1
|
Ma LP, Wu Z, Yin L, Zhang D, Dong S, Zhang Q, Chen ML, Ma W, Zhang Z, Du J, Sun DM, Liu K, Duan X, Ma D, Cheng HM, Ren W. Pushing the conductance and transparency limit of monolayer graphene electrodes for flexible organic light-emitting diodes. Proc Natl Acad Sci U S A 2020; 117:25991-25998. [PMID: 33020292 PMCID: PMC7584903 DOI: 10.1073/pnas.1922521117] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Graphene has emerged as an attractive candidate for flexible transparent electrode (FTE) for a new generation of flexible optoelectronics. Despite tremendous potential and broad earlier interest, the promise of graphene FTE has been plagued by the intrinsic trade-off between electrical conductance and transparency with a figure of merit (σDC/σOp) considerably lower than that of the state-of-the-art ITO electrodes (σDC/σOp <123 for graphene vs. ∼240 for ITO). Here we report a synergistic electrical/optical modulation strategy to simultaneously boost the conductance and transparency. We show that a tetrakis(pentafluorophenyl)boric acid (HTB) coating can function as highly effective hole doping layer to increase the conductance of monolayer graphene by sevenfold and at the same time as an anti-reflective layer to boost the visible transmittance to 98.8%. Such simultaneous improvement in conductance and transparency breaks previous limit in graphene FTEs and yields an unprecedented figure of merit (σDC/σOp ∼323) that rivals the best commercial ITO electrode. Using the tailored monolayer graphene as the flexible anode, we further demonstrate high-performance green organic light-emitting diodes (OLEDs) with the maximum current, power and external quantum efficiencies (111.4 cd A-1, 124.9 lm W-1 and 29.7%) outperforming all comparable flexible OLEDs and surpassing that with standard rigid ITO by 43%. This study defines a straightforward pathway to tailor optoelectronic properties of monolayer graphene and to fully capture their potential as a generational FTE for flexible optoelectronics.
Collapse
Affiliation(s)
- Lai-Peng Ma
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016 Shenyang, China
- School of Materials Science and Engineering, University of Science and Technology of China, 110016 Shenyang, China
| | - Zhongbin Wu
- State Key Laboratory of Polymers Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 130022 Changchun, China
| | - Lichang Yin
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016 Shenyang, China
- School of Materials Science and Engineering, University of Science and Technology of China, 110016 Shenyang, China
| | - Dingdong Zhang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016 Shenyang, China
- School of Materials Science and Engineering, University of Science and Technology of China, 110016 Shenyang, China
| | - Shichao Dong
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016 Shenyang, China
- School of Materials Science and Engineering, University of Science and Technology of China, 110016 Shenyang, China
| | - Qing Zhang
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016 Shenyang, China
- School of Materials Science and Engineering, University of Science and Technology of China, 110016 Shenyang, China
| | - Mao-Lin Chen
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016 Shenyang, China
- School of Materials Science and Engineering, University of Science and Technology of China, 110016 Shenyang, China
| | - Wei Ma
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016 Shenyang, China
- School of Materials Science and Engineering, University of Science and Technology of China, 110016 Shenyang, China
| | - Zhibin Zhang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871 Beijing, China
| | - Jinhong Du
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016 Shenyang, China
- School of Materials Science and Engineering, University of Science and Technology of China, 110016 Shenyang, China
| | - Dong-Ming Sun
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016 Shenyang, China
- School of Materials Science and Engineering, University of Science and Technology of China, 110016 Shenyang, China
| | - Kaihui Liu
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, 100871 Beijing, China
| | - Xiangfeng Duan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
| | - Dongge Ma
- State Key Laboratory of Luminescent Materials & Devices, South China University of Technology, 510640 Guangzhou, China
| | - Hui-Ming Cheng
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016 Shenyang, China
- School of Materials Science and Engineering, University of Science and Technology of China, 110016 Shenyang, China
- Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute, Tsinghua University, 518055 Shenzhen, China
| | - Wencai Ren
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 110016 Shenyang, China;
- School of Materials Science and Engineering, University of Science and Technology of China, 110016 Shenyang, China
| |
Collapse
|
2
|
Žabka J, Šimková L, Jalový Z, Polášek M. The unimolecular chemistry of protonated and deprotonated 2,2-dinitroethene-1,1-diamine (FOX-7) studied by tandem mass spectrometry and computational chemistry. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2014; 20:233-247. [PMID: 24892294 DOI: 10.1255/ejms.1273] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
2,2-Dinitroethene-1,1-diamine (FOX-7) was studied by means of electrospray ionization (ESI) and chemical ionization (CI) mass spectrometry in both positive and negative ion mode. Detailed mechanisms of unimolecular fragmentations of protonated and deprotonated FOX-7 were investigated using high- and low- energy collision-induced dissociation (CID) mass spectrometry, neutral fragment reionization mass spectrometry and quantum chemistry calculations. In deprotonated FOX-7, elimination of the carbodiimide molecule was identified as the energetically most favored fragmentation channel, closely resembling the base hydrolysis of FOX-7. The dinitromethanide ion is formed during this fragmentation as revealed by comparison with CID mass spectra of an isobaric ion prepared by the ESI of authentic sodium dinitromethanide. The proton affinity of FOX-7 was estimated as 855 kJ mo(-1) by high-accuracy quantum chemistry calculations. This value corresponds to protonation at the C-2 position, though the oxygen-protonated tautomer was found to be nearly isoenergetic in the gas phase. In acetonitrile, the nitro group-protonated FOX-7 was found to be significantly less stable then its C-2 tautomer. These theoretical findings are clearly reflected in differences in fragmentations of ESI- and CI-generated [M+H(]+) ions. Interestingly, the consecutive losses of OH∙ and NO2∙ radicals instead of a whole HNO3 molecule were found to account for the most abundant fragment ion in the positive ESI CID mass spectra. In the CI-generated [M+H](+) and [M+D](+) ions, substantial internal energy effects upon the CID were observed.
Collapse
Affiliation(s)
- Ján Žabka
- J. Heyrovský Institute of Physical Chemistry of the ASCR, v.v.i., Dolejškova 2155/3, 182 23 Praha 8, Czech Republic
| | - Ludmila Šimková
- J. Heyrovský Institute of Physical Chemistry of the ASCR, v.v.i., Dolejškova 2155/3, 182 23 Praha 8, Czech Republic
| | - Zdeněk Jalový
- University of Pardubice, Faculty of Chemical Technology, Institute of Energetic Materials, Studentská 95, 532 10 Pardubice, Czech Republic
| | - Miroslav Polášek
- J. Heyrovský Institute of Physical Chemistry of the ASCR, v.v.i., Dolejškova 2155/3, 182 23 Praha 8, Czech Republic.
| |
Collapse
|
3
|
Tureček F. Electron predators are hydrogen atom traps. Effects of aryl groups on N-C(α) bond dissociations of peptide radicals. JOURNAL OF MASS SPECTROMETRY : JMS 2010; 45:1280-1290. [PMID: 20812369 DOI: 10.1002/jms.1807] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Accepted: 08/05/2010] [Indexed: 05/29/2023]
Abstract
Effects of substituted aryl groups on dissociations of peptide aminoketyl radicals were studied computationally for model tetrapeptide intermediates GXD(•) G where X was a cysteine residue that was derivatized by S-(3-nitrobenzyl), S-(3-cyanobenzyl), S-(3,5-dicyanobenzyl), S-(2,3,4,5,6-pentafluorobenzyl), and S-benzyl groups. The aminoketyl radical was placed within the Asp amide group. Aminoketyl radicals having the S-(3-nitrobenzyl) group were found to undergo spontaneous and highly exothermic migration of the hydroxyl hydrogen atom onto the nitro group in conformers allowing interaction between these groups. Competing reaction channels were investigated for aminoketyl radicals having the S-(3-cyanobenzyl) and S-(3,5-dicyanobenzyl) groups, e.g. H-atom migration to the C and N atoms of the C≡N group, migration to the C-4 position of the phenyl ring, and dissociation of the radical-activated NC(α) bond between the Asp and Gly residues. RRKM kinetic analysis on the combined B3LYP and ROMP2/6-311++G(2d,p) potential energy surface indicated > 99% H-atom transfer to the C≡N group forming a stable iminyl intermediate. The NC(α) bond dissociation was negligible. In contrast, peptides with the S-(2,3,4,5,6-pentafluorobenzyl) and S-benzyl groups showed preferential NC(α) bond dissociation that outcompeted H-atom migration to the C-4 position and fluorine substituents in the phenyl ring. These computational results are used to suggest an alternative mechanism for the quenching effect on electron-based peptide backbone dissociations of benzyl groups with electron-withdrawing substitutents, as reported recently.
Collapse
Affiliation(s)
- František Tureček
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, WA 98195-1700, USA.
| |
Collapse
|
4
|
Chen X, Turecek F. Simple b ions have cyclic oxazolone structures. A neutralization-reionization mass spectrometric and computational study of oxazolone radicals. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2005; 16:1941-56. [PMID: 16257532 DOI: 10.1016/j.jasms.2005.07.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2005] [Revised: 07/27/2005] [Accepted: 07/27/2005] [Indexed: 05/05/2023]
Abstract
The 2-methyloxazol-5-on-2-yl radical (3) and its deuterium labeled analogs were generated in the gas-phase by femtosecond electron-transfer and studied by neutralization-reionization mass spectrometry and quantum chemical calculations. Radical 3 undergoes fast dissociation by ring opening and elimination of CO and CH(3)CO. Loss of hydrogen is less abundant and involves hydrogen atoms from both the ring and side-chain positions. The experimental results are corroborated by the analysis of the potential energy surface of the ground electronic state in 3 using density functional, perturbational, and coupled-cluster theories up to CCSD(T) and extrapolated to the 6-311 ++ G(3df,2p) basis set. RRKM calculations of radical dissociations gave branching ratios for loss of CO and H that were k(CO)/k(H) > 10 over an 80-300 kJ mol(-1) range of internal energies. The driving force for the dissociations of 3 is provided by large Franck-Condon effects on vertical neutralization and possibly from involvement of excited electronic states. Calculations also provided the adiabatic ionization energy of 3, IE(adiab) = 5.48 eV and vertical recombination energy of cation 3(+), RE(vert) = 4.70 eV. The present results strongly indicate that oxazolone structures can explain fragmentations of b-type peptide ions upon electron capture, contrary to previous speculations.
Collapse
Affiliation(s)
- Xiaohong Chen
- Department of Chemistry, University of Washington, Seattle, 98195, USA
| | | |
Collapse
|
5
|
Polášek M, Kaczorowska M, Hrušák J. Iso-nitrous acid radical cation in the gas phase: first experimental evidence. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2004.12.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
6
|
Robertson WH, Price EA, Weber JM, Shin JW, Weddle GH, Johnson MA. Infrared Signatures of a Water Molecule Attached to Triatomic Domains of Molecular Anions: Evolution of the H-bonding Configuration with Domain Length. J Phys Chem A 2003. [DOI: 10.1021/jp030474v] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- William H. Robertson
- Sterling Chemistry Laboratory, Yale University, P.O. Box 208107, New Haven, Connecticut 06520
| | - Erica A. Price
- Sterling Chemistry Laboratory, Yale University, P.O. Box 208107, New Haven, Connecticut 06520
| | - J. Mathias Weber
- Sterling Chemistry Laboratory, Yale University, P.O. Box 208107, New Haven, Connecticut 06520
| | - Joong-Won Shin
- Sterling Chemistry Laboratory, Yale University, P.O. Box 208107, New Haven, Connecticut 06520
| | - Gary H. Weddle
- Sterling Chemistry Laboratory, Yale University, P.O. Box 208107, New Haven, Connecticut 06520
| | - Mark A. Johnson
- Sterling Chemistry Laboratory, Yale University, P.O. Box 208107, New Haven, Connecticut 06520
| |
Collapse
|
7
|
Tureček F. Transient Intermediates of Chemical Reactions by Neutralization-Reionization Mass Spectrometry. Top Curr Chem (Cham) 2003. [DOI: 10.1007/3-540-36113-8_3] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
|
8
|
Srikanth R, Srinivas R, Bhanuprakash K, Vivekananda S, Syrstad EA, Turecek F. Generation and characterization of ionic and neutral P(OH)2+/* in the gas phase by tandem mass spectrometry and computational chemistry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2002; 13:250-264. [PMID: 11908805 DOI: 10.1016/s1044-0305(01)00360-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The bicoordinated dihydroxyphosphenium ion P(OH)2+ (1+) was generated specifically by charge-exchange dissociative ionization of triethylphosphite and its connectivity was confirmed by collision induced dissociation and neutralization-reionization mass spectra. The major dissociation of 1+ forming PO+ ions at m/z 47 involved another isomer, O=P-OH2+ (2+), for which the optimized geometry showed a long P-OH2 bond. Dissociative 70-eV electron ionization of diethyl phosphite produced mostly 1+ together with a less stable isomer, HP(O)OH+ (3+). Ion 2+ is possibly co-formed with 1+ upon dissociative 70-eV electron ionization of methylphosphonic acid. Neutralization-reionization of 1+ confirmed that P(OH)2* (1) was a stable species. Dissociations of neutral 1, as identified by variable-time measurements, involved rate-determining isomerization to 2 followed by fast loss of water. A competitive loss of H occurs from long-lived excited states of 1 produced by vertical electron transfer. The A and B states undergo rate-determining internal conversion to vibrationally highly excited ground state that loses an H atom via two competing mechanisms. The first of these is the direct cleavage of one of the O-H bonds in 1. The other is an isomerization to 3 followed by cleavage of the P-H bond to form O=P-OH as a stable product. The relative, dissociation, and transition state energies for the ions and neutrals were studied by ab initio and density functional theory calculations up to the QCISD(T)/6-311+G(3df,2p) and CCSD(T)/aug-cc-pVTZ levels of theory. RRKM calculations were performed to investigate unimolecular dissociation kinetics of 1. Excited state geometries and energies were investigated by a combination of configuration interaction singles and time-dependent density functional theory calculations.
Collapse
Affiliation(s)
- R Srikanth
- National Center for Mass Spectrometry, Indian Institute of Chemical Technology, Hyderabad
| | | | | | | | | | | |
Collapse
|
9
|
Polášek M, Tureček F. Nitromethyl Radical, Cation, and Anion. A Neutralization and Electron Photodetachment−Reionization Mass Spectrometric and ab Initio Computational Study of [C,H2,N,O2] Isomers. J Phys Chem A 2001. [DOI: 10.1021/jp002758a] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Miroslav Polášek
- Department of Chemistry, Bagley Hall, University of Washington, Box 351700, Seattle, Washington 98195-1700
| | - František Tureček
- Department of Chemistry, Bagley Hall, University of Washington, Box 351700, Seattle, Washington 98195-1700
| |
Collapse
|
10
|
Turecek F. Proton affinity of peroxyacetyl nitrate. A computational study of topical proton affinities. JOURNAL OF MASS SPECTROMETRY : JMS 2000; 35:1351-1359. [PMID: 11114095 DOI: 10.1002/1096-9888(200011)35:11<1351::aid-jms73>3.0.co;2-q] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The structure and energetics of the peroxyacetyl nitrate conformers syn- and anti-PAN and several cations formed by PAN protonation were investigated by a combination of density functional theory and ab initio calculations. syn-PAN is the more stable conformer that is predicted to predominate in gas-phase equilibria. The acetyl carbonyl oxygen was found to be the most basic site in PAN, the oxygen atoms of the peroxide and NO(2) groups being less basic. The 298 K proton affinity of syn-PAN was calculated as 759-763 kJ mol(-1) by effective QCISD(T)/6-311 + G(3df,2p) and 771-773 kJ mol(-1) by B3-MP2/6-311 + G(3df,2p). The calculated values are 25-39 kJ mol(-1) lower than the previous estimate by Srinivasan et al. (Rapid Commun. Mass Spectrom. 1998; 12: 328) that was based on competitive dissociations of proton-bound dimers (the kinetic method). The calculated threshold dissociation energies predicted the formation of CH(3)CO(+) + syn - HOONO(2) and CH(3)COOOH + NO(2)(+) to be the most favorable fragmentations of protonated PAN that required 83 and 89 kJ mol(-1) at the respective thermochemical thresholds at 298 K. The previously observed dissociation to CH(3)COOH + NO(3)(+) was calculated by effective QCISD(T)/6-311 + G(3df,2p) to require 320 kJ mol(-1). The disagreement between the experimental data and calculated energetics is discussed.
Collapse
Affiliation(s)
- F Turecek
- Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700, USA.
| |
Collapse
|
11
|
Polášek M, Tureček F. Hydrogen Atom Adducts to Nitrobenzene: Formation of the Phenylnitronic Radical in the Gas Phase and Energetics of Wheland Intermediates. J Am Chem Soc 2000. [DOI: 10.1021/ja001229h] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
12
|
Polasek M, Turecek F. Protonation sites in methyl nitrate and the formation of transient CH4NO3 radicals. A neutralization-reionization mass spectrometric and computational study. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2000; 11:380-392. [PMID: 10790841 DOI: 10.1016/s1044-0305(00)00106-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Protonation sites in methyl nitrate (1) were evaluated computationally at the Gaussian 2(MP2) level of ab initio theory. The methoxy oxygen was the most basic site that had a calculated proton affinity of PA = 728-738 kJ mol-1 depending on the optimization method used to calculate the equilibrium geometry of the CH3O(H)-NO2+ ion (2+). Protonation at the terminal oxygen atoms in methyl nitrate was less exothermic; the calculated proton affinities were 725, 722, and 712 kJ mol-1 for the formation of the syn-syn, anti-syn, and syn-anti ion rotamers 3a+, 3b+, and 3c+, respectively. Ion 2+ was prepared by an ion-molecule reaction of NO2+ with methanol and used to generate the transient CH3O(H)-NO2. radical (2) by femtosecond collisional electron transfer. Exothermic protonation of 1 produced a mixture of 3a(+)-3c+ with 2+ that was used to generate transient radicals 3a-3c. Radical 2 was found to be unbound and dissociated without barrier to methanol and NO2. Radicals 3a-3c were calculated to be weakly bound. When formed by vertical neutralization, 3a-3c dissociated completely on the 4.2 microseconds time scale of the experiment. The main dissociations of 3a-3c were formations of CH3O. + HONO and CH3ONO + OH.. The gas-phase chemistry of radicals 3a-3c and their dissociation products, as studied by neutralization-reionization mass spectrometry, was dominated by Franck-Condon effects on collisional neutralization and reionization. The adiabatic ionization energies of 3a-3c were calculated as 7.54, 7.57, and 7.66 eV, respectively.
Collapse
Affiliation(s)
- M Polasek
- Department of Chemistry, University of Washington, Seattle 98195-1700, USA
| | | |
Collapse
|
13
|
Tureček F, Polášek M, Frank AJ, Sadílek M. Transient Hydrogen Atom Adducts to Disulfides. Formation and Energetics. J Am Chem Soc 2000. [DOI: 10.1021/ja993789q] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- František Tureček
- Contribution from the Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700
| | - Miroslav Polášek
- Contribution from the Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700
| | - Aaron J. Frank
- Contribution from the Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700
| | - Martin Sadílek
- Contribution from the Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700
| |
Collapse
|