Study of ethanolamine surface treatment on the metal-oxide electron transport layer in inverted InP quantum dot light-emitting diodes

Abstract

The present work shows the effect of ethanolamine surface treatment on inverted InP quantum dot light-emitting diodes (QD-LEDs) with inorganic metal oxide layers. In the inverted structure of ITO/ZnO/InP QDs/CBP/MoO3/Al, a sol-gel derived ZnO film was used as an electron transport layer (ETL) and MoO3 was used as a hole injection layer (HIL). First, ethanolamine was treated as a surface modifier on top of the ZnO electron transport layer. The optical performance of the QD-LED device was improved by the ethanolamine surface treatment. Second, low temperature annealing (<200°C) was performed on the ZnO sol-gel electron transport layer, followed by an investigation of the effect of the ZnO annealing temperature. The efficiency of the inverted QD-LEDs was significantly enhanced (more than 3-fold) by optimization of the ZnO annealing temperature

51‐3: Efficient InP/ZnS Quantum Dot Light‐emitting Diodes with Improved Electron Confinement

“…Parasitic emission was in the blue region of the spectrum, as indicated in Figure 1(b). The parasitic emission in InP-based QLED was frequently reported in previous publications (7,16,17). Due to the poor quality of ZnS shell and small offset between the CBMs of InP and ZnS, the electrons in InP QDs were highly delocalized.…”

Recent Progress of Quantum Dot‐Based Photonic Devices and Systems: A Comprehensive Review of Materials, Devices, and Applications

“…[ 126 ] More recently, new material synthesis toward less‐toxic and more efficient synthesis of QDs has been reported. For example, indium arsenide (InAs) QDs, [ 127 ] indium phosphide (InP) QDs, [ 128–131 ] and silver selenide (Ag 2 Se) QDs [ 132–136 ] were developed to replace the toxic heavy metal components ( Figure ). However, the optoelectronic performances are still inferior to the heavy metal‐based QDs, requiring further studies to improve the efficiency as well as the cost‐effective synthesis routes.…”

Development of InP Quantum Dot-Based Light-Emitting Diodes

“…23,98,99 This was explained by the prevention of excess electron injection and better balance of carriers. The two references 88,89 studied how the preparation conditions of ZnO interlayer affect the performance of InP QLED with the same device structure. The device structure with energy levels is shown in Figure 9a.…”

“…However, after thorough analysis of the published results from the literature and our own unpublished results, we realized that this was not always correct, especially in InP-based QLEDs with poor electron confinement. From 2013 to 2017, there were four publications with careful studies on the ETL in InP QLEDs. ,− The following paragraphs summarize the analysis on the results from these four publications.…”

“…Later in 2015, the experimental facts from two similar publications seemed to suggest less efficient electron injection, rather than improved electron injection, was helpful to improve the performance of green InP QLEDs. , It has also been reported many times that suppression of electron injection improved the performance of CdSe-based QLEDs by inserting insulating organic polymers or electron-blocking polymers between QDs and ZnO layer. ,, This was explained by the prevention of excess electron injection and better balance of carriers. The two references , studied how the preparation conditions of ZnO interlayer affect the performance of InP QLED with the same device structure. The device structure with energy levels is shown in Figure a.…”