Ten-Chin Wen

CH3NH3PbI3 Perovskite/Fullerene Planar‐Heterojunction Hybrid Solar Cells

All-solid-state donor/acceptor planar-heterojunction (PHJ) hybrid solar cells are constructed and their excellent performance measured. The deposition of a thin C60 fullerene or fullerene-derivative (acceptor) layer in vacuum on a CH3 NH3 PbI3 perovskite (donor) layer creates a hybrid PHJ that displays the photovoltaic effect. Such heterojunctions are shown to be suitable for the development of newly structured, hybrid, efficient solar cells.

Nickel Oxide Electrode Interlayer in CH3NH3PbI3 Perovskite/PCBM Planar-Heterojunction Hybrid Solar Cells

This study successfully demonstrates the application of inorganic p-type nickel oxide (NiOx ) as electrode interlayer for the fabrication of NiOx /CH3 NH3 PbI3 perovskite/PCBM PHJ hybrid solar cells with a respectable solar-to-electrical PCE of 7.8%. The better energy level alignment and improved wetting of the NiOx electrode interlayer significantly enhance the overall photovoltaic performance.

Indirect oxidation effect in electrochemical oxidation treatment of landfill leachate

Treatment of a low BODCOD ratio landfill leachate was conducted by means of electrochemical oxidation process in this investigation. Under the operating conditions of 15 A/dm2 current density and 7500 mg/l additional chloride concentration, 92% of the COD in the landfall leachate was removed after electrolysis for 240 min with a ternary SnPdRu oxide-coated titanium (SPR) anode. At the same time, about 2600 mg/l of ammonium in the landfill leachate was also removed completely. These results indicate that the electrochemical oxidation process is effective in removing pollutants from landfill leachate. In this investigation, the effects of operating parameters including anode material, current density, and chloride concentration on both chlorine/hypochlorite production and landfill leachate treatment efficiency were studied. It was found that the operating factors have the same effects on both chlorine/hypochlorite production efficiency and landfill leachate treatment efficiency. The results suggest that the removal of pollutants from landfill leachate by electrochemical oxidation process could be mainly attributed to the indirect oxidation effect of chlorine/hypochlorite produced during the electrolysis. Among the four anode materials investigated in this study, including graphite, PbO2Ti, DSAR, and SPR anodes, the SPR anode having a high electrocatalytic activity gave the best chlorine/hypochlorite production efficiency and landfill leachate treatment efficiency. In addition, the increases in both operating current density and chloride concentration also enhanced the indirect oxidation effect in the electrochemical oxidation treatment of landfill leachate.

Polyaniline-deposited porous carbon electrode for supercapacitor

Electrodes for supercapacitors were fabricated by depositing polyaniline (PANI) on high surface area carbons. The chemical composition of the PANI-deposited carbon electrode was determined by X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to investigate the electrochemical properties of electrodes. An equivalent circuit was proposed to successfully fit the EIS data, and the significant contribution of pseudocapacitance from PANI was thus identified. A comparative analysis on the electrochemical properties of bare-carbon electrodes was also conducted under similar conditions. The performance of the capacitors equipped with the resulting electrodes in 1 M H2SO4 was evaluated by constant current charge–discharge cycling within a potential range from 0 to 0.6 V. The PANI-deposited electrode exhibits high specific capacitance of 180 F/g, in comparison with a value of 92 F/g for the bare-carbon electrode.

p-type Mesoscopic nickel oxide/organometallic perovskite heterojunction solar cells.

In this article, we present a new paradigm for organometallic hybrid perovskite solar cell using NiO inorganic metal oxide nanocrystalline as p-type electrode material and realized the first mesoscopic NiO/perovskite/[6,6]-phenyl C61-butyric acid methyl ester (PC61BM) heterojunction photovoltaic device. The photo-induced transient absorption spectroscopy results verified that the architecture is an effective p-type sensitized junction, which is the first inorganic p-type, metal oxide contact material for perovskite-based solar cell. Power conversion efficiency of 9.51% was achieved under AM 1.5 G illumination, which significantly surpassed the reported conventional p-type dye-sensitized solar cells. The replacement of the organic hole transport materials by a p-type metal oxide has the advantages to provide robust device architecture for further development of all-inorganic perovskite-based thin-film solar cells and tandem photovoltaics.

400-nm InGaN-GaN and InGaN-AlGaN multiquantum well light-emitting diodes

The 400-nm In/sub 0.05/Ga/sub 0.95/N-GaN MQW light-emitting diode (LED) structure and In/sub 0.05/Ga/sub 0.95/N-Al/sub 0.1/Ga/sub 0.9/N LED structure were both prepared by organometallic vapor phase epitaxy. It was found that the use of Al/sub 0.1/Ga/sub 0.9/N as the material for barrier layers would not degrade crystal quality of the epitaxial layers. It was also found that the 20-mA electroluminescence intensity of InGaN-AlGaN multiquantum well (MQW) LED was two times larger than that of the InGaN-GaN MQW LED. The larger maximum output intensity and the fact that maximum output intensity occurred at larger injection current suggest that AlGaN barrier layers can provide a better carrier confinement and effectively reduce leakage current.

Influence of Si-doping on the characteristics of InGaN-GaN multiple quantum-well blue light emitting diodes

A detailed study on the effects of Si-doping in the GaN barrier layers of InGaN-GaN multiquantum well (MQW) light-emitting diodes (LEDs) has been performed. Compared with unintentionally doped samples, X-ray diffraction results indicate that Si-doping in barrier layers can improve the crystal and interfacial qualities of the InGaN-GaN MQW LEDs. It was also found that the forward voltage is 3.5 and 4.52 V, the 20-mA luminous intensity is 36.1 and 25.1 mcd for LEDs with a Si-doped barrier and an unintentionally doped barrier, respectively. These results suggests that one can significantly improve the performance of InGaN-GaN MQW LEDs by introducing Si doping in the GaN barrier layers.

Hydrogen and Oxygen Evolutions on Ru‐Ir Binary Oxides

The electrocatalytic activity of mixed Ru-Ir oxide electrodes fabricated by thermal decomposition are compared (using cyclic voltammetry and potentiodynamic technique), for their ability to evolve hydrogen and oxygen in both 1N H 2 SO 4 and 1N NaOH solutions. Cyclic voltammetry provides information about the redox transitions of surface oxyruthenium and oxiridium groups, and also generates an effective index, (voltammetric charge (q * )), which can be used to determine the electrocatalytic activity of the electrode

Chicken Albumen Dielectrics in Organic Field‐Effect Transistors

IO N Biomaterials for organic electronics have gained considerable attention in recent years. [ 1–3 ] The advantages of biomaterials are that they are biodegradable, bioresorbable, biocompatible, typically environmentally friendly, and do not require chemical synthesis. Bio-organic fi eld-effect transistors (BiOFETs) use biomaterials as semiconductors, dielectrics, and substrates. For example, β -carotene [ 4 ] has been applied as semiconductors. DNA-hexadecyltrimethylammmonium chloride (DNACTMA), [ 5–7 ] nucleobases, [ 8 ] and silk [ 9 ] have been used as gate dielectrics. Silk [ 10 ] and poly ( L -lactideco -glycolide) (PLGA) [ 11 ]

Identification of inductive behavior for polyaniline via electrochemical impedance spectroscopy

Abstract Polyaniline (PANI) film electrodeposited in HCl medium using cyclic voltammetry (CV) with an upper potential limit of 0.90 V, exhibited an inductive behavior. PANI films deposited with different conditions were subjected to various applied potentials and the impedance characteristics were recorded through electrochemical impedance spectroscopy (EIS). The impedance results clearly reveal the existence of inductive behavior to PANI. Inductive behavior was observed for PANI films deposited with conditions which favor benzoquinone/hydroquinone (BQ/HQ) formation and further evidenced by X-ray photoelectron spectroscopy (XPS). A comparative analysis of the EIS and XPS results of PANI films prepared under similar conditions with the upper potential limits of 0.75 and 0.90 V, respectively, clearly documented that the presence of BQ/HQ, the degradation product of PANI, formed during the electrochemical polymerization at the upper potential limits causes inductive behavior to PANI.