Solution Processed Light Emitting Diode Based on InP Quantum Dots with Hybrid Emissive Layer

Abstract

Solution-processable Cadmium-based Quantum dots light emitting diodes (QLEDs) are regarded as a good candidate for good performance display devices due to excellent color purity and inexpensive production. However, the toxicity still poses a severe risk. Although the most effective cadmium-free substance is thought to be InP for producing efficient QLEDs, its efficiency falls far short of its cadmium-based counterparts. We made a homogeneous thin film by mixing the organic compound 4, 4-bis (N-carbazyle)-1, 1-biphenyl (CBP) with InP/ZnSe quantum dots (QDs). Then, in our QLED design, we utilized this film as an emissive layer. The new QDs-based device showed a higher luminance of 14600 cd/m2 and having higher external quantum efficiency (EQE) of 11.6%. We discovered that the mixed QDs without any phase separation had a consistent distribution of CBP, which facilitated transfer of energy to QDs and injection of holes into the emissive layer. The blended QD was also shown to restrict injection of electrons into the hole transport/injection layers, protecting the device’s structural integrity. Developing a balanced charge in stable optoelectronic devices densities has a high potential when a homogeneous QD layer is combined with an effective charge transport material.