Single-layered hybrid DBPPV-CdSe-ZnS quantum-dot light-emitting diodes

We have demonstrated the fabrication and characterization of single-layered hybrid polymer-quantum-dot light-emitting diodes (PQD-LEDs) with the emissive composite film of 2,3-dibutoxy-1,4-poly(phenylene vinylene) (DBPPV) and inorganic CdSe-ZnS core/shell quantum dots (QDs). It is observed that both the electrical and optical characteristics are significantly improved by adjusting the thickness of the emissive layer. For the device with composite film thickness of 103 nm, the turn-on voltage is 4.1 V, and the maximum luminance of 4100 cd/m(2) as well as maximum luminous efficiency of 1.35 cd/A are achieved at 9.6 and 7.6 V, respectively. The optimum emission contribution of luminescence from QDs to the whole luminance is 38%. However, the QD luminescence is mainly limited by the Forster energy transfer mechanism and no obvious QD-related injected carrier trapping is observed. To our knowledge, this is the first demonstration of PQD-LEDs that consist of DBPPV and CdSe-ZnS QDs.