Effects of impurities on operational mechanism of organic bulk heterojunction solar cells.

Photoconductive atomic force microscopy in conjunction with transient absorption spectroscopy and charge transport study were used to investigate the effect of impurities (TCNQ and PC84 BM) on the performance of low band gap conjugated polymer and fullerene solar cells to gain insight into whether differing impurity shapes may lead to different loss mechanisms.

Reconstruction of conjugated oligoelectrolyte electron injection layers.

Surface reconstruction of electron injection layers based on conjugated oligoelectrolytes atop an electroluminescent layer occurs in the presence of air. The proposed mechanism involves hydration and concomitant increase of the interfacial energy with the underlying hydrophobic surface followed by dewetting via a nucleation process. No such changes are observed in the case of a conjugated polyelectrolyte, presumably because the lower mobility of the polymer chains leads to a kinetically locked bilayer.