Jayachandran Jayakumar

Jayachandran Jayakumar
National Tsing Hua University | NTHU · Department of Chemistry

Ph.D in Organometallic Chemistry
Academic Researcher and YouTube Channel Creator

About

65
Publications
6,222
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Introduction
Find my You Tube Chanel: https://www.youtube.com/@Jayakumar-taiwan/feature Visit my YouTube channel, where I engage in discussions regarding the challenges that researchers face in their day-to-day lives and provide insights into potential solutions and improvements. Additionally, my channel features children's activity videos. As an academic researcher, I strive to create content that is informative, beneficial, and enjoyable. Your valuable feedback and insights would be very useful to address.

Publications

Publications (65)
Article
Full-text available
This study investigates the enhancement of organic light-emitting diode (OLED) performance through the integration of titanium dioxide (TiO2) nanocomposites within a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT/PSS) matrix. The nanocomposite films were prepared using a controlled dispersion of TiO2 belts into the PEDOT/PSS solution...
Article
Full-text available
mRNA vaccines for cancer immunotherapy are commonly delivered using lipid nanoparticles (LNPs), which, when administered intravenously, may accumulate in the liver, potentially limiting their therapeutic efficacy. To overcome this challenge, the study introduces an oral mRNA vaccine formulation tailored for efficient uptake by immune cells in the g...
Article
Full-text available
Over the past few decades, organic light-emitting diodes (OLEDs) find applications in smartphones, televisions, and the automotive sector. However, this technology is still not perfect, and its application for lighting purposes has been slow. For further development of the OLEDs, we designed twisted donor-acceptor-type electroactive bipolar derivat...
Article
Addressing the critical requirement for real-time monitoring of tumor progression in cancer care, this study introduces an innovative wearable platform. This platform employs a thermoplastic polyurethane (TPU) film embedded with hafnium oxide nanoparticles (HfO2 NPs) to facilitate dynamic tracking of tumor growth and regression in real time. Signif...
Article
sı Supporting Information 5 ABSTRACT: The utilization of a suitable hole transport material 6 (HTM) is considered to be an effective strategy to advance the 7 efficiency of OLEDs. High triplet energy (E T) HTMs reduce the 8 exciton quenching at the hole injection layer (HIL)/emissive layer 9 (EML) interface and lead to better device performance. In...
Article
Ultra-efficient and stable OLED devices can be 7 obtained via effective charge injection, accumulation, and exciton 8 confinement into the emissive layer. However, the leakage of 9 charge and excitons from the EML to adjacent layers can lead to 10 low device performance. Thus, high-triplet-energy charge-transfer 11 materials (CTMs) are required to...
Article
The strategy of acceptor modification is a powerful technique for tuning the emission color of thermally activated delayed fluorescence (TADF) emitters. In this study, we have successfully designed and synthesized three TADF emitters with donor-acceptor (D-A) structures using a 4-(diphenylamino)-2,6-dimethylphenyl (TPAm) donor and various pyridine-...
Article
Several functional and internal layers have been used to improve the performance of solution-processed Organic Light Emitting Diodes (OLED) devices. In the case of thermally activated delayed fluorescence (TADF) OLEDs, a large number of emitter materials have already been reported, but the design and development of potential host materials are over...
Article
Herein, we reveal a homologous series of liquid crystals involving perylene tetraesters as the core connected to the four trialkoxyphenyl units at the periphery using the triazole moiety as the linker. A thorough analysis using differential scanning calorimetry, polarized optical microscopy, and small- and wide-angle X-ray scattering studies confir...
Article
While organic light emitting diodes (OLEDs) technology is evolving at a fast pace, the development of flexible and full-color display panels with low power consumption provides superiority to these devices as eco-friendly lighting sources. Several strategies and methods have been attempted to improve the OLED device performance, especially in light...
Article
Full-text available
Photocatalytic water splitting is attracting considerable interest because it enables the conversion of solar energy into hydrogen for use as a zero-emission fuel or chemical feedstock. Herein, we present a universal approach for inserting hydrophilic non-conjugated segments into the main-chain of conjugated polymers to produce a series of disconti...
Article
Herein, we investigated the role of Pt metal cocatalyst and hydroxyl additives in the mechanism and activity of hydrogen evolution over the PCBM/PF3T organic nanohybrid. We show, for the first time, the addition of hydroxyl additives to improve the HER performance of the system, recording up to 70 mmol g⁻¹h⁻¹(AQY = 2.0%), which is among the best fo...
Article
Three pyridine-carbonitrile (PPC) fluorophores with amine-type donors, carbazole, tert-butylcarbazole, and spiroacridine have been designed and synthesized. These PPC-based emitters exhibit excellent photoluminescence quantum yields of 92~100%, thermally activated delayed fluorescence (TADF) and thermal stability. More importantly, with increasing...
Article
Deep-blue organic emitters have attracted considerable attention from both industrial as well as academic research in organic light-emitting diodes (OLEDs). In this context, three novel deep blue fluorophores based on benzothiazole 2-(4'-(1,4,5-triphenyl-1H-imidazole-2-yl)-[1,1′-biphenyl]-4-yl)benzo [d]thiazole (PHBISN), 2-(4'-(1-(4-(tert-butyl)phe...
Preprint
Full-text available
Photocatalytic water splitting is attracting considerable interest because it enables abundant solar energy to be converted into hydrogen for use as a zero-emission fuel or chemical feedstock. Herein, we present a universal approach for inserting hydrophilic non-conjugated building blocks into the main-chain of conjugated polymers to produce a seri...
Article
Exciton generation and charge balance play a dominant character in organic light-emitting diode (OLED). Performance concerning power management is a crucial requirement in consumer electronics. Improving exciton generation requires key considerations, such as excellent intermolecular charge transfer and high predisposition for effective electron-ho...
Article
Polymeric photocatalysts for hydrogen evolution by water splitting have drawn tremendous research interest in recent years. However, the relatively low photocatalytic hydrogen evolution efficiency still needs to be overcome for...
Article
Full-text available
The fabrication of crystalline COF materials with predictable structures and desirable features is one of the crystal engineering strategic goals. Many synthetic factors play an invisible role in the crystallization...
Article
Conjugated polymer dots (Pdots) based on a series of BDT-based polymers with varied biaxially extended side-chain conjugations were prepared and employed for photocatalytic hydrogen production under visible light irradiation from aqueous solutions. The BDT-based polymers consisted of a dithiophedifluorobenzo[c][1,2,5]thiadiazole (DFBT) moiety as th...
Article
A library of donor-acceptor system consisting of cyclopentadithiophene-based polymer photocatalysts have been designed and synthesized. Among all photocatalysts, the active PCPDTBSO achieved hydrogen evolution rates of 24.6 mmol h–1 g–1 with apparent quantum yields of 8.7 % at 500 nm. More importantly, combined the results of photocatalytic efficie...
Chapter
Arynes (or) benzynes are unique reactive coupling partners with various organic reactants that led to the efficient synthesis of carbocyclic and heterocyclic compounds in the presence of metal catalysts. Particularly, Kobayashi's aryne precursor (ortho‐silyl aryltriflates) has found numerous synthetic applications in metal‐catalyzed organic reactio...
Article
Full-text available
Highly efficient thermally activated delayed fluorescence (TADF) molecules are in urgent demand for solid-state lighting and full-color displays. Here, the design and synthesis of three triarylamine-pyridine-carbonitrile-based TADF compounds, TPAPPC, TPAmPPC, and tTPAmPPC, are shown. They exhibit excellent photoluminescence quantum yields of 79−100...
Article
Synthesis, characterization, and photophysical properties of heteroleptic Zn(II) complex. The complexes (Zn-1 and Zn-2) were well-characterized by UV–Vis, fluorescence spectroscopy, phosphorescence spectroscopy, cyclic voltammetry, photoluminescence quantum yield, thermogravimetric analysis, and atomic force microscopy. Moreover, density functional...
Article
Full-text available
A series of new functional pyridine-appended pyrene derivatives, viz., 2,6-diphenyl-4-(pyren-1-yl)pyridine (Py-03), 2,6-bis(4-methoxyphenyl)-4-(pyren-1-yl)pyridine (Py-MeO), 4-(pyren-1-yl)-2,6-di-p-tolylpyridine (Py-Me), and 2,6-bis(4-bromophenyl)-4-(pyren-1-yl)pyridine (Py-Br) were designed, developed, and studied as the hole-transporting material...
Patent
The present invention provides 11-arylcinnolino[2,3-f]phenanthridinium salt compounds and method for producing the same by highly regioselective synthesis of 11-phenylimino[2,3-f]phenanthridin-9-ium salts from 2-azobiaryls and alkenes under catalysis of palladium, through double oxidative C—H coupling of alkenes, to give the polycyclic cinnolinophe...
Article
Full-text available
Unique dual‐emissive and deep‐blue/green fluorescent multi‐substituted 4‐azapyrenes with bathochromic shift emission, quantum yields up to 0.60 and long excited‐state lifetime were synthesized successfully by annulative π‐extension reactions. This synthesis constitutes a palladium‐catalyzed dehydrogenative annulation of N‐acyl‐2‐aminobiaryls with i...
Article
After the revelation of nonvisual lighting impact on human health, the lighting engineers are more concerned about the human benign light with low cost and high efficiency. The solution-processed fabrication technique with smart device engineering for high efficacy OLED devices is being anticipated to drastically reduce the fabrication cost leading...
Article
Thermally activated delayed fluorescence (TADF) emitters are highly useful to achieve 100% internal quantum efficiency (IQE) and high external quantum efficiency (EQE) by reverse intersystem crossing. Herein, four sky-blue to...
Article
Highly thermal stable two-electron transport materials (ETMs) based on the triptycene containing phenylpyridine derivatives were designed and synthesized by Suzuki-Miyaura coupling reactions efficiently. Among them, TPP shows a high triplet energy gap (ET = 2.85 eV), high glass transition temperature (Tg = 142 °C), deep HOMO level (7.0 eV) and good...
Article
Given the photocatalytic properties of semiconducting polymers and carbon quantum dots (CQDs), we report a new structure for a metal-free photocatalytic system with a promising efficiency for hydrogen production through the combination of an organic semiconducting polymer (PFTBTA) and N-doped carbon quantum dots (NCQDs) covered by PS-PEGCOOH to pro...
Article
Transforming triplet excitons into singlet excitons is a topic of great interest to material scientists in order to surpass the exciton utilization efficiency (EUE) limit of 25% in electro-fluorescent devices. Towards this goal, the donor–acceptor strategy of molecular design has been proven to be an effective approach to obtain high electrolumines...
Article
We have designed and synthesized a series of conjugated polymers with fluorene or carbazole and phenylphosphine oxide derivatives as polymer photocatalysts for visible-light-driven hydrogen evolution. The optimized polymer photocatalyst PCzBPO provided the excellent hydrogen evolution rate (HER) over two-orders of magnitude greater than its counter...
Article
For the application of organic light-emitting diodes (OLEDs) in lighting and panels, the basic requirement is to include a full spectrum color range. Compared with the development of blue and green luminophores in thermally activated delayed fluorescence (TADF) technology, the progress of orange-to-red materials is slow and needs further investigat...
Article
Full-text available
Efficient polymer photocatalysts that mimic natural photosynthesis to generate H2 through the visible‐light‐promoted splitting of water are ideal systems for the conversion of solar energy into usable fuel with high energy density and in an environmentally friendly manner. In this article, we review recent reports on donor‐acceptor‐based π‐conjugat...
Article
Full-text available
Quaternary ammonium salts were synthesized in moderate to good yields through double oxidative C−H bond activation on azobenzenes. The mechanism of the highly regioselective reaction of 2‐azobiaryls with alkenes to give orange‐red‐fluorescent cinnolino[2,3‐f]phenanthridin‐9‐ium salts and 15H‐cinnolino[2,3‐f]phenanthridin‐9‐ium‐10‐ide is proposed to...
Article
By mimicking nature photosynthesis, a library of cycloplatinated polymer dots (Pdots) and pristine Pdots are presented and investigated the importance of selecting acceptor comonomers. A clear design strategy for the selection of acceptor comonomers of Pdots to achieve environmental-friendly, high efficiency, and long stability of photocatalytic re...
Article
The first palladium‐catalyzed synthesis of quaternary ammonium salts through double oxidative C‐H bond activation on azobenzenes in moderate to good yields is reported. In this study, we disclose a highly regioselective synthesis of orange‐red fluorescent cinnolino[2,3‐ f ]phenanthridin‐9‐ium salts and 15 H ‐cinnolino[2,3‐ f ]phenanthridin‐9‐ium‐10...
Article
We report three yellow-green to yellow TADF dopants 26DAcBPy, 25DAcBPy and 26DPXZBPy containing dibenzoyl pyridine as the acceptor and dimethylacridine (Ac) and phenoxazine (PXZ) as the donors with short delayed fluorescence lifetimes of 2.3 µs, 1.9 µs, and 1.0 µs, respectively. The crystal structures show that 26DAcBPy and 26DPXZBPy have a U shape...
Article
Searching an efficient and robust photocatalyst is important in converting solar energy into chemical energy for the clean and renewable fuel. Thiophene and fluorene has been used in this field widely, however, no study exits for understanding the effect of increasing the number of fused thiophene and fluorene rings. Here, we demonstrate a series o...
Article
Three carbonitrile-pyridine-carbazole-based thermally activated delayed fluorescence (TADF) materials with highly sterically congested struc-tures have been synthesized. The donor-acceptor type TADF emitters, (26-, 246-, and 35tCzPPC) consist of a 2,6-diphenylpyridine-3,5-dicarbonitrile core (PPC) as the acceptor and di(t-butyl)carbazole-substitute...
Article
Three new quinoline TADF emitters, 2QPM-mDC, 2QPM-mDTC and 4QPM-mDTC, were designed and synthesized and the emitters show ΔEST as low as 0.07 eV and high PL quantum yield (PLQY) up to 98%. An electroluminescence device based on 2QPM-mDTC can reach high EQE over 24%. Compared with the reported TADF devices, the device shows narrow emission band widt...
Article
Highly efficient deep-blue emission is crucial to realize energy efficient and high-quality display and solid-state lighting applications. A solution processable deep-blue emitter is essential for producing cost-effective large-area devices via roll-to-roll fabrication. Here, we demonstrate a highly efficient solution processable deep-blue organic...
Article
Highly efficient deep-blue emission is crucial to realize energy efficient and high-quality display and solid-state lighting applications. A solution processable deep-blue emitter is essential for producing cost-effective large-area devices via roll-to-roll fabrication. Here, we demonstrate a highly efficient solution processable deep-blue organic...
Article
Reaction mechanisms for the synthesis of indenamines, indenols, and isoquinolinium salts through cobalt- and rhodium-catalysis were investigated using density functional theory calculations. We found that the valence charge of transition metals dramatically influences the reaction pathways. Catalytic reactions involving lower-oxidation-state transi...
Article
Highly substituted cationic heterocyclic nitrogen salts are versatile building blocks for a number of naturally occurring products and functional materials. In this paper, we review the very recently reported Co(III)-, Rh(III)- and Ir(III)-catalyzed inter- and intra-molecular sp² CH activation/annulations with alkynes or alkenes for the synthesis o...
Article
Various substituted indolizidinium, quinolizinium and pyrido[1,2-a]azepinium salts synthesized from benzaldehydes (or α,β-unsaturated aldehydes) and alkyne-amines catalyzed by rhodium complexes via C-H activation are demonstrated. The reaction was carried out under mild reaction conditions using Cu(BF4)2·6H2O as oxidant and anion source and inexpen...
Article
A highly regioselective synthesis of pyrido[2,1‐ a ]isoindolium salts from 2‐arylpyridines and two equivalents of electron‐deficient alkenes catalyzed by rhodium is demonstrated. The reaction was carried out in aqueous medium at 110 °C using inexpensive oxygen as oxidant. Reverse aza‐Michael addition of the isoindolium salt occurs when the salt was...
Article
A one-pot reaction of substituted benzaldehydes with alkyne—amines by Rh-catalyzed C—H activation and annulation to afford various natural and unnatural protoberberine alkaloids is reported.
Article
A one-pot reaction of substituted benzaldehydes with alkyne-amines by a Rh-catalyzed CH activation and annulation to afford various natural and unnatural protoberberine alkaloids is reported. This reaction provides a convenient route for the generation of a compound library of protoberberine salts, which recently have attracted great attention bec...
Article
A synthetic method for highly substituted pyridinium salts from the multicomponent reaction of vinyl ketones/aldehydes, amines, and alkynes using a rhodium catalyst is demonstrated. The catalytic reaction proceeds via an in situ generated imine-assisted Rh(III)-catalyzed vinylic C-H activation.
Article
A new method for the synthesis of highly substituted naphthyridine-based polyheteroaromatic compounds in high yields proceeds through rhodium(III)-catalyzed multiple CH bond cleavage and CC and CN bond formation in a one-pot process. Such highly substituted polyheteroaromatic compounds have attracted much attention because of their unique π-conjuga...
Article
A new method for the synthesis of highly substituted naphthyridine-based polyheteroaromatic compounds in high yields proceeds through rhodium(III)-catalyzed multiple CH bond cleavage and CC and CN bond formation in a one-pot process. Such highly substituted polyheteroaromatic compounds have attracted much attention because of their unique π-conjuga...
Article
A convenient, mild, and efficient method for the synthesis of a broad range of substituted isoquinolinium salts from pyridines and alkynes is presented.
Article
An efficient synthesis of highly substituted isoquinolinium salts from ketimines and alkynes via a Rh(iii)-catalyzed C-H bond activation and annulation reaction is described.
Article
Full-text available
Palladium-catalyzed oxidative carbonylation of 2-arylphenols through C-H bond activation and C-C and C-O bond formation under acid-base free and mild conditions has been developed. The reaction tolerates a variety of substrates and provides biologically important benzopyranone derivatives in up to 87% isolated yield.
Article
An efficient and convenient method for the synthesis of highly substituted polycyclic pyridinium salts from the reaction of various 2-aryl-pyridines and 2-aryl-sp(2) -nitrogen-atom-containing heterocycles with alkynes through rhodium(III)-catalyzed CH activation and annulation under an O2 atmosphere is described. A possible mechanism that involves...
Article
An efficient method for the synthesis of substituted isoquinolinium salts from benzaldehydes, amines, and alkynes via ruthenium-catalyzed C-H bond activation and annulation in one pot is described.
Article
Various substituted isoquinolinium salts are available by coupling of aromatic aldehydes with internal alkynes and primary amines under conditions A).
Article
BF(3).Et(2)O-catalysed O-glycosylation of 1,2,3-tri-O-acetyl-4,6-O-butylidene- and ethylidene-beta-d-glucopyranose with different aliphatic and aromatic alcohols proceeds for the most part with complete retention of anomeric configuration. Antioxidant activity of O-glycosides shows significant inhibition (IC(50) approximately 77%). 1,3-Dipolar cycl...

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The triplet energy stands as a crucial factor in adjusting the emission of TADF compounds. Discovering how to measure and calculate it using simple techniques is essential.
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Ionic liquids synthesis and purification is important task in chemical laboratories because of the liquid phases.
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