Chemistry of Materials
DOI: 10.1021/acs.chemmater.1c03688
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22 Mar 06:01
[ASAP] Rational Design of a Triplet Afterglow Sensitizer Allowing for Bright Long-Wavelength Afterglow Room-Temperature Emission
by Kikuya Hayashi, Kei Fukasawa, Takashi Yamashita, and Shuzo Hirata
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20 Feb 17:25
An Efficient Rechargeable Aluminium–Amine Battery Working Under Quaternization Chemistry
by Gang Wang,
Evgenia Dmitrieva,
Benjamin Kohn,
Ulrich Scheler,
Yannan Liu,
Valeriya Tkachova,
Lin Yang,
Yubin Fu,
Ji Ma,
Panpan Zhang,
Faxing Wang,
Jin Ge,
Xinliang Feng
An efficient rechargeable Al battery was built based on the electrochemical amine quaternization reaction, in which nitrogen (radical) cations (R3N.+ or R4N+) function as the redox-active sites to store the anionic Al complex. The constructed Al–amine battery exhibits a high reversible capacity, fast charge capability, and superior stability against long-term cycling and self-discharge.
Abstract
Rechargeable aluminium (Al) batteries (RABs) have long-been pursued due to the high sustainability and three-electron-transfer properties of Al metal. However, limited redox chemistry is available for rechargeable Al batteries, which restricts the exploration of cathode materials. Herein, we demonstrate an efficient Al–amine battery based on a quaternization reaction, in which nitrogen (radical) cations (R3N.+ or R4N+) are formed to store the anionic Al complex. The reactive aromatic amine molecules further oligomerize during cycling, inhibiting amine dissolution into the electrolyte. Consequently, the constructed Al–amine battery exhibits a high reversible capacity of 135 mAh g−1 along with a superior cycling life (4000 cycles), fast charge capability and a high energy efficiency of 94.2 %. Moreover, the Al–amine battery shows excellent stability against self-discharge, far beyond conventional Al–graphite batteries. Our findings pave an avenue to advance the chemistry of RABs and thus battery performance.
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20 Feb 17:24
Covalent Organic Framework with Highly Accessible Carbonyls and π‐Cation Effect for Advanced Potassium‐Ion Batteries
by Xiao-Xi Luo,
Wen-Hao Li,
Hao-Jie Liang,
Hong-Xia Zhang,
Kai-Di Du,
Xiao-Tong Wang,
Xin-Fang Liu,
Jing-Ping Zhang,
Xing-Long Wu
We prepare a polyimide covalent organic framework composite anode by effective in-situ condensation of anhydride and amine on the surface of single-walled carbon nanotubes. The construction of the conductive network accelerates the transport of electron. Dual electroactive sites in the framework, carbonyls and aromatic naphthalene rings, could store more potassium ions by the enolization and π-K+ effect.
Abstract
Covalent organic frameworks (COF) possess a robust and porous crystalline structure, making them an appealing candidate for energy storage. Herein, we report an exfoliated polyimide COF composite (P-COF@SWCNT) prepared by an in situ condensation of anhydride and amine on the single-walled carbon nanotubes as advanced anode for potassium-ion batteries (PIBs). Numerous active sites exposed on the exfoliated frameworks and the various open pathways promote the highly efficient ion diffusion in the P-COF@SWCNT while preventing irreversible dissolution in the electrolyte. During the charging/discharging process, K+ is engaged in the carbonyls of imide group and naphthalene rings through the enolization and π-K+ effect, which is demonstrated by the DFT calculation and XPS, ex-situ FTIR, Raman. As a result, the prepared P-COF@SWCNT anode enables an incredibly high reversible specific capacity of 438 mA h g−1 at 0.05 A g−1 and extended stability. The structural advantage of P-COF@SWCNT enables more insights into the design and versatility of COF as an electrode.
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14 Feb 18:05
Accelerating Radiative Decay in Blue Through‐Space Charge Transfer Emitters by Minimizing the Face‐to‐Face Donor–Acceptor Distances
by Tianyu Huang,
Qi Wang,
Guoyun Meng,
Lian Duan,
Dongdong Zhang
Thermally activated delayed fluorophores are constructed with strong through-space donor–acceptor interactions by minimizing their face-to-face distance of 2.7–2.8 Å, realizing efficient blue emission and fast radiative decay. The materials show maximum external quantum efficiencies of 27.8 % and 34.7 % with relieved efficiency roll-off and CIE y coordinates of 0.29 and 0.15, when used as emitter and sensitizer in organic light-emitting diodes.
Abstract
Thermally activated delayed fluorophors (TADF) featuring through-space charge transfers (TSCT) suffer from low radiative decay rates (k rs), especially for blue emitters. Here, a xanthene bridge is adopted to construct space-confined face-to-face donor–acceptor alignment and minimize their distances down to 2.7–2.8 Å, even shorter than the interlayer distance of graphite and thus strengthening the electronic interactions. The resulting blue TSCT-TADF emitters exhibit peaks around ≈460 nm, photoluminescence quantum yields of >90 %, and k rs of nearly 107 s−1, almost 2–10 times higher than previously observed values with comparable reverse intersystem crossing rates. The corresponding blue organic light-emitting diodes show maximum external quantum efficiencies of 27.8 % and 34.7 % with Commission Internationale de L'Eclairage y coordinates of 0.29 and 0.15 using those molecules as emitters and sensitizers, respectively.
Rong-Huei Yi, 以昇陳 and one other like this
14 Feb 18:03
Side‐Chain‐Tuned Molecular Packing Allows Concurrently Boosted Photoacoustic Imaging and NIR‐II Fluorescence
by Yulin Zhu,
Hanjian Lai,
Heng Guo,
Dinglu Peng,
Liang Han,
Ying Gu,
Zixiang Wei,
Duokai Zhao,
Nan Zheng,
Dehua Hu,
Lei Xi,
Feng He,
Leilei Tian
A process to enhance the NIR-II FLI and PAI brightness of an organic semiconducting nanoparticle concurrently by 4.6 and 1.4 times, respectively, is described by tuning the molecular packing in the aggregated state of NPs, which provides a new strategy to develop multi-modal phototheranostic materials for more capable clinical applications.
Abstract
It is generally considered that photoacoustic imaging (PAI) and fluorescence imaging (FLI) cannot be enhanced concurrently, as they are dependent on competitive photophysical processes at the single-molecule level. Herein, we reveal that BDTR9-OC8 and BDTR9-C8, which have identical π-conjugated backbones but are substituted by side chains of different rigidity, show distinct phototheranostic properties in the aggregated state. The NIR-II FLI and PAI brightness of BDTR9-C8 nanoparticles are enhanced by 4.6 and 1.4 times compared with BDTR9-OC8 nanoparticles. Theoretical calculations and GIWAXS analysis revealed that BDTR9-C8 with rigid side chains shows a relative amorphous condensed state, which will benefit the efficient transportation of photo-generated excitons and phonons, subsequently enhancing the FLI and PAI signals. Besides, both nanoparticles exhibit excellent photothermal conversion efficiency due to their strong light-harvesting capability and are considered effective photothermal therapy materials. This work provides an illuminating strategy for material design in the future.
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13 Feb 16:25
A Rational Molecular Design Strategy of TADF Emitter for Achieving Device Efficiency Exceeding 36%
by Chih‐Lun Yi,
Chun‐Yen Lin,
Yukun Tang,
Chun‐Yu Wang,
Chih‐Wei Huang,
Xu Gong,
Shaolong Gong,
Chung‐Chih Wu,
Ken‐Tsung Wong
A rational strategy for designing thermally activated delayed fluorescence emitter is reported, using dimethylacridine as a common donor to select the acceptor PyoCN that comprises pyridine and ortho-dicarbonitrile benezene. PyoCN links to rigid donors spiroacridine and spiro-bisacridine, leading to high photoluminescence quantum yield and high horizontal emission dipole ratio. The best device accomplishes a maximum external quantum efficiency up to 36.1%.
Abstract
An excellent thermally activated delayed fluorescence (TADF) emitter requires a sophisticated molecular design strategy to incorporate structural features to simultaneously achieve high photoluminescence quantum yield (PLQY) and high horizontal emission dipole ratio (Θ//). This work reports the uses of heteroarenes and dicarbonitrile benzenes to design four new acceptors PymCN, PyoCN, PmmCN, and PmoCN, which are linked to a common donor dimethylacridine (DMAC) for making new TADF emitters. The emission wavelength, ΔE ST, k risc, k r, and the resulting PLQY of the target TADF emitters are governed by the combined natures of the heteroaryl bridges (Py vs Pm) and the CN-substituted patterns (o-CN vs m-CN). The photophysical and device characteristics reveal the best acceptor to be PyoCN, which is further coupled with spiroacridine to afford a new emitter SpiroAC-PyoCN with an enhanced PLQY of 100% compared to that (91%) of the DMAC-based counterpart DMAC-PyoCN. Furthermore, linking PyoCN with spiro-bisacridine (SBAC) gives an A–D–A-configured TADF emitter SBAC-PyoCN with both enhanced PLQY (100%) and Θ// (90%). The device employing SBAC-PyoCN as emitter renders a maximum external quantum efficiency up to 36.1% owing to its unity PLQY and superior light out-coupling efficiency. This rational molecular design strategy provides a feasible means to achieve an excellent TADF emitter design.
Rong-Huei Yi, 以昇陳 likes this
13 Feb 16:23
A Bipolar Delayed Fluorescence Luminogen with Fast Reverse Intersystem Crossing and High Horizontal Dipole Orientation for High‐Performance Sky‐Blue and White OLEDs
by Yan Fu,
Hao Liu,
Dezhi Yang,
Dongge Ma,
Zujin Zhao,
Ben Zhong Tang
A tailor-made sky-blue delayed fluorescence luminogen with strong photoluminescence, fast reverse intersystem crossing, balanced carrier transport, horizontal dipole orientation, and large light out-coupling efficiency is explored, which furnishes outstanding external quantum efficiencies of 32.6% as emitter in sky-blue organic light-emitting diodes (OLEDs) and 21.6% as emitter and host simultaneously in all-fluorescence white OLEDs.
Abstract
The development of robust luminescent materials plays a key role for organic light-emitting diodes (OLEDs). Herein, a tailor-made sky-blue delayed fluorescence luminogen (DCPC-BP-SFAC) containing a carbonyl acceptor and spiro[acridine-9,9″-fluorene] and 9,9″-(cyclohexane-1,1-diylbis(4,1-phenylene))bis(9H-carbazole) donors is explored, which holds merits of excellent thermal stability, strong photoluminescence, balanced carrier transport, and horizontal dipole orientation. Owing to a charge-transfer dominated singlet state and a charge-transfer and local-excitation hybrid triplet state, DCPC-BP-SFAC has a small energy gap between singlet and triplet as well as a large spin–orbit coupling constant, which result in a fast reverse intersystem crossing process and thus efficient delayed fluorescence. High-performance sky-blue OLEDs with outstanding external quantum efficiencies (ηext) reaching 32.6% are achieved based on DCPC-BP-SFAC, benefiting from high exciton utilization and large light out-coupling efficiency. Moreover, using DCPC-BP-SFAC as blue emitter and host material simultaneously, efficient all-fluorescence out-of-phase sensitizing white OLEDs without interlayer are fabricated, providing high ηext of up to 21.6% and stable warm-white light with a high color rendering index of 84. The outstanding electroluminescence performances demonstrate the great potentials of DCPC-BP-SFAC in practical display and lighting devices.
Rong-Huei Yi, 以昇陳 likes this
13 Feb 16:20
Extremely High Power Efficiency Solution‐Processed Orange‐Red TADF OLEDs via a Synergistic Strategy of Molecular and Device Engineering
by Dehao Jiang,
Hisahiro Sasabe,
Hiroki Arai,
Kohei Nakao,
Kengo Kumada,
Junji Kido
In this study, two orange-red TADF emitters are developed by a novel donor–acceptor–functional-group (D-A-R) molecular design strategy. This design makes the molecules highly soluble and inhibits concentration quenching of excitons. By optimizing the device structure, the solution-processed, orange-red OLEDs achieve a record-high maximum external quantum efficiency of 23.7% and an unprecedented-high maximum power efficiency of 48.8 lm W−1.
Abstract
The development of high-performance, solution-processed, orange-red organic light-emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) emitters is a challenging endeavor. In this study, two orange-red TADF emitters, namely 2DMAC-DBP-2tBuCz and 2SPAC-DBP-2tBuCz, are developed by a novel donor–acceptor–functional-group (D-A-R) molecular design strategy. This design makes the molecules highly soluble and inhibits concentration quenching of excitons, rendering the emitter suitable for use in devices with high concentration to boost their performance. The solution-processed, orange-red OLEDs manufactured in this study achieve a state-of-the-art maximum external quantum efficiency (EQE max ) value of 23.7% and an extremely high maximum power efficiency (PE max ) of 48.8 lm W−1, which is nearly twice higher than the previously reported best value (27.1 lm W−1). Therefore, the collaboration of molecular engineering and sophisticated device design provides a novel method for extremely low power consumption solution-processed OLEDs.
Rong-Huei Yi, 以昇陳 likes this
13 Feb 16:20
In Situ Quantifying the Physical Parameters Determining the Efficiency of OLEDs Relying on Triplet–Triplet Annihilation Up‐Conversion
by Shu Xiao,
Xianfeng Qiao,
Chengwei Lin,
Liangjian Chen,
Runda Guo,
Ping Lu,
Lei Wang,
Dongge Ma
Triplet–triplet annihilation (TTA) bimolecular channel can bring two triplets into one singlet which can emit delay fluorescence. The proportion of the intensity of delay and prompt fluorescence is related to the rate constants of the two triplet consuming channels. Parameters determining the efficiency of TTA organic light-emitting diodes can be deduced from this relation, and device efficiency can be improved guided by these parameters.
Abstract
Triplet–triplet annihilation (TTA) up-conversion is an effective way to utilize triplet excitons in organic light-emitting diodes (OLEDs). However, the parameters characterizing the triplet excitons and relevant TTA process in OLEDs under working conditions have not been quantified. Here, an in situ method is established to map these parameters for further ascertaining their impact on device efficiency. The physical parameters, including triplet recombination rate, TTA rate, typical current J TTA, and saturated ratio, can be in situ quantified by transient electroluminescence technique. The expression of J TTA shows that minimizing the triplet quenching and maximizing the TTA rate are effective ways to lower J TTA. While highly efficient devices require a lower J TTA. Guided by these criteria, the device efficiency is promoted by weakening the triplet quenching via blending two materials. These investigations establish an in situ method to quantify the physical parameters that allow identifying the useful TTA materials and optimizing the design of device structures.
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13 Feb 12:00
Novel Oligomer Enables Green Solvent Processed 17.5% Ternary Organic Solar Cells: Synergistic Energy Loss Reduction and Morphology Fine‐Tuning
by Hao Xia,
Ying Zhang,
Wanyuan Deng,
Kuan Liu,
Xinxin Xia,
Chun‐Jen Su,
U‐Ser Jeng,
Miao Zhang,
Jiaming Huang,
Jingwei Huang,
Cenqi Yan,
Wai‐Yeung Wong,
Xinhui Lu,
Weiguo Zhu,
Gang Li
Low energy loss ternary organic solar cells (OSCs) based on PM6:BTP-BO4Cl achieve significantly improved power conversion efficiencies of 17.54% and 17.32% by introducing novel oligomers with higher HOMO level as third-components, representing the state-of-the-art OSCs by green solvent. The significance of high electroluminescence quantum efficiency is highlighted and new understanding of energy loss mechanisms is provided toward high-performance, ecofriendly OSCs.
Abstract
The large non-radiative recombination is the main factor that limits state-of-the-art organic solar cells (OSCs). In this work, two novel structurally similar oligomers (named 5BDTBDD and 5BDDBDT) with D-A-D-A-D and A-D-A-D-A configuration are synthesized for high-performance ternary OSCs with low energy loss. As third components, these PM6 analogue oligomers effectively suppress the non-radiative recombination in OSCs. Although the highest occupied molecular orbital (HOMO) levels of 5BDTBDD and 5BDDBDT are higher than that of PM6, the oligomers enabled ultra-high electroluminescence quantum efficiency (EQEEL) of 0.05% and improved V OC, indicating suppressing non-radiative recombination overweighs the common belief of deeper HOMO requirement in third component selection. Moreover, the different compatibility of 5BDTBDD and 5BDDBDT with PM6 and BTP-BO4Cl fine-tunes the active layer morphology with synergistic effects. The ternary devices based on PM6:5BDTBDD:BTPBO4Cl and PM6:5BDDBDT:BTP-BO4Cl achieve a significantly improved PCEs of 17.54% and 17.32%, representing the state-of-the art OSCs processed by green solvent of o-xylene. The strategy using novel oligomer as third component also has very wide composition tolerance in ternary OSCs. This is the first work that demonstrates novel structurally compatible D-A type oligomers are effective third components, and provides new understanding of synergetic energy loss mechanisms towards high performance OSCs.
13 Feb 11:58
Segregated Array Tailoring Charge‐Transfer Degree of Organic Cocrystal for the Efficient Near‐Infrared Emission beyond 760 nm
by Ming‐Peng Zhuo,
Yi Yuan,
Yang Su,
Song Chen,
Ye‐Tao Chen,
Zi‐Qi Feng,
Yang‐Kun Qu,
Ming‐De Li,
Yang Li,
Bing‐Wen Hu,
Xue‐Dong Wang,
Liang‐Sheng Liao
Through changing mixed stacking into segregated stacking mode, triphenylene (TP)-2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) charge-transfer (CT) complex demonstrates a low CT degree and a small counter pitch angle between TP and F4TCNQ molecules, benefiting for breaking the forbidden electronic transitions of CT state for realizing the near-infrared emission with a maximum peak of 770 nm and a photoluminescence quantum yield of 5.4%.
Abstract
Harvesting the narrow bandgap excitons of charge-transfer (CT) complexes for the achievement of near-infrared (NIR) emission has attracted intensive attention for its fundamental importance and practical application. Herein, the triphenylene (TP)-2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) CT organic complex is designed and fabricated via the supramolecular self-assembly process, which demonstrates the NIR emission with a maximum peak of 770 nm and a photoluminescence quantum yield (PLQY) of 5.4%. The segregated stacking mode of TP-F4TCNQ CT complex based on the multiple types of intermolecular interaction has a low CT degree of 0.00103 and a small counter pitch angle of 40° between F4TCNQ and TP molecules, which breaks the forbidden electronic transitions of CT state, resulting in the effective NIR emission. Acting as the promising candidates for the active optical waveguide in the NIR region beyond 760 nm, the self-assembled TP-F4TCNQ single-crystalline organic microwires display an ultralow optical-loss coefficient of 0.060 dB µm−1. This work holds considerable insights for the exploration of novel NIR-emissive organic materials via an universal “cocrystal engineering” strategy.
Rong-Huei Yi, 以昇陳 likes this
09 Feb 17:01
[ASAP] Clusterization-Triggered Color-Tunable Room-Temperature Phosphorescence from 1,4-Dihydropyridine-Based Polymers
by Yue Ren, Wenbo Dai, Shuai Guo, Lichao Dong, Siqi Huang, Jianbing Shi, Bin Tong, Nairong Hao, Lianwei Li, Zhengxu Cai, and Yuping Dong
Journal of the American Chemical Society
DOI: 10.1021/jacs.1c11607
09 Feb 17:01
[ASAP] High-Performance Organic Electronic Materials by Contorting Perylene Diimides
by Cedric Schaack, Austin M. Evans, Fay Ng, Michael L. Steigerwald, and Colin Nuckolls
Journal of the American Chemical Society
DOI: 10.1021/jacs.1c11544
以昇陳, Promeet Saha and 4 others like this
07 Feb 06:38
[ASAP] Thermally Activated Fluorescence vs Long Persistent Luminescence in ESIPT-Attributed Coordination Polymer
by Peng-Yan Fu, Bao-Ning Li, Qiang-Sheng Zhang, Jun-Ting Mo, Shi-Cheng Wang, Mei Pan, and Cheng-Yong Su
Journal of the American Chemical Society
DOI: 10.1021/jacs.1c11874
07 Feb 02:29
[ASAP] Amplification of Activated Near-Infrared Afterglow Luminescence by Introducing Twisted Molecular Geometry for Understanding Neutrophil-Involved Diseases
by Chao Chen, Heqi Gao, Hanlin Ou, Ryan T. K. Kwok, Youhong Tang, Donghui Zheng, and Dan Ding
Journal of the American Chemical Society
DOI: 10.1021/jacs.1c11455
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07 Feb 02:28
[ASAP] In Situ Hypoxia-Induced Supramolecular Perylene Diimide Radical Anions in Tumors for Photothermal Therapy with Improved Specificity
by Hua Wang, Ke-Fei Xue, Yuchong Yang, Hao Hu, Jiang-Fei Xu, and Xi Zhang
Journal of the American Chemical Society
DOI: 10.1021/jacs.1c13067
Guangwei Shao, 以昇陳 and one other like this
07 Feb 02:28
[ASAP] Active Regulation of Supramolecular Chirality through Integration of CdSe/CdS Nanorods for Strong and Tunable Circular Polarized Luminescence
by Rongjuan Liu, Zhenyu Feng, Caikun Cheng, Hui Li, Jiaming Liu, Jingjing Wei, and Zhijie Yang
Journal of the American Chemical Society
DOI: 10.1021/jacs.1c12676
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07 Feb 02:27
[ASAP] ER-Targeting Cyanine Dye as an NIR Photoinducer to Efficiently Trigger Photoimmunogenic Cancer Cell Death
by He Ma, Yang Lu, Zhibin Huang, Saran Long, Jianfang Cao, Zhen Zhang, Xiao Zhou, Chao Shi, Wen Sun, Jianjun Du, Jiangli Fan, and Xiaojun Peng
Journal of the American Chemical Society
DOI: 10.1021/jacs.1c11886
20 Jan 14:23
Diluted exciplex concentrations in organic light emitting diodes for blue-shifted spectra and improved efficiency
J. Mater. Chem. C, 2022, 10,2173-2180
DOI: 10.1039/D1TC05029J, Paper
DOI: 10.1039/D1TC05029J, Paper
Jiakui Yan, Bizheng Dong, Yabo Xu, Bo Zhao, Fangming Jin, Hua Wang, Wenlian Li
Diluting exciplex concentrations by adjusting the acceptor ratio or inserting a spacer in organic light emitting diodes for achieving blue-shifted spectra and improved efficiency.
The content of this RSS Feed (c) The Royal Society of Chemistry
Diluting exciplex concentrations by adjusting the acceptor ratio or inserting a spacer in organic light emitting diodes for achieving blue-shifted spectra and improved efficiency.
The content of this RSS Feed (c) The Royal Society of Chemistry
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20 Jan 14:21
Phenol‐Functionalized Perylene Bisimides as Amine‐Free Electron Transporting Interlayers for Stable Nonfullerene Organic Solar Cells
by Xinbo Wen,
Yu Zhang,
Guojing Xie,
Rodger Rausch,
Ningning Tang,
Nan Zheng,
Linlin Liu,
Frank Würthner,
Zengqi Xie
Highly efficient durable nonfullerene organic solar cells (OSCs) are achieved with a new cathode interlayer based on biradical-forming phenol-functionalized perylene bisimides. These OSCs take advantage of good compatibility between the interlayer material and Y6 electron acceptor dyes and good interlayer thickness tolerance.
Abstract
A new type of cathode interlayer composed of 2,6-di-tert-butyl-phenol-functionalized perylene bisimide (PBI-2P) is successfully applied as an electron transporting layer for fused-ring nonfullerene organic solar cells (OSCs). The stable contact between these novel electron transporting layers and the representative nonfullerene acceptor Y6 greatly enhances the device stability compared to conventional amine-group containing cathode interlayers. Moreover, the easily formed biradical species in the interlayers yields rather good thickness tolerance of the PBI-2P layer in photovoltaic devices. The OSCs based on the PBI-2P interlayer show a power conversion efficiency up to 17.20% and good stability compared to amino-group functionalized interlayers. The findings demonstrate a promising design principle for cathode interlayer engineering based on pigment chromophores equipped with the 2,6-di-tert-butylphenoxy groups that are prone to form the respective ultrastable butylphenoxy radicals for stable nonfullerene OSCs.
20 Jan 14:21
Designing Artificial Fluorescent Proteins: Squaraine‐LmrR Biophosphors for High Performance Deep‐Red Biohybrid Light‐Emitting Diodes
by Sara Ferrara,
Sara H. Mejias,
Mantas Liutkus,
Giacomo Renno,
Francesca Stella,
Irene Kociolek,
Juan Pablo Fuenzalida‐Werner,
Claudia Barolo,
Pedro B. Coto,
Aitziber L. Cortajarena,
Rubén D. Costa
Design of deep-red biophosphors with artificial fluorescent proteins combining Lactococcal multidrug resistance Regulator (host) and a highly emissive squaraine (guest), realizing deep-red Bio-HLEDs with external quantum efficiencies of 7% and month stabilities.
Abstract
Biophosphors with fluorescent proteins (FPs) are promising candidates to replace rare-earth color down-converting filters for white light-emitting diodes (LEDs). There is, however, a lack of deep-red FPs meeting high photostabilities, photoluminescence quantum yields (ϕ), and throughput expression yields. Herein, a new approach for the design of highly emissive and stable deep-red biophosphors combining an artificial FP (Lactococcal multidrug resistance Regulator (LmrR) as protein host and an archetypal red-emitting squaraine (S) as guest) with a polymer network is demonstrated toward high performing deep-red biohybrid LEDs (Bio-HLEDs). At first, the best protein pocket (aromaticity, polarity, charge, etc.) to stabilize S in water is determined using four LmrR variants (position 96 with tryptophan, histidine, phenylalanine, and alanine). Computational and time-resolved spectroscopic findings suggest that the tryptophan is instrumental toward achieving artificial red-emitting FPs with ϕ > 50% stable over weeks. These features are further enhanced in the polymer coating (ϕ > 65% stable over months) without affecting emission color. Finally, deep-red Bio-HLEDs are fabricated featuring external quantum efficiencies of 7% and stabilities of ≈800 h. This represents threefold enhancement compared to reference devices with S-polymer color filters. Overall, this work highlights a new design for highly emissive deep-red biophosphors, achieving record performance in deep-red protein-LEDs.
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07 Jan 06:17
Disorder‐Induced Dispersive Magneto‐Electroluminescence of Blue Emitters in Organic Light Emitting Diodes
by Xin Pan,
Ohyun Kwon,
Dipak Raj Khanal,
Byoungki Choi,
Zeev Valy Vardeny
A modified dispersive “Δg mechanism” is used to reveal the disorder-induced inhomogeneity in OLEDs based on blue molecule emitters via magneto-electroluminescence (MEL). The dispersive MEL(B) response originates from intrinsic disorder, which is examined by various injection conditions and different temperatures. The disorder-induced MEL(B) approach is supported by photoinduced absorption spectrum of photocarriers that shows dispersive free-carrier absorption spectrum.
Abstract
Disorder-induced inhomogeneity in blue-fluorescent-based organic light-emitting diodes (OLEDs) based on mixtures of host and guest molecules is studied using magneto-electroluminescence, MEL(B), response based on the so called “Δg mechanism”, where Δg is the difference in the Landé g-factor of electrons and holes. The disorder in the organic active layer is manifested by a unique non-Lorentzian MEL(B) response that is analyzed using a distribution of spin lifetimes for the injected electron–hole pairs that is determined by a dispersive parameter, α (<1). The carriers’ inhomogeneous response also influences the free carrier absorption spectrum, which shows characteristic properties described by a dispersive parameter β (<1). From the measured MEL(B) response at various injection conditions it is found that α is robust at increasing current density showing that the inhomogeneity is governed by intrinsic disorder in the device active layer. Also the obtained increase in α at low temperature indicates that the organic layer becomes more ordered, where longer-lived electron–hole spin pairs are formed.
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07 Jan 06:16
Ultrahigh EQE (38.1%) Deep‐UV Photodiode with Chemically‐Doped Graphene as Hole Transport Layer
by Titao Li,
Siqi Zhu,
Lemin Jia,
Richeng Lin,
Wei Zheng,
Feng Huang
The chemical doping of graphene hole transport layer has a significant impact on the open-circuit voltage (V OC) of photovoltaic devices. Specifically, a 0.88 V increase of V OC by nitrogen dioxide (NO2) doping promotes an ≈75% enhancement of external quantum efficiency (EQE) and responsivity in solar-blind ultraviolet photovoltaic detectors, of which the 2.02 V V OC and 38.1% EQE are finally obtained.
Abstract
Improving the open-circuit voltage (V OC) is a fundamental target for photovoltaic devices to obtain high photoelectric conversion efficiency (PCE). Here, it is reported that the chemical doping of graphene hole transport layer has a significant impact on the V OC of solar-blind ultraviolet (SBUV) photovoltaic detectors. It has been demonstrated that the external quantum efficiency (EQE) of graphene/AlGaN/SiC heterojunction photovoltaic detectors increases from 21.6% to 38.1% when the Fermi level of graphene is precisely pulled down by a simple charge transfer process. Without sacrificing response speed, the ≈75% increase in EQE together with responsivity is the result of the enhancement of V OC from 1.10 to 2.02 V. This work sheds light on the correlation between V OC and graphene Fermi level in SBUV detectors, and provides effective avenues to modulate the PCE of photovoltaics.
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07 Jan 06:10
Efficient Interfacial Upconversion Enabling Bright Emission at an Extremely Low Driving Voltage in Organic Light‐Emitting Diodes
by Seiichiro Izawa,
Masahiro Morimoto,
Shigeki Naka,
Masahiro Hiramoto
An efficient organic light-emitting diode (OLED) operable by a 1.5 V battery that produces bright emission equivalent to the luminance of a typical display is reported. The OLED is based on an upconversion (UC) transition near its donor/acceptor interface. The efficient UC is realized by controlling a character of a charge transfer state, which is a key intermediate.
Abstract
A remaining frontier in the field of organic light-emitting diodes (OLEDs) is reducing their operating voltage. Herein, an efficient OLED is reported, operable by a 1.5 V battery, that produces bright emission equivalent to the luminance of a typical display. The OLED has a smaller turn-on voltage at 0.97 V than an optical energy of emitted photons at 2.04 eV (608 nm), because the OLED is based on an upconversion (UC) transition associated with triplet–triplet annihilation that doubles the energy of excited states. The characteristics of charge transfer (CT) state at the interface have been revealed, which are key to efficient UC, and the percentage of excited states deactivated by parasitic loss processes during the UC transition is significantly reduced from over 90% to approximately 10% by introducing a highly crystalline acceptor material and an emissive dopant. Consequently, the UC-OLED achieves a quantum efficiency that is two orders of magnitude higher than that in the previous report.
Rong-Huei Yi, 以昇陳 likes this
04 Jan 09:06
Dinuclear PtII Complexes with Strong Blue Phosphorescence for Operationally Stable Organic Light‐Emitting Diodes with EQE up to 23 % at 1000 cd m−2
by Kar-Wai Lo,
Glenna So Ming Tong,
Gang Cheng,
Kam-Hung Low,
Chi-Ming Che
A series of new dinuclear PtII blue emitters bridged by phenylalkoxy-tethered pyrazole are reported with emission quantum yields up to 95 %, emission lifetimes down to 1.3 μs and radiative decay rate constants up to 7.3×105 s−1. Efficient hyper-OLEDs fabricated exhibit a maximum EQE of 23.4 %, a FWHM of 18 nm and a device lifetime >250 h at 1000 cd m−2.
Abstract
Here we describe the synthesis and characterization of a new class of dinuclear PtII complexes with blue phosphorescence. Bulky N-heterocyclic carbene and tethered bridging ligands were employed to suppress photo-induced structural changes and to improve thermal stability of the complexes. These complexes show mixed 3IL/3MLCT blue emission (≈460 nm) with emission quantum yields of up to 0.95, emission lifetimes of as low as 1.3 μs and radiative decay rate constants of up to 7.3×105 s−1 in 4 wt % doped PMMA films; the latter is attributed to a 1MLCT excited state having high metal character (resulting in a large SOC) and a large transition dipole moment, based on DFT calculations. Phosphor-sensitized blue hyper-OLEDs with Commission Internationale de L'Eclairage (CIE) coordinates of (0.13, 0.12) showed a maximum EQE of 23.4 % with a full-width-at-half-maximum of 18 nm and a LT50 >250 h at an L 0 of 1000 cd m−2.
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04 Jan 09:05
Design of Near‐Infrared Nonfullerene Acceptor with Ultralow Nonradiative Voltage Loss for High‐Performance Semitransparent Ternary Organic Solar Cells
by Wuyue Liu,
Shaoming Sun,
Liang Zhou,
Yong Cui,
Wenkai Zhang,
Jianhui Hou,
Feng Liu,
Shengjie Xu,
Xiaozhang Zhu
An N-substituted asymmetric nonfullerene acceptor SN with an over 40 nm bathochromically shifted absorption compared to Y6 is designed and synthesized. The PM6 : SN-based binary cell exhibits the lowest nonradiative voltage loss of 0.15 eV ever achieved by organic solar cells (OSCs). Benefiting from extended NIR absorption and lowered voltage loss, PM6 : Y6 : SN-based semitransparent (ST)-OSCs, for the first time, achieve a power conversion efficiency of 14 % with an average visible transmittance over 20 %.
Abstract
Semitransparent organic solar cells (ST-OSCs) are considered as one of the most valuable applications of OSCs and a strong contender in the market. However, the optical band gap of current high-performance ST-OSCs is still not low enough to achieve the optimal balance between power conversion efficiency (PCE) and average visible transmittance (AVT). An N-substituted asymmetric nonfullerene acceptor SN with over 40 nm bathochromically shifted absorption compared to Y6 was designed and synthesized, based on which the device with PM6 as donor obtained a PCE of 14.3 %, accompanied with a nonradiative voltage loss as low as 0.15 eV. Meanwhile, ternary devices with the addition of SN into PM6 : Y6 can achieve a PCE of 17.5 % with an unchanged open-circuit voltage and improved short-circuit current. Benefiting from extended NIR absorption and lowered voltage loss, ST-OSCs based on PM6 : SN : Y6 were fabricated and the optimized device demonstrated a PCE of 14.0 % at an AVT of 20.2 %, which is the highest PCE at an AVT over 20 %.
04 Jan 01:49
[ASAP] Modulations of a MetalLigand Interaction and Photophysical Behaviors by HuckelMobius Aromatic Switching
by Jinseok Kim, Juwon Oh, Seongchul Park, Tomoki Yoneda, Atsuhiro Osuka, Manho Lim, and Dongho Kim
Journal of the American Chemical Society
DOI: 10.1021/jacs.1c11705
以昇陳, Achim Link and one other like this
04 Jan 01:48
[ASAP] One-Shot Synthesis of Expanded Heterohelicene Exhibiting Narrowband Thermally Activated Delayed Fluorescence
by Susumu Oda, Bungo Kawakami, Yuki Yamasaki, Ryuji Matsumoto, Mayu Yoshioka, Daisuke Fukushima, Soichiro Nakatsuka, and Takuji Hatakeyama
Journal of the American Chemical Society
DOI: 10.1021/jacs.1c11659
04 Jan 01:48
[ASAP] Reversible Iodine Capture by Nonporous Adaptive Crystals of a Bipyridine Cage
by Dan Luo, Yanlei He, Jinya Tian, Jonathan L. Sessler, and Xiaodong Chi
Journal of the American Chemical Society
DOI: 10.1021/jacs.1c11731
23 Dec 02:53
[ASAP] Dual-Channel Fluorescent Probe for the Simultaneous Monitoring of Peroxynitrite and Adenosine-5′-triphosphate in Cellular Applications
by Luling Wu□, Jihong Liu, Xue Tian, Robin R. Groleau, Beidou Feng, Yonggang Yang, Adam C. Sedgwick, Hai-Hao Han, Yang Wang□, Han-Min Wang, Fang Huang, Steven D. Bull, Hua Zhang, Chusen Huang□, Yi Zang, Jia Li, Xiao-Peng He, Ping Li, Bo Tang, Tony D. James, and Jonathan L. Sessler
Journal of the American Chemical Society
DOI: 10.1021/jacs.1c07954