Fabrication of Light-Emitting Devices using Polyelectrolyte Films and Quantum Dots

The fabrication of light-emitting devices (LEDs) through the integration of polyelectrolyte films and quantum dots is a new approach to making light-emitting devices. The research involves the construction of these devices and studying their electroluminescent properties. The devices are made of two alternating layers of polyelectrolyte films (cationic and anionic) which are separated by a monolayer of Cd-Se quantum dots. The alternating polyelectrolyte films are deposited from an aqueous solution using layer-by-layer self assembly. One of the alternating polyelectrolyte films serves as the electron transport layer (ETL) at the cathode and the other alternating polyelectrolyte film serves as the hole transport later (HTL) (a hole is an electron vacancy) at the anode. The Langmuir-Blodgett trough is used to perform the Langmuir-Schaefer technique for the deposition of the Cd-Se quantum dot monolayer onto the HTL. The ETL is then deposited on top of the Cd-Se quantum dot monolayer. Once a device is constructed a voltage is applied to it, and the current density and the brightness of the device are investigated. These devices have applications in making flat panel displays, and also result in better resolution in displays and a longer life in displays.