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Research

1. Dye sensitised solar cells (DSC) (Grätzel cells)

NANOCRYSTALLINE SOLAR CELLS

CHARGED COLLOIDAL SYSTEMS

Las células solares nanocristalinas o nanoestructuradas de colorante, también conocidas como “Células Grätzel” o células DSC (“Dye Solar Cell”), se construyen a partir de suspensiones coloidales de un óxido de amplio salto de banda (TiO₂, ZnO) que actúa como conductor electrónico, un colorante orgánico u órgano-metálico que hace las veces de captador de la luz solar, y un electrolito que contiene un par redox (I₃^-/I^-) y que permite el transporte de huecos. Debido a la sencillez de fabricación y a los materiales de bajo coste que emplea, estos dispositivos fotovoltaicos se han convertido desde su aparición en la década de los 90 en una alternativa prometedora frente a las células solares fotovoltaicas convencionales.

Research activities on DSCs:

(1) Theory, simulation and modelization of DSC and analogous devices

Illustration of the CTRW, (“Continuous Time Random Walk”) simulation of charge transport through nanocrystalline networks.

· Continuous time random walk simulation of short-range electron transport in TiO₂ layers compared with transient surface photovoltage measurements. I. Mora-Seró, J. A. Anta, G. García-Belmonte, T. Dittrich y J. Bisquert , Journal of Photochemistry and Photobiology A. 2006, 182, 280

· Charge transport model for disordered materials: application to sensitised TiO_2,J. A. Anta, J. Nelson y N. Quirke, Phys. Rev. B. 2002, 65, 125324

· Models of Electron Trapping and Transport in Polyethylene: Current-Voltage characteristics. J. A. Anta, G. Marcelli, M. Meunier y N. Quirke, J. Appl. Phys. 2002, 92, 1002

Illustration of the output of a macroscopic model based on the solution of the continuity equation with density dependent difussion and recombination constants.

Here we see the result of the fitting and the fitting parameters for a cell sensitised with chlorophyll

A Numerical Model for Charge Transport and Recombination in Dye-Sensitised Solar Cells. J. A. Anta, F. Casanueva and G. Oskam. J. Phys. Chem. B. 2006, 110, 5372

(2) Experimental studies on DSCs

Experimental benchmark for solar cell characterization, Xe lamp, monochromator, potenciostat, etcc.

Experimental techniques

1. IV curves

2. IPCE (spectral quatum efficiencies)

3. OCVD (Open Circuit Voltaje Decay)

Research

interests

Alternative Semiconductor materials

Alternative dyes

Alternative electrolytes

ZnO

Organic dyes

Natural dyes

Protic ionic liquids

To learn more:

DSC Online Resource

anthocyanine

chlorophyll

Example: IPCE curves for different dyes extracted from natural sources

Example: Open circuit voltaje decays for different electrolyte compositions

2. Charged colloidal systems

Charged colloidal systems pose a very interesting problem from the statistical mechanics point of view since they are a very assymetric mixtures where very different length and time scales are envolved, as well as long-range coulombic forces.

DVLO POTENTIAL

RHNC theory

MONOCOMPONENTE

Prediction of secondary minimum coagulation

· Integral equation prediction of reversible coagulation in charged colloidal suspensions, V. Morales, J. A. Anta y S. Lago, Langmuir, 2003, 19, 475

· Secondary minimum coagulation from Statistical mechanics methods, M. Cortada, J. A. Anta y J.A. Molina-Bolívar, J. Phys. Chem. B. 2007, 111, 1110

(A)

(B)

Colloids + ions

MULTICOMPONENT RHNC THEORY

CGHNC THEORY

EFFECTIVE POTENTIALS AND DOUBLE LAYER STRUCTURES

· Partially converged integral equations for charged colloidal suspensions with added salt , J. A. Anta, J. Phys: Condens. Matt , 2005, 17, 7935

· Integral Equation Studies of charged colloids: non-solution boundaries and bridge functions, J. A. Anta, F. Bresme and S. Lago. J. Phys: Condens. Matt , 2003, 15, S3491

· Self-consistent effective interactions in charged colloidal suspensions, J. A. Anta and S. Lago, J. Chem. Phys. 2002, 116, 10514