Study of the effect of capping agent variation on P3HT:CdSe hybrid solar cells

We present here a new study on the incorporation of cadmium selenide (CdSe) nanoparticles (NPs) in Poly-3-hexylthiophene (P3HT) polymer matrix. Our aim is to improve the performance of the hybrid solar devices by varying capping agents on top of CdSe NPs for each active layer sample. We investigated the optical properties of differently capped Bulk Heterojunction (BHJ) P3HT:CdSe cells. We extracted the optical constants (refractive index n, extinction coefficient k, real ε′ and imaginary ε′′ parts of dielectric permittivity) from fitted Transmittance T and Reflectance R spectra. Then, we were able to determine the static refractive index ns and permittivity εs, the plasma frequency ωp, the carrier density to effective mass ratio N = me, the optical conductivity roc, the optical band gap Eg and the oscillation and dispersion energies E0 and Ed, using equations proposed by the theoretical models such as Cauchy model, Drude-Lorentz, Tauc model, and Wemple-DiDomenico.