Substrate Influences on the Properties of SnS Thin Films Deposited by Chemical Spray Pyrolysis Technique for Photovoltaic Applications

The final publication is available at Springer via http://dx.doi.org/10.1007/s10853-016-0039-9.Herein, we report on tin monosulfide (SnS) thin films elaborated by the Chemical Spray Pyrolysis (CSP) technique onto various substrates as simple glass, ITO-, and Mo-coated glasses in order to study the influence of substrates on the physical and chemical properties of Sns thin films. Structural analysis revealed that all films crystallize in orthorhombic structure with (111) as the sole preferential direction without secondary phases. In addition, film prepared onto pure glass exhibits a better crystallization compared to films deposited onto coated glass substrates. Raman spectroscopy analysis confirms the results obtained by X-ray diffraction with modes corresponding well to SnS single crystal orthorhombic ones (47, 65, 94, 160, 186, and 219 cm21) without any additional parasite secondary phase like Sn2S3 or SnS2. Field emission scanning electron microscope revealed that all films have a cornflake-like particles surface morphology, and energy dispersive X-ray spectroscopy analysis showed the presence of sulfur and tin with a nearly stoichiometric ratio in films deposited onto pure glass. High surface roughness and large grains are observable in film deposited onto glass. From optical spectroscopy, it is inferred that band gap energy of SnS/glass and SnS/ITO were 1.64 and 1.82 eV, respectively.This work was supported by Ministerio de Economia y Competitividad (ENE2013-46624-C4-4-R) and Generalitat valenciana (Prometeus 2014/044).Sall, T.; Mollar García, MA.; Marí, B. (2016). Substrate Influences on the Properties of SnS Thin Films Deposited by Chemical Spray Pyrolysis Technique for Photovoltaic Applications. Journal of Materials Science. 51(16):7607-7613. https://doi.org/10.1007/s10853-016-0039-9S760776135116Reddy KTR, Prathap P, Miles RW (2010) Thin films of tin sulphide for application in photovoltaic solar cells in Photovoltaics. In: Tanaka H, Yamashita K (eds) Photovoltaics: developments, applications and impact. Nova Science, New York, pp 1–27Herzenberg R (1932) Rev Miner 4:33Juarez AS, Silver AT, Ortiz A (2005) Fabrication of SnS 2 /SnS heterojunction thin film diodes by plasma-enhanced chemical vapor deposition. Thin Solid Films 480–481:452–456Mathews NR, Anaya HBM, Cortes-Jacome MA, Angeles-Chavez C, Toledo-Antonio JA (2010) Tin sulfide thin films by pulse electrodeposition: structural, morphological, and optical properties. J Electrochem Soc 157:H337–H341Reddy NK, Ramesh K, Ganesan R, Reddy K, Gunasekhar KR, Gopal E (2006) Synthesis and characterization of co-evaporated tin sulphide thin films. Appl Phys A 83:133–138Ramakrishna Reddy KT, Koteswara Reddy N, Miles RW (2006) Photovoltaic properties of SnS based solar cells. Sol Energy Mater Sol Cells 90:3041–3046Ullah H, Marí B (2014) Numerical analysis of SnS based polycrystalline solar Cells. Superlattice Microst 72:148–155Avellaneda D, Nair MTS, Nair PK (2008) Polymorphic tin sulfide thin films of zinc blende and orthorhombic structures by chemical deposition. J Electrochem Soc 155:D517–D525Sinsermsuksakul P, Heo J, Noh W, Hock AS, Gordon RG (2011) Atomic layer deposition of tin monosulfide thin films. Adv Energ Mater 1:1116–1125Jeyaprakash BG, kumar RA, Kesavan K, Amalarani A (2010) Structural and optical characterization of spray deposited SnS thin film. J Am Sci 6:22–26Hibbert TG, Mahon MF, Molloy KC, Price LS, Parkin IP (2001) Deposition of tin sulfide thin films from novel, volatile (fluoroalkythiolato) tin (IV) precursors. J Mater Chem 11:469–473Senthilarasu S, Hahn YB, Lee SH (2007) Structural analysis of zinc phthalocyanine (ZnPc) thin films: x-ray diffraction study. J Appl Phys 102:043512Willeke G, Dasbach R, Sailer B, Bucher E (1992) Thin pyrite (FeS2) films prepared by magnetron sputtering. Thin Solid Films 213:271–276Chowdhury A, Biswas B, Majumder M, Sanyal MK, Mallik B (2012) Studies on phase transformation and molecular orientation in nanostructured zinc phthalocyanine thin films annealed at different temperatures. Thin Solid Films 520:6695–6704Deepa KG, Vijayakumar KP, Kartha CS (2012) Lattice vibrations of sequentially evaporated CuInSe2 by raman microspectrometry. Mat Sci Semicond Proc 15:120–124Nikolic PM, Lj Miljkovic P, Mihajlovic Lavrencic B (1977) Splitting and coupling of lattice modes in the layer compound SnS. J Phys C 10:L289–L292Chandrasekhar HR, Humphreys RG, Zwick U, Cardona M (1977) Infrared and raman of IV-IV compounds SnS and SnSe. Phys Rev B 15:2177–2183Revathi N, Bereznev S, Iljina J, Safonova M, Mellikov E, Volobujeva O (2013) PVD grown SnS thin films onto different substrate surfaces. J Mater Sci: Mater Electron 24:4739–4744Wang Y, Gong H, Fan BH, Hu GX (2010) Photovoltaic behavior of nanocrystalline SnS/TiO2. J Phys Chem C 114:3256–3259Tanusevski A, Poelman D (2003) Optical and photoconductive properties of SnS thin films prepared by electron beam evaporation. Sol Energy Mater Sol Cells 80:297–303Sajeesh TH, Poornima N, Kartha CS, Vijayakumar KP (2010) Unveiling the defect levels in SnS thin films for photovoltaic applications using photoluminescence technique. Phys Status Solidi A 207:1934–1939Sinsermsuksakul P, Heo J, Noh W, Hock AS, Gordon RG (2011) Atomic layer deposition of tin monosulfide thin films. Adv Energy Mater 1:116–125Bashkirov Simon A, Lazenka Vera V, Gremenok Valery F, Bente Klaus (2011) Microstructure of SnS thin films obtained by hot wall vacuum deposition method. J Adv Microsc Res 6:153–158Sall T, Marí Soucase B, Mollar M, Hartitti B, Fahoume M (2015) Chemical spray pyrolysis of B-In2S3 thin films deposited at different temperatures. J Phys Chem Solids 76:100–10

Tin-mono-sulfide (SnS) Thin Films Prepared by Chemical Spray Pyrolysis with Different [S]/[Sn] Ratios

[EN] SnS thin films were deposited by chemical spray pyrolysis using cost-effective and low-toxicity sources materials like tin (II) chloride dihydrate and thiourea as sources of tin and sulphur, respectively. We have studied the properties of sprayed SnS thin films with [S]/[Sn] ratios were varied from 1 to 4 in order to optimize these parameters. X-ray diffraction was used for analyzing the films structure, Raman Spectroscopy for assessing the films quality and structure, scanning electron microscope (SEM) for surface morphology and energy dispersive energy (EDS) for compositional element in samples, atomic force microscopy (AFM) for the topography of surfaces and optical spectroscopy for measuring transmittances and then deducing the band gap energies. All films obtained are polycrystalline with (111) as preferential direction for films with [S]/[Sn] ratio equals to one while for [S]/[Sn] ratios from 2 to 4 the main peak becomes (101) and the (111) peak decreases in intensity. Raman spectroscopy confirms the presence of only one SnS phase without any additional parasite secondary phases. SEM images revealed that films are well adhered onto glass surface with rounded grain. AFM confirms this result being films with [S]/[Sn] = 1 the roughest and also with the largest grain size. EDS results show an improvement of stoichiometry with the increase of the [S]/[Sn] ratio. From optical analysis, it is inferred that the band gap energy decreases from 1.83 to 1.77 eV when the [S]/[Sn] ratio changes from 2 to 4.This work was supported by Ministerio de Economia y Competitividad (ENE2016-77798-C4-2-R) and Generalitat valenciana (Prometeus 2014/044).Sall, T.; Mollar García, MA.; Marí, B. (2017). Tin-mono-sulfide (SnS) Thin Films Prepared by Chemical Spray Pyrolysis with Different [S]/[Sn] Ratios. Optical and Quantum Electronics. 49(11). https://doi.org/10.1007/s11082-017-1219-9S3864911Avellaneda, D., Nair, M.T.S., Nair, P.K.: Polymorphic tin sulfide thin films of zinc blende and orthorhombic structure by chemical deposition. J. Electrochem. Soc. 55, D517–D525 (2008)Brownson, J.R.S., Georges, C., Levy-Clement, C.: Synthesis of δ-SnS polymorph by electrodeposition. Chem. Mater. 18, 6397–6402 (2006)Chandrasekhar, H.R., Humphreys, R.G., Zwick, U., Cardona, M.: Infrared and Raman spectra of the IV-VI compounds SnS and SnSe. Phys. Rev. B 15, 2177–2183 (1977)Gao, C., Shen, H., Sun, L., Huang, H., Lu, L., Cai, H.: Preparation of SnS films with zinc blende structure by successive ionic layer adsorption and reaction method. Mater. Lett. 64, 2177–2179 (2010)Koteeswara Reddy, N., Ramesh, K., Ganesan, R., Reddy, K., Gunasekhar, K.R., Gopal, E.: Synthesis and characterization of co-evaporated tin sulphide thin films. J. Appl. Phys. A 83, 133–138 (2006)Loferski, J.J.: Theoretical considerations governing the choice of the optimum semiconductor for photovoltaic solar energy conversion. J. Appl. Phys. 27, 777–784 (1956)Malaquias, J., Fernandes, P.A., Salome, P.M.P., da Cunha, A.F.: Assessment of the potential of tin sulphide thin films prepared by sulphurization of precursors as cell absorbers. Thin Solid Films 519, 7416–7420 (2011)Mathews, N.R., Anaya, H.B.M., Cortes-Jacome, M.A., Angeles-Chavez, C., Toledo-Antonio, J.A.: Tin sulfide thin films by pulse electrodeposition: structural, morphological, and optical properties. J. Electrochem. Soc. 157, H337–H341 (2010)Reddy, K.T.R., Reddy, N.K., Miles, R.W.: Photovoltaic properties of SnS based solar cells. Sol. Energy Mater. Sol. Cells 9, 3041–3046 (2006)Sall, T., Mollar, M., Marí, B.: Substrates influences on the properties of SnS thin films deposited by chemical spray pyrolysis technique for photovoltaic applications. J. Mater. Sci. 51, 7607–7613 (2016)Sinsermsuksakul, P., Heo, J., Noh, W., Hock, A.S., Gordon, R.G.: Atomic layer deposition of tin monosulfide thin films. Adv. Energy Mater. 1, 1116–1125 (2011)Sivaramasubramaniam, R., Muhamad, M.R., Radhakrishna, S.: Optical properties of annealed tin (II) oxide in different ambients. Phys. Status Solidi (a) 136, 215–222 (1993)Ullah, H., Marí, B.: Numerical analysis of SnS based polycrystalline solar cells. Superlattices Microstruct. 72, 148–155 (2014

Synthesis of MAPbBr3-iYi (Y=I, Cl; i=0 ,1 ,2, 3) perovskite thin films

This is the peer reviewed version of the following article: Vega-Fleitas, Erica, Mollar García, Miguel Alfonso, Marí, B.. (2016). Synthesis of MAPbBr3-iYi (Y=I, Cl; i=0 ,1 ,2, 3) perovskite thin films .physica status solidi (c), 13, 1, 30-34. DOI: 10.1002/pssc.201510107, which has been published in final form at http://doi.org/10.1002/pssc.201510107. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] Methylammonium lead halide perovskites with different halides (iodide, bromide and chloride) have been synthetized from methylamine, lead nitrate and the corresponding hydroX acid (X = I, Br, Cl) precursors. Subsequently MAPbBr3-iYi (Y= I, Cl; i=0, 1, 2, 3) perovskites were deposited as thin films onto FTO substrates by spin coating or dipping. Thin film perovskites were then characterized by X-Ray Diffraction, elemental analysis and optical spectrometry. Crystallites sizes are between 100-600 nm depending on the synthesis temperature. All synthetized MAPbX3-iYi perovskites crystallized in the same cubic phase irrespective of the X and Y components and a unique phase is observed. Elemental analy- sis shows that in all cases the atomic components meet the expected stoichiometric formulae. The bandgap of thin film MAPbX3-iYi perovskites were inferred from transmittance and reflectance spectral measurements. It is found that the on-set of the absorption edge for thin film MAPbX3 perovskites is about 1.66, 2.55 and 3.37 eV for X= I, Br, Cl, respectively "and it reaches intermediate values for mixed MAPbX3-iYi perovskites.This work was supported by Ministerio de Economía y Competitividad (ENE2013-46624-C4-4-R)Vega-Fleitas, E.; Mollar García, MA.; Marí, B. (2016). Synthesis of MAPbBr3-iYi (Y=I, Cl; i=0 ,1 ,2, 3) perovskite thin films. physica status solidi (c). 13(1):30-34. https://doi.org/10.1002/pssc.201510107S303413

Effect of guanidinium on the optical properties and structure of the methylammonium lead halide perovskite

[EN] The stability and performance of perovskite-based solar cells can be improved by changing the nature of the organic cation. Herein, mixed methylammoniumeguanidinium perovskites (MA1-xGAxPbI3) are structurally and optically characterized. The Pawley fit method confirmed the formation of the iodide halide GAPbI3 tetragonal phase (P42_NMC). Up to 20% of the guanidinium cation was incorporated in the methylammonium lead iodide perovskite, producing a lattice enlargement, which was investigated studying the shift of the diffraction peaks of the MAPbI3 (I4_CM) tetragonal lattice. Long-term stability was tested, resulting in improved mixed perovskites with a low GA content. The bandgap shifted to lower energies. The absorption bandgap diminished slightly when the GA cation substituted up to 20% of MA in MAPbI3, degrading when the GA amount in the mixed perovskite is larger. FESEM morphological analysis was performed showing that a uniform thin film was deposited. PL studies showed that only shallow defects had been introduced.This work was supported by Ministerio de Economia y Competitividad [ENE2016-77798-C4-2-R] and Generalitat Valenciana [Prometeus 2014/044].Vega-Fleitas, E.; Mollar García, MA.; Marí, B. (2018). Effect of guanidinium on the optical properties and structure of the methylammonium lead halide perovskite. Journal of Alloys and Compounds. 739:1059-1064. https://doi.org/10.1016/j.jallcom.2017.12.177S1059106473

Experimental characterisation of the motion of an inverted pendulum

[EN] : In this paper, we present a home-made experimental set-up to study the falling movement of an inverted pendulum. The experimental set-up allows preparing a laboratory session for first year Physics or Engineering students. This set-up has been used in the Bachelor's Degree in Mechanical Engineering at the School of Design Engineering of the Universitat Politècnica de València. The experimental data are fitted to the theoretical equation of motion, obtaining a very good agreement between experiment and theory. In addition, direct measurement of the parameters involved in the equations was carried out, showing a very good agreement with the calculated parameters.Gómez Tejedor, JA.; Mollar, M.; Monsoriu Serra, JA. (2015). Experimental characterisation of the motion of an inverted pendulum. En 1ST INTERNATIONAL CONFERENCE ON HIGHER EDUCATION ADVANCES (HEAD' 15). Editorial Universitat Politècnica de València. 588-592. https://doi.org/10.4995/HEAD15.2015.331OCS58859

Luminescence Properties of CaAl2O4:Eu3+, Gd3+ Phosphors Synthesized by Combustion Synthesis Method

[EN] CaAl2O4:Eu3+ (1 mol.%) co-doped with varying concentration of Gd3+ (1, 2, 5, and 10 mol.%) were prepared by combustion synthesis method at 600 C and further annealed at 1000 ºC. All the compositions were investigated for their structural and photoluminescence properties. It was observed that both states of europium i.e. Eu3+ and Eu2+ were present and ratio of these states changes on heating at 1000 ºC. The materials synthesized at 600 ºC showed high intense peak around 440 nm due to presence of Eu2+ and less intense peaks in the red region which were due to presence of Eu3+. On annealing the compounds at 1000 ºC, intensity of peak around 440 nm decreases and intensity of peaks in the red region increases significantly. The 5D0 !7 F3 transition due to Eu3+ at 657 nm appears as the highest intensity peak. All co-doped samples annealed at 1000 ºC showed the higher intensity than the mono doped sample which is due to energy transfer from the Gd3+ to Eu3+. The second rare-earth ion (Gd3+) acts as sensitizer and enhances the photoluminescence intensity. The X-ray diffraction spectra reveal the monoclinic phase of CaAl2O4 in all the samples which showed that Eu3+ and Gd3+ do not change the crystalline structure of calcium aluminate.This work was supported by the Generalitat Valenciana through grant PROMETEUS 2009/2013 and the European Commission through Nano CIS project (FP7-PEOPLE-2010-IRSES ref. 269279).This work was supported by the Generalitat Valenciana through grant PROMETEUS 2009/2013 and the European Commission through Nano CIS project (FP7- PEOPLE-2010-IRSES ref. 269279).Verma, N.; Singh, K.; Marí, B.; Mollar García, MA.; Jindal, J. (2017). Luminescence Properties of CaAl2O4:Eu3+, Gd3+ Phosphors Synthesized by Combustion Synthesis Method. Acta Physica Polonica A. 132(4):1261-1264. https://doi.org/10.12693/APhysPolA.132.1261S12611264132

Electrochemical Fabrication and Characterization of p-CuSCN/n-Fe2O3 Heterojunction Devices for Hydrogen Production

[EN] p-CuSCN/n-Fe2O3 heterojunctions were electrochemically prepared by sequentially depositing alpha-Fe2O3 and CuSCN films on FTO (SnO2:F) substrates. Both alpha-Fe2O3 and CuSCN films and alpha-Fe2O3/CuSCN heterojunctions were characterized by field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). Pure crystalline CuSCN films were electrochemically deposited on alpha-Fe2O3 films by fixing the SCN/Cu molar ratio in an electrolytic bath to 1:1.5 at 60 degrees C, and at a potential of -0.4 V. The photocurrent measurements showed increased intrinsic surface states or defects at the alpha-Fe2O3/CuSCN interface. The photoelectrochemical performance of the alpha-Fe2O3/CuSCN heterojunction was examined by chronoamperometry and linear sweep voltammetry techniques. The alpha-Fe2O3/CuSCN structure exhibited greater photoelectrochemical activity compared to the alpha-Fe2O3 thin films. The highest photocurrent density was obtained for the alpha-Fe2O3/CuSCN films in 1 M NaOH electrolyte. This strong photoactivity was attributed to both the large active surface area and the external applied bias, which favored the transfer and separation of the photogenerated charge carriers in the alpha-Fe2O3/CuSCN heterojunction devices. The flatband potential and donor density were maximal for the heterojunction. These results suggest a substantial potential to achieve heterojunction thin films in photoelectrochemical water splitting applications. (c) 2017 The Electrochemical Society. All rights reserved.This work was supported by the Ministry of High Education and Scientific Research (Tunisia), Ministerio de Economia y Competitividad (ENE2016-77798-C4-2-R) and Generalitat Valenciana (Prometeus 2014/044).Bouhjar, F.; Ullah, S.; Mollar García, MA.; Marí, B.; Bessais, B. (2017). Electrochemical Fabrication and Characterization of p-CuSCN/n-Fe2O3 Heterojunction Devices for Hydrogen Production. Journal of The Electrochemical Society. 164(13):936-945. https://doi.org/10.1149/2.1431713jes9369451641

SnS Thin Films Prepared by Chemical Spray Pyrolysis at Different Substrate Temperatures for Photovoltaic Applications

[EN] The preparation and analysis of morphological, structural, optical, vibrational and compositional properties of tin monosulfide (SnS) thin films deposited on glass substrate by chemical spray pyrolysis is reported herein. The growth conditions were evaluated to reduce the presence of residual phases different to the SnS orthorhombic phase. X-ray diffraction spectra revealed the polycrystalline nature of the SnS films with orthorhombic structure and a preferential grain orientation along the (111) direction. At high substrate temperature (450A degrees C), a crystalline phase corresponding to the Sn2S3 phase was observed. Raman spectroscopy confirmed the dominance of the SnS phase and the presence of an additional Sn2S3 phase. Scanning electron microscopy (SEM) images reveal that the SnS film morphology depends on the substrate temperature. Between 250A degrees C and 350A degrees C, SnS films were shaped as rounded grains with some cracks between them, while at substrate temperatures above 400A degrees C, films were denser and more compact. Energy-dispersive x-ray spectroscopy (EDS) analysis showed that the stoichiometry of sprayed SnS films improved with the increase of substrate temperature and atomic force microscopy micrographs showed films well covered at 350A degrees C resulting in a rougher and bigger grain size. Optical and electrical measurements showed that the optical bandgap and the resistivity decreased when the substrate temperature increased, and smaller values, 1.46 eV and 60 Omega cm, respectively, were attained at 450A degrees C. These SnS thin films could be used as an absorber layer for the development of tandem solar cell devices due to their high absorbability in the visible region with optimum bandgap energy.This work was supported by Ministerio de Economia y Competitividad (ENE2013-46624-C4-4-R) and Generalitat valenciana (Prometeus 2014/044).Sall, T.; Marí, B.; Mollar García, MA.; Sans-Tresserras, JÁ. (2017). SnS Thin Films Prepared by Chemical Spray Pyrolysis at Different Substrate Temperatures for Photovoltaic Applications. Journal of Electronic Materials. 46(3):1714-1719. https://doi.org/10.1007/s11664-016-5215-9S17141719463N.R. Mathews, H.B.M. Anaya, M.A. Cortes-Jacome, C. Angeles-Chavez, and J.A. Toledo-Antonio, J. Electrochem. Soc. 157, H337 (2010).N. Koteeswara Reddy, K. Ramesh, R. Ganesan, K. Reddy, K.R. Gunasekhar, and E. Gopal, Appl. Phys. A 83, 133 (2006).J.J. Loferski, J. Appl. Phys. 27, 777 (1956).K.T.R. Reddy, N.K. Reddy, and R.W. Miles, Sol. Energy Mat. Sol. C 90, 3041 (2006).C. Gao, H.L. Shen, L. Sun, H.B. Huang, L.F. Lu, and H. Cai, Mater. Lett. 64, 2177 (2010).D. Avellaneda, M.T.S. Nair, and P.K. Nair, J. Electrochem. Soc. 155, D517 (2008).J.R.S. Brownson, C. Georges, and C. Levy-Clement, Chem. Mater. 19, 3080 (2007).P. Sinsermsuksakul, J. Heo, W. Noh, A.S. Hock, and R.G. Gordon, Adv. Eng. Mat 1, 1116 (2011).T. Sall, M. Mollar, and B. Marí, J. Mater. Sci. 51, 7607 (2016).K. Otto, A. Katerski, O. Volobujeva, A. Mere, and M. Krunks, Energy Proc. 3, 63 (2011).J. Malaquias, P.A. Fernandes, P.M.P. Salomé, and A.F. da Cunha, Thin Solid Films 519, 7416 (2011).T.H. Sajeesh, A.R. Warrier, C. Sudha Kartha, and K.P. Vijayakumar, Thin Solid Films 518, 4370 (2010).M. Vasudeva Reddy, G. Sreedevi, C. Park, R.W. Miles, and K.T. Ramakrishna Reddy, Curr. Appl. Phys. 15, 588 (2015).A. Molenaar, Extended Abstracts, vol. 84-2, Pennington, N.J., 634 (1984)S. López, S. Granados, and A. Ortiz, Semicond. Sci. Technol. 11, 433 (1996).B. Cullity, Elements of X-ray Diffraction (New York: Addision-Wesley Publishing Company Inc, 1967), p. 501.G. Willeke, R. Dasbach, B. Sailer, and E. Bucher, Thin Solid Films 213, 271 (1992).H.R. Chandrasekhar, R.G. Humphreys, U. Zwick, and M. Cardona, Phys. Rev. B 15, 2177 (1977).S. Cheng and G. Conibeer, Thin Solid Films 520, 837 (2011)

Influence of a Compact Fe2O3 Layer on the Photovoltaic Performance of Perovskite-Based Solar Cells

[EN] In this study, uniform and dense iron oxide ¿-Fe2O3 thin films were used as an electron-transport layer (ETL) in CH3NH3PbI3-based perovskite solar cells (PSCs), replacing the Titanium dioxide (TiO2) ETL conventionally used in planar heterojunction perovskite solar cells. The ¿-Fe2O3 films were synthesized using an electrodeposition method for the blocking layer and a hydrothermal method for the overlaying layer, while 2,2¿,7,7¿-tetrakis (N, N¿-di-p-methoxyphenylamine)-9,9¿ spirobifluorene (spiro-OMeTAD) was employed as a hole conductor in the solar cells. Based on the above synthesized ¿-Fe2O3 films the photovoltaic performance of the PSCs was studied. The ¿-Fe2O3 layers were found to have a significant impact on the photovoltaic conversion efficiency (PCE) of the PSCs. This was attributed to an efficient charge separation and transport due to a better coverage of the perovskite on the ¿-Fe2O3 films. As a result, the PCE measured under standard solar conditions (AM 1.5G, 100 mW cm¿2) reached 5.7%.This work was supported by the Ministry of High Education and Scientific Research, Tunisia and Ministerio de Economia y Competitividad (ENE2013-46624-C4-4-R) and Generalitatvalenciana (Prometeus 2014/044).Bouhjar, F.; Mollar García, MA.; Ullah, S.; Marí, B.; Bessais, B. (2018). Influence of a Compact Fe2O3 Layer on the Photovoltaic Performance of Perovskite-Based Solar Cells. Journal of The Electrochemical Society. 165(2):30-38. https://doi.org/10.1149/2.1131802jesS3038165

Hydrothermal synthesis of nanostructured Cr-doped hematite with enhanced photoelectrochemical activity

[EN] Using the easily applicable hydrothermal method Cr-doped hematite thin films have been deposited polycrystalline on conductive glass substrates. The hydrothermal bath consisted of an aqueous solution containing a mixture of FeCl3.6H(2)O and NaNO3 at pH = 1.5. The samples were introduced in an autoclave and heated for a fixed time at a fixed temperature and then annealed in air at 550 degrees C. The concentration of the incorporated Cr atoms (Cr4+ ions) was controlled by varying the concentration of the Cr(ClO4)(3) precursor solution, varied from 0% to 20%. All samples followed morphological and structural studies using field-emission scanning electron microscopy, high-resolution transmission electron microscopy and X-ray diffraction. Chronoamperometry measurements showed that Cr-doped hematite films exhibited higher photoelectrochemical activity than the undoped films. The maximum photocurrent density and incident photon conversion efficiencies (IPCE) were obtained for 16 at.% Cr-doped films. This high photoactivity can be attributed to both the large active surface area and increased donor density caused by Cr-doping in the alpha-Fe2O3 films. All samples reached their best IPCE at 400 nm. IPCE values for 16 at.% Cr-doped hematite films were thirty times higher than that of undoped samples. This high photoelectrochemical performance of Cr-doped hematite films is mainly attributed to an improvement in charge carrier properties. (C) 2017 Elsevier Ltd. All rights reserved.This work was supported by the Ministry of Higher Education and Scientific Research, Tunisia and Ministerio de Economia y Competitividad (ENE2016-77798-C4-2-R) and Generalitat Valenciana (Prometeus 2014/044).Bouhjar, F.; Mollar García, MA.; Chourou, M.; Marí, B.; Bessais, B. (2018). Hydrothermal synthesis of nanostructured Cr-doped hematite with enhanced photoelectrochemical activity. Electrochimica Acta. 260:838-846. https://doi.org/10.1016/j.electacta.2017.12.049S83884626