Cho, Ikjun Jung, Heeyoung Jeong, Byeong Guk Chang, Jun Hyuk Kim, Younghoon Char, Kookheon Lee, Doh C. Lee, Changhee Cho, Jinhan Bae, Wan Ki 2024-01-20T02:32:50Z 2024-01-20T02:32:50Z 2021-09-04 2017-01 1936-0851 https://pubs.kist.re.kr/handle/201004/123273 We present multifunctional dendrimer ligands that serve as the charge injection controlling layer as well as the adhesive layer at the interfaces between quantum dots (QDs) and the electron transport layer (ETL) in quantum dot light-emitting diodes (QLEDs). Specifically, we use primary amine-functionalized dendrimer ligands (e.g., a series of poly(amidoamine) dendrimers (PADs, also referred to PAMAM)) that bind to the surface of QDs by replacing the native ligands (oleic acids) and also to the surface of ZnO ETL. PAD ligands control the electron injection rate from ZnO ETL into QDs by altering the electronic energy levels of the surface of ZnO ETL and thereby improve the charge balance within QDs in devices, leading to the enhancement of the device efficiency. As an ultimate achievement, the device efficiency (peak external quantum efficiency) improves by a factor of 3 by replacing the native ligands (3.86%) with PAD ligands (11.36%). In addition, multibranched dendrimer ligands keep the QD emissive layer intact during subsequent solution processing, enabling us to accomplish solution-processed QLEDs. The approach and results in the present study emphasize the importance of controlling the ligands of QDs to enhance QLED performance and also offer simple yet effective chemical mean toward all-solution-processed QLEDs. English AMER CHEMICAL SOC INP-AT-ZNSES SEMICONDUCTOR NANOCRYSTALS COMPOSITION GRADIENT AUGER RECOMBINATION SHELL THICKNESS PERFORMANCE DEVICES POLYMER Multifunctional Dendrimer Ligands for High Efficiency, Solution-Processed Quantum Dot Light-Emitting Diodes Article 10.1021/acsnano.6b07028 1 ACS NANO, v.11, no.1, pp.684 - 692 ACS NANO 11 1 684 692 scie scopus 000392886500070 2-s2.0-85018521447 Chemistry, Multidisciplinary Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Chemistry Science & Technology - Other Topics Materials Science Article INP-AT-ZNSES SEMICONDUCTOR NANOCRYSTALS COMPOSITION GRADIENT AUGER RECOMBINATION SHELL THICKNESS PERFORMANCE DEVICES POLYMER dendrimer ligands quantum dot-based light-emitting diode charge injection adhesive layer interface engineering