Fabrizio Giordano

Series-Connection Designs for Dye Solar Cell Modules

We present a vis-à-vis experimental and PSPICE circuital comparison and optimization of W- and Z-type dye solar cell (DSC) modules. Important design and technological aspects which can, at the same time, promote and hamper each scheme were identified, including differing photocurrents (by a factor 1.6) between front- and back-illuminated cells, sheet-resistance-induced halving of fill factor (FF) when increasing cell width (2-20 mm), and vertical connections with resistances that can affect FF. The modules fabricated showed efficiencies of 4.7% and 4.2% over active area for Z and W modules and 3.4% over total area for both (due to different aperture ratios). Our simulations showed that geometrically optimized front-illuminated DSC Z modules would yield higher efficiencies than W modules built with the same materials if ideal vertical connections can be achieved. Pointers for further differing optimization of each scheme are laid out.

Multiscale Modeling of Dye Solar Cells and Comparison With Experimental Data

In this paper, we investigate the electrical properties of dye solar cells (DSCs) under illumination and in dark conditions when an external bias is applied. The measurements performed on the cells will be compared with theoretical calculations. The modeling is made using two approaches: a finite-element code based on Tiber computer-aided design (CAD) software to describe in detail the electrical properties of the cell and a circuital model implemented on PSpice. The latter has been developed in the perspective of simulating larger systems, such as modules and panels. It should be a phenomenological model to fit I-V characteristics of real cells. The CAD instead allows to calculate steady-state properties and I-V characteristics of the cell, solving a set of differential equations on meshes in one, two, and three dimensions. The two models are compared to experimental values, and the microscopic model is used to shine light over the fitting parameters of the circuital model.

Smart Materials and Concepts for Photovoltaics: Dye Sensitized Solar Cells

Recently the issue of clean energy generation for powering an ever growing and developing civilization has come to the fore in international communities. A range of strategic actions have been identified in order to reach the renewable energy goals of 2020. The photovoltaic will play an important role with annual growth rate of the order of 30%. Particular emphasis has been given to organic solar cells and in particular to dye solar cells (DSC). These have the potential to greatly reduce materials and fabriccation costs. In this chapter we will be giving a brief survey of dye solar cell science and technology: both the material aspects, highlighting the contribution to the photovoltaic process played by the electrolyte and counter electrode materials, and the engineering issues involved in creating a module of interconnected cells, using different architectures, on a common substrate. It is the possibility of using solution processed techniques with many of the active materials of the cell that contributes to make organic semiconductor and hybrid DSC technology so promising.

PSPICE models for Dye solar cells and modules

A Circuital model for Dye Sensitized Solar Cell is proposed. Experimental comparisons and module design are carried out with the present model.

Analysis of changes in efficiency by simulating dye-sensitized solar cells varying the characteristics of TiO2

Dye Sensitized solar cells (DSC) are an interesting alternative to conventional silicon based solar cells. Although DSCs are very close to be commercialized, still many issues need to be addressed. Part of the problem is related to the lack of a reliable and consistent simulator able to catch the physics and the chemistry underlining the functioning of the cell. The need of a reliable simulator and modelling is particularly important for the engineering of the cell and to define trends not only in the component characteristics, but also in the building of the device. Among the different parts which compone a DSC the relevance of semiconductor titanium oxide substrate can hardly be underestimated. TiO2 is where the dye molecule is chemisorbed and where the recombination occurs. Moreover, changes in the topology of the semiconductor paste can lead to other smaller effects in the total efficiency. In this paper we investigate the effects of changing working parameters for the titanium oxide and varying its topology. The simulations are performed using a finite element code based on TiberCAD software1 to describe in details the electrical properties of the cell. The CAD allows to calculate steady-state properties and ideal I-V characteristics of the cell solving a set of differential equations on meshes in 1, 2 and 3 dimensions.