Hi Rekha,

Plot the quantum efficiency of your PV cell irradiated with an optical light source (400 to 2500 nm) in function of layer thickness. If there is an optimum in the curve you obtain, that's the thickness you need; Quantum efficiency in function of layer thickness.

Simple no?

Frank

Hi there, 

Scientifically agreed to what Dr. Frank said. Also, you can use the EIS method to estimate the thickness of thin file, see following link :http://www.sciencedirect.com/science/article/pii/S1388248105004005

Best wishes, 

Qahtan

The thickness of the absorbing layer depends on the diffusion length of the electrons injected ( the average distance that electrons can travel before recombine), a meassure of the IPCE in function of thickness is a good aproximations since the diffusion length is implicit in the collection efficiency in the IPCE expresion. through IMPS and IMVS experiments the diffusion coefficient and electron life time can be obtained and with the use of charge extraction meassurements at short circuit and open circuit conditions is posible to relate the voltage with the electron density in the film, thus Ln = (Dn*Tn)^(1/2) at the same electron density. The latter only aplies if the electron transport is a diffusion limited process.

I hope it helps! My best.