Enhancing the Performance of Blue Quantum Dots Light‐Emitting Diodes through Interface Engineering with Deoxyribonucleic Acid

Abstract

Colloidal quantum dots light‐emitting diodes (QD‐LEDs) have been investigated for several decades. Compared with their green and red counterparts, the hole injection is more difficult for blue QDs due to their large optical band gap and relatively low highest occupied molecular orbital level. High‐performance blue QD‐LEDs are demonstrated by inserting a thin deoxyribonucleic acid (DNA) buffer layer between hole transport layer and ZnCdS/ZnS core/shell QDs layer. This DNA buffer layer can effectively enhance the hole injection efficiency, meanwhile its high lowest unoccupied molecular orbital level can help the injected electrons to be confined in the emitting layer, thus ensuring the charge balance in the QDs layer and an excellent recombination efficiency. After utilizing DNA as buffer layer, the maximum luminance is significantly increased from 10 218 to 16 655 cd m−2 and the external quantum efficiency is increased from 4.39% to 5.65%. These devices provide a saturated blue emission with emission peak located at 462 nm and full width at half maximum of 21 nm. This saturated blue emission makes it suitable for commercial applications. The results indicate that DNA is a promising material for regulating charge balance in the emitting layer for manufacturing high performance QD‐LEDs.

Blue quantum dot-based electroluminescent light-emitting diodes

“…4b). 43 Apart from introducing additional functional layers, doping HTLs with high-mobility small molecules (such as TCTA or TPD) is another effective strategy to improve the charge mobility and reduce the hole injection barrier of polymer hole-transport materials. The dopant TPD was added to a PVK HTL to form a composite HTL.…”

Highly Efficient and Super Stable Full‐Color Quantum Dots Light‐Emitting Diodes with Solution‐Processed All‐Inorganic Charge Transport Layers

“…[ 4,5 ] Studies reveal that, in addition to the QDs themselves, the properties of other functional layers (charge injection and transport layers), as well as interlayer interfaces, also play a critical role in device stability. [ 6,7 ] First, the environmental instability of some organic materials will deteriorate the stability of QLEDs under both storage and operating conditions. For example, the commonly used hole injection material, Polyethylene dioxythiophene:polystyrene sulfonate (PEDOT:PSS), may cause stability issues due to its hygroscopic and acidic property.…”

Solvent Effect to the Uniformity of Surfactant-Free Salmon-DNA Thin Films

“…Specifically, the band gap of DNA makes it favorable to function as a hole injection/electron blocking layer in organic-based electronic devices [ 7 , 8 , 9 ]. Previous authors have demonstrated the ability of DNA to improve LED performance [ 7 , 8 , 9 , 10 , 11 , 12 , 13 ] and as a component in the fabrication of photovoltaics [ 14 , 15 , 16 , 17 ]. Moreover, DNA films can be used as a matrix and doped with functional materials that can alter the optical and electronic properties of the thin film, which may be useful for different types of organic devices [ 18 , 19 , 20 ].…”