Wide band gap p-type windows by CBD and SILAR methods

Department of Solar Energy Research, Hahn-Meitner-Institut, Glienicker Strasse 100, D-14109 Berlin, Germany
Thin Solid Films (Impact Factor: 1.76). 03/2004; 451:128-132. DOI: 10.1016/j.tsf.2003.11.002


Chemical deposition methods, namely, chemical bath deposition (CBD) and successive ionic layer adsorption and reaction (SILAR) have been used to deposit wide band gap p-type CuI and CuSCN thin films at room temperature (25 °C) in aqueous medium. Growth of these films requires the use of Cu (I) cations as a copper ions source. This is achieved by complexing Cu (II) ions using Na2S2O3. The anion sources are either KI as iodine or KSCN as thiocyanide ions for CuI and CuSCN films, respectively. The preparative parameters are optimized with the aim to use these p-type materials as windows for solar cells. Different substrates are used, namely: glass, fluorine doped tin oxide coated glass and CuInS2 (CIS). X-ray diffraction, scanning electron microscopy, atomic force microscopy and optical absorption spectroscopy are used for structural, surface morphological and optical studies, and the results are discussed.

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    • "Being a wide band gap semiconductor, CuSCN with a bandgap of 3.7 eV, can be very favorable to use as a window layer in bulk heterojunction solar cells. CuSCN can be deposited by various methods, such as drop-casting[2] [3], spin coating[4], electro-chemical deposition[5] [6] [7] [8] SILAR method[9], alumina template process[10] etc. Among these only a few reports on nanostructured CuSCN as a building block material can be found. "
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    ABSTRACT: ScienceDirect 1876-6102 © 2014 Shaibal K. Sarkar. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/). Selection and peer-review under responsibility of Organizing Committee of ICAER 2013 Abstract CuSCN is a p-type semiconductor essentially used in semiconductor sensitized solar cells for scavenging the photogenerated holes. Here we report, cathodic electrodeposition of CuSCN using NaSCN and Cu 2+ . Control over the film morphology is found to be highly dependent on the applied potential. One-dimensional rod like morphology with a strong (003) orientation is obtained under lower applied potential. Under higher applied potential the morphology changes to a more granular type. Films are structurally characterized by x-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) with small angle electron diffraction (SAED).
    Energy Procedia 12/2014; 54:777-781. DOI:10.1016/j.egypro.2014.07.320
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    • "CuSCN was previously deposited on ZnO using various techniques , including solution deposition [9,13–15], SILAR [16], and electrochemical deposition [10,17–19]. The latter is a simple, efficient method for coating complex shapes. "
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    ABSTRACT: Pulsed electrodeposition at room temperature is shown to be a facile, simple and fast method for super-filling of CuSCN onto ZnO nanowire arrays for applications in transparent diodes and optoelectronic devices. Compared to previously suggested methods for CuSCN superfilling, it offers the advantages of low cost, room temperature deposition in a one-pot process, combined with fast deposition rates, making it highly accessible for lab-scale deposition as well as scale up for industrial processes. Each pulse consisted of a working time ton, at which the potential was -500 mV vs. Ag/AgCl, and an off period toff, at which zero potential vs. Ag/AgCl was applied. The toff interval discharged the charged layer and regenerated the ion concentration near the cathode surface, resulting in denser nucleation and a more uniform coating. The pulse sequence controlled the deposition rate and the S/Cu ratio in the deposited CuSCN films, which was larger than in corresponding electrostatic depositions, due to higher SCN− concentration near the ZnO surface accomplished during the toff interval. Current-voltage characteristics showed excellent diode properties, significantly better than those of potentiostatic deposited CuSCN/ZnO diodes. We conclude that when high currents in transparent diodes are desirable, as in photovoltaic applications, pulsed electrodeposition and super-filling have significant advantages, with the pulse sequence ton = 2 sec, toff = 1 sec resulting in high deposition rates and optimized diode parameters.
    Electrochimica Acta 04/2014; 125:65 - 70. DOI:10.1016/j.electacta.2014.01.090 · 4.50 Impact Factor
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    • "More recently, it was also successfully used in conventional polymer solar cells as an interfacial layer [18] [19]. CuSCN thin films could be prepared by: electrochemical deposition [20] [21] [22] [23] [24], successive ionic layer adsorption and reaction (SILAR) [25] [26] and chemical bath deposition [27]. "
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    ABSTRACT: After the first report describing copper thiocyanate (CuSCN) nanowires (NWs) electrochemical deposition from an aqueous electrolyte at room temperature [1], the present study provides additional information on the effect of complexing agent and pH on their formation. The CuSCN electrodeposition from an aqueous solution is a two-step reaction, where in the first step Cu2+ is reduced to Cu+, and in the second step Cu+ chemically precipitates with SCN- to form CuSCN. In this study, CuSCN NWs are electrodeposited either potentiostatically or galvanostatically on flexible polyethylene terephthalate (PET) substrates covered with a transparent conductive oxide. It is shown that the nature of the Cu2+ chelating agent (diamino-tetraacetic acid compounds) and the pH value (between 1 and 2) of the electrolyte are the main parameters responsible for the CuSCN nanowire formation. The concentration limits of the Cu2+ chelating agent, Cu2+ and SCN- ions in the electrolyte are established to precise the region where CuSCN NWs could be grown. The CuSCN nanowire diameter and density could be tailored by the applied potential and SCN- concentration in the electrolyte. The possibility to deposit at room temperature CuSCN of good crystalline quality on flexible substrates is very promising and could further contribute to the decrease of the optoelectronic and photovoltaic device cost.
    Electrochimica Acta 11/2013; 110:375-381. DOI:10.1016/j.electacta.2013.03.124 · 4.50 Impact Factor
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