Interface-Induced Crystallinity Enhancement of Perovskite Quantum Dots for Highly Efficient Light-Emitting Diodes

Perovskite quantum dot light-emitting diodes (QLEDs)with highcolor purity and wide color gamut have good application prospectsin the next generation of display technology. However, colloidal perovskitequantum dots (PQDs) may introduce a large number of defects duringthe film-forming process, which is not conducive to the luminous efficiencyof the device. Meanwhile, the disordered film formation of PQDs willform interfacial defects and reduce the device performance. Here,we report an interface-induced crystallinity enhancement (IICE) strategyto increase the crystallinity of PQDs at the hole transport layer(HTL)/PQD interface. As a result, both the Br- vacanciesin the PQD film and the interfacial defects were well passivated andthe leakage current was also suppressed. We achieved QLEDs with amaximum external quantum efficiency (EQE) of 16.45% and current efficiency(CE) of 61.77 cd/A, showing improved performance to more than twicethat of the control devices. The IICE strategy paves a new way toenhance the crystallinity of PQD films, so as to improve the performanceof QLEDs for application in the future display field.