Fast-response, high-stability, and high-efficiency full-color quantum dot light-emitting diodes with charge storage layer

Recently, solution-processed quantum dot light-emitting diodes (QLEDs) have emerged as a promising candidate for next-generation lighting and display devices. However, when given a constant voltage or current, the QLEDs need a certain working time to reach their maximum brightness. Such positive aging challenge, dramatically reducing the response speed of the device and causing a luminescence delay, is urgent to be investigated and resolved. In the current work, we introduce a charge-storage layer architecture by inserting copper(I) thiocyanate (CuSCN) between the organic hole-injection layer and hole-transport layer. The extracted holes will be released during the next electrical signal stimulation to increase the efficiency of charge transport. As a result, the response speed of the QLEDs is improved by an order of magnitude. In addition, by inserting an inorganic CuSCN layer, the efficiency, lifetime, and environmental stability of red/green/blue full-color QLEDs are enhanced simultaneously. Moreover, this work provides a generic strategy for the fabrication of fast-response and high-efficiency full-color QLEDs without luminescence delay, which plays a critical role in the practical industrialization of QLEDs.