Photoluminescence Of Copper Indium Sulfide Based Quantum Dots And Their Application In LED

As a new kind of nanomaterial, semiconductor quantum dots have shown a bright prospect in optoelectronics due to their unique optical properties. Given the concept of sustainable development of green environment, this thesis focuses on CIS based colloidal quantum dots, including the synthesis methods, optical properties and applications in LEDs. The main results are as follows:(1) The synthesis and analysis of quantum dots:We synthesized alloyed CIZS QDs based on CIS QDs via an approach of cation exchange. The formation of the alloyed structure can not only tune the emission wavelength from a range of 550 nm to 700nm, but also significantly enhance the quantum yield and photoluminescence lifetime. Moreover, the formation process of CIZS QDs was also studied by X-ray diffraction and transmission electron microscope.(2) The development of quantum dot LEDs:In order to avoid the silver sol polluting the organic layer and quantum dots during the baking process, we optimized the structure through photolithography and etching. And red-light emission of CIZS QDs LEDs was realized by an organic-inorganic structure.(3) The fabrication of down-converted LED:We fabricated colorful down-converted LEDs using green (550nm) and red (635nm) CIZS QDs as down conversion material, by capping the 460nm blue LED chips.