- In this paper a new design process for Organic Solar Cells ( O S C s ) are proposed and developed using t h e c o m m e r c i a l modeling software for technical design and a simulation tool Comsol vers. 5.3. Comsol was used to determine the electromagnetic fields on O S C s e l e m e n t interfaces and to optimize aluminum and active layers. A more efficient geometry was founded in order to maximize the light trapping and increase the photovoltaic market. The first experimental results on the new OSCs are reported.
The third-generation solar cells can be made of low-cost
and sustainable materials such as polymers however with less
efficiency than the standard silicon cells mainly limited by the
ability of the active layer to absorb light and convert it into
electricity. A good solution could be investigate new light
trapping techniques and the impact of geometry in new model
and architecture design [
For specific types of geometrically shaped solar panels a simpler method was derived and applied, however with the limitations to broaden the applicability of the model to a wider range of geometric shapes.
Deepak K. Gupta et al present an efficient manner to maximize the power output with the application of topology optimization (TO) to optimize the front metallization patterns for free-form solar cells that are cells of unconventional shapes (e.g. hexagonal, leaf-shaped, circular, motorbike fairings etc) with flexible shape added to the aesthetics of the surround- ings
and an important factors of metallization design [8]. In order to provide more absorbtion of solar radition graphene nanostructures are incorporates from 0.5 to 5 µm in the device design or reduced graphene oxide as anode buffer layer is used. Graphene has a high optical transmittance, an excellent electron/hole transport properties, superior mechanical stiffness and flexibility. The Graphene can be used as transparent electrode to retard charge recombination in OPVs .To reduce or retard the carrier recombination we could form a direct channel between anode and cathode creating an alternating of graphene and ITO patterns. Other authors have investigate the electromagnetic field induced on solar devices in order to evaluate the interactions of the optical model at several frequencies and the magnetic field using as tool COMSOL to calculate the electric field effects starting from an organic sample. In this work we have presented different threedimensional models of multilayer bulk hetero- junction organic nanoscale solar cells. The 3D simulations of electromagnetic fields applied to OSCs presented in this work clearly reveal that the physical mechanisms depend on this particular contact design [9]. Using a cross-platform finite element analysis, solver and Multiphysics simulation software, we have analyzed specific geometrical patterns that could be optimal for capturing and holding light in thin-cell organic solar cells.
A solar organic cell is schematized in Fig. 1. In order to
investigate the shape in OSCs we proposed new design with
different geometry types that could lead to more efficient
organic solar cells. Five main parts are assembled in the
electronic device such as a rigid glass support, an anode, an
intermediate layer, a photo-active layer and cathode layer [8].
The glass support has the peculiarity to be transparent for light.
Furthermore, Indium Tin Oxide (ITO)is used as anode or
positive electrode with a work function greater than metal [
The parametric modeling of the OSCs was performed in a
similar way to that described by Calì et al. [
The parametric 3D design software of Solidworks has been an useful tool to model mechanical and electronic device.
In our case we have considered the device manufactured
(Fig.4) in the laboratories in the University of Ben Gurion [
V1 = V2 = = (1)
This means that the surface charge density of the smaller sphere is larger, i.e. that the charge is more crowded per unit area on the smaller sphere.In particular the ratio between the charge density Q on the surface of the sphere and the radius R is constant and with the same potential. For smaller surface namely largest curvature, lower surface charge density distribution is observed than larger surface.
The surface charge densities are calculated: (3) (4) (5)
The surface charge density is lower on second sphere. Thus the curvatures and apertures of the tip apex strongly influence the density charges. The effects of different apertures, curvature and sharpness of tip are analyzed to enhance the efficiency and electromagnetic field in OSCs. To model the cell with the rectangular cathode a 2D sketch was created on the upper face of the active layer and using the ”rectangle of the corner” function, it was possible to draw the cathodes. Through the “basic extrusion” function, it was possible to realize the final form. To create the Arabic cell, a 2D sketch was created on the upper face of the active layer 5. Using the ”spline” function, it was possible to draw the curved profile of the cathode.
The rectangular part was created using the ”rectangle of the corner” function. Extruding the sketch the shape of an Arabic shape was created. The nine-pointed star shape was also created by a 2D sketch on the upper face of the active layer12. First a circumference with a radius equal to 2245 µm was drawn using the ”circle” function, then another circle with a radius of 300 µm and a geometric center on the first circumference was drawn. First of all using the ”circular repetition” function and then the ”shorten entities” function, it was possible to obtain the definitive profile The pentagonal shape was configured by means a 2D sketch on the upper face of active layer 6. Using the ”polygon” function a hexagon has (6) been created inscribed in a circumference having a diameter equal to 1376 µm, with the ”tangent arc” function it was possible to realize the curved shape of the sides as shown in Fig. 7.
The types of geometric models proposed of the samples processed in SolidWorks have been imported in COMSOL and then the physical parameters has been set useful for the simulation of electromagnetic field. We have considered the Maxwell equations with particular referring to the electric field E and the magnetic flux density B as reported below: ∇ · E = 0 ∇ × E = ∇ · B = 0 (7) (8) (9)
The material properties are described using relative
permeability ε and the relative permittivity µ. In this application RF
module is used for Multiphysics simulation models for
wavelengths of the visible spectrum from 400 nm to 700 nm. In
order to guarantee the simulation phenomena, optical values
and electric properties of different materials are used as
reported in [
In this paper the ultrathin organic solar cells costitued by GLASS/ITO/PEDOT: PSS/ PF3HT:PCBM/ Al layers with different geometry of aluminum cathode are investigated. In particular different geometrical models of OSCs are proposed using the 3D design software SolidWorks and processed in COMSOL to simulate the physical phenomena of electromagnetic fields.
The proposed shape of Aluminum cathode are rectangular, pentagonal and nine-pointed stars and are simulated using the RF Module of Comsol Multiphysics. The optimal results of electric field are obtained for cathode of 5.5 mm with pentagonal shape. Thus we have demonstrated that the shape of cathode influences the performances of solar cells.
Fig. 11. Electric Field Aluminum pentagonal Shape
Fig. 12. Electric Field Aluminum rectangular Shape
In our case based on charge density distribution it is observed that for lower curvature of Aluminum cathode the electric field increases also for lenght dimensions of 5.5 nm.