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Anion exchange membranes prepared through cyclopolymerization of crosslinking of diallylammonium precursors were subjected to various physical, mechanical, and chemical stability property analysis for anion exchange membrane water electrolyzers.

A photocrosslinkable donor, PM6-X30, has been designed by engineering the side chains of the PM6 backbone. A high PCE of 12.33% was achieved with significantly enhanced thermal stability.

We present the advancement of the photocatalytic water pollutant degradation efficiency of a porous organic polymer material via post-synthetic modification with platinum clusters.

A polymer and a small molecule were developed as a mixed host with an exciplex for high performance of green TADF OLEDs.

Solvent mediated thermodynamically supramolecular assemblies of derivative 4 in aqueous media and recognition behavior in the presence of achiral/chiral analytes.

New photocrosslinkable conjugated donor–acceptor block copolymer bearing oxetane side chains is synthesized by one-pot polymerization to improve the thermal and morphological properties.

The universal organic pseudohalide treatment applicable to both green and sky-blue LEDs presented in this study promises superior photoluminescence and electroluminescence properties.

Herein, a novel hole transport polymer, P-CzAc, for solution-processed green quantum dot light-emitting diodes (QD-LEDs) was synthesized. P-CzAc consists of a polystyrene backbone and 10-(9H-carbazol-3-yl)-9,9-dimethyl-9,10-dihydroacridine as side-chain pendants. The design strategy aims to improve the hole transportability and achieve the low-lying highest occupied molecular orbital (HOMO) level for P-CzAc for reducing the charge injection barrier from the hole injection layer to the hole transport layer. P-CzAc showed good solubility in tetrahydrofuran, methylene chloride, and aromatic solvents, but high solvent tolerance for hexane and octane, similar to poly(N-vinylcarbazole) (PVK). Compared to PVK (HOMO = −5.58 eV), P-CzAc exhibited a relatively high-lying HOMO level of −5.33 eV. In particular, the hole mobility (μh) of P-CzAc was estimated to be 2.24 × 10−6 cm2 V−1 s−1, which is much higher than that of PVK (μh = 4.11 × 10−9 cm2 V−1 s−1). In solution-processed green QD-LEDs, the P-CzAc-based device exhibited a relatively low turn-on voltage (Von) of 2.8 V and a high maximum external quantum efficiency (EQE) of 11.6%. In comparison with a PVK-based device (Von = 4.4 V; EQE = 8.6%), the P-CzAc-based device is more efficient owing to the significant improvement in hole injection.

This study reports the design, synthesis, and characterization of two new bipolar host materials, DCzCP and TCzCP. Both materials were implemented as hosts by doping a known green thermally activated delayed fluorescent (TADF) emitter (t4CzIPN) in solution-processable OLEDs. DCzCP-based devices afford the best performance with the maximum external quantum efficiency (EQE) of 21.2%. Notably, the EQE was maintained at 20.7% and 19.7% at a practical luminance of 500 cd m-2 and 1000 cd m-2, respectively, demonstrating very small roll-off.

Thermally activated delayed fluorescence (TADF) materials have attracted significant attention owing to their state-of-the-art performance in the field of organic light-emitting diodes (OLEDs). TADF materials have the capability of harvesting both singlet and triplet excitons through reverse intersystem crossing, thus, the maximum internal quantum efficiency can be expected to be 100%. Thanks to TADF materials that are developed from pure organic entities so that they are inexpensive and external quantum efficiencies as high as 38% have been achieved to date. Despite the high performance of doped OLEDs, precise control of the host–guest ratio and phase separation at high driving voltages are the foremost challenges. In order to circumvent these demerits, the use of numerous small molecules, dendritic molecules, and polymers as non-doped emitters has been reported. Non-doped OLEDs consist of only a single molecule emitter in the emissive layer, thus simplifying the device fabrication process. Furthermore, non-doped OLEDs exhibit better device stability compared to doped devices, because the former do not exhibit phase separation or crystallinity and maintain a homogeneous surface film morphology during device operation. As a result, non-doped OLEDs are capable of overcoming the most pivotal issues of device complexity and stability, which makes them effective in rendering OLEDs commercially viable. Although maximum external quantum efficiencies of nearly 23.0% in blue, 22.0% in green, 22.0% in yellow, 17.0% in orange, and 10.0% in red emitting materials have been realized with non-doped OLEDs, still further progress is essential to reach the doped devices. This review systematically describes the molecular design, photophysical properties, and electroluminescence performance data of non-doped TADF emitters. We strongly believe that this review will be beneficial in terms of presenting a specific direction for the design of a variety of non-doped TADF emitters in the near future.

Highly soluble functional materials acting as hosts for thermally activated delayed-fluorescence (TADF) emitters are urgently needed to stimulate the development of cost-effective, solution-processable, high-performance organic light-emitting diodes (OLEDs). An organic material, 10-(6-(9H-carbazol-9-yl)pyridin-3-yl)-9,9-diphenyl-9,10-dihydroacridine (APC), was designed and facilely synthesized by integrating electron-donating diphenyl acridine and carbazoles at the 2- and 5-positions of electron-accepting pyridine (D–A–D′ type architecture). The high triplet energy (2.82 eV), thermal robustness (thermal decomposition beyond 350 °C), appropriate highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels, balanced charge-carrier transport ability, and good solubility of APC supported its designation as a host material for solution-processable TADF-OLEDs. Two different types of TADF OLEDs were fabricated by varying the hole transport material (HTM) while consistently using APC as the host and familiar t4CzIPN as the green TADF emitter, and their device characteristics were compared. At first, the devices fabricated using PVK as HTM (ITO/PEDOT:PSS/PVK/EML/TPBi/LiF/Al) that could use an orthogonal solvent system displayed a state-of-the-art performance with external quantum efficiency (EQE)/current efficiency (CE)/power efficiency (PE) as high as 24.0%/82.2 cd A−1/46.9 lm W−1, respectively. In particular, over 90.0% of EQE was retained (EQE of 21.7%) at the practical luminance of 1000 cd m−2, which is advantageous for display technology. Another class of devices was fabricated by replacing PVK with our recently reported thermally cross-linkable X-TPACz as the HTM, realizing a very low turn-on voltage (2.9 V) and excellent PE of 70.1 lm W−1 (with a similar EQE of 22.8%), which could be very effective for lighting equipment. These excellent outcomes demonstrate the potential of APC as a host material for future solution-processable display and lighting technologies.

The importance of thermally activated delayed fluorescence (TADF) materials in organic light-emitting diode (OLED) applications continues to grow as a consequence of their unique properties and excellent performance. Herein, a new green-emitting TADF polymer, P(DMTRZ-Cp), for solution-processable OLEDs was designed and synthesized based on the structure of DMAC-TRZ that shows typical TADF characteristics as a small molecule. The 1,1-diphenylcyclohexane (Cp) moiety introduced into the structure of the polymeric emitter not only acts as a linker between the conjugated monomeric units, but also helps enhancing solubility while disconnecting conjugation along the polymer backbones. P(DMTRZ-Cp) exhibits obvious TADF features such as a small energy gap (0.023 eV) between its lowest singlet and triplet excited states, and obvious delayed photoluminescence (PL) decay behavior. Moreover, this new polymeric emitter exhibits high PL quantum yield over 90% in the film state. By applying solution-processed TADF-OLED devices, P(DMTRZ-Cp) exhibited the maximum external quantum efficiency of up to 15.4% with green emission. As far as we know, this is the first report to introduce a non-conjugated linker, Cp, in the main-chain type polymeric emitter structure that presents TADF characteristics. The Cp linker is considered to be a promising moiety for the development of solution-processable polymeric emitters with high efficiencies.

New versatile host materials with good solubility in common organic solvents are greatly desired to promote solution-processable thermally activated delayed fluorescence organic light-emitting diodes. This paper describes the design and synthesis of two new host materials, namely 3′-(9H-carbazol-9-yl)-[1,1′-biphenyl]-3,5-diylbis(diphenylphosphine oxide) (CDPO) and 3′,5′-di-(9H-carbazol-9-yl)-[1,1′-biphenyl]-3,5-diylbis (diphenylphosphine oxide) (mCPDPO), featuring hole-transporting carbazole and electron-transporting diphenylphosphine oxide (DPO) entities. The donor strength was varied to a constant n-type DPO core to tune the functional properties. The detailed studies proved that the resulting two new materials exhibit excellent solubility in common organic solvents, high triplet energy (>2.80 eV), high glass transition temperature (up to 133 °C), and good bipolar electronic nature. Consequently, both compounds were used as hosts in solution-processable blue and green thermally activated delayed fluorescence (TADF) OLEDs. In particular, the devices using mCPDPO as a host in the emissive layer showed outstanding performance with a maximum current efficiency, power efficiency, and external quantum efficiency of 35.3 cd A−1, 17.0 lm W−1 and 15.4% in the blue-emitting diode, and 61.5 cd A−1, 29.7 lm W−1 and 18.8% in the green-emitting diode, respectively. These results corroborated the potential of carbazole-phosphine oxide derivatives as host materials in solution-processable blue and green TADF OLEDs.

Solution-processable thermally activated delayed fluorescence (TADF)-assisted materials have been identified as promising materials for future applications as organic light-emitting diodes (OLEDs) owing to their numerous advantageous such as easy fabrication, large area applications, low cost, and state-of-the-art performance. Herein, two new carbazole-dendronized TADF emitters, namely, TB2CZ-ACTRZ and TB14CZ-ACTRZ, were designed and synthesized. Two different-sized carbazole dendron wedges were utilized as the encapsulating groups for the TADF core via methylene groups. The influence of the encapsulated dendrons on the thermal, optical, electrochemical, and OLED device performances of both dendritic molecules was studied in detail. The photophysical studies of TB2CZ-ACTRZ and TB14CZ-ACTRZ disclosed their extremely small singlet–triplet energy gaps (ΔEST) of 79 and 134 meV, respectively. Consequently, the solution-processed non-doped OLEDs without any hole injection/transport layers featuring TB2CZ-ACTRZ and TB14CZ-ACTRZ as the TADF emitters demonstrated the maximum external quantum efficiencies (EQEs) of 9.5 and 8.1%, respectively, while the device fabricated with their simple emissive core ACTRZ had an EQE of only 1.2%. These results clearly demonstrated that the development of multifunctional TADF dendritic emitters is an extremely worthwhile objective for the realization of highly efficient solution-processable non-doped OLEDs with simple device architectures.

We developed a facile method for treating polyimide-based organic gate insulator (OGI) surfaces with self-assembled monolayers (SAMs) by introducing metal-oxide interlayers, called the metal-oxide assisted SAM treatment (MAST). To create sites for surface modification with SAM materials on polyimide-based OGI (KPI) surfaces, the metal-oxide interlayer, here amorphous alumina (α-Al2O3), was deposited on the KPI gate insulator using spin-coating via a rapid sol–gel reaction, providing an excellent template for the formation of a high-quality SAM with phosphonic acid anchor groups. The SAM of octadecylphosphonic acid (ODPA) was successfully treated by spin-coating onto the α-Al2O3-deposited KPI film. After the surface treatment by ODPA/α-Al2O3, the surface energy of the KPI thin film was remarkably decreased and the molecular compatibility of the film with an organic semiconductor (OSC), 2-decyl-7-phenyl-[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-C10), was increased. Ph-BTBT-C10 molecules were uniformly deposited on the treated gate insulator surface and grown with high crystallinity, as confirmed by atomic force microscopy (AFM) and X-ray diffraction (XRD) analysis. The mobility of Ph-BTBT-C10 thin-film transistors (TFTs) was approximately doubled, from 0.56 ± 0.05 cm2 V−1 s−1 to 1.26 ± 0.06 cm2 V−1 s−1, after the surface treatment. The surface treatment of α-Al2O3 and ODPA significantly decreased the threshold voltage from −21.2 V to −8.3 V by reducing the trap sites in the OGI and improving the interfacial properties with the OSC. We suggest that the MAST method for OGIs can be applied to various OGI materials lacking reactive sites using SAMs. It may provide a new platform for the surface treatment of OGIs, similar to that of conventional SiO2 gate insulators.

Thermally activated delayed fluorescence (TADF) materials have attracted much attention in the field of organic light-emitting diodes (OLEDs), with their state-of-the-art performance in terms of external quantum efficiencies (EQEs), turn-on voltages, and color coordinates. TADF materials exhibited EQEs above 25% due to harvesting both singlet and triplet excitons via reverse intersystem crossing (RISC). A small singlet–triplet energy gap (ΔEST) is essential for TADF materials to exhibit efficient upconversion from the lowest triplet excited state (T1) to the lowest singlet excited state (S1, T1 → S1). Moreover, these materials are purely organic and thus not costly. Therefore, the TADF approach provides the best alternative to conventional fluorescent and phosphorescent OLEDs, regarding device efficiency and cost. On the other hand, blue light-emitting devices are facing several issues related to their stability and efficiency, making their development quite challenging for researchers. Herein, we review the recent advances in the use of blue TADF dopants and hosts in OLEDs.

Correction for ‘Novel dendritic large molecules as solution-processable thermally activated delayed fluorescent emitters for simple structured non-doped organic light emitting diodes’ by Mallesham Godumala et al., J. Mater. Chem. C, 2018, 6, 1160–1170.

This article critically reviews the emerging field of DNA materials science, which is expected to add a new horizon to the conventional materials science landscape. The introduction provides a short overview on recent developments in the non-biological application of DNA and DNA science. We discuss the roles of DNA in photonics and optoelectronics, DNA-assisted preparation of inorganic nanoparticles and aggregates, and electrical and magnetic properties of DNA and their influence on nanoscience and technology. We also explore the potential applications of DNA in the development of innovative memory and communication devices. Self-assembly and new sensing technologies based on DNA are only briefly discussed, partly because of the many excellent published reviews on these subjects.

Correction for ‘Thermally activated delayed fluorescence blue dopants and hosts: from the design strategy to organic light-emitting diode applications’ by Mallesham Godumala et al., J. Mater. Chem. C, 2016, DOI: 10.1039/c6tc04377a.

A new tellurophene-based π-conjugated polymer, PDTDPPTe, was synthesized. PDTDPPTe exhibits a smaller optical band gap (E(g)(opt) = 1.25 eV) than thiophene-based PDTDPPT (E(g)(opt) = 1.30 eV). Thin-film transistors comprising PDTDPPTe displayed outstanding performance (μ(max) = 1.78 cm(2) V(-1) s(-1), I(on)/I(off) = 10(5-6)).

A new pyrene-cored π-conjugated molecule has been synthesized through Sonogashira coupling reaction. The single-crystalline microribbon-based FET exhibited the highest mobility of 0.7 cm(2) V(-1) s(-1) (I(on)/I(off)10(6)). Single-crystalline microribbons were employed to operate in an organic phototransistor (OPT) under very low light intensity (I = 5.6 μW cm(-2)).

Ladder-like structured polysilsesquioxane with carbazole groups showed unexpected high photo- and electroluminescence efficiencies both in solution and solid states due to its rigid silicone ladder structures, which efficiently isolated the carbazole groups and thus suppressed their excimer formations by inter- and intramolecules.