High-Efficiency Cu-In-S Quantum-Dot-Light-Emitting Device Exceeding 7%

초록

We report on the unique synthesis of hetetostructured core/shell Cu-In-S (CIS)/ZnS quantum dots (QDs), from a shelling perspective and fabrication of high-efficiency QD light-emitting diodes (QLEDs) with a standard device architecture. Onto CIS core QDs ZnS shelling of extraordinarily long duration is attempted along with the multiple injections of shell, precursors. Three CIS/ZnS QDs obtained through different Shelling periods of time are prepared and then individually employed as an emitting layer (EML) of solution-processed, multilayered QLED comprising a hole transport layer of Poly((9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-s-butylphenyl))diphenyl-amine) (TFB) and an electron transport layer of ZnO nanoparticles. We observe a remarkable dependence of device performance on the type of QDs and attribute this presumably to different QD heterostructural details as a function of shelling duration. Our best device, integrated with the longest-shelled QDs displays excellent current efficiency of 18.2 cd/A and external quantum efficiency of 7.3%, corresponding to the record-high values among CIS QLEDs reported.

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