Colloidal quantum dot light emitting devices (QD-LEDs) have generated considerable interest for applications such as thin film displays with improved color saturation and white lighting with high color rendering index. In this talk, we demonstrate that air-stable metal oxides can be used to achieve QD-LEDs that have long shelf lives and operate at constant luminance in ambient conditions, unpackaged. Because metal oxides range from conductors to dielectrics, they can be used to develop a variety of different device architectures to explore mechanisms for electrical excitation of QDs. We present three distinct light emitting devices (LEDs) with metal oxides surrounding a QD active layer, and use these novel metal oxide based QD-LEDs to study mechanisms for electrical excitation of QDs. We report the first all-inorganic QD-LEDs with n- and p-type metal oxide charge transport layers and present design rules to enable systematic improvement of device efficiency. To shift away from direct charge injection as a means for electroluminescence (EL) in inorganic-based QD-LED structures, we develop a unipolar device architecture that presents the first evidence of field driven EL in QDs. To further explore this field driven excitation mechanism, we develop a structure that eliminates the need for energy band alignment and enables EL from QDs with emission peaks from 450 nm-1500 nm as well as from novel nanoparticles, such as phosphor doped-core/shell nanocrystals.