Short-circuit current improvement in CdTe solar cells by combining a ZnO buffer layer and a solution back contact

2017 ◽  
Vol 17 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Eun Seok Cha ◽  
Young Min Ko ◽  
Seon Cheol Kim ◽  
Byung Tae Ahn
Keyword(s):  
Solar Cells ◽  
Buffer Layer ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Back Contact ◽  
Cdte Solar Cells ◽  
Zno Buffer Layer

scholarly journals CuSCN as the Back Contact for Efficient ZMO/CdTe Solar Cells

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1991
Author(s):  
Deng-Bing Li ◽  
Zhaoning Song ◽  
Sandip S. Bista ◽  
Fadhil K. Alfadhili ◽  
Rasha A. Awni ◽  
...  
Keyword(s):  
Solar Cells ◽  
Power Conversion Efficiency ◽  
Buffer Layer ◽  
Conversion Efficiency ◽  
Short Circuit ◽  
Power Conversion ◽  
Open Circuit ◽  
Full Potential ◽  
Back Contact ◽  
Cdte Solar Cells

The replacement of traditional CdS with zinc magnesium oxide (ZMO) has been demonstrated as being helpful to boost power conversion efficiency of cadmium telluride (CdTe) solar cells to over 18%, due to the reduced interface recombination and parasitic light absorption by the buffer layer. However, due to the atmosphere sensitivity of ZMO film, the post treatments of ZMO/CdTe stacks, including CdCl2 treatment, back contact deposition, etc., which are critical for high-performance CdTe solar cells became crucial challenges. To realize the full potential of the ZMO buffer layer, plenty of investigations need to be accomplished. Here, copper thiocyanate (CuSCN) is demonstrated to be a suitable back-contact material with multi-advantages for ZMO/CdTe solar cells. Particularly, ammonium hydroxide as the solvent for CuSCN deposition shows no detrimental impact on the ZMO layer during the post heat treatment. The post annealing temperature as well as the thickness of CuSCN films are investigated. Finally, a champion power conversion efficiency of 16.7% is achieved with an open-circuit voltage of 0.857 V, a short-circuit current density of 26.2 mA/cm2, and a fill factor of 74.0%.

scholarly journals Band diagrams and performance of CdTe solar cells with a Sb2Te3 back contact buffer layer

AIP Advances ◽  
2011 ◽  
Vol 1 (4) ◽  
pp. 042152 ◽  
Author(s):  
Songbai Hu ◽  
Zhe Zhu ◽  
Wei Li ◽  
Lianghuan Feng ◽  
Lili Wu ◽  
...  
Keyword(s):  
Solar Cells ◽  
Buffer Layer ◽  
Back Contact ◽  
Cdte Solar Cells ◽  
And Performance

scholarly journals Optical Losses of Frontal Layers in Superstrate CdS/CdTe Solar Cells Using OPAL2

Coatings ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 943
Author(s):  
Nowshad Amin ◽  
Mohammad Rezaul Karim ◽  
Zeid Abdullah ALOthman
Keyword(s):  
Solar Cells ◽  
Short Circuit ◽  
Contact Potential Difference ◽  
Short Circuit Current ◽  
Optical Losses ◽  
Contact Potential ◽  
Conducting Oxides ◽  
Cdte Solar Cells ◽  
First Time ◽  
Defect Densities

In this paper, optical losses in CdS/CdTe solar cells are calculated on the basis of the designated reflective index of various frontal layers using an OPAL2 calculator for the first time. Two types of glass (0.1 mm ultra-thin Schott and 1.1 mm standard borosilicate glass) were assumed to be coated by different Transparent-Conducting-Oxides (TCOs) such as SnO2:F, ZnO:Al, and ITO forming frontal layers for CdS/CdTe solar cells in superstrate configuration. Absorption, reflectance, transmittance, and consequently optical bandgap energies are calculated as a function of common thicknesses, used in the literature. The results show that an increase in TCO thickness led to a decrease in optical band gap as well as an enhancement in contact potential difference, which can deteriorate device performance. The optimum thickness of 100 nm for SnO2:F was calculated, while 200 nm for ZnO:Al and ITO show reasonable optical losses caused by reflections at the interfaces’ and the layer’s absorption. It is seen that 80 to 150 nm CdS on ITO might be an effective range to satisfy a high short circuit current and low defect densities at the CdS/CdTe interface. Finally, a minimum 2 μm thickness for the CdTe on the ultra-thin Schott glass coated by optimum layers can result in the highest short circuit current of 28.69 mA/cm2. This work offers a practical equivalent strategy to be applied for any superstrate solar cells containing TCO and CdS frontal layers.

Enhanced Light Absorption in a-Si:H Layers of Solar Cells by Applying Tco/Metal Back Contacts

1993 ◽  
Vol 297 ◽  
Author(s):  
G. Tao ◽  
B.S. Girwar ◽  
G.E.N. Landweer ◽  
M. Zeman ◽  
J.W. Metselaar
Keyword(s):  
Solar Cells ◽  
Metal Layer ◽  
Spectral Response ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Back Contact ◽  
Flat Substrate ◽  
Metal Layers ◽  
Metal Back

The optimization of the back contact reflectivity for thin film a-Si:H solar cells has been performed. The results of optical calculations show that a-Si:H/TCO/Metal interfaces with a proper TCO thickness reflect much more than their a-Si:H/Metal counterparts. We compared solar cells which were deposited on a flat substrate with different back contacts. The back contacts consisted of a metal layer (aluminum, silver/aluminum) or combined TCO/metal layers (TCO/Al, TCO/Ag/Al). The same was done with solar cells which were deposited on a textured substrate. The solar cells with a TCO/metal back contact showed not only a significantly increased short-circuit current density but also an increase in the spectral response. The cells with TCO/Ag/Al back contact showed the best result.

Effect of CdTe thickness reduction in high efficiency CdS/CdTe solar cells

2001 ◽  
Vol 668 ◽  
Author(s):  
Akhlesh Gupta ◽  
I. Matulionis ◽  
J. Drayton ◽  
A.D. Compaan
Keyword(s):  
Solar Cells ◽  
High Efficiency ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Cdte Film ◽  
Open Circuit ◽  
Thickness Reduction ◽  
X Ray Diffraction ◽  
Cell Parameters ◽  
Cdte Solar Cells

ABSTRACTHigh efficiency CdTe solar cells are typically grown with CdTe thicknesses from 3 to 15 μm, although the thickness required for 90% absorption of the incident irradiation at 800 nm is only ∼1 μm. In this paper, we present the effect of CdTe thickness reduction on the performance of CdS/CdTe solar cells in which both the CdS and CdTe films were grown by sputtering. We produced a series of cells with different CdTe thickness (from 0.5 to 3.0 μm), and held the CdS thickness and back-contact-processing constant. The effect of CdTe thickness reduction on the diffusion of CdS into CdTe was studied using optical absorption and x-ray diffraction techniques. Only slight decreases occur in open-circuit voltage, short-circuit current, and fill factor with decrease in CdTe film thickness to 1.0 μm. Almost 10% efficient cells were obtained with 1 μm CdTe. Below 1 μm, all cell parameters decrease more rapidly, including the red quantum efficiency.

scholarly journals Optical developments for silicon thin film solar cells in the substrate configuration

2008 ◽  
Vol 1101 ◽  
Author(s):  
Thomas Soderstrom ◽  
Franz-Joseph Haug ◽  
Xavier Niquille ◽  
Oscar Cubero ◽  
Stéphanie Perregaux ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Series Resistance ◽  
Light Trapping ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Silicon Solar Cells ◽  
Back Contact ◽  
Silicon Thin Film ◽  
Optical Behavior

AbstractIn the nip or substrate configuration thin film silicon solar cells, the choice of front TCO contact is critical because there is a trade off between its transparency which influences the current in the solar cell and its conductivity which influences the series resistance. Here, we investigate the optical behavior of two different TCO front contacts, either a 70 nm thick, nominally flat ITO or a 2 μm thick rough LPCVD ZnO. The back contact consists of LP-CVD ZnO with random texture. First we investigate the influence of the rough and flat front TCOs in μc-Si:H and a-Si:H solar cells. With the back contact geometries used in this work, the antireflection properties of ITO are effective at providing as much light trapping as the rough LP-CVD ZnO. In the second part, we demonstrate that total of 25 to 26 mA/cm2is achievable in nip micromorph tandem cells and show short circuit current up to 11.7 mA/cm2 using an SIO based intermediate reflector.

scholarly journals Structural and compositional dependence of the CdTexSe1−x alloy layer photoactivity in CdTe-based solar cells

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Jonathan D. Poplawsky ◽  
Wei Guo ◽  
Naba Paudel ◽  
Amy Ng ◽  
Karren More ◽  
...  
Keyword(s):  
Solar Cells ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Atom Probe ◽  
Alloy Layer ◽  
Bandgap Engineering ◽  
Cdte Solar Cells ◽  
Transmission Electron ◽  
Electron Beam Induced Current ◽  
Composition Structure

Abstract The published external quantum efficiency data of the world-record CdTe solar cell suggests that the device uses bandgap engineering, most likely with a CdTe x Se1−x alloy layer to increase the short-circuit current and overall device efficiency. Here atom probe tomography, transmission electron microscopy and electron beam-induced current are used to clarify the dependence of Se content on the photoactive properties of CdTe x Se1−x alloy layers in bandgap-graded CdTe solar cells. Four solar cells were prepared with 50, 100, 200 and 400 nm-thick CdSe layers to reveal the formation, growth, composition, structure and photoactivity of the CdTe x Se1−x alloy with respect to the degree of Se diffusion. The results show that the CdTe x Se1−x layer photoactivity is highly dependent on the crystalline structure of the alloy (zincblende versus wurtzite), which is also dependent on the Se and Te concentrations.

scholarly journals The Band Structures of Zn1−xMgxO(In) and the Simulation of CdTe Solar Cells with a Zn1−xMgxO(In) Window Layer by SCAPS

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 291
Author(s):  
Xu He ◽  
Lili Wu ◽  
Xia Hao ◽  
Jingquan Zhang ◽  
Chunxiu Li ◽  
...  
Keyword(s):  
Solar Cells ◽  
Band Gap ◽  
Conduction Band ◽  
Short Circuit ◽  
Wavelength Region ◽  
Short Circuit Current ◽  
Window Layer ◽  
Short Wavelength Region ◽  
Conduction Band Offset ◽  
Cdte Solar Cells

Wider band-gap window layers can enhance the transmission of sunlight in the short-wavelength region and improve the performance of CdTe solar cells. In this work, we investigated the band structure of In-doped Zn1−xMgxO (ZMO:In) by using first-principles calculations with the GGA + U method and simulated the performance of ZMO:In/CdTe devices using the SCAPS program. The calculation results show that with the increased Mg doping concentration, the band gap of ZMO increases. However, the band gap of ZMO was decreased after In incorporation due to the downwards shifted conduction band. Owing to the improved short circuit current and fill factor, the conversion efficiency of the ZMO:In-based solar cells show better performance as compared with the CdS-based ones. A highest efficiency of 19.63% could be achieved owing to the wider band gap of ZMO:In and the appropriate conduction band offset (CBO) of ~0.23 eV at ZMO:In/CdTe interface when the Mg concentration x approaches 0.0625. Further investigations on thickness suggest an appropriate thickness of ZMO:In (x = 0.0625) in order to obtain better device performance would be 70–100 nm. This work provides a theoretical guidance for designing and fabricating highly efficient CdTe solar cells.

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