PHOTOELECTRIC CHARACTERIZATION OF P3HT POLYMER/PbS NANOCRYSTAL COMPOSITS

Abstract

Photoelectric properties of new type conjugated polymer-semiconductor nanocrystals hybrid solar cells were investigated. Dependencies of charge carrier generation, mobility and recombination on composition of samples and the way how the samples were prepared were evaluated by using ultrafast time-resolved fluorescence, transient photocurrent and delayed collection field techniques. The combination of several investigation techniques enabled to distinguish and investigate three processes determining solar cell efficiency: charge carrier generation, carrier recombination and extraction. Charge carrier generation was found to be limited by relatively slow electron transfer from photoexcited polymer to PbS nanoparticles, but this process was determined being independent of the electric field strength. Carrier recombination and extraction rates strongly depend on the PbS nanoparticle concentration and determine the extraction efficiency. Efficient carrier extraction at short circuit conditions is possible only in chemically and thermally treated samples with high PbS nanoparticle concentration.