Enhancing the efficiency of solution-processed inverted quantum dot light-emitting diodes via ligand modification with 6-mercaptohexanol

In this Letter, the surface hydrophilicity of the quantum dot (QD) emitting layer (EML) was modified via a ligand exchange to prevent QD EML damage upon hole transport layer (HTL) deposition for all-solution-processed inverted QD-light-emitting diodes (QLEDs). The conventional hydrophobic oleic acid ligand (OA-QDs) was partially replaced with a hydrophilic 6-mercaptohexanol (OH-QDs) through a one-pot ligand exchange. Owing to this replacement, the contact angle of a water droplet on the OH-QD films was reduced to 71.7° from 89.5° on the OA-QD films, indicating the conversion to hydrophilic hydroxyl ligands. The OH-QD EML maintained its integrity without any noticeable damage, even after HTL deposition, enabling all-solution processing for inverted QLEDs with well-organized multilayers. Inverted QLEDs with the OH-QD EMLs were compared with those with OA-QD EMLs; the maximum current efficiency of the device with the OH-QD EML significantly improved to 39.0 cd A-1 from 5.3 cd A-1, and the peak external quantum efficiency improved to 9.3% from 1.2%, which is a seven-fold increase over the OA-QD device. This approach is believed to be effective for forming solid QD films with resistance to chlorobenzene, a representative HTL solvent, and consequently contributes to high-efficiency all-solution-processed inverted QLEDs.

Medienart:

E-Artikel

Erscheinungsjahr:

2021

Erschienen:

2021

Enthalten in:

Zur Gesamtaufnahme - volume:46

Enthalten in:

Optics letters - 46(2021), 6 vom: 15. März, Seite 1434-1437

Sprache:

Englisch

Beteiligte Personen:

Lee, Woosuk [VerfasserIn]
Lee, Changmin [VerfasserIn]
Kim, Boram [VerfasserIn]
Choi, Yonghyeok [VerfasserIn]
Chae, Heeyeop [VerfasserIn]

Links:

Volltext

Themen:

Journal Article

Anmerkungen:

Date Revised 16.03.2021

published: Print

Citation Status PubMed-not-MEDLINE

doi:

10.1364/OL.414574

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM322769604