Study On The Packaging Structures And Mechanisms Of Quantum Dot Light-Emitting Diodes

The conventional rare-earth based phosphor-converted light-emitting diodes(LEDs)are hard to satisfy the demand on display aaplications with a wide-color gamut,which can be attributed to their wide emission spectra,leading to a narrow-color gamut of only ?90%NTSC.Recently,integrating quantum dots(QDs)with LED chips to adjust the emission spectra is one of the most promising technique in display applications,successfully achieving a wide-color gamut over 120%NTSC by color conversion processes(the full width at half maximum of red,green,and blue spectra can be smaller than 20 nm).At present,the packaging design and manufacturing of QD-LED devices are extremely lacked of effective guidelines.Moreover,the optical and thermal perperties of QDs show great differences to conventional phosphor materials,previous packaging structures are hard to satisfy the harsh demand on highperformance QD convertors and their intergration with LED chips.This study focuses on the packaging design and manufacturing of QD-LED devices with high optical efficiency and stability,including device modeling,packaging design theory,manufacturing of high-performance QD convertors in packages,and optical-thermal coupled optimization in packaging strcutrues.The main research contents are as follows:(1)This study has investigated the modeling theory of QD-LED devices and proposed a full-spectral steadyiteration modeling method,successfully characterizing the infinite iteration processes in devices and providing a novel model for subsequent packaging design and mechanism investigation;(2)The packaging optical mechanisms of QD-LEDs are studied based on the proposed modeling method.For the first time,this paper reveals that the reabsorption effect and aggregation-induced scattering(AIS)effect are the behind mechanisms that lead to a low efficiency of QD-LED devices,providing critical guidelines for the packaging design and manufacturing of QD-LED devices;(3)Considering the packaging optical mechanisms revealed above,this study proposes the design and manufacturing methods of multiscale structures,including the interfacial patterned array with surface rough morphology and the hybrid particle structure with functional two-dimensional pore array.The enhanced light-extraction mechanisms at the interface and the inside of QD convertors are revealed,comprehensively improving the pumping light incident and converted light emission.After optimizing the key packaging parameters based on the above methods,this study successfully achieves the record luminous efficacy of QD-LED devices up to over 200 lm/W@20 m A(certificated by CNAS);(4)This study has investigated the effects of integration structures between chips and QDs on the optical and thermal performance of QD-LED devcies.The thermal-isolation inverted packaging structure is proposed and the light-extraction mechnisms for inverted chips and QDs are revealed,comprehensively improving the optical efficiency and stability of QD-LED devices.This study can make great contribution to accelerating the practical applications of QD-LED devices.