modification

Abstract: Anode modification by doping silver nano-particles (Ag NPs) into poly(3,4-ethylene dioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) and cathode interfacial modification by inserting solution-processed bathophenanthroline (sBphen) in CH3NH3PbI3−xClx based planar perovskite solar cells are investigated. Prior to the optical effect such as localized surface plasmon resonance, the Ag-NPs distributed in PEDOT:PSS mainly cause an improvement in the electrical property of PEDOT:PSS–Ag NPs composite films. The sBphen interfacial layer modified the surface morphology of perovskite/phenyl-C61-butyric acid methyl ester (PC61BM) films by filling the voids on the surface of perovskite/PC61BM effectively, which led to an obvious improvement in the fill factor. Accordingly, an efficient device with a power conversion efficiency of 15.75% was achieved due to the simultaneous cathode and anode interfacial modification.