Electrochemical oxidative 5-exo-dig-oxo-halocyclization of o-alkynylbenzamides was achieved using readily available NaX (X = Cl, Br and I) salts under mild reaction conditions. The use of cheap and highly stable sodium...

Poly(3,4-ethylenedioxythiophene) (PEDOT) thin films have attracted considerable attention as cathodes for dye-sensitized solar cells (DSSCs) due to their air-stable, light-weight and conductive nature. To demonstrate their thermal stability as cathodes, PEDOT thin films coated via electrochemical polymerization on fluorine doped tin oxide (FTO) plates were sintered at different temperatures (50, 100, 150, 200, and 300 C) for 1 h and a comparison was made with the as-prepared PEDOT thin films. We observed a negative temperature coefficient effect up to 200 C along with lower surface roughness upon increasing the sintering temperature. Dye solar cells were fabricated using PEDOT thin films (sintered at different temperatures) and as-prepared PEDOT cathodes, and their respective performances were studied. The results showed increased efficiency with the increase in sintering temperatures of the cathode up to 200 C (h ¼ 4.33%) under the present experimental conditions. Cathodes sintered at 300 C had poor electrochemical behavior and J-V performance, which may be due to polymer degradation.

Herein, we report the light-harvesting property (LHP) from a self-assembled cobalt nanoaggregate (S-CoNA) for an efficient hydrogen evolution. The syntheses of S-CoNAs were achieved using 3-mercaptopropylsulfonate (MPS) as the stabilizer, and the as-formed compound exhibits broad absorption at 407 and 496 nm which appears in the visible region that prompts us to investigate the photo-electrochemical studies. Interestingly, the as-prepared S-CoNAs achieved enhanced hydrogen energy production in the visible region. To know the mechanism of LHP from S-CoNAs and to examine the (M/L) ratios and varying the M/L contribution in detail, we further synthesized S-CoNAs in different metal to ligand ratios (M/ L). Out of the five different ratios, the M/L (1:4) ratio resulted in a maximum response of 15 mA cm −2 at 0.3 V applied potential (vs Ag/AgCl). Further, we performed electrochemical studies by tuning the potentials (0, 0.3 V) followed by illumination in the presence and absence of visible light. Furthermore, Fourier-transform infrared spectroscopy analysis before and after photo-electrochemical reaction resulted in a notable peak at 998 and 2115 cm −1 , respectively, which is attributed to a metal sulfur linkage via both the thiol (−SH) and sulfonate (−SO 3 H) terminals of MPS. The photo-electrochemical reaction which is observed after this effective stabilization for S-CoNAs via Co−S linkages was responsible for the hydrogen energy production.

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