Identification of the dye adsorption modes in dye-sensitised solar cells with X-ray spectroscopy techniques: a computational study

2015 ◽  
Vol 17 (16) ◽  
pp. 10849-10855 ◽  
Author(s):  
Ali Akbari ◽  
Javad Hashemi ◽  
Johannes Niskanen ◽  
Simo Huotari ◽  
Mikko Hakala

X-ray photoelectron spectroscopy of O 1s is shown to be the most reliable technique in assessing adsorption geometry of dye molecules in a dye-sensitised solar cell.

2010 ◽  
Vol 1268 ◽  
Author(s):  
Krishna C. Mandal ◽  
Sandip Das ◽  
Ramesh Krishna ◽  
Peter G. Muzykov ◽  
Shuguo Ma ◽  
...  

AbstractGaTe and GaTe:In single crystals were grown from high purity Ga (7N) and zone refined Te (>7N) precursor materials. InSe thin films were deposited by thermal evaporation onto the sulfur passivated GaTe:In substrates at various substrate temperatures from 450K-550K to fabricate p-GaTe:In/n-InSe heterojunction solar cells. Scanning electron microscopy (SEM), X-ray diffraction (XRD), electron probe microanalysis (EPMA), and X-ray photoelectron spectroscopy (XPS) were used to characterize GaTe:In crystals and InSe thin film surfaces. The current-voltage characteristics of p-GaTe:In/n-InSe solar cells were measured under dark and under illumination of 75mW/cm2. Dark J-V measurements showed that the reverse saturation current density (J0) decreased from 3.8 x 10-6 A/cm2 to 1.5 x 10-9 A/cm2 and the ideality factor was reduced from 2.04 to 1.15 as a result of surface passivation. Under illumination of 75 mW/cm2, the open-circuit voltage (Voc) increased from 0.54V to 0.68V and short-circuit current density (Jsc) increased from 7.19 mA/cm2 to 8.65 mA/cm2 for solar cells with surface passivated GaTe:In substrates, leading to an increased solar cell efficiency of 5.03%. EPMA measurements revealed that the InSe thin films deposited at 550 K on GaTe:In substrates were near stoichiometric with enhanced grain size contributing also to better solar cell performance.


2021 ◽  
Author(s):  
◽  
Alexander Riches

Copper zinc tin sulphide (CZTS) is a p-type semiconductor that can be used as the light absorbing layer in thin-film heterojunction solar cells, with the specific advantage of being comprised only of non-toxic, earth abundant elements. There are many methods through which CZTS can by synthesised, one of which is electrodeposition, which is an industrially scalable process used extensively in the steel industry. This thesis details a study of the electrodeposition of stacked elemental layers and their subsequent sulphurisation in the manufacture of CZTS. A range of electrodeposition parameters are tested for each elemental layer, each of which is characterised through a range of techniques, including scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), which enables the development of optimised conditions. It was found that the deposition of copper favoured potentiostatic deposition, with a smooth granular structure being deposited onto molybdenum at -0.98V vs Hg|HgO from a sodium hydroxide based electrolyte, while tin required galvanostatic deposition from a methanesulfonic acid electrolyte in order to return consistent results. This was optimised to an initial high current density period of -20 mA cm-2 for 1.2 s to nucleate grains, falling to -5 mA cm-2 to minimise hydrogen evolution thereafter. Trial of numerous electrolyte formulae found that an acid-sulphate electrolyte gave the most promising results, with galvanostatic deposition at -50 mA cm-2 being found to be suitable. Optimised stacked elemental layer precursors are then progressed to the annealing and sulphurisation stage for conversion into CZTS. One key area of study is the inclusion of a pre-alloying annealing step prior to sulphurisation, and its effect on the morphology of the CZTS films and subsequent solar cell device performance. Pre-alloyed metallic films are extensively characterised by means of X-ray photoelectron spectroscopy (XPS) depth profiling, X-ray diffractometry (XRD) and EDS elemental mapping as part of an optimisation process, and Raman spectroscopy is used in conjunction with XRD and EDS in the analysis of CZTS films sulphurised in a rapid thermal processing (RTP) furnace. A pre-alloying step at 300 °C for 10 minutes was found to be sufficient for the deposited elements to fully intermix. It was discovered that not only does the inclusion of an optimised pre-alloying step improve the morphology of the CZTS films and the subsequent solar cell performance, but the integration of a pre-alloying stage with the sulphurisation in a single furnace operation does not lead to any evidence of disadvantage when compared with pre-alloying and sulphurisation processes conducted separately. In fact, 8 out of 45 cells with an integrated pre-alloying process achieved 0.1% efficiency or greater, compared to 5 out of 45 for those that underwent a separate pre-alloying process, and 0 out of 45 for those that received no pre-alloying process. This positive result for the integration of the pre-alloy offers simplification of the manufacturing process for a potential future scaled-up CZTS solar cell device.


Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2638
Author(s):  
Nguyen Thi Kim Chung ◽  
Phat Tan Nguyen ◽  
Ha Thanh Tung ◽  
Dang Huu Phuc

In this study, we provide the reader with an overview of quantum dot application in solar cells to replace dye molecules, where the quantum dots play a key role in photon absorption and excited charge generation in the device. The brief shows the types of quantum dot sensitized solar cells and presents the obtained results of them for each type of cell, and provides the advantages and disadvantages. Lastly, methods are proposed to improve the efficiency performance in the next researching.


Nanomaterials ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 10 ◽  
Author(s):  
Yuelong Xu ◽  
Bin Ren ◽  
Ran Wang ◽  
Lihui Zhang ◽  
Tifeng Jiao ◽  
...  

In the present study, nanoscale rod-shaped manganese oxide (MnO) mixtures were successfully prepared from graphitic carbon nitride (C3N4) and potassium permanganate (KMnO4) through a hydrothermal method. The as-prepared MnO nanomixtures exhibited high activity in the adsorption and degradation of methylene blue (MB). The as-synthesized products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), surface area analysis, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Furthermore, the effects of the dose of MnO nanomixtures, pH of the solution, initial concentration of MB, and the temperature of MB removal in dye adsorption and degradation experiments was investigated. The degradation mechanism of MB upon treatment with MnO nanomixtures and H2O2 was studied and discussed. The results showed that a maximum adsorption capacity of 154 mg g−1 was obtained for a 60 mg L−1 MB solution at pH 9.0 and 25 °C, and the highest MB degradation ratio reached 99.8% under the following optimum conditions: 50 mL of MB solution (20 mg L−1) at room temperature and pH ≈ 8.0 with 7 mg of C, N-doped MnO and 0.5 mL of H2O2.


2013 ◽  
Vol 117 (33) ◽  
pp. 17033-17038 ◽  
Author(s):  
Mitsunori Honda ◽  
Masatoshi Yanagida ◽  
Liyuan Han ◽  
Kenjiro Miyano

1999 ◽  
Vol 06 (01) ◽  
pp. 53-75 ◽  
Author(s):  
M. NEUBER ◽  
M. ZHARNIKOV ◽  
J. WALZ ◽  
M. GRUNZE

The adsorption geometry of benzoic acid on Ni(110) was investigated by X-ray photoelectron spectroscopy, angle-resolved near edge X-ray absorption fine structure spectroscopy at the C1s and O1s excitation edges, and thermal desorption spectroscopy. At a substrate temperature of 360 K and saturation coverage the adsorbate forms a benzoate with molecules adsorbed on the surface via two equivalent oxygen atoms. For this dense adsorbate layer the molecular plane was found to be azimuthally rotated by about ± 30° with respect to the [Formula: see text] surface azimuth and tilted by ≈ 30° with respect to the surface normal. At about half the saturation coverage some rearrangement of molecules occurs in such a way that their planes become directed along the [001] surface direction, which is different from the adsorption geometry observed after annealing the saturated layer. At even smaller coverage the benzoate molecules appear to adsorb with their molecular planes nearly parallel to the surface. Semiempirical quantum-mechanical cluster calculations indicate that the carboxylate oxygens favor the highly coordinated sites in the [Formula: see text]-oriented troughs of the Ni(110) surface. Possible adsorption models are discussed.


2009 ◽  
Vol 131 (19) ◽  
pp. 194701 ◽  
Author(s):  
Peter L. Cook ◽  
Xiaosong Liu ◽  
Wanli Yang ◽  
F. J. Himpsel

1998 ◽  
Vol 524 ◽  
Author(s):  
S. A. McHugo ◽  
A. C. Thompson ◽  
G. Lamble ◽  
A. MacDowell ◽  
R. Celestre ◽  
...  

ABSTRACTThe work presented here directly measures metal impurity distributions and their chemical state in as-grown and fully processed polycrystalline silicon used for terrestrial-based solar cells. The goal was to determine if a correlation exists between poorly performing regions of solar cells and metal impurity distributions as well as to ascertain the chemical state of the impurities. Synchrotron-based x-ray fluorescence mapping and x-ray absorption spectroscopy, both with a spatial resolution of lμm, were used to measure impurity distributions and chemical state, respectively, in poorly performing regions of polycrystalline silicon. The Light Beam Induced Current method was used to measure minority carrier recombination in the material in order to identify poor performance regions. We have detected iron, chromium, nickel, gold and copper impurity precipitates and we have recognized a direct correlation between impurity distributions and poor performing regions in both as-grown and fully processed material. Furthermore, from x-ray absorption studies, we have initial results, indicating that the Fe in this material is in oxide form, not FeSi2,. These results provide a fundamental understanding into the efficiency-limiting factors of polycrystalline silicon solar cells as well as yielding insight for methods of solar cell improvement.


2013 ◽  
Vol 645 ◽  
pp. 154-159
Author(s):  
Xue Wen Wang ◽  
Zhou Hu Deng ◽  
Yuan Zhang

Since CuInSe2 (commonly called as CIS) materials has become one of most important photovoltaic materials, they are investigated with optical spectroscopies in this paper. The crystal structure, surface microstructure morphology and composition of the samples are analyzed in XRD and SEM with EDX, and the surface electronic state and optical properties of the samples are characterized in X-ray photoelectron spectroscopy (XPS) and Ultraviolet-visible Spectrum instruments. The results show that CIS phase is very uniform, some impurity phases appear in the samples, the atomic distributing percentages of the surfaces of bulk samples are very consistent in the composition ratio forming the crystal phases of the samples, and the atomic electrons are more active than ones in the relevant elements. Furthermore, the thin film of the sample has high solar energy absorptivity, and is suitable for to be manufactured as solar cell.


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