Synthesis, characterization, and performance of oligothiophene cyanoacrylic acid derivatives for solar cell applications

New dye sensitizers based on an oligothiophene cyanoacrylic acid derivative were synthesized and characterized for solar cell applications. The structures of the new dyes prepared as sensitizers based on oligothiophenes, namely5,5''-di-2-cyanoacrylic acid [2,2':5',2''-terthiophene] (dye1), [2,2':5',2''-terthiophene]-5-cyanoacrylic acid(dye2), and [2,2':5',2'':5'',2'''-quaterthiophene]-5-cyanoacrylic acid(dye3) were confirmed by elemental analysis, mass spectrometry, and 1H-NMR spectral data. The P3HT/dye2/nc-TiO2 solar cell produced the highest efficiency of 0.05% with an open circuit voltage of 0.65V compared to dyes 1 and 3 solar cells. That may have been attributed to the dyes’ molecular structure, which had different chain lengths and numbers of groups of cyanoacrylic connected to the dyes’ thiophene moiety The dark current suppressed in the P3HT/dye2/nc-TiO2 solar cells indicated the formation of the charge blocking layer, which produced an enhanced open-circuit voltage accompanied by a high onset voltage.

Finite Element Solution of the Corona Discharge of Wire-Duct Electrostatic Precipitators at High Temperatures—Numerical Computation and Experimental Verification

Global warming is the greatest challenge faced by humankind, and the only way to reduce or totally eliminate its effects is by minimizing CO2 emissions. Electrostatic precipitators are very useful as a means to reduce emissions from heavy industry factories. This paper aims to examine the performance of wire-duct electrostatic precipitators (WDESP) as affected by high-temperature incoming gases with a varying number of discharge wires while increasing their radius. The precipitator performance is expressed in terms of the corona onset voltage on the stressed wires and the corona current–voltage (I–V) characteristic of the precipitators working with incoming gases at high temperatures. The start of the corona onset voltage on the surface of the discharge wires is calculated for the precipitators under high temperatures based on the standard of the self-repeat of avalanches’ electrons developing on the surface of the stressed wires at high temperatures. For this, calculating the electrostatic field in the precipitators with single- and multi-discharge wires due to the stressed wire with the use of the well-known charge simulation method (CSM) with high-temperature incoming gases is important. The modeling of corona I–V characteristics is adopted using the finite element method (FEM) for single- and multi- (3-, 5-, and 7-) discharge wires of WDESP with high-temperature incoming gases. Additionally, the electrostatic field, potential, and space charge of WDESP are calculated by a simultaneous solution of equations of Poisson, current density, and the continuity current density. A WDESP was set up in the Laboratory of High Voltage Engineering of Czech Technical University (CTU) in Prague, the Czech Republic, to measure the corona onset voltage values and corona I–V characteristics for different WDESP configurations at high temperatures with a varying number of discharge wires while increasing their radius. The calculated values of the corona onset voltage based on CSM and the calculated corona I–V characteristics based on FEM agree reasonably with those measured experimentally with high-temperature WDESP.

A Cellulose Electrolysis Cell with Metal-Free Carbon Electrodes

Biomass raw materials, including agricultural residues, collected weeds, and wood chips, are important feedstocks for hydrogen production. Numerous attempts have been made to electrolyze biomass directly or indirectly to hydrogen because these processes allow for the production of hydrogen with less power consumption than water electrolysis. However, expensive metal-based electrocatalysts are needed, especially for the cathode reaction, in the electrolysis cells. Results from the present study demonstrate the production of hydrogen directly from cellulose, using an optimal mesoporous carbon as the cathode in addition to a partially oxygenated carbon anode at a temperature of 150 °C, with an electrolysis onset voltage of ca. 0.2 V, a current density of 0.29 A cm−2 at an electrolysis voltage of 1 V, and a current efficiency of approximately 100% for hydrogen production. These characteristics were comparable to those recorded when using a Pt/C anode and cathode under the same conditions. The sp2 planes of the carbon allowed π electrons to be donated to protons at the cathode. In addition, the mesoporous structure provided a sufficient amount of sp2 planes on the surface of the cathode.