Synchrotron x-ray characterization of alkali elements at grain boundaries in Cu(In, Ga)Se<inf>2</inf> solar cells

TiO2nanotubes were successfully synthesized by anodization method of Ti foils. The electrolyte was composed of ethylene glycol (EG), ammonium fluoride (0.3%wt NH4F) and de-ionized water (2% vol H2O). A constant DC power supply of 50 V was used during anodization with anodizing times of 1 hour, 2 hours, 4 hours and 6 hours. The samples were annealed at 450 °C for 2 hours. The TiO2nanotubes were studied by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Structural analysis revealed the presence of pure Ti, and the crystalline anatase phase due to transformation of amorphous TiO2after annealing. The morphology of TiO2nanotube sizes showed an increase in tube diameter with anodizing time from approximately 50 nm to 200 nm. However, the efficiency of dye-sensitized solar cells increased with anodizing times up to a maximum of 5.74 % for anodizing time of 4 hours.

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Preparation of CIGSS Thin-Film Solar Cells by Rapid Thermal Processing

Journal of Solar Energy Engineering ◽

10.1115/1.2735349 ◽

2006 ◽

Vol 129 (3) ◽

pp. 323-326

Author(s):

Sachin S. Kulkarni ◽

Jyoti S. Shirolikar ◽

Neelkanth G. Dhere

Keyword(s):

Thin Film ◽

Solar Cells ◽

Thermal Processing ◽

Rapid Thermal Processing ◽

Electrical Characterization ◽

Soda Lime ◽

Thin Film Solar Cells ◽

Soda Lime Glass ◽

X Ray

Rapid thermal processing (RTP) provides a way to rapidly heat substrates to an elevated temperature to perform relatively short duration processes, typically less than 2–3min long. RTP can be utilized to minimize the process cycle time without compromising process uniformity, thus eliminating a bottleneck in CuIn1−xGaxSe2−ySy (CIGSS) module fabrication. Some approaches have been able to realize solar cells with conversion efficiencies close or equal to those for conventionally processed solar cells with similar device structures. A RTP reactor for preparation of CIGSS thin films on 10cm×10cm substrates has been designed, assembled, and tested at the Florida Solar Energy Center’s PV Materials Lab. This paper describes the synthesis and characterization of CIGSS thin-film solar cells by the RTP technique. Materials characterization of these films was done by scanning electron microscopy, x-ray energy dispersive spectroscopy, x-ray diffraction, Auger electron spectroscopy, electron probe microanalysis, and electrical characterization was done by current–voltage measurements on soda lime glass substrates by the RTP technique. Encouraging results were obtained during the first few experimental sets, demonstrating that reasonable solar cell efficiencies (up to 9%) can be achieved with relatively shorter cycle times, lower thermal budgets, and without using toxic gases.

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Charge Collection Characterization of Polycrystalline n-GaAs Layers for Solar Cells

MRS Proceedings ◽

10.1557/proc-5-223 ◽

1981 ◽

Vol 5 ◽

Author(s):

O. Paz ◽

K. N. Bhat ◽

J. M. Borrego

Keyword(s):

Solar Cells ◽

Single Crystal ◽

Grain Boundaries ◽

Random Distribution ◽

Charge Collection ◽

Typical Cell ◽

Metal Organic ◽

Organic Process ◽

Excitation Volume

ABSTRACTN–type Ga-As polycrystalline layers, grown on Mo substrates by the metal-organic process were investigated using the SEM. Micrographs of charge collection contrast indicate a fairly random distribution of high collection (bright) grains. In a typical cell about 1/3 of its area is bright, with nonuniformities in collection current within and between grains. These results correlate well with Isc measurements, and some of the variations betweencells is explained in terms of insufficient doping of the grain boundaries.Reducing the penetrating depth of the carriers' excitation volume results in lowering of the collection current. The measurements were normalized for changes in beam and EBIC current by a comparison with a single crystal cell of the same geometry. This degradation is explained in terms of contamination or damage of the layer close to the surface during growth.

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Growth and Characterization of Cu2Zn1−xFexSnS4 Thin Films for Photovoltaic Applications

Materials ◽

10.3390/ma13061471 ◽

2020 ◽

Vol 13 (6) ◽

pp. 1471

Author(s):

Vanira Trifiletti ◽

Giorgio Tseberlidis ◽

Marco Colombo ◽

Alberto Spinardi ◽

Sally Luong ◽

...

Keyword(s):

Thin Films ◽

Solar Cells ◽

Raw Materials ◽

Sol Gel ◽

Elementary Cell ◽

Production Costs ◽

X Ray ◽

Earth Abundant ◽

Copper Zinc

Photovoltaics is a promising technology to produce sustainable energy, thanks to the high amount of energy emitted by the sun. One way of having solar cells with low production costs is to apply thin-film technology and with earth-abundant raw materials. A keen interest is arising in kesterite compounds, which are chalcogenides composed of abundant and non-toxic elements. They have already achieved excellent performance at the laboratory level. Here, we report the synthesis and characterization of mixed chalcogenides based on copper, zinc, iron, and tin. Solutions have been studied with different zinc and iron ratios. The distortion of the elementary cell of kesterite increases with the addition of iron until a phase transition to stannite occurs. The process of synthesis and deposition proposed herein is cheap and straightforward, based on the sol-gel technique. These thin films are particularly attractive for use in cheap and easily processable solar cells. The synthesized layers have been characterized by X-ray diffraction, UV-Vis absorption, and Raman, X-ray photoelectron, and energy-dispersive X-ray spectroscopy measurements.

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Microstructural Characterization of Sulfurization Effects in Cu(In,Ga)Se2 Thin Film Solar Cells

Microscopy and Microanalysis ◽

10.1017/s1431927619000151 ◽

2019 ◽

Vol 25 (2) ◽

pp. 532-538 ◽

Cited By ~ 6

Author(s):

Hisham Aboulfadl ◽

Jan Keller ◽

Jes Larsen ◽

Mattias Thuvander ◽

Lars Riekehr ◽

...

Keyword(s):

Solar Cells ◽

Elemental Sulfur ◽

Microstructural Characterization ◽

Atom Probe ◽

Thin Film Solar Cells ◽

Device Performance ◽

Sulfur Vapor ◽

X Ray ◽

Absorber Material

AbstractSurface sulfurization of Cu(In,Ga)Se2 (CIGSe) absorbers is a commonly applied technique to improve the conversion efficiency of the corresponding solar cells, via increasing the bandgap towards the heterojunction. However, the resulting device performance is understood to be highly dependent on the thermodynamic stability of the chalcogenide structure at the upper region of the absorber. The present investigation provides a high-resolution chemical analysis, using energy dispersive X-ray spectrometry and laser-pulsed atom probe tomography, to determine the sulfur incorporation and chemical re-distribution in the absorber material. The post-sulfurization treatment was performed by exposing the CIGSe surface to elemental sulfur vapor for 20 min at 500°C. Two distinct sulfur-rich phases were found at the surface of the absorber exhibiting a layered structure showing In-rich and Ga-rich zones, respectively. Furthermore, sulfur atoms were found to segregate at the absorber grain boundaries showing concentrations up to ~7 at% with traces of diffusion outwards into the grain interior.

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Properties of Cu(In,Ga) Thin Films and Solar Cells Deposited by Hybrid Process

International Journal of Photoenergy ◽

10.1155/2012/385185 ◽

2012 ◽

Vol 2012 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

S. Marsillac ◽

H. Khatri ◽

K. Aryal ◽

R.W. Collins

Keyword(s):

Solar Cells ◽

Critical Points ◽

Hybrid Process ◽

Angle Of Incidence ◽

X Ray Diffraction ◽

X Ray ◽

Current Voltage ◽

High Series ◽

Uniform Composition

Cu(In,Ga)Se2solar cells were fabricated using a hybrid cosputtering/evaporation process, and efficiencies as high as 12.4% were achieved. The films were characterized by energy-dispersive X-ray spectroscopy, glancing incidence X-ray diffraction, scanning electron microscopy, auger electron spectroscopy, and transmittance and reflectance spectroscopy, and their properties were compared to the ones of films deposited by coevaporation. Even though the films were relatively similar, the ones deposited by the hybrid process tend to have smaller grains with a slightly preferred orientation along the (112) axis and a rougher surface. Both types of films have uniform composition through the depth. Characterization of these films by variable angle of incidence spectroscopic ellipsometry allowed for the calculation of the position of the critical points, via calculation of the second derivative of the dielectric function and fit with critical points parabolic band oscillators. The solar cells were then characterized by current-voltage and quantum efficiency measurements. An analysis of the diode parameters indicates that the cells are mostly limited by a low fill factor, associated mostly with a high diode quality factor () and high series resistance ( ) .

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