Bright and Color-Saturated Emission from Blue Light-Emitting Diodes Based on Solution-Processed Colloidal Nanocrystal Quantum Dots

Abstract

We report a multilayer solution-processed blue light-emitting diode based on colloidal core/shell CdS/ZnS nanocrystal quantum dots (QDs). At a low-operating voltage of 5.5 V, the device emits spectrally pure blue radiation at 460 nm with a narrow full-width-at-half-maximum bandwidth of 20 nm and high brightness up to 1600 cd/m2. Broad-band, long-wavelength emission from the polymer components and deep traps in the QDs are minimized to less than 5% of the total emission.

A New Class of Nanostructured Inorganic–Organic Hybrid Semiconductors Based on II–VI Binary Compounds

“…Semiconductor QDs bridge the gap between molecules and bulk materials, but the boundaries among molecules, QDs and bulk regimes are not well defined and are material dependent. Over the past 20 years, tremendous research efforts have been made to develop II-VI quantum dots because of their great potential to revolutionize numerous traditional and emerging technologies [e.g., light emitting diodes (LEDs) (37)(38)(39)(40)(41)(42), solar cells (43)(44)(45)(46)(47)(48)(49)(50)(51), lasers (52)(53)(54)(55), nonlinear optical devices (56)(57)(58)(59)(60)(61)(62), and biological imaging (44,(63)(64)(65)(66)]. A major milestone in this research field is to quantify the size-dependent properties of II-VI quantum dots and to map the transition from molecular to macroscopic crystal properties.…”

Fully inorganic oxide-in-oxide ultraviolet nanocrystal light emitting devices

“…Over the last few years, a variety of solution-based synthesis methods have become available for producing high quality nanocrystals (NCs), either as self-standing colloidal nanoparticles [1][2][3] or as highly controlled crystalline nanophases in suitable host matrices [4][5][6][7] , thus combining the superior resistance of inorganic emitters over organic dyes to degradation with the advantages of inexpensive and large-scale fabrication processes, such as spin coating, contact and ink jet printing and layer-by-layer deposition [8][9][10][11] . Several examples of light-emitting diodes (LEDs) based on nanostructured (NS) materials have been reported by different groups [11][12][13][14] , and have shown a remarkable tunability across the visible spectrum 8,[15][16][17][18] . The extension of the emission into the ultraviolet (UV) region is problematic and increasing efforts are being devoted to this task because of the technological relevance of UV-emitting solution processable nanomaterials 13,[17][18][19][20] .…”

Recent Developments in Applications of Quantum-Dot Based Light-Emitting Diodes

“…This undesired emission perturbs the color purity when a saturated monochromatic emission is wanted. Several authors have shown that in certain cases the perturbing emission could be eliminated [51][52][53] and in other cases, it could be utilized to build an efficacious white QD-LED [54,55]. The researchers established that the highest efficiency devices with the best construction architecture are QD-LEDs from type IV class.…”