COLLOIDAL PEROVSKITE NANOCRYSTALS AND LED APPLICATIONS

Abstract

Colloidal perovskite nanocrystals, recently, attracted a great amount of research interest because of their near-unity photoluminescence quantum yield efficiency, narrow emission linewidth, easy tunability of wavelength covering full visible spectrum thanks to quantum confinement effect and halogen composition dependence, as well as the compatibility with the flexible substrates. All these properties make colloidal perovskite nanocrystals a serious candidate for use as emissive layers in next-generation light-emitting diodes (LEDs) and displays. In this thesis, syntheses of colloidal nanocrystals were demonstrated, and red and green light-emitting diodes which contain perovskite nanocrystals as emissive layer were fabricated, optimized, and measured. The main challenges of perovskite nanocrystals based light-emitting diode applications are identified, such as stability and toxicity. Additionally, blue and green light-emitting diodes which employ CdSe based semiconductor nanocrystals as emissive layer were fabricated on ITO coated PET (Polyethylene terephthalate) and glass substrates. A flexible white LED is presented as a proof of concept, by fixing a flexible polymer layer consists of red and green InP based semiconductor nanocrystals on top of the CdSe based blue LED.