Organic light-emitting diodes having exclusive near-infrared electrophosphorescence

Abstract

Near-infrared (NIR) emission is demonstrated from phosphorescent organic light-emitting diodes containing blends of polymeric host and heavy metal complex, iridium(III) bis(1-pyrenyl-isoquinolinato-N,C′) acetylacetonate. The devices exhibit exclusive NIR emission with a peak value at 720nm. Forward light output exceeds 100μW∕cm2, and the external quantum efficiency is nearly 0.1%. These values are shown to increase upon using a hole blocking layer in the device architecture.

Efficient red electroluminescence from diketopyrrolopyrrole copolymerised with a polyfluorene

“…1 Whereas initially significant effort was dedicated to development of blueemitting materials, 2-5 the focus has recently shifted to low-energy-gap materials for applications as long-wavelength absorbers in solar cells, 6 charge transporters in field-effect transistors, 7,8 as well as red 9,10 and near-infrared [11][12][13][14][15][16] emitters in organic light-emitting diodes (OLEDs). Many approaches have been proposed to obtain red and infrared emission from organic and solutionprocessable LEDs, including semiconductor nanoparticles, [17][18][19] conjugated small molecules, [11][12][13][14]20 conjugated polymers, 9,10,[21][22][23] and electrophosphorescence from transition metal 15 and rare earth complexes.…”

“…Many approaches have been proposed to obtain red and infrared emission from organic and solutionprocessable LEDs, including semiconductor nanoparticles, [17][18][19] conjugated small molecules, [11][12][13][14]20 conjugated polymers, 9,10,[21][22][23] and electrophosphorescence from transition metal 15 and rare earth complexes. 16,24 Of these, rare earth complexes offer some of the highest external quantum efficiencies, 25 with some reports in excess of 20%.…”

Efficient Near‐Infrared Electroluminescence at 840 nm with “Metal‐Free” Small‐Molecule:Polymer Blends

“…[7] In the search for ever-higher efficiencies, several classes of materials have been investigated, such as perovskite-structured methylammonium lead halides, [8][9][10] quantum dots, [11] and organometallic phosphorescent complexes. [12][13][14][15][16][17][18][19] However, although such hybrid materials afford substantial electroluminescence (EL) external quantum efficiency (EQE) in the NIR, in some cases exceeding 10% [8,10] or even 20% or so, [13] their use of heavy, toxic, and/or costly metals is not ideal for manufacturing, sustainability, environmental impact, and, in perspective, biocompatibility. Furthermore, in such hybrid systems, and in general in materials that leverage triplet excitons to boost the EQE, [20,21] exciton recombination dynamics typically fall in the hundreds of nanoseconds or even in the microsecond (or longer) range, which intrinsically limits the bandwidth when integrated in devices for telecommunications.…”

Remotely Interrogated Passive Polarizing Dosimeter (RIPPeD).

“…Creating a film of polymer from solution using a spinner is a straightforward process that has been used successfully to create films with good uniformity and conductivity 1,2,5,11,12,14,16,17 . Unfortunately, a single spin coated film has a thickness on the order of 100 nm.…”

“…Electrically conducting polymers are an active area of research with optical applications ranging from photodetectors 1 and photovoltaic cells 2 to light emitting diodes [3][4][5] . Here we report on the development of a subwavelength grating utilizing conductive polymer.…”