| Quantum dots are emerging as new functional materials to enhance the color performance of display devices. After many years of development, quantum dots based LED backlight has been applied in liquid crystal display, producing TV and computer screen in the market. To reduce the price and enlarge the market, urgent works is needed to solve the engineering problems from material to process. From the viewpoint of materials, we need to further optimize the materials and explore their stability. From the process view, the packaging process is essential for application, we have to pay more attentions to the process for the incorporation of quantum dots. These challenges still hinder the commercialization of quantum dots based technology.(1) Synthesis of alloying CdxZn1-xSeyS1-y and CdxZn1-xSeyS1-y/ZnS quantum dots. By adapting a method of one pot injection method, we developed the synthetic chemistry to fabricate alloyed green emissive quantum dots with highly quantum yield(about 90%), wavelength tunable(510-540 nm) and narrow FWHM(<35 nm).(2) Shell engineering was designed and developed to optimize the photoluminescence properties. We further studied the correlation of thermal stability with shell thickness, alloying gradient. The results can be explained by thermally activated crossover from the excited state to the ground state by considering the trap states in the interface and surface.(3)With using green emissive CdxZn1-xSeyS1-y/ZnS quantum dots and red K2SiF6:Mn(KSF) phosphor, we fabricate white light-emitting diodes with wide color gamut up to 120%(100% matching degree with NTSC), high luminous efficiency of 35-60 lm/W. |
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