Photoelectrochemical Deposition of CdZnSe Thin Films on the Se-Modified Au Electrode

Sunyoung Ham,명노승,이웅기,팽기정,Soyeon Jeon 대한화학회 2008 Bulletin of the Korean Chemical Society Vol.29 No.5

Photoelectrochemical deposition of CdZnSe thin films on the Se-modified Au electrode using electrochemical quartz crystal microgravimetry (EQCM) and voltammetry is described. Corrosion of pre-deposited Se electrodes by illumination at a fixed potential resulted in Se²- species, which was manifest from the EQCM frequency changes. Se²- species generated from the photocorrosion reacted with Cd²+ and Zn²+ ions in the electrolyte to form CdZnSe films on the Au electrode. The effect of electrolyte composition on the composition and band gap of CdZnSe films was studied in detail. Also, photoelectrochemistry, EDX, Raman spectroscopy were used for the characterization of CdZnSe thin films.

Photoelectrochemical Deposition of CdZnSe Thin Films on the Se-Modified Au Electrode

Ham, Sun-Young,Jeon, So-Yeon,Lee, Ungki,Paeng, Ki-Jung,Myung, No-Seung Korean Chemical Society 2008 Bulletin of the Korean Chemical Society Vol.29 No.5

Photoelectrochemical deposition of CdZnSe thin films on the Se-modified Au electrode using electrochemical quartz crystal microgravimetry (EQCM) and voltammetry is described. Corrosion of pre-deposited Se electrodes by illumination at a fixed potential resulted in $Se^{2-}$ species, which was manifest from the EQCM frequency changes. $Se^{2-}$ species generated from the photocorrosion reacted with $Cd^{2+}$ and $Zn^{2+}$ ions in the electrolyte to form CdZnSe films on the Au electrode. The effect of electrolyte composition on the composition and band gap of CdZnSe films was studied in detail. Also, photoelectrochemistry, EDX, Raman spectroscopy were used for the characterization of CdZnSe thin films.

Exploring the photoelectrocatalytic behavior of free-standing TiO₂ nanotube arrays on transparent conductive oxide electrodes: Irradiation direction vs. alignment direction

Jeong, Hye Won,Park, Kyu Jun,Park, Yiseul,Han, Dong Suk,Park, Hyunwoong Elsevier 2019 CATALYSIS TODAY - Vol.335 No.-

<P><B>Abstract</B></P> <P>Although one-dimensional TiO<SUB>2</SUB> nanotube arrays (TNA) grown on Ti substrates via electrochemical anodization are extensively studied in photoelectrochemistry, the photo(electro)catalytic activity of TNA detached from the Ti substrates remains unexplored. Herein, we synthesize TNA samples with various pore sizes (40–100 nm) and tube lengths (4–15 μm) via two-step electrochemical anodization, and transfer them to transparent conducting oxide (i.e. fluorine-doped tin oxide; FTO) substrates in normal (<I>n</I>) alignment (front plane outward) and reverse (<I>r</I>) alignment (backplane outward). The front and back planes of the as-fabricated TNA film are the same based on X-ray diffraction (anatase structure), X-ray photoelectron spectroscopy (Ti and O), and UV–vis transmittance data, though the tubes are open in the front and closed in the back. Regardless of the direction of irradiation (<I>SE</I>: FTO → TNA vs. <I>EE</I>: TNA → FTO), longer tubes generate a higher photocurrent (<I>I</I> <SUB>ph</SUB>) due to the large light absorption. However, for the same alignment of TNA (either <I>n-</I> or <I>r</I>-TNA), <I>SE</I> irradiation leads to a very large <I>I</I> <SUB>ph</SUB> (e.g., <I>nSE</I> ><I>nEE</I>), whereas <I>n</I>-TNA consistently generates a larger <I>I</I> <SUB>ph</SUB> than <I>r</I>-TNA for a given irradiation direction (i.e., <I>n</I> ><I>r</I>). The photocatalytic decomposition of phenol follows the same tendency (<I>n</I> ><I>r</I>); however, the Faraday efficiency (based on the photocharge) is higher with <I>EE</I> (<I>nEE</I> 28%, <I>rEE</I> 20%) than <I>SE</I> (<I>rSE</I> 11%, <I>nSE</I> 7%) irradiation. These photoelectrochemical and photocatalytic behaviors are explained in terms of charge carrier generation (FTO/TNA vs. TNA/solution), dissimilar charge carrier transfer pathways (<I>e</I> <SUP>−</SUP> transfer through tube framework vs. <I>h</I> <SUP>+</SUP> transfer via radial direction), and charge injection at the tube (open vs. clogged tube mouth)/solution interface. The time-resolved photoluminescence (TRPL) emission and incident photon-to-current efficiency (IPCE) are also studied to gain insight into the charge transfer kinetics.</P> <P><B>Highlights</B></P> <P> <UL> <LI> TNA films grown on Ti substrates are transferred onto FTO via a two-step anodization. </LI> <LI> TNA films are vertically aligned in normal and reverse ways, and irradiated through FTO (SE) or solution (EE). </LI> <LI> The front and back planes of TNA films are the same in XRD, XPS, and UV–vis transmittance. </LI> <LI> Irradiation direction is a key factor in photocurrent generation. </LI> <LI> In photocatalysis, the effect of alignment direction is comparable to that of irradiation direction. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Iron oxide nanostructures for photoelectrochemical applications: Effect of applied potential during Fe anodization

Bianca Lucas-Granados,Rita Sánchez-Tovar,Ramón M. Fernández-Domene,José García-Antón 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.70 No.-

In photoelectrochemistry, a suitable photoanode leading to high efficiencies in photocatalytic processesis a research challenge. Iron oxide nanostructures are promising materials to be used as photoanodes. Inthis work, different potentials during iron anodization were applied to study the properties of thesynthesized nanostructures. Results revealed that nanostructures anodized at 50 V presentedwell-defined nanotubular structures with open-tube tops, and they achieved values of photocurrentdensity of 0.11 mA cm 2 at 0 rpm and 0.14 mA cm 2 at 1000 rpm (measured at 0.50 VAg/AgCl),corresponding to the oxygen evolution reaction from water, i.e. 2H2O + 4 h+→ 4H+ + O2, demonstratingtheir good photoelectrochemical behavior.

Solution processed growth and photoelectrochemistry of Bi₂S₃ nanorods thin film

Patil, S.A.,Hwang, Y.T.,Jadhav, V.V.,Kim, K.H.,Kim, H.S. Elsevier Sequoia 2017 Journal of photochemistry and photobiology. A, Che Vol.332 No.-

Bismuth sulfide (Bi<SUB>2</SUB>S<SUB>3</SUB>) belongs to a family of metal chalcogenides in a class of non-toxic semiconductor materials, whose importance in photovoltaic and thermoelectric applications is well recognized. We have successfully prepared crystalline Bi<SUB>2</SUB>S<SUB>3</SUB> nanorod (NR) thin films from a solution of bismuth chloride and thioacetamide via a solution process method. A possible mechanism for the growth process of the Bi<SUB>2</SUB>S<SUB>3</SUB> NRs is proposed. Prepared Bi<SUB>2</SUB>S<SUB>3</SUB> NR films characterized via X-ray diffraction (XRD), energy dispersive analysis (EDX), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), brunauer-emmett-teller (BET) surface area, and photoelectrochemical cells are studied. The morphology of the Bi<SUB>2</SUB>S<SUB>3</SUB> NR reveals a photocurrent density of 0.20mA/cm<SUP>2</SUP> at 0V bias condition under 1 sun illumination. The charge transport properties of the Bi<SUB>2</SUB>S<SUB>3</SUB> NRs are studied via impedance spectroscopy analysis. This preparation method is economical for scale-up processes, and can also applied to the preparation of other metal sulfide semiconductors.

CdSe Quantum Dot–Fullerene Hybrid Nanocomposite for Solar Energy Conversion: Electron Transfer and Photoelectrochemistry

Bang, Jin Ho,Kamat, Prashant V. American Chemical Society 2011 ACS NANO Vol.5 No.12

<P>The development of organic/inorganic hybrid nanocomposite systems that enable efficient solar energy conversion has been important for applications in solar cell research. Nanostructured carbon-based systems, in particular C<SUB>60</SUB>, offer attractive strategies to collect and transport electrons generated in a light harvesting assembly. We have assembled CdSe–C<SUB>60</SUB> nanocomposites by chemically linking CdSe quantum dots (QDs) with thiol-functionalized C<SUB>60</SUB>. The photoinduced charge separation and collection of electrons in CdSe QD–C<SUB>60</SUB> nanocomposites have been evaluated using transient absorption spectroscopy and photoelectrochemical measurements. The rate constant for electron transfer between excited CdSe QD and C<SUB>60</SUB> increased with the decreasing size of the CdSe QD (7.9 × 10<SUP>9</SUP> s<SUP>–1</SUP> (4.5 nm), 1.7 × 10<SUP>10</SUP> s<SUP>–1</SUP> (3.2 nm), and 9.0 × 10<SUP>10</SUP> s<SUP>–1</SUP> (2.6 nm)). Slower hole transfer and faster charge recombination and transport events were found to dominate over the forward electron injection process, thus limiting the deliverance of maximum power in CdSe QD–C<SUB>60</SUB>-based solar cells. The photoinduced charge separation between CdSe QDs and C<SUB>60</SUB> opens up new design strategies for developing light harvesting assemblies.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2011/ancac3.2011.5.issue-12/nn204350w/production/images/medium/nn-2011-04350w_0010.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn204350w'>ACS Electronic Supporting Info</A></P>

Mesoporous TiO₂: Comparison of Classical Sol−Gel and Nanoparticle Based Photoelectrodes for the Water Splitting Reaction

Hartmann, Pascal,Lee, Doh-Kwon,Smarsly, Bernd M.,Janek, Juergen American Chemical Society 2010 ACS NANO Vol.4 No.6

<P>This paper describes a systematic comparison of the photoelectrochemical properties of mesoporous TiO<SUB>2</SUB> films prepared by the two most prevalent templating methods: The use of preformed, crystalline nanoparticles is generally considered advantageous compared to the usage of molecular precursors such as TiCl<SUB>4</SUB>, since the latter requires a separate heat treatment at elevated temperature to induce crystallization. However, our photoelectrochemical experiments clearly show that sol−gel derived mesoporous TiO<SUB>2</SUB> films cause an about 10 times higher efficiency for the water splitting reaction than their counterparts obtained from crystalline TiO<SUB>2</SUB> nanoparticles. This result indicates that for electrochemical applications the performance of nanoparticle-based metal oxide films might suffer from insufficient electronic connectivity.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2010/ancac3.2010.4.issue-6/nn1004765/production/images/medium/nn-2010-004765_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn1004765'>ACS Electronic Supporting Info</A></P>

Photoelectrochemical water splitting over Sn doping and oxygen vacancies coupled hematite electrodes

전태화,김형일,최원용 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.1

To improve the activity of electrodeposited hematite (α-Fe₂O₃) electrodes on photoelectrochemical (PEC) water oxidation, metal element (Sn) was doped on hematite during the synthesis. When hematite is doped with Sn⁴⁺, carrier density is significantly increased due to an extra electron in substituted Sn⁴⁺ at Fe³⁺ sites so electrical conductivity of hematite is enhanced. Along with dopant substitution, hydrogenation is also facile and effective method to improve the electrical conductivity of hematite by making oxygen deficient sites (Fe²⁺ and/or oxygen vacancy) in hematite. In this work, a dual modification (Sn⁴⁺ doping and hydrogenation) was subsequently carried out on hematite electrodes. In dual modified Fe₂O₃ (H-Sn-Fe₂O₃), simultaneous Sn⁴⁺ substitution and Fe²⁺ generation by hydrogenation can compromise mutual charge mismatch similar with co-doping (e.g., substitutional M²⁺ and M⁴⁺ co-doping in M³⁺ core metal oxide) and maximize the generation of donor density in its structure.

Photoelectrochemical Deposition of SnSe Thin Films on a Se-Modified Polycrystalline Gold Substrate

Sunyoung Ham,Seungun Choi,Yujin Chae,Woo Ju Lee,팽기정,Whan-Gi Kim,명노승 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.11

Photoelectrochemical Deposition of SnSe Thin Films on a Se-Modified Polycrystalline Gold Substrate

Ham, Sun-Young,Choi, Seung-Un,Chae, Yu-Jin,Lee, Woo-Ju,Paeng, Ki-Jung,Kim, Whan-Gi,Myung, No-Seung Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.11