A new series of panchromatic ruthenium(II) sensitizers derived from carboxylated terpyridyl complexes of tris-thiocyanato Ru(II) have been developed. Black dye containing different degrees of protonation {(C2H5)3NH}[Ru(H3tcterpy)(NCS)3] 1, {(C4H9)4N}2[Ru(H2tcterpy)(NCS)3] 2, {(C4H9)4N}3[Ru(Htcterpy)(NCS)3] 3, and {(C4H9)4N}4[Ru(tcterpy)(NCS)3] 4 (tcterpy = 4,4‘,4‘ ‘-tricarboxy-2,2‘:6‘,2‘ ‘-terpyridine) have been synthesized and fully characterized by UV−vis, emission, IR, Raman, NMR, cyclic voltammetry, and X-ray diffraction studies. The crystal structure of complex 2 confirms the presence of a RuIIN6 central core derived from the terpyridine ligand and three N-bonded thiocyanates. Intermolecular H-bonding between carboxylates on neighboring terpyridines gives rise to 2-D H-bonded arrays. The absorption and emission maxima of the black dye show a bathochromic shift with decreasing pH and exhibit pH-dependent excited-state lifetimes. The red-shift of the emission maxima is due to better π-acceptor properti...

Engineering of Efficient Panchromatic Sensitizers for Nanocrystalline TiO2-Based Solar Cells

Reference LPI-ARTICLE-2000-012View record in Web of Science Record created on 2006-02-21, modified on 2017-05-12

Perspectives for dye‐sensitized nanocrystalline solar cells

The effect of the presence of a photonic crystal on the optical absorption of dye-sensitized titanium oxide solar cells is theoretically investigated herein. Different configurations in which a colloidal crystal can be implemented in such devices are modeled, and their absorptances compared. Experimental results on light-harvesting enhancement recently reported for periodically structured photoelectrodes are satisfactorily explained in terms of the appearance of multiple resonant modes localized in the absorbing layer when this is deposited onto one of the optical lattice surfaces. Longer matter-radiation interaction times for such frequencies result in higher absorption of those modes when compared to standard dye-sensitized solar cells. The effect of the finite size and the different characteristics of the photonic crystal on the optical absorption amplification effect is also discussed, new perspectives for colloidal-crystal-based photovoltaics being proposed.

Origin of Light-Harvesting Enhancement in Colloidal-Photonic-Crystal-Based Dye-Sensitized Solar Cells

https://www.solideas.com/papers/GPS25_1992_51.pdf

Luminescence and current-voltage characteristics of solar cells and optoelectronic devices

On some thermodynamic aspects of photovoltaic solar energy conversion

The operation of a photovoltaic solar cell is discussed with a quantum two‐level system as a model. A detailed‐balance calculation is carried out, from which the parameters of the converter, illuminated by radiation from a black body, are exactly obtained in different geometries, taking into account radiative recombination processes. It is shown that in a 4π geometry (source fully surrounding the converter) with total radiative recombination, the thermodynamic efficiency is equal to the Carnot efficiency at zero current (open circuit): the converter behaves as an ideal thermal engine, fully reversible when delivering no power (the practical efficiency is evidently zero). The reversibility is ensured by the complete exchange of photons between the source and the converter. The current‐voltage relation is obtained in all cases, and it is shown that the two‐level system follows the ideal diode equation. The calculation of the thermodynamic efficiency is generalized to an energy band system (real semiconductor) with radiative recombination and is shown to be maximum at open circuit, but lower than the Carnot efficiency because of irreversibilities induced by the thermalization of carriers. The effective source temperature concept is discussed. It is shown to be valid for a two‐level system, but has less physical meaning for a two‐band system.

P. Baruch

Papers

A two‐level system as a model for a photovoltaic solar cell