Photovoltaic devices employing ternary PbSxTe1-x nanocrystals

Colloidal quantum dots (CQDs), especially lead chalcogenide CQDs, are regarded as promising materials for the next generation solar cells, due to their large absorption coefficient, excellent charge transport, and multiple exciton generation effect. We successfully synthesized highly-crystalline, monodispersed, well-alloyed PbSxTe1-x nanocrystals via a one-pot, hot injection reaction method. Energy-filtered transmission electron microscopy suggested that the S and Te anions were uniformly distributed in the alloy nanoparticles. The photovoltaic performance of CQD solar cells based on ternary PbSxTe1-x was reported for the first time. The photovoltaic devices using PbSxTe1-x were more efficient than either the pure PbS or the PbTe based devices. In addition, the PbSxTe1-x based devices showed a significantly improved stability than that of the PbTe based devices.