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  • Efficient Triplet–Triplet Annihilation Upconversion in an Electroluminescence Device with a Fluorescent Sensitizer and a Triplet‐Diffusion Singlet‐Blocking Layer
Title: Efficient Triplet–Triplet Annihilation Upconversion in an Electroluminescence Device with a Fluorescent Sensitizer and a Triplet‐Diffusion Singlet‐Blocking Layer
Abstract

Solid‐state triplet–triplet annihilation upconversion (TTAUC) blue emission in an electroluminescence device (i.e., an organic light‐emitting diode (OLED)) is demonstrated. A conventional green fluorophore, tris‐(8‐hydroxyquinoline)aluminum (Alq3), is employed as the sensitizer that generates 75% triplet under electrical pumping for the blue triplet–triplet annihilation emitter, 9,10‐bis(2′‐naphthyl) anthracene (ADN), with the heterojunction bilayer structure. The operation lifetime is elongated both for ADN blue (4.1x) and Alq3green (34.8%) emission due to efficient use of excitons and separation of recombination and emission zone. To reduce the singlet quenching (SQ) of blue TTAUC signal by the Alq3sensitizer with lower bandgap, 1‐(2,5‐dimethyl‐4‐(1‐pyrenyl)phenyl)pyrene (DMPPP) is inserted between the Alq3and ADN as a triplet‐diffusion‐and‐singlet‐blocking layer. DMPPP exhibits triplet energy close to Alq3and higher than ADN, as well as higher singlet energy than both Alq3and ADN. It allows triplet diffusion from Alq3to ADN, but blocks the SQ of the blue TTAUC signal by Alq3. 86.1% intrinsic efficiency of TTAUC is demonstrated in this trilayer (Alq3/DMPPP/ADN) OLED.

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Award ID(s):
1800187
NSF-PAR ID:
10078124
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Advanced Materials
Volume:
30
Issue:
50
ISSN:
0935-9648
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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