Exciplex‐Based Organic Light‐Emitting Diodes with Near‐Infrared Emission

Abstract

Near‐infrared exciplex can weaken molecular design difficulties, and has the advantage of easy bathochromic‐shift spectra via selecting the suitable electron donors and acceptors. In this contribution, exciplex is applied to fabricate near‐infrared (NIR) organic light‐emitting diodes (OLEDs) incorporating a synthesized fluorescent material 3‐([1,1″:3′,1″‐terphenyl]‐5′‐yl)acenaphtho[1,2‐b]pyrazine‐8,9‐dicarbonitrile (APDC‐tPh) and a commercially available material 4,4′,4″‐tris(carbazol‐9‐yl)triphenylamine (TCTA). The device having a mixed TCTA:APDC‐tPh as an emitting layer shows a 730 nm NIR emission with a maximum external quantum efficiency (EQE) of about 0.1%, while the device having 2‐[4‐(diphenylamino)phenyl]‐10,10‐dioxide‐9H‐thioxanthen‐9‐one (TXO‐TPA):APDC‐tPh as the emitting layer exhibits an emission peak of 704 nm with a maximum EQE of 1.27%. These results prove the feasibility of fabricating the efficient exciplex‐based NIR OLEDs.

Advances in engineering near-infrared luminescent materials

“…Hu et al. designed exciplex-based OLED materials with NIR emission at either 704 or 730 nm based on combinations of a novel synthesized fluorescent compound and commercially available materials ( Hu et al., 2020 ). Zhang et al.…”

Harvesting triplet excitons for near-infrared electroluminescence via thermally activated delayed fluorescence channel

“…Blending 10% POZ-DBPHZ in m-MTDATA could realize an efficient exciplex emission with a peak at 741 nm and an EQE of about 5%. In 2020, our group reported a series NIR exciplex system based on a fluorescence material, APDC-tPh, which possesses a low LUMO level ( Hu et al., 2020 ). The exciplex-based devices exhibited turntable emission from 615 to 945 nm by changing various donors (m-MTDATA, Zn(BTZ) 2 , TCTA, and CBP).…”

“…(2020) Non-doped 100 – −/− – 1010 −/−/- mMTDATA/POZ-DBPHZ Exciplex 90/10 – −/− 5 741 35,000/−/− Data et al. (2016) TXOTPA/APDC-tPh Exciplex 50/50 9 -/0.318 1.27 704 −/−/13,000 Hu et al. (2020) MPPA-Cz Non-doped 100 6 -/0.56 0.064 728 24/−/− Sun et al.…”

Non-toxic near-infrared light-emitting diodes

“… Class Host-guest EML Host λ EL [nm] EQE max [%] Ref. λ PL [nm] HOMO [eV] LUMO [eV] Small molecule CBP: 30% TBtz1 400 5.8 2.7 702 a) 1.52 ( Sudyoadsuk et al., 2020 ) CBP: 30% TBtz2 400 5.8 2.7 723 a) 1.22 ( Sudyoadsuk et al., 2020 ) CBP: 10% CAT-1 390 5.6 2.4 719 b) 1.6 ( Congrave et al., 2019 ) mCP: 20% Nd(TTA) 3 phen 395 5.9 2.4 890 b) 0.02 ( Shahalizad et al., 2017 ) TPBi: 30% TPA-QCN 381 6.2 2.7 700 b) 9.4 ( Li et al., 2017 ) TCTA: APDC-tPh (1:1) 385 5.8 2.4 730 b) 0.1 ( Hu et al., 2020 ) Alq 3 : 40% DTPS-PT 512 5.6 2.8 842 b) NA ( Jiang et al., 2019 ) ADO-TPA: 20% APDC-DTPA …”