Son Dong-Ick, Park Dong-Hee, Ie Sang-Yub, Choi Won-Kook, Choi Ji-Won, Li Fushan, Kim Tae-Whan
Korea Institute of Science and Technology, Materials Science and Technology Research Division, Cheongryang, PO Box 131, Seoul 130-650, Korea. Department of Information Display, Division of Electronics and Computer Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791, Korea.
Nanotechnology. 2008 Oct 1;19(39):395201. doi: 10.1088/0957-4484/19/39/395201. Epub 2008 Aug 8.
We demonstrate hybrid polymer-quantum dot dual-function devices with a single active-layer structure consisting of CdSe/ZnS semiconductor quantum dots dispersed with poly N-vinylcarbazole (PVK) and 1,3,5-tirs-(N-phenylbenzimidazol-2-yl) benzene (TPBi) fabricated on an indium-tin-oxide (ITO)/glass substrate by using a simple spin-coating technique. The dual-function devices are composed of light-emitting diodes (LED) on the top side and nonvolatile organic bistable memory devices (OBD) on the bottom side and can show electroluminescence (EL) along with electrical bistability concurrently. Both the functionality of LEDs and OBDs can be successfully achieved by adding an electron transport layer (ETL) TPBi to the OBD to attain an LED in which the lowest unoccupied molecular orbital (LUMO) level of TPBi is positioned at the energy level between the conduction band of CdSe/ZnS and the LiF/Al electrode. Through transmission electron microscopy (TEM) study, it is revealed that CdSe/ZnS QDs distributed on the interface of the hole transport layer (HTL) and ETL significantly take part in the electroluminescence process rather than those existing at the outer surface of the ETL.
我们展示了具有单一活性层结构的混合聚合物-量子点双功能器件，该结构由分散有聚N-乙烯基咔唑（PVK）和1,3,5-三（N-苯基苯并咪唑-2-基）苯（TPBi）的CdSe/ZnS半导体量子点组成，通过简单的旋涂技术制备在氧化铟锡（ITO）/玻璃基板上。双功能器件由顶部的发光二极管（LED）和底部的非易失性有机双稳态存储器件（OBD）组成，并且可以同时显示电致发光（EL）和电双稳性。通过向OBD中添加电子传输层（ETL）TPBi，可成功实现LED和OBD的功能，从而获得一种LED，其中TPBi的最低未占据分子轨道（LUMO）能级位于CdSe/ZnS的导带与LiF/Al电极之间的能级处。通过透射电子显微镜（TEM）研究发现，分布在空穴传输层（HTL）和ETL界面上的CdSe/ZnS量子点在电致发光过程中起重要作用，而不是那些存在于ETL外表面的量子点。
