Very narrow In2S3 nanorods and nanowires from a single source precursor

Author’s Accepted Manuscript

Very narrow In2S3 Nanorods and Nanowires from a Single Source Precursor Ahmed Lutfi Abdelhady, Karthik Ramasamy, Mohammad A. Malik, Paul O’Brien

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S0167-577X(13)00241-3 http://dx.doi.org/10.1016/j.matlet.2013.02.061 MLBLUE14923

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Materials Letters

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8 November 2012 14 February 2013

Cite this article as: Ahmed Lutfi Abdelhady, Karthik Ramasamy, Mohammad A. Malik and Paul O’Brien, Very narrow In2S3 Nanorods and Nanowires from a Single Source Precursor, Materials Letters, http://dx.doi.org/10.1016/j.matlet.2013.02.061 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Very narrow In2S3 Nanorods and Nanowires from a Single Source Precursor Ahmed Lutfi Abdelhady,§ Karthik Ramasamy, ‡Mohammad A. Malik and Paul O’Brien* The School of Chemistry and ManchesterMaterialsCenter, The University ofManchester, Oxford Road, Manchester, UKM13 9PL.

§

Present address:

Department of Chemistry, Faculty of Science, Mansoura University, Egypt. E-mail: [email protected] ‡

Present address:

Center for Materials for Information Technology, The University of Alabama, Tuscaloosa, Al. USA. E-mail: [email protected] * Proofs to Professor Paul O’Brien School of Chemistry The University of Manchester Oxford Road, Manchester, M13 9PL Fax: 44-161 275 4598; Tel: 44-161 275 4653; E-mail: [email protected]  Abstract: Ultra-thin (< 1.0 nm) nanorods or nanowires of β-In2S3were synthesized from the thermolysis of the indium(III) complex of 1,1,5,5-tetra-iso-propyl-2-thiobiuret in hot oleylamine.

Highlights • β-In2S3 nanorods or nanowires were prepared from indium thiobiuret complex. • TEM showed that the nanorods/nanowires are very thin (< 1.0 nm). • Morphology (rods/wires) can be controlled by altering the growth temperature. Keywords: Indium sulfide, Single source precursor, Ultra-thin nanorods, nanowires.

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1. Introduction: One-dimensional (1D) nanostructures such as wires, rods and tubes are proven to be showing enhancement in electrical or thermal transport as compared to zero-dimensional nanostructures [1,2]. These structures (1D) are involved in the fabrication of electronic, optoelectronic and electrochemical devices [2]. Indium sulfide is a semiconductor which exists in different stable forms, specifically, InS, In2S3, In6S7 [3]. InS is orthorhombic and In6S7 is monoclinic, whereas, In2S3 has three different structures: a defect cubic (α-In2S3), cubic or tetragonal defect spinel (β-In2S3) and layered structure (γ-In2S3) [3-5].β-In2S3is stable at room temperature and up to 420 °C, with a high degree of vacancies ordering [5,6]. Above 420 °C the In atoms become randomly distributed as the α-In2S3 is formed and above 754 °C the trigonal layered structure γ-In2S3 becomes the stable phase [7]. The beta form has been used in green or red phosphors for colour televisions [8], as buffer layer instead of toxic CdS in CuInSe2-based solar cells [9]and as an electrode material in lithium ion batteries [10]because of its high defects and band gap (2.0-2.3 eV) [11]. Various synthetic methods have been used for the preparation of indium sulfide nanostructures including: hydrothermal [12], solvothermal [10,13], arrested precipitation [14], sonochemical [15] and thermal decomposition in hot coordinating solvent [16]. However, the synthesis of In2S3 nanowires and/or nanorods with high aspect ratio is limited. The applicability of indium sulfide nanowires and nanorods can indisputably be augmented if they can be synthesised in narrow size distribution with large surface area. Very few reports are available on the use of single source precursor for the synthesis of monodispersed indium sulfide nanostructures. Although we have previously used single source precursors for the deposition of indium sulfide thin films [17]. Examples of the single source precursor explored for the synthesis of indium sulfide nanoparticles include: [In(S2CNEt2)3] and the polymeric complex [MeIn(SCH2CH2S)]n which produced InS and In2S3, respectively [18,19] Herein we report the facile synthesis of ultra-thin (< 1.0 nm) nanorods or nanowires of β-In2S3with large surface area from the thermolysis of the single source precursor [In(SON(CNiPr2)2)3] [20] in hot oleylamine. To the best of our knowledge this work reports the thinnest indium sulfide nanorods and nanowires to date. 2. Experimental details: All preparations were performed under an inert atmosphere of dry nitrogen using standard Schlenk techniques. The complex was prepared as described in our previous report [20].A solution of di-isopropylcarbamoyl chloride (1.0 g, 6 mmol) and sodium thiocyanate (0.49 g, 6 mmol) in acetonitrile (25 mL) was

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heated to reflux with continuous stirring for 1 h, during which time a fine precipitate of sodium chloride formed. The cooled reaction mixture was added to di-iso-propylamine (1.49 mL, 12 mmol) followed by stirring for 30 min and addition of indium(III) chloride (0.45 g, 2 mmol) gave the product as white powder which was dried under vacuum for 24 h before use. The nanowires and nanorods were synthesized by thermal decomposition of the single source precursor [In(SON(CNiPr2)2)3]. Thermolysis experiments were carried out under different conditions; using three different concentrations of the precursor (5, 10 and 20 mM) at 200 °C, three different temperatures (200, 240 and 280 °C) at the concentration of 5 mM and different solvent/capping agent combinations. In a typical experiment, oleylamine OLA (15 mL) was degassed under reduced pressure at 100 °C for 30 minutes and then heated to the desired temperature under nitrogen. The required amount of the precursor [In(SON(CNiPr2)2)3] was dispersed in OLA (5 mL) and injected into the hot OLA. The reaction temperature was maintained for 1 h. The mixture was then cooled to approximately 70 °C before adding an excess of methanol to give a yellowish precipitate which was separated by centrifugation. After several washings with methanol, the solid was redispersed in toluene for further characterization. The crystallographic phase of nanowires or nanorods was confirmed by X-ray diffraction studies on a Bruker AXS D8 diffractometer using Cu-Kα radiation. The morphology and dimensions of nanowires or nanorods were identified using Tecnai F30 FEG transmission electron microscopy (TEM), operating at 300 kV, all samples deposited over carbon coated copper grids.The absorption spectra were recorded on a UV-Vis spectrophotometer (Thermo Spectronic Helios Beta) in the wavelength range of 350-750 nm. 3. Results and discussion: p-XRD pattern of indium sulfide nanocrystals prepared from a 5 mM solution of the precursor in OLA at 200 °C (Fig. 1) correspond to β-In2S3 (ICDD card No. 32-0456). The broad peaks in the pattern suggest the ultrasmall diameter of nanorods or the nanowires as was confirmed by TEM images (Fig. 2). The absence of the (220), (422) and (511) peaks indicates a preferred growth direction, resulting in the 1D nanorods/nanowires structure. All these results are consistent with previously reported very thin one-dimensional nanocrystals [21-23].

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20

(440)

(400)

(311)

Relative Intensity (a. u.) ( Relative Intensity 10

30

40

50

60

2 Theta (deg.) 2 Theta (deg.)

Fig. 1. TEM images revealed that the material synthesised at 200 °C, is composed of very thin nanorods. The width and length of the nanorods decreased on increasing the concentration of precursor. The nanorods prepared at 5 m M had dimensions of 0.9 ± 0.1 nm and 11.8 ± 3.5 nm, which decreased to 0.7 ± 0.1 nm and 7.1 ± 2.6 nm at 10mM. A further decrease in dimensions to 0.6 ± 0.1 nm and 5.8 ± 1.6 nm was observed at 20mM (Fig. 2(a-c)). Increasing the growth temperature from 200 °C, at the lowest concentration (5 m M), to 240 °C produced nanowires without any change in the width (0.9 ± 0.1 nm) but with a significant change in the length (Fig. 2(d)). A further increase (280 °C) in the growth temperature resulted in a considerable increase in the diameter of the nanowires with a broader distribution (1.4 ± 0.4 nm) (Fig. 2(e)). Ultra-thin indium sulfide nanowires and nanotubes were previously reported as oriented nanoplates [22,23]. In our results, there was no evidence of the formation of any plates, which makes our indium sulfide nanorods/nanowires, to the best of our knowledge, the thinnest prepared. The deposition of these nanorods can only be possible by oriented attachment mechanism. The SAED of the nanowires prepared from a 5 mM solution of the precursor in OLA at 240 °C confirmed the formation of β-In2S3with strong diffraction rings matching the (311) and the (440) planes (Fig. 2(f)). Unfortunately, due to the ultra-thinness of the nanorods/nanowires, HRTEM could not produce images to determine their lattice spacing or the growth direction [22].

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Fig. 2. Progress of the reaction time was investigated by withdrawing a couple of drops from the reaction mixture at different time intervals (5, 30 and 60 minutes) for the sample prepared at 200 °C using the lowest concentration (5 mM) of precursor. The width of the nanorods increased slightly from 0.6 ± 0.2 nm to 0.7 ± 0.1 and finally 0.9 ± 0.1 nm, whilst the nanorods length showed a more rapid growth from 7.7 ± 2.3 nm to 10.2 ± 2.6 nm and 11.8 ± 3.5 nm after 5, 30 and 60 minutes from the injection, respectively (Fig. 3). Injecting an ODE solution of the precursor into hot OLA or an OLA solution into hot DDT also produced ultra-thin nanorods of β-In2S3 (Supporting Information).

Fig. 3.

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The absorption spectra of all nanorods or nanowires dispersed in toluene showed almost no difference in the band edge. Absorption spectra of samples obtained after different reaction times (UV-Vis spectra is given in supporting information) showed the little difference, which suggests only small changes in the width of the rods/wires. The step like shape of the absorption spectra is because of the conduction to valence band transition as observed previously [21,22,24]. 4. Conclusion: In conclusion, we report the facile synthesis of β-In2S3 nanorods or nanowires of extreme thinness (< 1.0 nm) from the thermolysis of the single source precursor [In(SON(CNiPr2)2)3] in hot oleylamine. Acknowledgement: A. L. A. gratefully acknowledges financial support from the Egyptian Cultural Affairs and Missions Sector. KR thankful to ORS, UK. The authors also thank EPSRC, UK for the grants to POB that have made this research possible. References: [1] Xia Y, Yang P. Adv Mater 2003;15:351-352. [2] Xia Y, Yang P. Sun Y, Wu Y, Mayers B, Gates B, Yin Y, Kim F, Yan H.Adv Mater 2003; 15:353-389. [3] Ansell HG, Boorman RS. J ElectrochemSoc 1971;118:133-136. [4] Ueda M, Suzuki H, Kido O, Shintaku M, Kurumada M, Sato T, Saito Y, Kaito C. J PhysSocJpn 2005;74:16211624. [5] Diehl R, Nitsche R. J Cryst Growth 1975;28:306-310. [6] Kambas K, Spyridelis J, Balkanski M, Phys Stat Sol (b), 1981;105:291-296. [7] Rehwald W, Harbeke G, J PhysChem Solids 1965;26:1309-1324. [8] Yu A, Shu L, Qian Y, Xie Y, Yang J, Yang L, Mater Res Bull 1998;33:717–721. [9] (a) NaghaviN, SpieringS, PowallaM, CavanaB, LincotD.ProgPhotovolt: Res Appl2003;11:437–443. (b) Sterner J, Malmstrom J, Stolt L. ProgPhotovolt: ResAppl 2005;13:179. [10] Liu Y, Xu H, Qian Y. Cryst Growth Des 2006;6:1304-1307. [11] Asikainen T, Ritala M, Leskela M. Appl SurfSci 1994;82/83:122-125.

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[12] (a) Fu X, Wang Z, Chen Z, Zhang Z, Li Z, Leung DYC, Wu L, Fu X. ApplCatal B: Environ 2010;95:393-399. (b) Xing Y, Zhang H, Song S, Feng J, Lei Y, Zhao L, Li M.ChemCommun 2008;1476-1478. (c) Chen L-Y, Zhang Z-D, Wang W-Z. JPhysChem C 2008;112:4117-4123. [13] (a) Du W, Zhu J, Li S, Qian X.CrystGrwoth Des 2008;8:2130-2136. (b) Liu L, Liu H, Kou H-Z, Wang Y, Zhou Z, Ren M, Ge M, He X. Cryst Growth Des 2009; 9:113-117. [14] Nagesha DK, Liang X, Mamedov, AA, Gainer G, Eastman MA, Giersig M, Song J-J, Ni T, Kotov NA. JPhysChem B 2001;105:7490-7498. [15] Li Z, Tao X, Wu Z, Zhang P, Zhang Z. UltrasonSonochem 2009;16:221-224. [16] Tabernor J, Christian P, O’Brien P. J Mater Chem 2006;16:2082-2087. [17] (a) Haggata SW, Malik MA, Motevalli M, O’Brien P, Knowles JC. Chem Mater 1995;7:716-724. (b) Afzaal M, Malik, MA; O’Brien P. ChemCommun 2004;334-335. [18] Revaprasadu N, Malik MA, Carstens J, O’Brien P. J Mater Chem 1999;9:2885-2888. [19] Dutta DP, Sharma G, Tyagi AK, Kulshreshtha SK. Mater SciEng B 2007;138:60-64. [20] Ramasamy K, Malik MA, O’Brien P. Dalton Trans 2010;39:1460-1463. [21] Franzman MA, Brutchey RL. Chem Mater 2009;21:1790-1792. [22] Park KH, Jang K, Song SU.AngewChemInt Ed 2006;45:4608-4612. [23] Kim YH, Lee JH, Shin D-W, Park SM, Moon JS, Nam JG, Yoo J-B.ChemCommun 2010; 46:2292-2294. [24] Ning J, Men K, Xiao G, Zhao L, Wang L, Liu B, Zou B.J Colloid Interface Sci 2010;347:172-176.

Figure Caption: Fig. 1P-XRD pattern of β-In2S3nanorods prepared from a 5 mM solution of the precursor in OLA at 200 °C. Inset shows crystal structure of β-In2S3 Fig. 2 (a-c) TEM of In2S3nanorods synthesised at 200 °C using 5 mM, 10mM and 20mM respectively. (d and e) TEM of In2S3 nanowires synthesised using 5 m M at 240 °C and at 280 °C respectively. (f) SAED of (d). All scale bars, 20 nm. Fig. 3 (a-c) TEM of In2S3 nanorods after 5, 30 and 60 minutes, respectively. All scale bars, 20 nm.

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