Highly Efficient Quantum-Dot Light-Emitting Diodes with DNA−CTMA as a Combined Hole-Transporting and Electron-Blocking Layer

Abstract

Owing to their narrow bright emission band, broad size-tunable emission wavelength, superior photostability, and excellent flexible-substrate compatibility, light-emitting diodes based on quantum dots (QD-LEDs) are currently under intensive research and development for multiple consumer applications including flat-panel displays and flat lighting. However, their commercialization is still precluded by the slow development to date of efficient QD-LEDs as even the highest reported efficiency of 2.0% cannot favorably compete with their organic counterparts. Here, we report QD-LEDs with a record high efficiency (approximately 4%), high brightness (approximately 6580 cd/m(2)), low turn-on voltage (approximately 2.6 V), and significantly improved color purity by simply using deoxyribonucleic acid (DNA) complexed with cetyltrimetylammonium (CTMA) (DNA-CTMA) as a combined hole transporting and electron-blocking layer (HTL/EBL). This, together with controlled thermal decomposition of ligand molecules from the QD shell, represents a novel combined, but simple and very effective, approach toward the development of highly efficient QD-LEDs with a high color purity.

Toward biomaterial-based implantable photonic devices

“…To date, a number of individual LED components made using biocompatible, organic materials have been reported. For example, DNA was used as electron/hole transport/blocking layer material [185][186][187] or as phosphorescent host [188] in OLED devices. Individual nucleobases were also used as electron/hole transport/blocking layer material [189,190].…”

Lateral carrier confinement in InGaN quantum-well nanorods

“…Physically, the energy transfer is Förster type originating from the Coulomb interactions [68]. In comparison to the conventional absorptionbased approaches, the non-radiative energy-transfer pumping can eliminate energy losses associated with the intermediate steps (including blue light emission, light extraction and re-absorption) [42], and it can overcome the difficulty of current injection in the conventional p-n junction diodes with organic emitters or nanocrystals [69][70][71][72][73][74]. The energy-transfer-based white-light LEDs have been demonstrated with improved performances in brightness, conversion efficiency, and color quality [33][34][35]37,38,41,67,75].…”

Printed Biopolymer-Based Electro-Optic Device Components

“…These materials are completely environmental friendly since they are biodegradable. Biopolymers are also actively investigated for several applications like electron blocking layer in organic light emitting diode (LED), low gate voltage bio-field effect transistors and chemical sensors [7].…”