High performance hybrid near-infrared LEDs using benzenedithiol cross-linked PbS colloidal nanocrystals

We report an all solution-based processing method to produce efficient hybrid polymer–nanocrystal multilayered heterostructures for electroluminescence in the near-infrared (1050–1600 nm). We employ for the first time the benzenedithiol cross-linking method to produce high-quality PbS nanocrystalline films acting both as an electron-transporting and electroluminescent layer within a near-infrared light emitting diode (LED) architecture. Due to the large volume of nanocrystals and the good carrier-transport properties within the cross-linked nanocrystalline films, this device architecture yields high emission powers and good quantum efficiencies. In contrast, using ethanedithiol cross-linking molecules results in nanocrystalline films with low photo- and electro-luminescence efficiencies.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► PbS nanocrystalline films and polymers are used to form hybrid heterostructures. ► Ethanedithiol (EDT) and benzenedithiol (BDT) ligand-exchange treatments are compared. ► The BDT treatment provides a mobility barrier keeping excitons at the interface. ► The lower conductivity in the BDT-treated films also preserves the carrier balance. ► This provides superior hybrid near-infrared LEDs using solution-based processing.