RECTIFYING EFFECT OF POLYANILINE(PANI)/N-TYPE POROUS SILICONE HETEROJUNCTION

Heterojunctions between polyaniline (PANI) and n-type porous silicon (PS), Al/PS-PANI/Au cell, were fabricated, and the rectifying parameters of this heterojunction diode were measured as a function of the preparation conditions of PANI and PS, the electronic structure of PANI as well as cell structure. The rectifying parameters of Al/PS-PANI/Au cell were determined to be gamma = 1.8x10(1) similar to 1.0x10(5) for the rectifying ratio at 3V, n = 3 similar to 12 for the ideal factor, j(0) = 8.0x10(-5) similar to 5.6x10(-2) mA/cm(2) for the reversed saturated current density, and phi(0) = 0.67 similar to 0.83 V for the barrier height, respectively. The best rectifying heterojunction diode made between PANI and n-type PS with higher rectifying factor (gamma = 1.0x10(5) at 3V), output current (>1500 mA/cm(2) at 3V) and lower ideal factor (n = 3.3) was obtained by preventing the oxidation of PS before evaporating Al electrode.

Rectifying effect of heterojunction fabricated in freestanding thin film of polyaniline containing azobenzene side-chain

An innovative heterojunction is fabricated between two sides of a freestanding thin film of HCl-doped polyaniline （PANI） derivative containing azobenzene side-chain, which is synthesized through an N-alkyl-substituted reaction. of the film, the side with being irradiated by UV light during preparation is represented as ＇A side＇; the other side without being irradiated is represented as ＇N side＇. The electrical properties of the heterojunction are measured and the rectifying effect is observed in the current voltage characteristic curves with the values of rectifying ratio （30 being 20 at ±0.06 V at T = 77 K and 4 at ±0.02 V at T = 300 K separately.

Rectifying effect of heterojunctions between metals and doped conducting polymer nanostructure pellets

This paper reports that the Schottky junctions between low work function metals （e.g. Al and In） and doped semiconducting polymer pellets （e.g. polyaniline （PANI） microsphere pellet and polypyrrole （PPy） nanotube pellet） have been prepared and studied. Since Ag is a high work function metal which can make an ohmic contact with polymer, silver paste was used to fabricate the electrodes. The Al/PANI/Ag heterojunction shows an obvious rectifying effect as shown in I - V characteristic curves （rectifying ratio γ = 5 at ±6 V bias at room temperature）. As compared to the Al/PANI/Ag, the heterojunction between In and PANI （In/PANI/Ag） exhibits a lower rectifying ratio γ= 1.6 at ±2 V bias at room temperature. In addition, rectifying effect was also observed in the heterojunctions Al/PPy/Ag （γ = 3.2 at ±1.6 V bias） and In/PPy/Ag （γ = 1.2 at ±3.0 V bias）. The results were discussed in terms of thermoionic emission theory.

Promoting selective electroreduction of nitrates to ammonia over electron-deficient Co modulated by rectifying Schottky contacts

Developing efficient electrocatalysts for selective nitrate contamination reduction into value-added ammonia is significant.Here,heterostructured Co/CoO nanosheet arrays(Co/CoO NSAs)exhibited excellent Faradaic efficiency(93.8%)and selectivity(91.2%)for nitrate electroreduction to ammonia,greatly outperforming Co NSAs.15N isotope labeling experiments and 1H nuclear magnetic resonance(NMR)quantitative testing methods confirmed the origin of the produced ammonia.Electrochemical in situ Fourier transform infrared(FTIR)spectroscopy,online differential electrochemical mass spectrometry(DEMS)data and density functional theory(DFT)results revealed that the superior performances arose from the electron deficiency of Co induced by the rectifying Schottky contact in the Co/CoO heterostructures.The electron transfer from Co to CoO at the interface could not only suppress the competitive hydrogen evolution reaction,but also increase energy barriers for by-products,thus leading to high Faradaic efficiency and selectivity of ammonia.