Modulation of molecular energy level of the polymer based on Benzodithiophene can raise efficiency of polymer solar cells (30% of present efficiency) [1].
As to planning of organic cells, photocurrent generation is described in charming electrodynamical models by Pettersson, Roman, Inganäs [2], Peumans, Yakimov, Forrest [3], Burkhard, Hoke, McGehee [4];
multilayer stackswith multiple reflections and interferences, with thin or thick films are treated by Transter Matrix Method [4].Here simulations are made considering the following layers:

1) glass
2) ITO (Indium Tin Oxide)
3)PEDOT:PSS (poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate)
4) P3HT:PCBM (poly-3-hexylthiophene:[6,6]-phenyl- -butyric acid methyl ester)
5) Ca electrode
6) Al electrode

Thicknesses in examples of Figs.1 and 2 are:

0, 110, 35, ,7, 200 nm with active film thickness;these figures show normalized electric field intensity.

Useful experiments that have been carried on as to sunlight concentration for organic cells [5] evidence remarkable saturation results (far different behaviour compared with inorganic cells): further research for many organic materials could clarify this behaviour and improve concentration efficacy.