1
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Li Z, Florian M, Datta K, Jiang Z, Borsch M, Wen Q, Kira M, Deotare PB. Enhanced Exciton Drift Transport through Suppressed Diffusion in One-Dimensional Guides. ACS NANO 2023; 17:22410-22417. [PMID: 37874891 DOI: 10.1021/acsnano.3c04870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
Drift-diffusion dynamics is investigated in a one-dimensional (1D) exciton guide at room temperature. Spatial engineering of the exciton energy in a WSe2 monolayer is achieved using local strain to confine and direct exciton transport. An unexpected and massive deviation from the Einstein relation is observed and correlated to exciton capture by defects. We find that the capture reduces exciton temperature and diffusion so much that drift transport visibility improves to 38% as excitons traverse asymmetrically over regions with occupied defect states. Based on measurements over multiple potential gradients, we estimate the exciton mobility to be 169 ± 39 cm2/(eV s) at room temperature. Experiments at elevated exciton densities reveal that the exciton drift velocity monotonically increases with exciton density, unlike exciton mobility, due to contributions from nonequilibrium many-body effects.
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Affiliation(s)
- Zidong Li
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Matthias Florian
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Kanak Datta
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Zhaohan Jiang
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Markus Borsch
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Qiannan Wen
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Mack Kira
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Parag B Deotare
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
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2
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Jašinskas V, Franckevičius M, Gelžinis A, Chmeliov J, Gulbinas V. Direct Tracking of Charge Carrier Drift and Extraction from Perovskite Solar Cells by Means of Transient Electroabsorption Spectroscopy. ACS APPLIED ELECTRONIC MATERIALS 2023; 5:317-326. [PMID: 38616982 PMCID: PMC11008527 DOI: 10.1021/acsaelm.2c01346] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 01/01/2023] [Indexed: 04/16/2024]
Abstract
The best perovskite solar cells currently demonstrate more than 25% efficiencies, yet many fundamental processes that determine the operation of these devices are still not fully understood. In particular, even though the device performance strongly depends on charge carrier transport across the perovskite layer to selective electrodes, information about this process is still very controversial. Here, we investigate charge carrier motion and extraction from an archetypical CH3NH3PbI3 (MAPI) perovskite solar cell. We use the ultrafast electric-field-modulated transient absorption technique, which allows us to evaluate the electric field dynamics from the time-resolved electroabsorption spectra and to visualize the motion of charge carriers with subpicosecond time resolution. We demonstrate that photogenerated holes drift across the mesoporous TiO2/perovskite layer during hundreds of picoseconds. On the other hand, their extraction into the spiro-OMeTAD hole transporting layer lasts for more than 1 nanosecond, suggesting that the hole extraction is limited by the perovskite/spiro-OMeTAD interface rather than by the hole transport through the perovskite layer. Additionally, we use the ultrafast time-resolved fluorescence technique that reveals fluorescence decay during tens of picoseconds, which we attribute to the spatial separation of electrons and holes.
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Affiliation(s)
- Vidmantas Jašinskas
- Department
of Molecular Compound Physics, Center for
Physical Sciences and Technology, Saulėtekio av. 3, VilniusLT-10257, Lithuania
| | - Marius Franckevičius
- Department
of Molecular Compound Physics, Center for
Physical Sciences and Technology, Saulėtekio av. 3, VilniusLT-10257, Lithuania
| | - Andrius Gelžinis
- Department
of Molecular Compound Physics, Center for
Physical Sciences and Technology, Saulėtekio av. 3, VilniusLT-10257, Lithuania
- Institute
of Chemical Physics, Faculty of Physics, Vilnius University, Saulėtekio av. 9, VilniusLT-10222, Lithuania
| | - Jevgenij Chmeliov
- Department
of Molecular Compound Physics, Center for
Physical Sciences and Technology, Saulėtekio av. 3, VilniusLT-10257, Lithuania
- Institute
of Chemical Physics, Faculty of Physics, Vilnius University, Saulėtekio av. 9, VilniusLT-10222, Lithuania
| | - Vidmantas Gulbinas
- Department
of Molecular Compound Physics, Center for
Physical Sciences and Technology, Saulėtekio av. 3, VilniusLT-10257, Lithuania
- Institute
of Chemical Physics, Faculty of Physics, Vilnius University, Saulėtekio av. 9, VilniusLT-10222, Lithuania
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3
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Navamani K, Rajkumar K. Generalization on Entropy-Ruled Charge and Energy Transport for Organic Solids and Biomolecular Aggregates. ACS OMEGA 2022; 7:27102-27115. [PMID: 35967056 PMCID: PMC9366796 DOI: 10.1021/acsomega.2c01118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 07/13/2022] [Indexed: 05/27/2023]
Abstract
Herein, a generalized version of the entropy-ruled charge and energy transport mechanism for organic solids and biomolecular aggregates is presented. The effects of thermal disorder and electric field on electronic transport in molecular solids have been quantified by entropy, which eventually varies with respect to the typical disorder (static or dynamic). Based on our previous differential entropy (h s )-driven charge transport method, we explore the nonsteady carrier energy flux principle for soft matter systems from small organic solids to macrobiomolecular aggregates. Through this principle, the synergic nature of charge and energy transport in different organic systems is addressed. In this work, entropy is the key parameter to classify whether the carrier dynamics is in a nonsteady or steady state. Besides that, we also propose the formulation for unifying the hopping and band transport, which provides the relaxation time-hopping rate relation and the relaxation time-effective mass ratio. The calculated disorder drift time (or entropy-weighted carrier drift time) for hole transport in an alkyl-substituted triphenylamine (TPA) molecular device is 9.3 × 10-7 s, which illustrates nuclear dynamics-coupled charge transfer kinetics. The existence of nonequilibrium transport is anticipated while the carrier dynamics is in the nonsteady state, which is further examined from the rate of traversing potential in octupolar molecules. Our entropy-ruled Einstein model connects the adiabatic band and nonadiabatic hopping transport mechanisms. The logarithmic current density at different electric field-assisted site energy differences provides information about the typical transport (whether trap-free diffusion or trap-assisted recombination) in molecular devices, which reflects in the Navamani-Shockley diode equation.
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Affiliation(s)
- Karuppuchamy Navamani
- Department
of Physics, Centre for Research and Development
(CFRD), KPR Institute of Engineering and Technology, Coimbatore 641407, India
| | - Kanakaraj Rajkumar
- Department
of Physics, Indian Institute of Technology
Madras, Chennai 600036, India
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4
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Wang J, Wang Y, Li K, Dai X, Zhang L, Wang H. Lateral Fully Organic P-N Diodes Created in a Single Donor-Acceptor Copolymer. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2106624. [PMID: 34717015 DOI: 10.1002/adma.202106624] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/28/2021] [Indexed: 06/13/2023]
Abstract
P-N junctions exist in many solid-state organic devices, such as light-emitting diodes, solar cells, and thermoelectric devices. Creating P-N junctions by bulk chemical doping in a single organic material (like silicon doped by boron and phosphorus) may capitalize the vast scientific and technological groundwork established in the inorganic semiconducting field. However, high-performance single-organic-material P-N junctions are seldom reported, because the diffusion of the dopant counterions often leads to transient rectification properties. Herein, a new type of lateral fully organic diodes created in single donor-acceptor (D-A) copolymer films with only one P-type dopant is reported. The achieved lateral devices exhibit high current densities of ≈3.83 A cm-2 and a high rectification ratio of ≈2100, which are beyond the requirements for high-frequency identification tags. The P- to N-type polarity switching mechanism is proposed after spectroscopic and structural tests. Decent stability of the organic diode is obtained, which is due to the long channel length and low diffusion speed of the large size of dopants. This work opens the opportunities to create P-N junctions in ways of silicon-based inorganic semiconductors and promises new opportunities for integrating organic materials for flexible and printable organic devices.
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Affiliation(s)
- Jing Wang
- Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, 710054, China
- School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, 710054, China
| | - Yizhuo Wang
- Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, 710054, China
| | - Kuncai Li
- Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, 710054, China
| | - Xu Dai
- Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, 710054, China
| | - Liuyang Zhang
- School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, 710054, China
| | - Hong Wang
- Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, 710054, China
- State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an, 710054, China
- School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an, 710054, China
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5
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Smith HL, Dull JT, Mohapatra SK, Al Kurdi K, Barlow S, Marder SR, Rand BP, Kahn A. Powerful Organic Molecular Oxidants and Reductants Enable Ambipolar Injection in a Large-Gap Organic Homojunction Diode. ACS APPLIED MATERIALS & INTERFACES 2022; 14:2381-2389. [PMID: 34978787 DOI: 10.1021/acsami.1c21302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Doping has proven to be a critical tool for enhancing the performance of organic semiconductors in devices like organic light-emitting diodes. However, the challenge in working with high-ionization-energy (IE) organic semiconductors is to find p-dopants with correspondingly high electron affinity (EA) that will improve the conductivity and charge carrier transport in a film. Here, we use an oxidant that has been recently recognized to be a very strong p-type dopant, hexacyano-1,2,3-trimethylene-cyclopropane (CN6-CP). The EA of CN6-CP has been previously estimated via cyclic voltammetry to be 5.87 eV, almost 300 meV higher than other known high-EA organic molecular oxidants. We measure the frontier orbitals of CN6-CP using ultraviolet and inverse photoemission spectroscopy techniques and confirm a high EA value of 5.88 eV in the condensed phase. The introduction of CN6-CP in a film of large-band-gap, large-IE phenyldi(pyren-1-yl)phosphine oxide (POPy2) leads to a significant shift of the Fermi level toward the highest occupied molecular orbital and a 2 orders of magnitude increase in conductivity. Using CN6-CP and n-dopant (pentamethylcyclopentadienyl)(1,3,5-trimethylbenzene)ruthenium (RuCp*Mes)2, we fabricate a POPy2-based rectifying p-i-n homojunction diode with a 2.9 V built-in potential. Blue light emission is achieved under forward bias. This effect demonstrates the dopant-enabled hole injection from the CN6-CP-doped layer and electron injection from the (RuCp*Mes)2-doped layer in the diode.
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Affiliation(s)
- Hannah L Smith
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Jordan T Dull
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Swagat K Mohapatra
- School of Chemistry and Biochemistry and Center for Organic Photonics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Department of Industrial and Engineering Chemistry, Institute of Chemical Technology─Indian Oil Odisha Campus, IIT Kharagpur Extension Center, Bhubaneswar 751013, Odisha, India
| | - Khaled Al Kurdi
- School of Chemistry and Biochemistry and Center for Organic Photonics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Stephen Barlow
- School of Chemistry and Biochemistry and Center for Organic Photonics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Seth R Marder
- School of Chemistry and Biochemistry and Center for Organic Photonics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Renewable and Sustainable Energy Institute (RASEI), University of Colorado Boulder, Boulder, Colorado 80309, United States
- Department of Chemical and Biological Engineering and Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Barry P Rand
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, New Jersey 08544, United States
| | - Antoine Kahn
- Department of Electrical and Computer Engineering, Princeton University, Princeton, New Jersey 08544, United States
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6
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Scaccabarozzi AD, Basu A, Aniés F, Liu J, Zapata-Arteaga O, Warren R, Firdaus Y, Nugraha MI, Lin Y, Campoy-Quiles M, Koch N, Müller C, Tsetseris L, Heeney M, Anthopoulos TD. Doping Approaches for Organic Semiconductors. Chem Rev 2021; 122:4420-4492. [PMID: 34793134 DOI: 10.1021/acs.chemrev.1c00581] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Electronic doping in organic materials has remained an elusive concept for several decades. It drew considerable attention in the early days in the quest for organic materials with high electrical conductivity, paving the way for the pioneering work on pristine organic semiconductors (OSCs) and their eventual use in a plethora of applications. Despite this early trend, however, recent strides in the field of organic electronics have been made hand in hand with the development and use of dopants to the point that are now ubiquitous. Here, we give an overview of all important advances in the area of doping of organic semiconductors and their applications. We first review the relevant literature with particular focus on the physical processes involved, discussing established mechanisms but also newly proposed theories. We then continue with a comprehensive summary of the most widely studied dopants to date, placing particular emphasis on the chemical strategies toward the synthesis of molecules with improved functionality. The processing routes toward doped organic films and the important doping-processing-nanostructure relationships, are also discussed. We conclude the review by highlighting how doping can enhance the operating characteristics of various organic devices.
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Affiliation(s)
- Alberto D Scaccabarozzi
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Thuwal 23955, Saudi Arabia
| | - Aniruddha Basu
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Thuwal 23955, Saudi Arabia
| | - Filip Aniés
- Department of Chemistry and Centre for Processable Electronics, Imperial College London, London W12 0BZ, U.K
| | - Jian Liu
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg 412 96, Sweden
| | - Osnat Zapata-Arteaga
- Materials Science Institute of Barcelona, ICMAB-CSIC, Campus UAB, 08193 Bellaterra, Spain
| | - Ross Warren
- Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
| | - Yuliar Firdaus
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Thuwal 23955, Saudi Arabia.,Research Center for Electronics and Telecommunication, Indonesian Institute of Science, Jalan Sangkuriang Komplek LIPI Building 20 level 4, Bandung 40135, Indonesia
| | - Mohamad Insan Nugraha
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Thuwal 23955, Saudi Arabia
| | - Yuanbao Lin
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Thuwal 23955, Saudi Arabia
| | - Mariano Campoy-Quiles
- Materials Science Institute of Barcelona, ICMAB-CSIC, Campus UAB, 08193 Bellaterra, Spain
| | - Norbert Koch
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Kekulé-Strasse 5, 12489 Berlin, Germany.,Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
| | - Christian Müller
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg 412 96, Sweden
| | - Leonidas Tsetseris
- Department of Physics, National Technical University of Athens, Athens GR-15780, Greece
| | - Martin Heeney
- Department of Chemistry and Centre for Processable Electronics, Imperial College London, London W12 0BZ, U.K
| | - Thomas D Anthopoulos
- King Abdullah University of Science and Technology (KAUST), KAUST Solar Center (KSC), Thuwal 23955, Saudi Arabia
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7
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Hu J, Al‐Salihy A, Wang J, Li X, Fu Y, Li Z, Han X, Song B, Xu P. Improved Interface Charge Transfer and Redistribution in CuO-CoOOH p-n Heterojunction Nanoarray Electrocatalyst for Enhanced Oxygen Evolution Reaction. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2103314. [PMID: 34643068 PMCID: PMC8596130 DOI: 10.1002/advs.202103314] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 08/27/2021] [Indexed: 05/26/2023]
Abstract
Electron density modulation is of great importance in an attempt to achieve highly active electrocatalysts for the oxygen evolution reaction (OER). Here, the successful construction of CuO@CoOOH p-n heterojunction (i.e., p-type CuO and n-type CoOOH) nanoarray electrocatalyst through an in situ anodic oxidation of CuO@CoSx on copper foam is reported. The p-n heterojunction can remarkably modify the electronic properties of the space-charge region and facilitate the electron transfer. Moreover, in situ Raman study reveals the generation of SO4 2- from CoSx oxidation, and electron cloud density distribution and density functional theory calculation suggest that surface-adsorbed SO4 2- can facilitate the OER process by enhancing the adsorption of OH- . The positively charged CoOOH in the space-charge region can significantly enhance the OER activity. As a result, the CuO@CoOOH p-n heterojunction shows significantly enhanced OER performance with a low overpotential of 186 mV to afford a current density of 10 mA cm-2 . The successful preparation of a large scale (14 × 25 cm2 ) sample demonstrates the possibility of promoting the catalyst to industrial-scale production. This study offers new insights into the design and fabrication of non-noble metal-based p-n heterojunction electrocatalysts as effective catalytic materials for energy storage and conversion.
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Affiliation(s)
- Jing Hu
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and StorageSchool of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin150001P. R. China
| | - Adel Al‐Salihy
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and StorageSchool of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin150001P. R. China
| | - Jing Wang
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and StorageSchool of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin150001P. R. China
| | - Xue Li
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and StorageSchool of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin150001P. R. China
| | - Yanfei Fu
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and StorageSchool of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin150001P. R. China
| | - Zhonghua Li
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and StorageSchool of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin150001P. R. China
| | - Xijiang Han
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and StorageSchool of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin150001P. R. China
| | - Bo Song
- National Key Laboratory of Science and Technology on Advanced Composites in Special EnvironmentsHarbin Institute of TechnologyHarbin150001P. R. China
| | - Ping Xu
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and StorageSchool of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin150001P. R. China
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8
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Sakai N, Warren R, Zhang F, Nayak S, Liu J, Kesava SV, Lin YH, Biswal HS, Lin X, Grovenor C, Malinauskas T, Basu A, Anthopoulos TD, Getautis V, Kahn A, Riede M, Nayak PK, Snaith HJ. Adduct-based p-doping of organic semiconductors. NATURE MATERIALS 2021; 20:1248-1254. [PMID: 33888905 DOI: 10.1038/s41563-021-00980-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 03/09/2021] [Indexed: 06/12/2023]
Abstract
Electronic doping of organic semiconductors is essential for their usage in highly efficient optoelectronic devices. Although molecular and metal complex-based dopants have already enabled significant progress of devices based on organic semiconductors, there remains a need for clean, efficient and low-cost dopants if a widespread transition towards larger-area organic electronic devices is to occur. Here we report dimethyl sulfoxide adducts as p-dopants that fulfil these conditions for a range of organic semiconductors. These adduct-based dopants are compatible with both solution and vapour-phase processing. We explore the doping mechanism and use the knowledge we gain to 'decouple' the dopants from the choice of counterion. We demonstrate that asymmetric p-doping is possible using solution processing routes, and demonstrate its use in metal halide perovskite solar cells, organic thin-film transistors and organic light-emitting diodes, which showcases the versatility of this doping approach.
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Affiliation(s)
- Nobuya Sakai
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - Ross Warren
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - Fengyu Zhang
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, USA
| | - Simantini Nayak
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, Oxford, UK
- Materials Chemistry Department, CSIR-Institute of Mineral and Materials Technology, Bhubaneswar, India
| | - Junliang Liu
- Department of Materials, University of Oxford, Oxford, UK
| | - Sameer V Kesava
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - Yen-Hung Lin
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - Himansu S Biswal
- School of Chemical Sciences, National Institute of Science Education and Research, Bhubaneswar, India
| | - Xin Lin
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, USA
| | - Chris Grovenor
- Department of Materials, University of Oxford, Oxford, UK
| | - Tadas Malinauskas
- Department of Organic Chemistry, Kaunas University of Technology, Kaunas, Lithuania
| | - Aniruddha Basu
- KAUST Solar Center (KSC), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Thomas D Anthopoulos
- KAUST Solar Center (KSC), King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Vytautas Getautis
- Department of Organic Chemistry, Kaunas University of Technology, Kaunas, Lithuania
| | - Antoine Kahn
- Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, USA
| | - Moritz Riede
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
| | - Pabitra K Nayak
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK.
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research, Hyderabad, India.
| | - Henry J Snaith
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK.
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9
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Navamani K, Pati SK, Senthilkumar K. Effect of site energy fluctuation on charge transport in disordered organic molecules. J Chem Phys 2019; 151:224301. [PMID: 31837669 DOI: 10.1063/1.5122695] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Effect of dynamics of site energy disorder on charge transport in organic molecular semiconductors is not yet well-established. In order to study the relationship between the dynamics of site energy disorder and charge transport, we have performed a multiscale study on dialkyl substituted thienothiophene capped benzobisthiazole (BDHTT-BBT) and methyl-substituted dicyanovinyl-capped quinquethiophene (DCV5T-Me) molecular solids. In this study, we explore the structural dynamics and correlated charge transport by electronic structure calculations, molecular dynamics, and kinetic Monte-Carlo simulations. We have also proposed the differential entropy dependent diffusion and charge density equations to study the electric field drifted diffusion property and carrier density. In this investigation, we have addressed the transformation mechanism from dynamic to static disorder in the extended stacked molecular units. Here, the decrease in the charge transfer rate due to site energy fluctuations reveals the dispersion transport along the extended π-stacked molecules. Furthermore, the calculated current density for a different set of site energy difference values shows the validity and the limitations of the Einstein relation. Based on the calculated ideality factor, we have classified the charge transport in these molecules as either the Langevin or the Shockley-Read-Hall type mechanism. Through the calculated mobility, current density, and ideality factor analysis, we categorize the applicability of molecules of interest for photovoltaic or light emitting diode applications.
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Affiliation(s)
- K Navamani
- Theoretical Sciences Unit, School of Advanced Materials (SAMat), Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560064, India
| | - Swapan K Pati
- Theoretical Sciences Unit, School of Advanced Materials (SAMat), Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur P.O., Bangalore 560064, India
| | - K Senthilkumar
- Department of Physics, Bharathiar University, Coimbatore 641046, India
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10
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Futscher MH, Schultz T, Frisch J, Ralaiarisoa M, Metwalli E, Nardi MV, Müller-Buschbaum P, Koch N. Electronic properties of hybrid organic/inorganic semiconductor pn-junctions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:064002. [PMID: 30523893 DOI: 10.1088/1361-648x/aaf310] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Hybrid inorganic/organic semiconductor heterojunctions are candidates to expand the scope of purely organic or inorganic junctions in electronic and optoelectronic devices. Comprehensive understanding of bulk and interface doping on the junction's electronic properties is therefore desirable. In this work, we elucidate the energy level alignment and its mechanisms at a prototypical hybrid pn-junction comprising ZnO (n-type) and p-doped N,N'-di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (α-NPD) as semiconductors, using photoelectron spectroscopy. The level alignment can be quantitatively described by the interplay of contact-induced band and energy level bending in the inorganic and organic component away from the interface, and an interface dipole due to the push-back effect. By adjusting the dopant concentration in α-NPD, the position of the frontier energy levels of ZnO can be varied by over 0.5 eV and that of α-NPD by over 1 eV. The tunability of this pn-junction's energy levels evidences the substantial potential of the hybrid approach for enhancing device functionality.
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Affiliation(s)
- Moritz H Futscher
- Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, 12489 Berlin, Germany. Physik-Department, Lehrstuhl für Funktionelle Materialien, Technische Universität München, 85748 Garching, Germany
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11
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Hiramoto M, Kikuchi M, Izawa S. Parts-per-Million-Level Doping Effects in Organic Semiconductor Films and Organic Single Crystals. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1801236. [PMID: 30118548 DOI: 10.1002/adma.201801236] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 06/01/2018] [Indexed: 06/08/2023]
Abstract
Controlling the pn-type behavior of a semiconductor such as silicon by adding an extremely small quantity of an impurity (doping) is a central part of inorganic semiconductor electronics since the 20th century. Recent progress in the doping of organic semiconductors strongly suggests the advent of a new era of doped organic semiconductors. Here, the principles and effects of doping at the level of parts per million (ppm) in organic semiconductor films and single crystals are described, including descriptions of complete pn-control, doping sensitization, ppm doping using an extremely low-speed deposition technique reaching 10-9 nm s-1 , and emerging ppm-level doping effects, such as trap filling, majority carriers, homojunction formation, and decreased mobility, as well as ppm-level doping effects in organic single crystals measured by the Hall effect, which shows a doping efficiency of 24%. The Wannier excitonic doping of organic single crystals possessing band conduction and the defect science of organic single crystals related to carrier trapping and scattering are introduced as a new scientific field. The dawn of organic single-crystal electronics is also discussed.
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Affiliation(s)
- Masahiro Hiramoto
- Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, 444-8787, Japan
| | - Mitsuru Kikuchi
- Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, 444-8787, Japan
| | - Seiichiro Izawa
- Institute for Molecular Science, 5-1 Higashiyama, Myodaiji, Okazaki, 444-8787, Japan
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12
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Navamani K, Samanta PK, Pati SK. Theoretical modeling of charge transport in triphenylamine–benzimidazole based organic solids for their application as host-materials in phosphorescent OLEDs. RSC Adv 2018; 8:30021-30039. [PMID: 35547290 PMCID: PMC9085285 DOI: 10.1039/c8ra03281e] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 08/18/2018] [Indexed: 11/21/2022] Open
Abstract
The dynamic disorder and electric field effects on charge transport in triphenylamine–benzimidazole based molecular solids have been investigated using electronic structure calculations, molecular dynamics and Monte-Carlo simulations. During the charge propagation, the energy loss of the carrier in each hopping step is monitored by Monte-Carlo simulation. We derive a survival probability correlated momentum–energy distribution for drift-diffusion analysis and we demonstrate the dispersion initiated charge trapping mechanism which is indeed ideal for light emission efficiency via recombination. In the present model, the proposed carrier drift energy–current density expression and Shockley diode current density equation are used to study the current density–voltage characteristics; accordingly the ideality factor (∼1.8–2.0) dictates the deviation of Einstein's classical diffusion–mobility relation (where the ideality factor is unity). The dual mechanism of electric field assisted site energy gap on coherent-like transport and the electric field stretched dispersion on recombination are observed in tris(3′-(1-phenyl-1H-benzimidazole-2-yl)biphenyl-4-yl)amine (TBBI) and tris(4′-(1-phenyl-1H-benzimidazole-2-yl)biphenyl-4-yl)amine (TIBN) molecular systems, which can be used as host materials in organic light emitting diodes (OLEDs). We find the transport going from coherent to incoherent, due to the conversion mechanism of dynamic to static disorder. This can also be a controlled by applied electric field. By adjusting the applied electric field, film thickness and changing the π-stacked molecular aggregation via substitutions, one can fix the dispersive parameter and accordingly calculate the charge transport properties to design efficient host-materials for photovoltaic and light emitting diode devices. Dynamic disorder and electric field affect the charge (hole and electron) transport in host-materials for OLEDs.![]()
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Affiliation(s)
- K. Navamani
- School of Advanced Materials (SAMat)
- Theoretical Sciences Unit
- Jawaharlal Nehru Centre for Advanced Scientific Research
- Bangalore 560064
- India
| | - P. K. Samanta
- School of Advanced Materials (SAMat)
- Theoretical Sciences Unit
- Jawaharlal Nehru Centre for Advanced Scientific Research
- Bangalore 560064
- India
| | - S. K. Pati
- School of Advanced Materials (SAMat)
- Theoretical Sciences Unit
- Jawaharlal Nehru Centre for Advanced Scientific Research
- Bangalore 560064
- India
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13
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Jacobs IE, Moulé AJ. Controlling Molecular Doping in Organic Semiconductors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1703063. [PMID: 28921668 DOI: 10.1002/adma.201703063] [Citation(s) in RCA: 177] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/24/2017] [Indexed: 05/23/2023]
Abstract
The field of organic electronics thrives on the hope of enabling low-cost, solution-processed electronic devices with mechanical, optoelectronic, and chemical properties not available from inorganic semiconductors. A key to the success of these aspirations is the ability to controllably dope organic semiconductors with high spatial resolution. Here, recent progress in molecular doping of organic semiconductors is summarized, with an emphasis on solution-processed p-type doped polymeric semiconductors. Highlighted topics include how solution-processing techniques can control the distribution, diffusion, and density of dopants within the organic semiconductor, and, in turn, affect the electronic properties of the material. Research in these areas has recently intensified, thanks to advances in chemical synthesis, improved understanding of charged states in organic materials, and a focus on relating fabrication techniques to morphology. Significant disorder in these systems, along with complex interactions between doping and film morphology, is often responsible for charge trapping and low doping efficiency. However, the strong coupling between doping, solubility, and morphology can be harnessed to control crystallinity, create doping gradients, and pattern polymers. These breakthroughs suggest a role for molecular doping not only in device function but also in fabrication-applications beyond those directly analogous to inorganic doping.
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Affiliation(s)
- Ian E Jacobs
- Department of Materials Science, University of California, Davis, 1 Shields Avenue, Davis, CA, 95616, USA
| | - Adam J Moulé
- Department of Chemical Engineering, University of California, Davis, 1 Shields Avenue, Davis, CA, 95616, USA
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14
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Jain V, Heurlin M, Karimi M, Hussain L, Aghaeipour M, Nowzari A, Berg A, Nylund G, Capasso F, Samuelson L, Borgström MT, Pettersson H. Bias-dependent spectral tuning in InP nanowire-based photodetectors. NANOTECHNOLOGY 2017; 28:114006. [PMID: 28211361 DOI: 10.1088/1361-6528/aa5236] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Nanowire array ensembles contacted in a vertical geometry are extensively studied and considered strong candidates for next generations of industrial scale optoelectronics. Key challenges in this development deal with optimization of the doping profile of the nanowires and the interface between nanowires and transparent top contact. Here we report on photodetection characteristics associated with doping profile variations in InP nanowire array photodetectors. Bias-dependent tuning of the spectral shape of the responsivity is observed which is attributed to a Schottky-like contact at the nanowire-ITO interface. Angular dependent responsivity measurements, compared with simulated absorption spectra, support this conclusion. Furthermore, electrical simulations unravel the role of possible self-gating effects in the nanowires induced by the ITO/SiO x wrap-gate geometry. Finally, we discuss possible reasons for the observed low saturation current at large forward biases.
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Affiliation(s)
- Vishal Jain
- Solid State Physics and NanoLund, Lund University, PO Box 118, SE-221 00 Lund, Sweden. Laboratory of Mathematics, Physics and Electrical Engineering, Halmstad University, PO Box 823, SE-301 18 Halmstad, Sweden
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15
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Rani V, Sharma A, Kumar P, Singh B, Ghosh S. Charge transport mechanism in copper phthalocyanine thin films with and without traps. RSC Adv 2017. [DOI: 10.1039/c7ra08316e] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We investigate the charge transport mechanism in copper phthalocyanine thin films with and without traps. We find that the density of interface states at the grain boundaries can decide the mechanism of charge transport in organic thin films.
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Affiliation(s)
- Varsha Rani
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
| | - Akanksha Sharma
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
| | - Pramod Kumar
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
| | - Budhi Singh
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
| | - Subhasis Ghosh
- School of Physical Sciences
- Jawaharlal Nehru University
- New Delhi 110067
- India
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Abstract
Organic field-effect transistors hold the promise of enabling low-cost and flexible electronics. Following its success in organic optoelectronics, the organic doping technology is also used increasingly in organic field-effect transistors. Doping not only increases device performance, but it also provides a way to fine-control the transistor behavior, to develop new transistor concepts, and even improve the stability of organic transistors. This Review summarizes the latest progress made in the understanding of the doping technology and its application to organic transistors. It presents the most successful doping models and an overview of the wide variety of materials used as dopants. Further, the influence of doping on charge transport in the most relevant polycrystalline organic semiconductors is reviewed, and a concise overview on the influence of doping on transistor behavior and performance is given. In particular, recent progress in the understanding of contact doping and channel doping is summarized.
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Affiliation(s)
- Björn Lüssem
- Department of Physics, Kent State University , Kent, Ohio 44242, United States
| | - Chang-Min Keum
- Department of Physics, Kent State University , Kent, Ohio 44242, United States
| | - Daniel Kasemann
- Institut für Angewandte Photophysik, TU Dresden , 01069 Dresden, Germany
| | - Ben Naab
- Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States
| | - Zhenan Bao
- Department of Chemical Engineering, Stanford University , Stanford, California 94305, United States
| | - Karl Leo
- Institut für Angewandte Photophysik, TU Dresden , 01069 Dresden, Germany
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17
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Assessment of Density-Functional Tight-Binding Ionization Potentials and Electron Affinities of Molecules of Interest for Organic Solar Cells Against First-Principles GW Calculations. COMPUTATION 2015. [DOI: 10.3390/computation3040616] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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18
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Affiliation(s)
- Nir Tessler
- The Sarah and Moshe Zisapel Nanoelectronic Center; Electrical Engineering Deparment, Technion Israel Institute of Technology; Haifa 32000 Israel
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20
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Siebert-Henze E, Lyssenko VG, Brückner R, Riede M, Leo K. Electroabsorption studies of organic p-i-n solar cells: evaluating the built-in voltage. ACTA ACUST UNITED AC 2014. [DOI: 10.1557/opl.2014.50] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTWe investigate the built-in voltage in organic bulk heterojunction solar cells using electroabsorption spectroscopy based on the Stark effect, i.e. the variation of the absorption energies of a material caused by an electric field. Due to spectral contributions of permanent dipoles, a novel approach for evaluating the EA spectra is required. We use a fitting routine analyzing a broad spectral range instead of using only a single wavelength. A reliable quantitative determination of the built-in voltage is achieved.
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21
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Guo S, Mohapatra SK, Romanov A, Timofeeva TV, Hardcastle KI, Yesudas K, Risko C, Brédas JL, Marder SR, Barlow S. n-Doping of Organic Electronic Materials Using Air-Stable Organometallics: A Mechanistic Study of Reduction by Dimeric Sandwich Compounds. Chemistry 2012; 18:14760-72. [DOI: 10.1002/chem.201202591] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Indexed: 11/11/2022]
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22
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Gutiérrez Lezama I, Nakano M, Minder NA, Chen Z, Di Girolamo FV, Facchetti A, Morpurgo AF. Single-crystal organic charge-transfer interfaces probed using Schottky-gated heterostructures. NATURE MATERIALS 2012; 11:788-94. [PMID: 22820687 DOI: 10.1038/nmat3383] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Accepted: 06/19/2012] [Indexed: 05/24/2023]
Abstract
Organic semiconductors based on small conjugated molecules generally behave as insulators when undoped, but the heterointerfaces of two such materials can show electrical conductivity as large as in a metal. Although charge transfer is commonly invoked to explain the phenomenon, the details of the process and the nature of the interfacial charge carriers remain largely unexplored. Here we use Schottky-gated heterostructures to probe the conducting layer at the interface between rubrene and PDIF-CN(2) single crystals. Gate-modulated conductivity measurements demonstrate that interfacial transport is due to electrons, whose mobility exhibits band-like behaviour from room temperature to ~150 K, and remains as high as ~1 cm(2) V(-1) s(-1) at 30 K for the best devices. The electron density decreases linearly with decreasing temperature, an observation that can be explained quantitatively on the basis of the heterostructure band diagram. These results elucidate the electronic structure of rubrene/PDIF-CN(2) interfaces and show the potential of Schottky-gated organic heterostructures for the investigation of transport in molecular semiconductors.
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23
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Pettersson H, Zubritskaya I, Nghia NT, Wallentin J, Borgström MT, Storm K, Landin L, Wickert P, Capasso F, Samuelson L. Electrical and optical properties of InP nanowire ensemble p⁺-i-n⁺ photodetectors. NANOTECHNOLOGY 2012; 23:135201. [PMID: 22418741 DOI: 10.1088/0957-4484/23/13/135201] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report on a comprehensive study of electrical and optical properties of efficient near-infrared p⁺-i-n⁺ photodetectors based on large ensembles of self-assembled, vertically aligned i-n⁺ InP nanowires monolithically grown on a common p⁺ InP substrate without any buffer layer. The nanowires have a polytype modulated crystal structure of wurtzite and zinc blende. The electrical data display excellent rectifying behavior with an ideality factor of about 2.5 at 300 K. The ideality factor scales with 1/T, which possibly reflects deviations from classical transport models due to the mixed crystal phase of the nanowires. The observed dark leakage current is of the order of merely ∼100 fA/nanowire at 1 V reverse bias. The detectors display a linear increase of the photocurrent with reverse bias up to about 10 pA/nanowire at 5 V. From spectrally resolved measurements, we conclude that the photocurrent is primarily generated by funneling photogenerated carriers from the substrate into the NWs. Contributions from direct excitation of the NWs become increasingly important at low temperatures. The photocurrent decreases with temperature with an activation energy of about 50 meV, which we discuss in terms of a temperature-dependent diffusion length in the substrate and perturbed transport through the mixed-phase nanowires.
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Affiliation(s)
- Håkan Pettersson
- Laboratory of Mathematics, Physics and Electrical Engineering, Halmstad University, Box 823, SE-30118 Halmstad, Sweden.
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24
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Mitsui C, Tsuji H, Sato Y, Nakamura E. Carbazolyl benzo[1,2-b:4,5-b']difuran: an ambipolar host material for full-color organic light-emitting diodes. Chem Asian J 2012; 7:1443-50. [PMID: 22461435 DOI: 10.1002/asia.201200062] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 02/27/2012] [Indexed: 11/10/2022]
Abstract
We have designed an ambipolar material, 3,7-bis[4-(N-carbazolyl)-phenyl]-2,6-diphenylbenzo[1,2-b:4,5-b']difuran (CZBDF), and synthesized it by zinc-mediated double cyclization. Its physical properties clarified that CZBDF possesses a wide-gap character, well-balanced and high hole and electron mobilities of larger than 10(-3) cm(2) V(-1) s(-1), and a high thermal stability. Using CZBDF as a host material for heterojunction OLED devices, a full range of visible emission was obtained. Notably, CZBDF also enabled us to fabricate RGB-emitting homojunction OLEDs, with performances comparable or superior to the heterojunction devices composed of several materials.
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Affiliation(s)
- Chikahiko Mitsui
- Department of Chemistry, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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25
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Guo S, Kim SB, Mohapatra SK, Qi Y, Sajoto T, Kahn A, Marder SR, Barlow S. n-Doping of organic electronic materials using air-stable organometallics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2012; 24:699-703. [PMID: 22057596 DOI: 10.1002/adma.201103238] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 10/04/2011] [Indexed: 05/16/2023]
Abstract
Air-stable dimers of sandwich compounds including rhodocene and (pentamethylcyclopentadienyl)(arene)ruthenium and iron derivatives can be used for n-doping electron-transport materials with electron affinities as small as 2.8 eV. A p-i-n homojunction diode based on copper phthalocyanine and using rhodocene dimer as n-dopant shows a rectification ratio of greater than 10(6) at 4 V.
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Affiliation(s)
- Song Guo
- School of Chemistry and Biochemistry and Center for Organic, Photonics and Electronics, Georgia Institute of Technology, Atlanta, GA 30332-0400, USA
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26
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Salzmann I, Heimel G, Duhm S, Oehzelt M, Pingel P, George BM, Schnegg A, Lips K, Blum RP, Vollmer A, Koch N. Intermolecular hybridization governs molecular electrical doping. PHYSICAL REVIEW LETTERS 2012; 108:035502. [PMID: 22400758 DOI: 10.1103/physrevlett.108.035502] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2011] [Indexed: 05/31/2023]
Abstract
Current models for molecular electrical doping of organic semiconductors are found to be at odds with other well-established concepts in that field, like polaron formation. Addressing these inconsistencies for prototypical systems, we present experimental and theoretical evidence for intermolecular hybridization of organic semiconductor and dopant frontier molecular orbitals. Common doping-related observations are attributed to this phenomenon, and controlling the degree of hybridization emerges as a strategy for overcoming the present limitations in the yield of doping-induced charge carriers.
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Affiliation(s)
- Ingo Salzmann
- Humboldt-Universität zu Berlin, Institut für Physik, D-12489 Berlin, Germany.
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27
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Huang L, Liu C, Qiao X, Tian H, Geng Y, Yan D. Tunable field-effect mobility utilizing mixed crystals of organic molecules. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2011; 23:3455-3459. [PMID: 21721054 DOI: 10.1002/adma.201101353] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 05/20/2011] [Indexed: 05/31/2023]
Affiliation(s)
- Lizhen Huang
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, PR China
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28
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Wetzelaer GAH, Koster LJA, Blom PWM. Validity of the Einstein relation in disordered organic semiconductors. PHYSICAL REVIEW LETTERS 2011; 107:066605. [PMID: 21902354 DOI: 10.1103/physrevlett.107.066605] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Indexed: 05/31/2023]
Abstract
It is controversial whether energetic disorder in semiconductors is already sufficient to violate the classical Einstein relation, even in the case of thermal equilibrium. We demonstrate that the Einstein relation is violated only under nonequilibrium conditions due to deeply trapped carriers, as in diffusion-driven current measurements on organic single-carrier diodes. Removal of these deeply trapped carriers by recombination unambiguously proves the validity of the Einstein relation in disordered semiconductors in thermal (quasi)equilibrium.
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Affiliation(s)
- G A H Wetzelaer
- Molecular Electronics, Zernike Institute for Advanced Materials, University of Groningen, The Netherlands
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29
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Olthof S, Kleemann H, Lüssem B, Leo K. Built-in Potential of a Pentacene Pin Homojunction Studied by Ultraviolet Photoemission Spectroscopy. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-1270-ii09-49] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractIn this paper we investigate the energetic alignment in an organic p-i-n homojunction using ultraviolet photoelectron spectroscopy. The device is made of pentacene and we emploay the small molecules NDN1 for n-doping and NDP2 for p-doping the layers. The full p-i-n structure is deposited stepwise on a silver substrate to learn about the interface dipoles and band bending effects present in the device. From the change in work function between the p- and n-doped layers we gain knowledge of the built-in potential of this junction.
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30
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Hu Y, Gao J. Direct Imaging and Probing of the p−n Junction in a Planar Polymer Light-Emitting Electrochemical Cell. J Am Chem Soc 2011; 133:2227-31. [DOI: 10.1021/ja1093106] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yufeng Hu
- Department of Physics, Engineering Physics, and Astronomy, Queen’s University, Kingston, Ontario K7L 3N6, Canada
| | - Jun Gao
- Department of Physics, Engineering Physics, and Astronomy, Queen’s University, Kingston, Ontario K7L 3N6, Canada
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31
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Kleemann H, Gutierrez R, Lindner F, Avdoshenko S, Manrique PD, Lüssem B, Cuniberti G, Leo K. Organic Zener diodes: tunneling across the gap in organic semiconductor materials. NANO LETTERS 2010; 10:4929-4934. [PMID: 21033756 DOI: 10.1021/nl102916n] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Organic Zener diodes with a precisely adjustable reverse breakdown from -3 to -15 V without any influence on the forward current-voltage curve are realized. This is accomplished by controlling the width of the charge depletion zone in a pin-diode with an accuracy of one nanometer independently of the doping concentration and the thickness of the intrinsic layer. The breakdown effect with its exponential current voltage behavior and a weak temperature dependence is explained by a tunneling mechanism across the highest occupied molecular orbital-lowest unoccupied molecular orbital gap of neighboring molecules. The experimental data are confirmed by a minimal Hamiltonian model approach, including coherent tunneling and incoherent hopping processes as possible charge transport pathways through the effective device region.
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Özdemir Ş, Balan A, Baran D, Doğan Ö, Toppare L. A ferrocene functionalized multichromic p and n dopable donor–acceptor–donor type conjugated polymer. J Electroanal Chem (Lausanne) 2010. [DOI: 10.1016/j.jelechem.2010.07.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Hains AW, Liang Z, Woodhouse MA, Gregg BA. Molecular Semiconductors in Organic Photovoltaic Cells. Chem Rev 2010; 110:6689-735. [PMID: 20184362 DOI: 10.1021/cr9002984] [Citation(s) in RCA: 789] [Impact Index Per Article: 56.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Alexander W. Hains
- National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
| | - Ziqi Liang
- National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
| | - Michael A. Woodhouse
- National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
| | - Brian A. Gregg
- National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401
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Abstract
The operation of organic diodes in solar cells and light-emitting displays strongly depends on the properties of the interfaces between hole- and electron-carrying organic semiconductors. Such interfaces are difficult to characterize, as they are usually buried under the surface or exist as an irregular "bulk heterojunction." Using a unique fluorinated barrier layer-based lithographic technique, we fabricated a lateral organic p-n junction, allowing the first observation of the potential at an organic p-n interface simultaneously with the charge transport measurements. We find that the diode characteristics of the device (current output and rectification ratio) are consistent with the changes in the surface potentials near the junction, and the current-voltage curves and junction potentials are strongly and self-consistently modulated by a third, gate electrode. The generality of our technique makes this an attractive method to investigate the physics of organic semiconductor junctions. The lithographic technique is applicable to a wide variety of soft material patterns. The observation of built-in potentials makes an important connection between organic junctions and textbook descriptions of inorganic devices. Finally, these kinds of potentials may prove to be controlling factors in charge separation efficiency in organic photovoltaics.
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35
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Balan A, Baran D, Gunbas G, Durmus A, Ozyurt F, Toppare L. One polymer for all: benzotriazole containing donor–acceptor type polymer as a multi-purpose material. Chem Commun (Camb) 2009:6768-70. [DOI: 10.1039/b912482a] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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36
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Lu J, Loh KP. High resolution electron energy loss spectroscopy study of Zinc phthalocyanine and tetrafluoro tetracyanoquinodimethane on Au (111). Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2008.11.076] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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37
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Ling QD, Liaw DJ, Zhu C, Chan DSH, Kang ET, Neoh KG. Polymer electronic memories: Materials, devices and mechanisms. Prog Polym Sci 2008. [DOI: 10.1016/j.progpolymsci.2008.08.001] [Citation(s) in RCA: 864] [Impact Index Per Article: 54.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Observation of a temperature-dependent transition of a copper-phthalocyanine thin film adsorbed on HOPG. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2007.11.072] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Muzikante I, Parra V, Dobulans R, Fonavs E, Latvels J, Bouvet M. A Novel Gas Sensor Transducer Based on Phthalocyanine Heterojunction Devices. SENSORS 2007; 7:2984-2996. [PMID: 28903274 PMCID: PMC3965227 DOI: 10.3390/s7112984] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Accepted: 11/23/2007] [Indexed: 11/23/2022]
Abstract
Experimental data concerning the changes in the current-voltage (I-V) performances of a molecular material-based heterojunction consisting of hexadecafluorinated nickel phthalocyanine (Ni(F16Pc)) and nickel phthalocyanine (NiPc), (Au|Ni(F16Pc)|NiPc|Al) are introduced as an unprecedented principle of transduction for gas sensing performances. The respective n- and p-type doped-insulator behaviors of the respective materials are supported, owing to the observed changes in surface potential (using the Kelvin probe method) after submission to electron donor (ammonia) and electron acceptor gases (ozone). On the other hand, the bilayer device exhibits strong variations in the built-in potential of the junction and in its rectification ratio. Moreover, large increases occur in forward and reverse currents in presence of ammonia vapors. These make possible a multimodal principle of detection controlled by a combined effect between the heterojunction and the NiPc|Al contact. Indeed, this metal/organic junction plays a critical role regarding the steady asymmetry of the I-V profiles during the device's doping even using high ammonia concentrations. This approach offers a more sophisticated alternative to the classically studied, but at times rather operation-limited, resistive gas sensors.
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Affiliation(s)
- Inta Muzikante
- Laboratory of Organic Materials, Institute of Solid State Physics. University of Latvia, Riga (Latvia).
| | - Vicente Parra
- Ecole Supérieure de Physique et Chimie Industrielles (ESPCI) and Laboratoire de Chimie Inorganique et Matériaux Moléculaires-CNRS UMR 7071. Université Pierre et Marie Curie-Paris 6, Paris (France)
| | - Rorijs Dobulans
- Laboratory of Organic Materials, Institute of Solid State Physics. University of Latvia, Riga (Latvia)
| | - Egils Fonavs
- Laboratory of Organic Materials, Institute of Solid State Physics. University of Latvia, Riga (Latvia)
| | - Janis Latvels
- Laboratory of Organic Materials, Institute of Solid State Physics. University of Latvia, Riga (Latvia)
| | - Marcel Bouvet
- Ecole Supérieure de Physique et Chimie Industrielles (ESPCI) and Laboratoire de Chimie Inorganique et Matériaux Moléculaires-CNRS UMR 7071. Université Pierre et Marie Curie-Paris 6, Paris (France).
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Chen W, Chen S, Qi DC, Gao XY, Wee ATS. Surface transfer p-type doping of epitaxial graphene. J Am Chem Soc 2007; 129:10418-22. [PMID: 17665912 DOI: 10.1021/ja071658g] [Citation(s) in RCA: 527] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Epitaxial graphene thermally grown on 6H-SiC(0001) can be p-type doped via a novel surface transfer doping scheme by modifying the surface with the electron acceptor, tetrafluoro-tetracyanoquinodimethane (F4-TCNQ). Synchrotron-based high-resolution photoemission spectroscopy reveals that electron transfer from graphene to adsorbed F4-TCNQ is responsible for the p-type doping of graphene. This novel surface transfer doping scheme by surface modification with appropriate molecular acceptors represents a simple and effective method to nondestructively dope epitaxial graphene for future nanoelectronics applications.
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Affiliation(s)
- Wei Chen
- Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore.
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Yaginuma S, Yamaguchi J, Haemori M, Itaka K, Matsumoto Y, Kondo M, Koinuma H. Continuous wave infrared laser deposition of organic thin films. ACTA ACUST UNITED AC 2007. [DOI: 10.1088/1742-6596/59/1/112] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Walzer K, Maennig B, Pfeiffer M, Leo K. Highly Efficient Organic Devices Based on Electrically Doped Transport Layers. Chem Rev 2007; 107:1233-71. [PMID: 17385929 DOI: 10.1021/cr050156n] [Citation(s) in RCA: 549] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- K Walzer
- Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden, Germany
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Porter WW, Vaid TP. Doping of an organic molecular semiconductor by substitutional cocrystallization with a molecular n-dopant. ACTA ACUST UNITED AC 2007. [DOI: 10.1039/b610806g] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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