title: Optoelectronic characteristics of inorganic/organic hybrid device based on poly(N-vinylcarbazole)/ cadmium selenide thin films.
abstract: Inorganic/organic hybrid light-emitting diodes were easily fabricated with a thin film containing water-soluble cadmium selenide nanocrystals and poly(N-vinylcarbazole) as an emitting layer by a spin-coating method. The cadmium selenide nanocrystals were synthesized in aqueous solution with L-cysteine hydrochloride as the stabilizer and were transferred from the aqueous solution into chloroform by a cationic surfactant cetyltrimethyl ammonium bromide. A broad emission spanning the whole visible wavelength range was obtained from the inorganic/organic hybrid devices whether poly(N-vinylcarbazole) was present in the devices or not, and the electroluminescence intensity of the devices increased as the applied voltages increased. However, an obvious blue-shift of the wavelength was observed with the increasing applied voltages in the device with poly(N-vinylcarbazole). Accordingly, the emission color of the device made with poly(N-vinylcarbazole) could be tuned from white to blue by varying the applied voltages, but the emission color of the device made without poly(N-vinylcarbazole) was almost constrained in the white region. This can be attributed to a limited contribution of poly(N-vinylcarbazole) emission to the electroluminescence spectra under the higher applied voltage. By comparing the electroluminescence intensity and the current-voltage characteristics of the devices made with and without poly(N-vinylcarbazole), the performance of the device with poly(N-vinylcarbazole) was improved greatly, which indicated that poly(N-vinylcarbazole) played an important role in the carrier injection and transportation in the device with poly(N-vinylcarbazole).
authors.affiliation: Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing JiaoTong University, Beijing 100044, China.
authors.forename: Aiwei
authors.initials: A
authors.lastname: Tang
authors.forename: Feng
authors.initials: F
authors.lastname: Teng
authors.forename: Yanbing
authors.initials: Y
authors.lastname: Hou
authors.forename: Sha
authors.initials: S
authors.lastname: Xiong
authors.forename: Bin
authors.initials: B
authors.lastname: Feng
authors.forename: Lei
authors.initials: L
authors.lastname: Qian
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Wang