Systematic in situ Raman microdroplet spectroelectrochemical (Raman-μSEC) characterization of copper (I) thiocyanate (CuSCN) prepared using electrodeposition from aqueous solution on various substrates (carbon-based, F-doped SnO2) is presented. CuSCN is a promising solid p-type inorganic semiconductor used in perovskite solar cells as a hole-transporting material. SEM characterization reveals that the CuSCN layers are homogenous with a thickness of ca. 550 nm. Raman spectra of dry CuSCN layers show that the SCN- ion is predominantly bonded in the thiocyanate resonant form to copper through its S-end (Cu-S-C≡N). The double-layer capacitance of the CuSCN layers ranges from 0.3 mF/cm2 on the boron-doped diamond to 0.8 mF/cm2 on a glass-like carbon. In situ Raman-μSEC shows that, independently of the substrate type, all Raman vibrations from CuSCN and the substrate completely vanish in the potential range from 0 to -0.3 V vs. Ag/AgCl, caused by the formation of a passivation layer. At positive potentials (+0.5 V vs. Ag/AgCl), the bands corresponding to the CuSCN vibrations change their intensities compared to those in the as-prepared, dry layers. The changes concern mainly the Cu-SCN form, showing the dependence of the related vibrations on the substrate type and thus on the local environment modifying the delocalization on the Cu-S bond.

J Heyrovský Institute of Physical Chemistry Czech Academy of Sciences Dolejškova 2155 3 182 23 Prague Czech Republic

Zobrazit více v PubMed

Bach U., Lupo D., Comte P., Moser J.E., Weissörtel F., Salbeck J., Spreitzer H., Gratzel M. Solid-state dye-sensitized mesoporous TiO2 solar cells with high photon-to-electron conversion efficiencies. Nat. Cell Biol. 1998;395:583–585. doi: 10.1038/26936. DOI

Kavan L. Electrochemistry and dye-sensitized solar cells. Curr. Opin. Electrochem. 2017;2:88–96. doi: 10.1016/j.coelec.2017.03.008. DOI

Zhang J., Freitag M., Hagfeldt A., Boschloo G. Solid-State Dye-Sensitized Solar Cells. Springer Science and Business Media LLC; Berlin/Heidelberg, Germany: 2017. pp. 151–185.

Kavan L. Electrochemistry and perovskite photovoltaics. Curr. Opin. Electrochem. 2018;11:122–129. doi: 10.1016/j.coelec.2018.10.003. DOI

Jena A.K., Kulkarni A., Miyasaka T. Halide Perovskite Photovoltaics: Background, Status, and Future Prospects. Chem. Rev. 2019;119:3036–3103. doi: 10.1021/acs.chemrev.8b00539. PubMed DOI

Hagen J., Schaffrath W., Otschik P., Fink R., Bacher A., Schmidt H.-W., Haarer D. Novel hybrid solar cells consisting of inorganic nanoparticles and an organic hole transport material. Synth. Met. 1997;89:215–220. doi: 10.1016/S0379-6779(97)81221-0. DOI

Sallenave X., Shasti M., Anaraki E.H., Volyniuk D., Grazulevicius J.V., Zakeeruddin S.M., Mortezaali A., Grätzel M., Hagfeldt A., Sini G. Interfacial and bulk properties of hole transporting materials in perovskite solar cells: Spiro-MeTAD versus spiro-OMeTAD. J. Mater. Chem. A. 2020;8:8527–8539. doi: 10.1039/D0TA00623H. DOI

O’Regan B., Schwartz D.T. Efficient Photo-Hole Injection from Adsorbed Cyanine Dyes into Electrodeposited Copper(I) Thiocyanate Thin Films. Chem. Mater. 1995;7:1349–1354. doi: 10.1021/cm00055a012. DOI

O’Regan B., Schwartz D.T. Large Enhancement in Photocurrent Efficiency Caused by UV Illumination of the Dye-Sensitized Heterojunction TiO2/RuLL‘NCS/CuSCN: Initiation and Potential Mechanisms. Chem. Mater. 1998;10:1501–1509. doi: 10.1021/cm9705855. DOI

Perera V.P.S., Pitigala P.K.D.D.P., Jayaweera P.V.V., Bandaranayake K.M.P., Tennakone K. Dye-Sensitized Solid-State Photovoltaic Cells Based on Dye Multilayer−Semiconductor Nanostructures. J. Phys. Chem. B. 2003;107:13758–13761. doi: 10.1021/jp0348979. DOI

Perera V., Senevirathna M., Pitigala P., Tennakone K. Doping CuSCN films for enhancement of conductivity: Application in dye-sensitized solid-state solar cells. Sol. Energy Mater. Sol. Cells. 2005;86:443–450. doi: 10.1016/j.solmat.2004.11.003. DOI

Sun L., Ichinose K., Sekiya T., Sugiura T., Yoshida T. Cathodic electrodeposition of p-CuSCN nanorod and its dye-sensitized photocathodic property. Phys. Procedia. 2011;14:12–24. doi: 10.1016/j.phpro.2011.05.005. DOI

Odobel F., Pellegrin Y., Gibson E.A., Hagfeldt A., Smeigh A.L., Hammarström L. Recent advances and future directions to optimize the performances of p-type dye-sensitized solar cells. Co-Ord. Chem. Rev. 2012;256:2414–2423. doi: 10.1016/j.ccr.2012.04.017. DOI

Premalal E., Dematage N., Kumara G., Rajapakse R., Shimomura M., Murakami K., Konno A. Preparation of structurally modified, conductivity enhanced-p-CuSCN and its application in dye-sensitized solid-state solar cells. J. Power Sources. 2012;203:288–296. doi: 10.1016/j.jpowsour.2011.12.034. DOI

Iwamoto T., Ogawa Y., Sun L., White M.S., Glowacki E.D., Scharber M.C., Sariciftci N.S., Manseki K., Sugiura T., Yoshida T. Electrochemical Self-Assembly of Nanostructured CuSCN/Rhodamine B Hybrid Thin Film and Its Dye-Sensitized Photocathodic Properties. J. Phys. Chem. C. 2014;118:16581–16590. doi: 10.1021/jp412463v. PubMed DOI PMC

Wijeyasinghe N., Regoutz A., Eisner F., Du T., Tsetseris L., Lin Y.-H., Faber H., Pattanasattayavong P., Li J., Yan F., et al. Copper(I) Thiocyanate (CuSCN) Hole-Transport Layers Processed from Aqueous Precursor Solutions and Their Application in Thin-Film Transistors and Highly Efficient Organic and Organometal Halide Perovskite Solar Cells. Adv. Funct. Mater. 2017;27:1701818. doi: 10.1002/adfm.201701818. DOI

Matebese F., Taziwa R., Mutukwa D. Progress on the Synthesis and Application of CuSCN Inorganic Hole Transport Material in Perovskite Solar Cells. Materials. 2018;11:2592. doi: 10.3390/ma11122592. PubMed DOI PMC

Yang I.S., Lee S., Choi J., Jung M.T., Kim J., Lee W.I. Enhancement of open circuit voltage for CuSCN-based perovskite solar cells by controlling the perovskite/CuSCN interface with functional molecules. J. Mater. Chem. A. 2019;7:6028–6037. doi: 10.1039/C8TA12217B. DOI

Kavan L., Zivcova Z.V., Hubik P., Arora N., Dar M.I., Zakeeruddin S.M., Grätzel M. Electrochemical Characterization of CuSCN Hole-Extracting Thin Films for Perovskite Photovoltaics. ACS Appl. Energy Mater. 2019;2:4264–4273. doi: 10.1021/acsaem.9b00496. DOI

Wijeyasinghe N., Eisner F., Tsetseris L., Lin Y.-H., Seitkhan A., Li J., Yan F., Solomeshch O., Tessler N., Patsalas P., et al. p-Doping of Copper(I) Thiocyanate (CuSCN) Hole-Transport Layers for High-Performance Transistors and Organic Solar Cells. Adv. Funct. Mater. 2018;28:1802055. doi: 10.1002/adfm.201802055. DOI

Patel M.J., Gupta S.K., Gajjar P. Electronic structure and optical properties of β-CuSCN: A DFT study. Mater. Today Proc. 2020;28:164–167. doi: 10.1016/j.matpr.2020.01.469. DOI

Pattanasattayavong P., Packwood D.M., Harding D.J. Structural versatility and electronic structures of copper(i) thiocyanate (CuSCN)–ligand complexes. J. Mater. Chem. C. 2019;7:12907–12917. doi: 10.1039/C9TC03198G. DOI

Ni Y., Jin Z., Fu Y. Electrodeposition of p-Type CuSCN Thin Films by a New Aqueous Electrolyte With Triethanolamine Chelation. J. Am. Ceram. Soc. 2007;90:2966–2973. doi: 10.1111/j.1551-2916.2007.01832.x. DOI

Arora N., Dar M.I., Hinderhofer A., Pellet N., Schreiber F., Zakeeruddin S.M., Grätzel M. Perovskite solar cells with CuSCN hole extraction layers yield stabilized efficiencies greater than 20% Science. 2017;358:768–771. doi: 10.1126/science.aam5655. PubMed DOI

Nakamoto K. Infrared and Raman Spectra of Inorganic and Coordination Compounds, Part B: Applications in Coordination, Organometallic, and Bioinorganic Chemistry. 5th ed. Wiley Interscience; New York, NY, USA: 1997. Infrared and Raman Spectra of Inorganic and Coordination Compounds, Part B: Applications in Coordination, Organometallic, and Bioinorganic Chemistry; pp. 1–273.

Aldakov D., Chappaz-Gillot C., Salazar R., Delaye V., Welsby K.A., Ivanova V., Dunstan P.R. Properties of Electrodeposited CuSCN 2D Layers and Nanowires Influenced by Their Mixed Domain Structure. J. Phys. Chem. C. 2014;118:16095–16103. doi: 10.1021/jp412499f. DOI

Yoshida T., Zhang J., Komatsu D., Sawatani S., Minoura H., Pauporté T., Lincot D., Oekermann T., Schlettwein D., Tada H., et al. Electrodeposition of Inorganic/Organic Hybrid Thin Films. Adv. Funct. Mater. 2008;19:17–43. doi: 10.1002/adfm.200700188. DOI

Zhang Q., Guo H., Feng Z., Lin L., Zhou J., Lin Z. n-ZnO nanorods/p-CuSCN heterojunction light-emitting diodes fabricated by electrochemical method. Electrochim. Acta. 2010;55:4889–4894. doi: 10.1016/j.electacta.2010.03.082. DOI

Chappaz-Gillot C., Salazar R., Berson S., Ivanova V. Room temperature template-free electrodeposition of CuSCN nanowires. Electrochem. Commun. 2012;24:1–4. doi: 10.1016/j.elecom.2012.07.030. DOI

Sanchez S., Chappaz-Gillot C., Salazar R., Muguerra H., Arbaoui E., Berson S., Lévy-Clément C., Ivanova V. Comparative study of ZnO and CuSCN semiconducting nanowire electrodeposition on different substrates. J. Solid State Electrochem. 2012;17:391–398. doi: 10.1007/s10008-012-1912-3. DOI

Sun L., Huang Y., Hossain A., Li K., Adams S., Wang Q. Fabrication of TiO2/CuSCN Bulk Heterojunctions by Profile-Controlled Electrodeposition. J. Electrochem. Soc. 2012;159:D323–D327. doi: 10.1149/2.028206jes. DOI

Chappaz-Gillot C., Salazar R., Berson S., Ivanova V. Insights into CuSCN nanowire electrodeposition on flexible substrates. Electrochim. Acta. 2013;110:375–381. doi: 10.1016/j.electacta.2013.03.124. DOI

Ramírez D., Álvarez K., Riveros G., González B., Dalchiele E.A. Electrodeposition of CuSCN seed layers and nanowires: A microelectrogravimetric approach. Electrochim. Acta. 2017;228:308–318. doi: 10.1016/j.electacta.2017.01.053. DOI

Shlenskaya N.N., Tutantsev A.S., Belich N.A., Goodilin E.A., Grätzel M., Tarasov A.B. Electrodeposition of porous CuSCN layers as hole-conducting material for perovskite solar cells. Mendeleev Commun. 2018;28:378–380. doi: 10.1016/j.mencom.2018.07.012. DOI

Chavhan S., Miguel O., Grande H.-J., Gonzalez-Pedro V., Sánchez R.S., Barea E.M., Mora-Seró I., Tena-Zaera R. Organo-metal halide perovskite-based solar cells with CuSCN as the inorganic hole selective contact. J. Mater. Chem. A. 2014;2:12754–12760. doi: 10.1039/C4TA01310G. DOI

Yang I.S., Sohn M.R., Sung S.D., Kim Y.J., Yoo Y.J., Kim J., Lee W.I. Formation of pristine CuSCN layer by spray deposition method for efficient perovskite solar cell with extended stability. Nano Energy. 2017;32:414–421. doi: 10.1016/j.nanoen.2016.12.059. DOI

Kavan L., Dunsch L. Spectroelectrochemistry of Carbon Nanostructures. ChemPhysChem. 2007;8:974–998. doi: 10.1002/cphc.200700081. PubMed DOI

Velický M., Bradley D.F., Cooper A.J., Hill E.W., Kinloch I.A., Mishchenko A., Novoselov K.S., Patten H.V., Toth P.S., Valota A.T., et al. Electron Transfer Kinetics on Mono- and Multilayer Graphene. ACS Nano. 2014;8:10089–10100. doi: 10.1021/nn504298r. PubMed DOI

Velický M., Bissett M.A., Woods C.R., Toth P.S., Georgiou T., Kinloch I.A., Novoselov K.S., Dryfe R.A.W. Photoelectrochemistry of Pristine Mono- and Few-Layer MoS2. Nano Lett. 2016;16:2023–2032. doi: 10.1021/acs.nanolett.5b05317. PubMed DOI

Velický M., Toth P.S., Woods C.R., Novoselov K.S., Dryfe R.A.W. Electrochemistry of the Basal Plane versus Edge Plane of Graphite Revisited. J. Phys. Chem. C. 2019;123:11677–11685. doi: 10.1021/acs.jpcc.9b01010. DOI

Wang Y., Alsmeyer D.C., McCreery R.L. Raman spectroscopy of carbon materials: Structural basis of observed spectra. Chem. Mater. 1990;2:557–563. doi: 10.1021/cm00011a018. DOI

Swain G.M., Ramesham R. The electrochemical activity of boron-doped polycrystalline diamond thin film electrodes. Anal. Chem. 1993;65:345–351. doi: 10.1021/ac00052a007. DOI

Pleskov Y., Mishuk V., Abaturov M., Elkin V., Krotova M., Varnin V., Teremetskaya I. Synthetic semiconductor diamond electrodes: Determination of acceptor concentration by linear and non-linear impedance measurements. J. Electroanal. Chem. 1995;396:227–232. doi: 10.1016/0022-0728(95)04018-J. DOI

McCreery R.L. Advanced Carbon Electrode Materials for Molecular Electrochemistry. Chem. Rev. 2008;108:2646–2687. doi: 10.1021/cr068076m. PubMed DOI

Zivcova Z.V., Frank O., Petrák V., Tarábková H., Vacik J., Nesládek M., Kavan L. Electrochemistry and in situ Raman spectroelectrochemistry of low and high quality boron doped diamond layers in aqueous electrolyte solution. Electrochim. Acta. 2013;87:518–525. doi: 10.1016/j.electacta.2012.09.031. DOI

MacPherson J.V. A practical guide to using boron doped diamond in electrochemical research. Phys. Chem. Chem. Phys. 2015;17:2935–2949. doi: 10.1039/C4CP04022H. PubMed DOI

Kavan L., Zivcova Z.V., Petrak V., Frank O., Janda P., Tarabkova H., Nesladek M., Mortet V. Boron-doped Diamond Electrodes: Electrochemical, Atomic Force Microscopy and Raman Study towards Corrosion-modifications at Nanoscale. Electrochim. Acta. 2015;179:626–636. doi: 10.1016/j.electacta.2015.04.124. DOI

Živcová Z.V., Frank O., Drijkoningen S., Haenen K., Mortet V., Kavan L. n-Type phosphorus-doped nanocrystalline diamond: Electrochemical and in situ Raman spectroelectrochemical study. Rsc Adv. 2016;6:51387–51393. doi: 10.1039/C6RA05217G. DOI

Zivcova Z.V., Petrák V., Frank O., Kavan L. Electrochemical impedance spectroscopy of polycrystalline boron doped diamond layers with hydrogen and oxygen terminated surface. Diam. Relat. Mater. 2015;55:70–76. doi: 10.1016/j.diamond.2015.03.002. DOI

Itoh T., McCreery R.L. In Situ Raman Spectroelectrochemistry of Electron Transfer between Glassy Carbon and a Chemisorbed Nitroazobenzene Monolayer. J. Am. Chem. Soc. 2002;124:10894–10902. doi: 10.1021/ja020398u. PubMed DOI

Kalbac M., Kavan L., Dunsch L. An in situ Raman spectroelectrochemical study of the controlled doping of semiconducting single walled carbon nanotubes in a conducting polymer matrix. Synth. Met. 2009;159:2245–2248. doi: 10.1016/j.synthmet.2009.07.059. DOI

Frank O., Dresselhaus M.S., Kalbac M. Raman Spectroscopy and in Situ Raman Spectroelectrochemistry of Isotopically Engineered Graphene Systems. Acc. Chem. Res. 2015;48:111–118. doi: 10.1021/ar500384p. PubMed DOI

Chandrasekhar R., Choy K. Electrostatic spray assisted vapour deposition of fluorine doped tin oxide. J. Cryst. Growth. 2001;231:215–221. doi: 10.1016/S0022-0248(01)01477-4. DOI

Shiell T.B., Wong S., Yang W., Tanner C.A., Haberl B., Elliman R.G., McKenzie D.R., McCulloch D.G., Bradby J.E. The composition, structure and properties of four different glassy carbons. J. Non-Cryst. Solids. 2019;522:119561. doi: 10.1016/j.jnoncrysol.2019.119561. DOI

Kawashima Y., Katagiri G. Fundamentals, overtones, and combinations in the Raman spectrum of graphite. Phys. Rev. B. 1995;52:10053–10059. doi: 10.1103/PhysRevB.52.10053. PubMed DOI

Tuinstra F., Koenig J.L. Raman Spectrum of Graphite. J. Chem. Phys. 1970;53:1126–1130. doi: 10.1063/1.1674108. DOI

Prawer S., Nemanich R.J. Raman spectroscopy of diamond and doped diamond. Philos. Trans. R. Soc. A Math. Phys. Eng. Sci. 2004;362:2537–2565. doi: 10.1098/rsta.2004.1451. PubMed DOI

Dennison J.R., Holtz M., Swain G. Raman Spectroscopy of Carbon Materials. Spectroscopy. 1996;11:38–45.

Williams A.W.S., Lightowlers E.C., Collins A.T. Impurity conduction in synthetic semiconducting diamond. J. Phys. C: Solid State Phys. 1970;3:1727–1735. doi: 10.1088/0022-3719/3/8/011. DOI

Mortet V., Taylor A., Živcová Z.V., Machon D., Frank O., Hubík P., Tremouilles D., Kavan L. Analysis of heavily boron-doped diamond Raman spectrum. Diam. Relat. Mater. 2018;88:163–166. doi: 10.1016/j.diamond.2018.07.013. DOI

Bian H., Chen H., Zhang Q., Li J., Wen X., Zhuang W., Zheng J. Cation Effects on Rotational Dynamics of Anions and Water Molecules in Alkali (Li+, Na+, K+, Cs+) Thiocyanate (SCN–) Aqueous Solutions. J. Phys. Chem. B. 2013;117:7972–7984. doi: 10.1021/jp4016646. PubMed DOI

Son Y., de Tacconi N.R., Rajeshwar K. Photoelectrochemistry and Raman spectroelectrochemistry of cuprous thiocyanate films on copper electrodes in acidic media. J. Electroanal. Chem. 1993;345:135–146. doi: 10.1016/0022-0728(93)80474-V. DOI

Laser D., Bard A.J. Semiconductor electrodes. IV. Electrochemical behavior of n- and p-type silicon electrodes in acetonitrile solutions. J. Phys. Chem. 1976;80:459–466. doi: 10.1021/j100546a008. DOI

Zou Y., Walton A.S., Kinloch I.A., Dryfe R.A.W. Investigation of the Differential Capacitance of Highly Ordered Pyrolytic Graphite as a Model Material of Graphene. Langmuir. 2016;32:11448–11455. doi: 10.1021/acs.langmuir.6b02910. PubMed DOI

Van Duyne R.P., Haushalter J.P. Resonance Raman spectroelectrochemistry of semiconductor electrodes: The photooxidation of tetrathiafulvalene at n-gallium arsenide(100) in acetonitrile. J. Phys. Chem. 1984;88:2446–2451. doi: 10.1021/j150656a006. DOI

Hao H., Xie Q., Ai J., Wang Y., Bian H. Specific counter-cation effect on the molecular orientation of thiocyanate anions at the aqueous solution interface. Phys. Chem. Chem. Phys. 2020;22:10106–10115. doi: 10.1039/D0CP00974A. PubMed DOI

Gans P., Gill J.B., Griffin M. Spectrochemistry of solutions. Part 5.—Raman spectroscopic study of the coordination of silver(I) ions in liquid ammonia by thiocyanate ions. J. Chem. Soc. Faraday Trans. 1 Phys. Chem. Condens. Phases. 1978;74:432–439. doi: 10.1039/f19787400432. DOI