Pyrolysis preparation of WO_3 thin films using ammonium metatungstate DMF/water solution for efficient compact layers in planar perovskite solar cells

The tungsten trioxide（WO3） thin films were firstly prepared by spin-coating-pyrolysis methods using the ammonium metatungstate（（NH4）6H2W12O40）DMF/water solution, and successfully applied as the efficient compact layers for the planar perovskite solar cells. The influence of the WO3 film thickness and the rinsing treatment of CH_3NH_3 PbI_3 thin film with isopropanol on the photovoltaic performance of the corresponding perovskite solar cells was systematically investigated. The results revealed that the perovskite solar cell with a 62 nm thick WO3 compact layer achieved a photoelectric conversion efficiency of 5.72%, with a short circuit photocurrent density of 17.39 mA/cm^2, an open circuit voltage of 0.58 V and a fill factor of 0.57. The photoelectric conversion efficiency was improved from 5.72% to 7.04% by the isopropanol rinsing treatment.

High-performance Sb:SnO_2 Compact Thin Film Based on Surfactant-free and Binder-free Sb:Sn_3O_4 Suspension

Surfactant-free and binder-free antimony-doped tin oxide （ATO） transparent conducting thin films were fabricated through spin coating and rapid annealing processes, in which nanosheets were assembled into a compact structure via self-contracting high pressure. The mechanism of this compact thin film for- mation was further proposed and analyzed. The compact ATO thin film had a low root mean square （RMS） roughness of 5.03 nm. This surfactant-free and binder-free compact ATO thin film delivered low resistivity of 3.04 × 10^-2 Ω cm, stable resistivity which only increased 13% after exposing in 65% RH air for half a month, high transmittance of 92.70% at 550 nm, and high band gap energy of 4.07 eV. This effective strategy will provide new insight into the synthesis of low-cost and high-performance compact thin films.

An Extension Landau-Lifshitz Model in Studying Soft Ferromagnetic Films

In this paper, we propose a model in studying soft ferromagnetic films, which is readily accessible experimentally. By using penalty approximation and compensated compactness, we prove that the dynamical equation in thin film has a local weak solution. Moreover, the corresponding linear equation is also dealt with in great detail.

Improving the volumetric specific capacitance of flexible polyaniline electrode:solution casting method and effect of reduced graphene oxide sheets

High volumetric specific capacitance is essential for flexible supercapacitors.In this paper,a flexible composite electrode with ultrahigh volumetric specific capacitance and good rate performance is designed and prepared.The film electrode is composed of non-porous compact polyaniline as the matrix and a small amount of reduced graphene oxide sheets as the conductive filler.The film is prepared by a newly developed solution casting method,where the casting solution is obtained by self-assembly of polyaniline and graphene oxide in a blended solution.A systematical investigation on the effect of reduced graphene oxide sheets reveals that they serve as both the conductive filler and the diffusion barrier.With the optimized reduced graphene oxide content,a large volumetric specific capacitance of 1354 F cm^−3 at 2.4 A cm^−3 is achieved,and good rate performance is also obtained because of the good ionic conductivity of polyaniline.This work provides a high performance electrode for flexible supercapacitors,and the solution casting method is also valuable in fabricating other organic electrode materials.