In this paper, the charge carrier generation in polymer blends by chemical doping has studied. In these studies, we employed n-type dopant molecule decamethylcobaltocene (DMC) which exhibit very strong electron donating nature. We have demonstrated that such type of doping favours the formation of charge transfer complex (CTC) and reduce the recombination probability. We have confirmed the CTC formation form the absorption spectroscopy. Further we have used transient photoluminescence spectroscopy to reveal the reduced initial recombination of charge transfer exciton. We interpret our results based on a reduced formation of emissive charge transfer excitons in doped blends, induced by state filling of immobile tail states in the polymer HOMO.