Benzonitrile-based AIE polymer host with a simple synthesis process for high-efficiency solution-processable green and blue TADF organic light emitting diodes
Abstract:Polymer host material have great potential for enable small molecular thermally activated delayed fluorescence (TADF) emitters to construct solution-processed organic light-emitting diodes (OLEDs). Herein, four novel benzonitrile-based polymer host, P4CzCN-PA,...
“…Additionally, the L values of the patterned SI-OLEDs were slightly reduced compared to those of the non-patterned SI-OLEDs, which could be attributed to the (i) reduced effective light-emitting area (6 µm × 6 µm) owing to the deposited PDL and (ii) inevitable exposure to O 2 and H 2 O during the RCP process. However, the V on and L characteristics of the patterned SI-OLEDs were comparable to those of previous studies on solution-processable, non-patterned, polymer-based, thermally activated delayed fluorescence OLEDs or perovskite light-emitting diodes 36 – 38 . Fig.…”
Ultrahigh-resolution patterning with high-throughput and high-fidelity is highly in demand for expanding the potential of organic light-emitting diodes (OLEDs) from mobile and TV displays into near-to-eye microdisplays. However, current patterning techniques so far suffer from low resolution, consecutive pattern for RGB pixelation, low pattern fidelity, and throughput issue. Here, we present a silicone engineered anisotropic lithography of the organic light-emitting semiconductor (OLES) that in-situ forms a non-volatile etch-blocking layer during reactive ion etching. This unique feature not only slows the etch rate but also enhances the anisotropy of etch direction, leading to gain delicate control in forming ultrahigh-density multicolor OLES patterns (up to 4500 pixels per inch) through photolithography. This patterning strategy inspired by silicon etching chemistry is expected to provide new insights into ultrahigh-density OLED microdisplays.
“…Additionally, the L values of the patterned SI-OLEDs were slightly reduced compared to those of the non-patterned SI-OLEDs, which could be attributed to the (i) reduced effective light-emitting area (6 µm × 6 µm) owing to the deposited PDL and (ii) inevitable exposure to O 2 and H 2 O during the RCP process. However, the V on and L characteristics of the patterned SI-OLEDs were comparable to those of previous studies on solution-processable, non-patterned, polymer-based, thermally activated delayed fluorescence OLEDs or perovskite light-emitting diodes 36 – 38 . Fig.…”
Ultrahigh-resolution patterning with high-throughput and high-fidelity is highly in demand for expanding the potential of organic light-emitting diodes (OLEDs) from mobile and TV displays into near-to-eye microdisplays. However, current patterning techniques so far suffer from low resolution, consecutive pattern for RGB pixelation, low pattern fidelity, and throughput issue. Here, we present a silicone engineered anisotropic lithography of the organic light-emitting semiconductor (OLES) that in-situ forms a non-volatile etch-blocking layer during reactive ion etching. This unique feature not only slows the etch rate but also enhances the anisotropy of etch direction, leading to gain delicate control in forming ultrahigh-density multicolor OLES patterns (up to 4500 pixels per inch) through photolithography. This patterning strategy inspired by silicon etching chemistry is expected to provide new insights into ultrahigh-density OLED microdisplays.
“…16). 161 All the developed hosts had high triplet energies of ∼2.68 eV and aggregation-induced emission properties. All the developed polymers were capable of trapping excitons and preventing exciton quenching.…”
Section: Reaction Chemistry and Engineering Reviewmentioning
Next generation green emitting materials are fast-emerging and potent both academia and industry that the history OLEDs advancement has still another season of even better devices coming.
“…Hu et al reported a through-space charge-transfer polymer containing a nonconjugated polystyrene backbone, and the maximum external quantum efficiencies (EQE max ) of deep-blue-, green-, and white-emitting solution-processed OLEDs were 7.1%, 16.2%, and 14.1%, respectively. Thus, this simple synthesis of a nonconjugated polystyrene-based chain polymer does show great potential for solution processing of OLEDs. − However, most of the polymers are simply applied to glass substrates, and very few attempts have been made for flexible substrates. Danyliv et al prepared a small-molecule CzPrSBI using sulfobenzimide as an acceptor, and EQE max of the nondoped TADF emitter was only 0.9% in a flexible OLEDs prepared on a poly(ethylene terephthalate) (PET) substrate using vacuum vapor deposition .…”
Thermally activated delayed fluorescence (TADF) polymer has great potential for the construction of flexible solution-processed organic light-emitting diodes (OLEDs). However, the relationship between polymerization engineering and device functions has rarely been reported. Here, two novel TADF polymers, P-Ph4CzCN and P-Ph5CzCN, with a small energy gap between the first excited singlet and triplet states (ΔE ST ; <0.16 eV) were newly developed by both solvent and in situ polymerization of a styrene component. Detailed device performance testing indicates that both polymerization strategies ensure that the TADF polymer achieves comparable high efficiencies in commonly rigid devices, and the maximum external quantum efficiencies (EQE max ) were 11.9%, 14.1%, and 16.2% for blue, green, and white OLEDs, respectively. Although in situ polymerization provides a simplified device fabrication process, which avoids the complicated synthesis and purification of the polymer, the inevitable hightemperature annealing makes it fail in a plastic substrate device. In contrast, P-Ph5CzCN achieved by solvent polymerization enables the successful fabrication of a flexible device on a poly(ethylene terephthalate) (PET) substrate, which was the first reported flexible OLED based on a TADF polymer. This work provides a strong guideline for the simple fabrication of TADF polymer devices and the application of TADF polymer materials in OLED flexible panels and flexible lighting.
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