scholarly journals Hydrometallurgical Treatment for the Extraction and Separation of Indium and Gallium from End-of-Life CIGS Photovoltaic Panels

2021 ◽  
Vol 5 (1) ◽  
pp. 51
Author(s):  
Minas Theocharis ◽  
Petros E. Tsakiridis ◽  
Pavlina Kousi ◽  
Artin Hatzikioseyian ◽  
Ioannis Zarkadas ◽  
...  

This study presents experimental results for the development of a process for the recovery of indium and gallium from EoL CIGS (CuGa1−xInxSe2) panels. The process consists of a thermal treatment of the panels, followed by a hydrometallurgical treatment, where quantitative leaching of In, Ga, Mo, Cu and Zn is achieved. The elements are subsequently separated and recovered from the leachate by solvent extraction. For the development of the process, samples of EoL CIGS PV panels were used, which contained a thin film of Mo (metal base electrode), sputtered on the supporting soda-lime glass and covered by the thin film containing In, Ga, Cu and Se (1 μm). These films were detected by SEM-EDS in polished sections. The thermal treatment at 550 °C for 15 min, in excess of air, led to the successful disintegration of ethyl vinyl acetate (EVA) and delamination of the thin film-coated glass from the front protective glass. The glass fragments coated by the thin film contained the following: Se: 0.03–0.05%; In: 0.02%; Cu: 0.05%; Ga: 0.004–0.006%; and Mo: 0.04%. Following thermal treatment, thin film-coated glass fragments of about 1.5 cm × 1.5 cm were used in acid leaching experiments using HNO3, HCl and H2SO4. Quantitative leaching of Cu, Ga, In, Mo, Zn and Cu was achieved by HNO3 at ambient temperature. The effects of pulp density and acid concentration on the efficiency of metal leaching were investigated. Part of Se volatilized during the thermal treatment, whereas the rest was insoluble and separated from the solution by filtration. Finally, the separation of the elements was achieved via solvent extraction by D2EHPA.

2006 ◽  
Vol 129 (3) ◽  
pp. 323-326
Author(s):  
Sachin S. Kulkarni ◽  
Jyoti S. Shirolikar ◽  
Neelkanth G. Dhere

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.


2010 ◽  
Vol 1268 ◽  
Author(s):  
Jeffrey L. Johnson ◽  
Haritha Nukala ◽  
Ashish Bhatia ◽  
W.M. Hlaing Oo ◽  
Loren W Rieth ◽  
...  

AbstractCu2ZnSnS4 (CZTS) is an alternative material to Cu(In,Ga)Se2 (CIGSe) for use in thin film photovoltaic absorber layers composed solely of commodity elements [1,2]. Thus, if similar material quality and performance can be realized, its use would allow scale-up of terrestrial thin film photovoltaic production unhindered by material price or supply constraints. Here we report on our research on the deposition of CZTS by RF sputtering from a single CZTS target and co-sputtering from multiple binary sources on Mo-coated glass. We find some samples delaminate during post-sputtering furnace annealing in S vapor. Samples on borosilicate glass (BSG) delaminate much more frequently than those on soda-lime glass (SLG). We investigate the influences of the formation of frangible phases such as MoS2 at the CZTS/Mo interface and residual and thermal mismatch stress on delamination. We implicate fracture in a layer of MoS2 as the mechanism of delamination between the Mo and CZTS layers using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Wafer curvature measurements show significant (˜400 MPa) deposition stress for minimally optimized Mo deposition; however nearly stress-free Mo layers with good adhesion can be deposited using a multi-step Mo deposition recipe. Co-sputtering CZTS adds 100 MPa of stress on both BSG and SLG, however delamination is nearly absent for samples deposited on low-stress Mo layers. We investigate metallic diffusion barrier layers to prevent the formation of MoS2 at the interface. Lastly we discuss the importance of removing Mo oxide by sputter etching before CZTS deposition and its effects on adhesion and series resistance.


2009 ◽  
Vol 620-622 ◽  
pp. 695-698
Author(s):  
Jing Ma ◽  
Wen Xiu Liu ◽  
Xiao Guang Qu ◽  
Dan Ni Yu ◽  
Wen Bin Cao

TiO2 thin film was prepared on soda lime glass by hydrolysis of Ti(OC4H9)4 in alcoholic solutions by sol-gel method combined with spin-coating and calcination different temperatures. Prepared samples were characterized by XRD, FESEM, and measurement of contact angles and transmittance. XRD identification reveals that the films are composed of anatase TiO2 when the annealing temperature was set at 450~550 oC. SiO2 layer was coated on the surface of the glass firstly to barrier the diffusing of sodium ions from the substrate. Light-induced superhydrophilicity of the TiO2 thin film has been investigated. To increase the illumination light intensity will decrease the water contact angle. The superhydrophilicity of the TiO2 thin film will disappear more slowly in the dark than that in the field of ultrasound.


2003 ◽  
Vol 763 ◽  
Author(s):  
Akhlesh Gupta ◽  
Alvin D. Compaan

AbstractAn Al-doped ZnO front contact was successfully used for the first time for the fabrication of high efficiency CdS/CdTe thin-film solar cells. The ZnO:Al films were deposited on aluminosilicate glass by RF sputtering from a ZnO:Al2O3 target. The ZnO:Al film has ∼95% average transmission in the visible spectrum with ∼3 ohm/square sheet resistance. The CdS and CdTe thin films were also deposited by RF sputtering and devices were completed with a vapor CdCl2 treatment and evaporated Cu/Au back contacts. The highest processing temperature was 387°C, reached during the vapor CdCl2 treatment. The devices were tested at NREL with efficiency of 14.0% which is a record for an all-sputtered CdS/CdTe solar cell. The ZnO-based cell had JSC of 23.6 mA/cm2 compared to 20.7 mA/cm2 for our recent NREL-tested 12.6% cell on a commercial soda-lime-glass/SnO2:F substrate. Other parameters of the 14% ZnO based cell are: FF = 73.25% and VOC = 814 mV. The improved performance is almost entirely due to higher current because of better optical and electrical properties of ZnO:Al TCO. We report also on relative stability between devices on SnO2:F and ZnO:Al TCO, under one-sun light soak at VOC.


1996 ◽  
Vol 426 ◽  
Author(s):  
Jeff Alleman ◽  
Dave Ginley ◽  
Falah Hasoon ◽  
Sally Asher ◽  
Rommel Noufi

AbstractA key element of current Copper Indium Diselenide (CIS) and Copper Indium Gallium Diselenide (CIGS) thin film solar cells is the use of a Mo back contact on soda lime glass (SGL). Because of surface preparation problems, high process temperatures, and mismatch of thermal expansion coefficients, adhesion of the Mo to the soda lime glass can be variable. Also beneficial is the Na facile diffusion of the glass into the absorber layer. We report on the use of thin Cr interlayers to improve the adhesion at the Mo/glass interface. The films were subsequently annealed in vacuum under normal process conditions. Adhesion was excellent and quite uniform for Mo layers with a Cr interlayer of 50 to 800 Å compared to control samples without Cr. X-ray Photoelectron Spectroscopy (XPS) data suggests CrO bonding at the glass interface and Cr metallic bonding at the Cr Mo interface. Secondary Ion Mass Spectrometry (SIMS) data for Mo/Cr films shows diffusion of Na throughout the Mo layer identical to that for Mo alone samples. Resistivities of the films have been measured to be 11 μhms-cm, twice that for bulk material of 5.7 μohms-cm. CIGS films were then grown for comparison to films grown on Mo only substrates.


2005 ◽  
Vol 865 ◽  
Author(s):  
Tokio Nakada ◽  
Keiichiro Yamada ◽  
Ryota Arai ◽  
Hiroki Ishizaki ◽  
Naoomi Yamada

AbstractAg(In1-xGax)Se2 thin films have been deposited on Mo-coated soda-lime glass substrates by the three-stage process using a molecular beam epitaxy (MBE) system. We found a remarkable decrease in the substrate temperature during the 2nd stage in which the film composition changes to a Ag excess. A single phase chalcopyrite AIGS thin film with a slightly Ag poor composition was obtained by using the temperature monitoring composition method. The cell performance of the AIGS thin film solar cell was found to strongly depend on the Ga/(In+Ga) and Ag/(In+Ga) atomic ratios.A high efficiency wide-gap (Eg=1.7eV) Ag(In0.2Ga0.8)Se2 thin film solar cell with a total-area efficiency of 9.3% (10.2% active area efficiency), Voc = 949mV, Jsc = 17.0 mA/cm2, FF = 0.577, and total area = 0.42 cm2 was achieved. The junction formation mechanism of AIGS devices is discussed based on electron beam induced current (EBIC) and scanning capacitance microscopy (SCM) analyses.


2018 ◽  
Vol 9 ◽  
pp. 2700-2707 ◽  
Author(s):  
Nima Khoshsirat ◽  
Fawad Ali ◽  
Vincent Tiing Tiong ◽  
Mojtaba Amjadipour ◽  
Hongxia Wang ◽  
...  

Molybdenum (Mo) is the most commonly used material as back contact in thin-film solar cells. Adhesion of Mo film to soda–lime glass (SLG) substrate is crucial to the performance of solar cells. In this study, an optimized bilayer structure made of a thin layer of Mo on an ultra-thin chromium (Cr) adhesion layer is used as the back contact for a copper zinc tin sulfide (CZTS) thin-film solar cell on a SLG substrate. DC magnetron sputtering is used for deposition of Mo and Cr films. The conductivity of Mo/Cr bilayer films, their microstructure and surface morphology are studied at different deposition powers and working pressures. Good adhesion to the SLG substrate has been achieved by means of an ultra-thin Cr layer under the Mo layer. By optimizing the deposition conditions we achieved low surface roughness, high optical reflectance and low sheet resistivity while we could decrease the back contact thickness to 600 nm. That is two thirds to half of the thickness that is currently being used for bilayer and single layer back contact for thin-film solar cells. We demonstrate the excellent properties of Mo/Cr bilayer as back contact of a CZTS solar cell.


2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Xia Yan ◽  
Selvaraj Venkataraj ◽  
Armin G. Aberle

Transparent conductive oxides (TCOs) play a major role as the front electrodes of thin-film silicon (Si) solar cells, as they can provide optical scattering and hence improved photon absorption inside the devices. In this paper we report on the surface texturing of aluminium-doped zinc oxide (ZnO:Al or AZO) films for improved light trapping in thin-film Si solar cells. The AZO films are deposited onto soda-lime glass sheets via pulsed DC magnetron sputtering. Several promising AZO texturing methods are investigated using diluted hydrochloric (HCl) and hydrofluoric acid (HF), through a two-step etching process. The developed texturing procedure combines the advantages of the HCl-induced craters and the smaller and jagged—but laterally more uniform—features created by HF etching. In the two-step process, the second etching step further enhances the optical haze, while simultaneously improving the uniformity of the texture features created by the HCl etch. The resulting AZO films show large haze values of above 40%, good scattering into large angles, and a surface angle distribution that is centred at around 30°, which is known from the literature to provide efficient light trapping for thin-film Si solar cells.


Sign in / Sign up

Export Citation Format

Share Document