摘要
近年来,有机-无机范德瓦尔斯异质结由于其低成本加工和高性能而在光电应用领域引起了极大的关注.无机的二维材料具有光暗电导比高、载流子迁移率高、稳定性高以及使用寿命长等优点,但是其吸收带窄、可选材料较少、生产成本高;而有机材料具有低成本、透明、柔性、重量轻和易加工等优点,但其介电常数低、载流子迁移率低.如果通过合理的界面设计将二者相结合,扬长避短,有望获得更加优良的光电性能.目前国际上已有多个研究组在这个领域进行了探索性的研究,主要集中在材料的探索和器件功能性的开发,但是其背后的物理原理还不清晰.而微观机理的研究离不开先进的表征技术和测量方法的发展,因此本文旨在总结目前该领域研究进展的基础上,重点介绍有机-无机范德瓦尔斯异质结界面光电子学的表征方法,主要集中在以下3个方面:界面处材料的结构与分子表征、电子结构与局域态表征和微观动力学过程.此外,还针对该领域存在的问题提出了潜在的表征手段,进一步讨论了该领域可能的发展方向.
The tragedy of creating inorganic van der Waals heterostructure has inspired worldwide efforts to integrate various organic materials and distinct inorganic two dimensional(2D) materials to construct organic-inorganic van der walls heterostructures, which hold the great potentials for future flexible electronic and optoelectronic applications. Inorganic 2D materials, e.g., graphene and transition metal dichalcogenides(TMDs), have been extensively investigated for next-generation flexible nanoelectronics, nanophotonics and optoelectronics applications. These materials are benefit in exceptional electronic, optical and optoelectronic properties, such as high tunable optical bandgaps, high carrier mobility, direct-indirect bandgap crossover, and strong spin-orbit coupling etc., but limited in narrow absorption band, high cost and relatively difficult fabrication of high-quality single-crystals. In contrast, organic materials have many advantages, such as low cost, transparency, flexibility, light weight and easy processing, which makes them great candidates for large-area displays, solid-state lighting, sensor and organic solar cell, however, they are shorted in low dielectric constant, low carrier mobility and poor thermo-stability. By marrying the fields of organics and 2D materials, it's easy to expect outstanding optoelectronic properties that are not present in either material alone. Recently, tremendous efforts have been made to explore the possible combination of organic materials and inorganic 2D materials to create optoelectronic flexible devices of organic-inorganic van der Waals heterostructures with better properties and even new functionalities that are not accessible to us in other heterostructures. Over the past few years, many research groups all over the world have shown substantial progress and excellent results have been generated from such organic-2D material heterostructures. Among them, finding the possible combination of organics and 2D materials, investigating the properties of such heterostructures, and testing the functionality of the corresponding devices are the main targets currently in this field. The optimization of such devices with excellent performance is strongly relied on a fundamental understanding of the organic-2D material interface. For instance, the band alignment at the interface of organic and 2D TMD directly determine the basic physical properties of heterostructures. However, the interfacial features of such heterostructures, e.g., interfacial charge transfer, surface screening effect, molecular doping and so on, are barely known. It's therefore vital to study the underlying physical mechanism. Here, we review the latest progress of this field first:(1) The fabrication of the organic-2D material heterostructures and the devices;(2) the performances of such devices. Substantially, the characterization methods and the related techniques are fully reviewed and discussed based on the specific demands of organic-2D material heterostructures. Three parts were included:(1) The characterization of interfacial material structure and molecular conformation;(2) interfacial electronic structure and defects;(3) carrier dynamics. The progress in this field including the utilization of several key techniques including transmission electron microscopy, scanning probe microscopy and transient absorption spectroscopy et al., are comprehensively reviewed, and the potential characterization and measurement methods are discussed in detail. Besides, the main challenges of such heterostructures in future flexible electronic and optoelectronic applications are discussed as well. We believe this review will therefore shed light on the booming the development of this field by guiding the selection of the proper materials, the creation of the desired organic-2D material heterostructures and the optimization of the devices.
引文
1 Kroem H.Quasi-electric fields and band offsets:Teaching electrons new tricks.Int J Modern Phys B,2002,16:677-697
2 Huang Y L,Zheng Y J,Song Z,et al.The organic-2D transition metal dichalcogenide heterointerface.Chem Soc Rev,2018,47:3241-3264
3 Gobbi M,Orgiu E,Samori P.When 2D materials meet molecules:Opportunities and challenges of hybrid organic/inorganic van der Waals heterostructures.Adv Mater,2018,30:1706103
4 Zhang Z,Chen P,Duan X,et al.Robust epitaxial growth of two-dimensional heterostructures,multiheterostructures and superlattices.Science,2017,357:788-792
5 Homan S,Sangwan V K,Balla I,et al.Ultrafast exciton dissociation and long-lived charge separation in a photovoltaic pentacene-MoS2van der Waals heterojunction.Nano Lett,2017,17:164-169
6 Jariwala D,Howell S L,Chen K S,et al.Hybrid,gate-tunable,van der Waals p-n heterojunctions from pentacene and MoS2.Nano Lett,2016,16:497-503
7 Gan L Y,Zhang Q,Cheng Y,et al.Photovoltaic heterojunctions of fullerenes with MoS2 and WS2 monolayers.J Phys Chem Lett,2014,5:1445-1449
8 Vélez S,Ciudad D,Island J,et al.Gate-tunable diode and photovoltaic effect in an organic-2D layered material p-n junction.Nanoscale,2015,7:15442-15449
9 Chen R,Lin C,Yu H,et al.Templating C60 on MoS2 nanosheets for 2D hybrid van der Waals p-n nanoheterojunctions.Chem Mater,2016,28:4300-4306
10 Dong J,Liu F,Wang F,et al.Configuration-dependent anti-ambipolar van der Waals p-n heterostructures based on pentacene single crystal and MoS2.Nanoscale,2017,9:7519-7525
11 Kim J K,Cho K,Kim T Y,et al.Trap-mediated electronic transport properties of gate-tunable pentacene/MoS2 p-n heterojunction diodes.Sci Rep,2016,6:36775
12 Li H M,Lee D,Qu D,et al.Ultimate thin vertical p-n junction composed of two-dimensional layered molybdenum disulfide.Nat Commun,2015,6:6564
13 Liu F,Chow W L,He X,et al.Van der Waals p-n junction based on an organic-inorganic heterostructure.Adv Funct Mater,2015,25:5865-5871
14 Presolski S,Wang L,Loo A H,et al.Functional nanosheet synthons by covalent modification of transition-metal dichalcogenides.Chem Mater,2017,29:2066-2073
15 Kim J S,Yoo H W,Choi H O,et al.Tunable volatile organic compounds sensor by using thiolated ligand conjugation on MoS2.Nano Lett,2014,14:5941-5947
16 Li B L,Luo H Q,Lei J L,et al.Hemin-functionalized MoS2 nanosheets:Enhanced peroxidase-like catalytic activity with a steady state in aqueous solution.RSC Adv,2014,4:24256
17 Liu X,Gu J,Ding K,et al.Photoresponse of an organic semiconductor/two-dimensional transition metal dichalcogenide heterojunction.Nano Lett,2017,17:3176-3181
18 Zhu T,Yuan L,Zhao Y,et al.Highly mobile charge-transfer excitons in two-dimensional WS2/tetracene heterostructures.Sci Adv,2018,4:3104
19 Kafle T R,Kattel B,Lane S D,et al.Charge transfer exciton and spin flipping at organic-transition-metal dichalcogenide interfaces.ACSNano,2017,11:10184-10192
20 Chen W,Qi D,Gao X,et al.Surface transfer doping of semiconductors.Prog Surface Sci,2009,84:279-321
21 He T,Ding H J,Naama P,et al.Silicon/molecule interfacial electronic modifications.J Am Chem Soc,2008,130:699-710
22 Zhong C,Sangwan V K,Wang C,et al.Mechanisms of ultrafast charge separation in a PTB7/monolayer MoS2 van der Waals heterojunction.J Phys Chem Lett,2018,9:2484-2491
23 Huang Y,Zhuge F,Hou J,et al.Van der Waals coupled organic molecules with monolayer MoS2 for fast response photodetectors with gate-tunable responsivity.ACS Nano,2018,12:4062-4073
24 Park J H,Sanne A,Guo Y,et al.Defect passivation of transition metal dichalcogenides via a charge transfer van der Waals interface.Sci Adv,2017,3:1701661
25 Huang Y M,Zheng W,Qiu Y F,et al.The effects of organic molecules with different structures and absorption bandwidth on modulating photoresponse of MoS2 photodetector.ACS Appl Mater Interfaces,2016,8:23362-23370
26 Mouri S,Miyauchi Y,Matsuda K.Tunable photoluminescence of monolayer MoS2 via chemical doping.Nano Lett,2013,13:5944-5948
27 Peimyoo N,Yang W,Shang J,et al.Chemically driven tunable light emission of charged and neutral excitons in monolayer WS2.ACSNano,2014,8:11320
28 Amani M,Lien D H,Kiriya D,et al.Near-unity photoluminescence quantum yield in MoS2.Science,2015,350:1065
29 Shi W,Song S,Zhang H.Hydrothermal synthetic strategies of inorganic semiconducting nanostructures.Chem Soc Rev,2013,42:5714-5743
30 Tian T,Shih C J.Molecular epitaxy on two-dimensional materials:The interplay between interactions.Ind Eng Chem Res,2017,56:10552-10581
31 Li X,Lin M W,Lin J,et al.Two-dimensional GaSe/MoSe2 misfit bilayer heterojunctions by van der Waals epitaxy.Sci Adv,2016,2:1501882
32 Duan X,Wang C,Shaw J C,et al.Lateral epitaxial growth of two-dimensional layered semiconductor heterojunctions.Nat Nanotechnol,2014,9:1024-1030
33 Li M Y,Shi Y,Cheng C C,et al.Epitaxial growth of a monolayer WSe2-MoS2 lateral p-n junction with an atomically sharp interface.Science,2015,349:524
34 Park C J,Seo C,Kim J,et al.Variation of photoluminescence of organic semiconducting-rubrene microplate depending on the thicknesses of two-dimensional MoS2 layers.Syn Metals,2016,220:8-13
35 Hara M,Sasabe H,Yamada A,et al.Epitaxial growth of organic thin films by organic molecular beam epitaxy.Jpn J Appl Phys,1989,28:306-308
36 Lee C H,Schiros T,Santos E J,et al.Epitaxial growth of molecular crystals on van der Waals substrates for high-performance organic electronics.Adv Mater,2014,26:2812-2817
37 Nakayama Y,Mizuno Y,Hosokai T,et al.Epitaxial growth of an organic p-n heterojunction:C60 on single-crystal pentacene.ACS Appl Mater Interfaces,2016,8:13499-13505
38 Yu Z,Pan Y,Shen Y,et al.Towards intrinsic charge transport in monolayer molybdenum disulfide by defect and interface engineering.Nat Commun,2014,5:5290
39 Wan C,Kodama Y,Kondo M,et al.Dielectric mismatch mediates carrier mobility in organic-intercalated layered TiS2.Nano Lett,2015,15:6302-6308
40 Choi J,Zhang H,Choi J H.Modulating optoelectronic properties of two-dimensional transition metal dichalcogenide semiconductors by photoinduced charge transfer.ACS Nano,2016,10:1671-1680
41 Shastry T A,Balla I,Bergeron H,et al.Mutual photoluminescence quenching and photovoltaic effect in large-area single-layer MoS2-polymer heterojunctions.ACS Nano,2016,10:10573-10579
42 Petoukhoff C E,Krishna M B,Voiry D,et al.Ultrafast charge transfer and enhanced absorption in MoS2-organic van der Waals heterojunctions using plasmonic metasurfaces.ACS Nano,2016,10:9899-9908
43 Grote J G,Sarma K R,Kajzar F,et al.Biopolymer-based gate dielectric for organic field effect transistors.Opt Mater Defence Sys Technol V,2008,7118:71180L
44 Chen H Y,Nikolka M,Wadsworth A,et al.A thieno[2,3-b]pyridine-flanked diketopyrrolopyrrole polymer as an n-type polymer semiconductor for all-polymer solar cells and organic field-effect transistors.Macromolecules,2017,51:71-79
45 Cho E H,Song W G,Park C J,et al.Enhancement of photoresponsive electrical characteristics of multilayer MoS2 transistors using rubrene patches.Nano Res,2015,8:790-800
46 Yu W J,Vu Q A,Oh H,et al.Unusually efficient photocurrent extraction in monolayer van der Waals heterostructure by tunnelling through discretized barriers.Nat Commun,2016,7:13278
47 Ren Q,Xu Q,Xia H,et al.High performance photoresponsive field-effect transistors based on MoS2/pentacene heterojunction.Org Electron,2017,51:142-148
48 Velusamy D B,Haque M A,Parida M R,et al.2D organic-inorganic hybrid thin films for flexible UV-visible photodetectors.Adv Funct Mater,2017,27:1605554
49 Buscema M,Groenendijk D J,Steele G A,et al.Photovoltaic effect in few-layer black phosphorus p-n junctions defined by local electrostatic gating.Nat Commun,2014,5:4651
50 Taniyasu Y,Kasu M,Makimoto T.An aluminium nitride light-emitting diode with a wavelength of 210 nm.Nature,2006,441:325-328
51 Geim A K,Grigorieva I V.Van der Waals heterostructures.Nature,2013,499:419-425
52 Novoselov K S,Mishchenko A,Carvalho A,et al.2D materials and van der Waals heterostructures.Science,2016,353:9439
53 Huo N,Yang J,Huang L,et al.Tunable polarity behavior and self-driven photoswitching in p-WSe2/n-WS2 heterojunctions.Small,2015,11:5430-5438
54 Huo N,Kang J,Wei Z,et al.Novel and enhanced optoelectronic performances of multilayer MoS2-WS2 heterostructure transistors.Adv Funct Mater,2014,24:7025-7031
55 Dhananjay,Ou C W,Yang C Y,et al.Ambipolar transport behavior in In2O3/pentacene hybrid heterostructure and their complementary circuits.Appl Phys Lett,2008,93:033306
56 Liu P T,Chou Y T,Teng L F,et al.High-gain complementary inverter with InGaZnO/pentacene hybrid ambipolar thin film transistors.Appl Phys Lett,2010,97:083505
57 Kim B,Jang S,Geier M L,et al.Inkjet printed ambipolar transistors and inverters based on carbon nanotube/zinc tin oxide heterostructures.Appl Phys Lett,2014,104:062101
58 Morana M,Wegscheider M,Bonanni A,et al.Bipolar charge transport in PCPDTBT-PCBM bulk-heterojunctions for photovoltaic applications.Adv Funct Mater,2008,18:1757-1766
59 Schlupp P,Schein F L,Wenckstern H V,et al.All amorphous oxide bipolar heterojunction diodes from abundant metals.Adv Electron Mater,2015,1:1400023
60 Jariwala D,Sangwan V K,Seo J W,et al.Large-area,low-voltage,antiambipolar heterojunctions from solution-processed semiconductors.Nano Lett,2015,15:416-421
61 Cheng R,Li D,Zhou H,et al.Electroluminescence and photocurrent generation from atomically sharp WSe2/MoS2 heterojunction p-n diodes.Nano Lett,2014,14:5590-5597
62 Furchi M M,Pospischil A,Libisch F,et al.Photovoltaic effect in an electrically tunable van der Waals heterojunction.Nano Lett,2014,14:4785-4791
63 Deng Y,Luo Z,Conrad N J,et al.Black phosphorus-monolayer MoS2 van der Waals heterojunction p-n diode.ACS Nano,2014,8:8292
64 Zhang W,Huang J K,Chen C H,et al.High-gain phototransistors based on a CVD MoS2 monolayer.Adv Mater,2013,25:3456-3461
65 Lopez S O,Lembke D,Kayci M,et al.Ultrasensitive photodetectors based on monolayer MoS2.Nat Nanotechnol,2013,8:497-501
66 Jariwala D,Sangwan V K,Wu C C,et al.Gate-tunable carbon nanotube-MoS2 heterojunction p-n diode.Proc Natl Acad Sci USA,2013,110:18076-18080
67 Wang Q H,Kalantar Z K,Kis A,et al.Electronics and optoelectronics of two-dimensional transition metal dichalcogenides.Nat Nanotechnol,2012,7:699-712
68 Mak K F,Lee C,Hone J,et al.Atomically thin MoS2:A new direct-gap semiconductor.Phys Rev Lett,2010,105:136805
69 Zhao W,Ghorannevis Z,Chu L,et al.Evolution of electronic structure in atomically thin sheets of WS2 and WSe2.ACS Nano,2013,7:791-797
70 Peimyoo N,Shang J,Cong C,et al.Nonblinking,intense two-dimensional light emitter:Monolayer WS2 triangles.ACS Nano,2013,7:10985-10994
71 Wu J,Xu H,Zhang J.Raman spectroscopy of graphene.Acta Chim Sin,2014,72:301
72 Huang M,Yan H,Heinz T F,et al.Probing strain-induced electronic structure change in graphene by Raman spectroscopy.Nano Lett,2010,10:4074-4079
73 Aleithan S H,Livshits M Y,Khadka S,et al.Broadband femtosecond transient absorption spectroscopy for a CVD MoS2 monolayer.Phys Rev B,2016,94:035445
74 Boughton A P,Yang P,Tesmer V M,et al.Heterotrimeric G proteinβ1γ2 subunits change orientation upon complex formation with Gprotein-coupled receptor kinase 2(GRK2)on a model membrane.Proc Natl Acad Sci USA,2011,108:667-673
75 Amenabar I,Poly S,Nuansing W,et al.Structural analysis and mapping of individual protein complexes by infrared nanospectroscopy.Nat Commun,2013,4:2890
76 Centrone A.Infrared imaging and spectroscopy beyond the diffraction limit.Annu Rev Anal Chem,2015,8:101-126
77 Lu F,Jin M,Belkin M.A tip-enhanced infrared nanospectroscopy via molecular expansion force detection.Nat Photon,2014,8:307-312
78 Dazzi A,Prater C B.AFM-IR:Technology and applications in nanoscale infrared spectroscopy and chemical imaging.Chem Rev,2016,117:5146-5173
79 Rajapaksa I,Uenal K,Wickramasinghe H K.Image force microscopy of molecular resonance:A microscope principle.Appl Phys Lett,2010,97:073121
80 Wang L,Xu X G.Scattering-type scanning near-field optical microscopy with reconstruction of vertical interaction.Nat Commun,2015,6:8973
81 Dong R,Fang Y,Chae J,et al.High-gain and low-driving-voltage photodetectors based on organolead triiodide perovskites.Adv Mater,2015,27:1912-1918
82 Strelcov E,Dong Q,Li T,et al.CH3NH3PbI3 perovskites:Ferroelasticity revealed.Sci Adv,2017,3:1602165
83 Tang F,Bao P,Su Z.Analysis of nanodomain composition in high-impact polypropylene by atomic force microscopy-infrared.Anal Chem,2016,88:4926-4930
84 Zhang X,Han X,Wu F,et al.Nano-bio interfaces probed by advanced optical spectroscopy:From model system studies to optical biosensors.Chin Sci Bull,2013,58:2537-2556
85 Yang F,Zhang X,Song L,et al.Controlled drug release and hydrolysis mechanism of polymer-magnetic nanoparticle composite.ACSAppl Mater Interfaces,2015,7:9410-9419
86 Zhang X,Myers J N,Bielefeld J D,et al.In situ observation of water behavior at the surface and buried interface of a low-k dielectric film.ACS Appl Mater Interfaces,2014,6:18951-18961
87 Palermo V,Palma M,SamorìP.Electronic characterization of organic thin films by Kelvin probe force microscopy.Adv Mater,2006,18:145-164
88 Yamaguchi S,Tahara T.Development of electronic sum frequency generation spectroscopies and their application to liquid interfaces.JPhys Chem C,2015,119:14815-14828
89 Deotare P B,Chang W,Hontz E,et al.Nanoscale transport of charge-transfer states in organic donor-acceptor blends.Nat Mater,2015,14:1130-1134
90 Cunningham P D,Mccreary K M,Hanbicki A T,et al.Charge trapping and exciton dynamics in large-area CVD grown MoS2.J Phys Chem C,2016,120:5819-5826
91 Wang H,Zhang C,Rana F.Ultrafast dynamics of defect-assisted electron-hole recombination in monolayer MoS2.Nano Lett,2015,15:339-345
92 Shi H,Yan R,Bertolazzi S,et al.Exciton dynamics in suspended monolayer and few-layer MoS2 2D crystals.ACS Nano,2013,7:1072-1080
93 Palummo M,Bernardi M,Grossman J C.Exciton radiative lifetimes in two-dimensional transition metal dichalcogenides.Nano Lett,2015,15:2794-2800
94 Salehzadeh O,Tran N H,Liu X,et al.Exciton kinetics,quantum efficiency,and efficiency droop of monolayer MoS2 light-emitting devices.Nano Lett,2014,14:4125-4130
95 Hong X,Kim J,Shi S F,et al.Ultrafast charge transfer in atomically thin MoS2/WS2 heterostructures.Nat Nanotechnol,2014,9:682-686
96 Ceballos F,Bellus M Z,Chiu H Y,et al.Ultrafast charge separation and indirect exciton formation in a MoS2-MoSe2 van der Waals heterostructure.ACS Nano,2014,8:12717-12724
97 Wang K,Huang B,Tian M,et al.Interlayer coupling in twisted WSe2/WS2 bilayer heterostructures revealed by optical spectroscopy.ACS Nano,2016,10:6612-6622
98 Ceballos F,Bellus M Z,Chiu H Y,et al.Probing charge transfer excitons in a MoSe2-WS2 van der Waals heterostructure.Nanoscale,2015,7:17523-17528
99 Rivera P,Schaibley J R,Jones A M,et al.Observation of long-lived interlayer excitons in monolayer MoSe2-WSe2 heterostructures.Nat Commun,2015,6:6242
100 Li Y,Wang J,Xiong W.Probing electronic structures of organic semiconductors at buried interfaces by electronic sum frequency generation spectroscopy.J Phys Chem C,2015,119:28083-28089
101 Xiang B,Li Y,Pham C H,et al.Ultrafast direct electron transfer at organic semiconductor and metal interfaces.Sci Adv,2017,3:1701508