Synthesis, characterization, and DNA-binding studies of ruthenium complexes [Ru(tpy)(ptn)]2+ and Ru(dmtpy)(ptn)]2+.

Two ruthenium(II) polypyridyl complexes [Ru(tpy)(ptn)](2+) (1) and Ru(dmtpy)(ptn)](2+) (2) (ptn=3-(1,10-phenanthrolin-2-yl)-as-triazino[5,6-f]naphthalene, tpy=2,2':6',2"-terpyridine, dmtpy=5,5'-dimethyl-2,2':6',2"-terpyridine) have been synthesized and characterized by elemental analysis, (1)H NMR, mass spectrometry and crystal structure analysis. Spectroscopic studies together with isothermal titration calorimetry (ITC) and viscosity measurements prove that two complexes bind to DNA in an intercalative mode. ITC experiments show that the binding mode for complex 2 is entropically driven, while an entropy-driven initial binding of complex 1 is followed by an entropically and enthalpically favorable process.

Dynamic study of highly efficient CdS/CdSe quantum dot-sensitized solar cells fabricated by electrodeposition.

An in situ electrodeposition method is described to fabricate the CdS or/and CdSe quantum dot (QD) sensitized hierarchical TiO(2) sphere (HTS) electrodes for solar cell application. Intensity modulated photocurrent spectroscopy (IMPS), intensity modulated photovoltage spectroscopy (IMVS) and electrochemical impedance spectroscopy (EIS) measurements are performed to investigate the electron transport and recombination of quantum dot-sensitized solar cells (QDSSCs) based on HTS/CdS, HTS/CdSe, and HTS/CdS/CdSe photoelectrodes. This dynamic study reveals that the CdSe/CdS cosensitized solar cell performs ultrafast electron transport and high electron collection efficiency (98%).