A Comparative Study of the Thin-Film CdTe Solar Cells with ZnSe/TCO and the CdS/TCO Buffer Layers

2011 ◽  
Vol 1324 ◽  
Author(s):  
Tamara Potlog ◽  
Nicolae Spalatu ◽  
Arvo Mere ◽  
Jaan Hiie ◽  
Valdek Mikli
Keyword(s):  
Solar Cells ◽  
Buffer Layer ◽  
Buffer Layers ◽  
Glass Substrates ◽  
Cdte Solar Cells ◽  
Zinc Blende ◽  
Photovoltaic Parameters ◽  
Cdte Films ◽  
First Time ◽  
Zinc Blende Structure

ABSTRACTThe growth of ZnSe and CdTe thin films by close spaced sublimation is examined. The investigations show that ZnSe films deposited on glass substrates are polycrystalline and exhibit wurtzite-zinc-blende polytypism. The CdTe films grown on glass/SnO2/ZnSe are polycrystalline and have an f.c.c. zinc-blende structure as in the case of a glass/SnO2/CdS buffer layer. The electric and photovoltaic parameters of ZnSe/CdTe solar cells depend on the ZnSe film thickness. Furthermore, it is shown for the first time that the best photovoltaic parameters are achieved using a Zn buffer layer at the interface between ZnSe and CdTe.

scholarly journals Solution-Processed CdTe Thin-Film Solar Cells Using ZnSe Nanocrystal as a Buffer Layer

2018 ◽  
Vol 8 (7) ◽  
pp. 1195 ◽  
Author(s):  
Yanru Chen ◽  
Xianglin Mei ◽  
Xiaolin Liu ◽  
Bin Wu ◽  
Junfeng Yang ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Buffer Layer ◽  
High Efficiency ◽  
Low Cost ◽  
Buffer Layers ◽  
Thin Film Solar Cells ◽  
Solution Processed ◽  
Cdte Nanocrystal ◽  
First Time

The CdTe nanocrystal (NC) is an outstanding, low-cost photovoltaic material for highly efficient solution-processed thin-film solar cells. Currently, most CdTe NC thin-film solar cells are based on CdSe, ZnO, or CdS buffer layers. In this study, a wide bandgap and Cd-free ZnSe NC is introduced for the first time as the buffer layer for all solution-processed CdTe/ZnSe NC hetero-junction thin-film solar cells with a configuration of ITO/ZnO/ZnSe/CdTe/MoOx/Au. The dependence of the thickness of the ZnSe NC film, the annealing temperature and the chemical treatment on the performance of NC solar cells are investigated and discussed in detail. We further develop a ligand-exchanging strategy that involves 1,2-ethanedithiol (EDT) during the fabrication of ZnSe NC film. An improved power conversion efficiency (PCE) of 3.58% is obtained, which is increased by 16.6% when compared to a device without the EDT treatment. We believe that using ZnSe NC as the buffer layer holds the potential for developing high-efficiency, low cost, and stable CdTe NC-based solar cells.

Electronic Properties of CdTe/CdS Solar Cells as Influenced by a Buffer Layer

MRS Advances ◽  
2016 ◽  
Vol 1 (14) ◽  
pp. 937-942 ◽  
Author(s):  
Y. G. Fedorenko ◽  
J. D. Major ◽  
A. Pressman ◽  
L. Phillips ◽  
K. Durose
Keyword(s):  
Solar Cells ◽  
Grain Boundary ◽  
Electronic Properties ◽  
Buffer Layer ◽  
Defect Density ◽  
Deep Trap ◽  
Energy Shift ◽  
Buffer Layers ◽  
Cdte Solar Cells ◽  
Strain Interaction

ABSTRACTWe considered modification of the defect density of states in CdTe as influenced by a buffer layer in ZnO(ZnS, SnSe)/CdS/CdTe solar cells. Compared to the solar cells employing ZnO buffer layers, implementation of ZnSe and ZnS resulted in the lower net ionized acceptor concentration and the energy shift of the dominant deep trap levels to the midgap of CdTe. The results clearly indicated that the same defect was responsible for the inefficient doping and the formation of recombination centers in CdTe. This observation can be explained taking into account the effect of strain on the electronic properties of the grain boundary interface states in polycrystalline CdTe. In the conditions of strain, interaction of chlorine with the grain boundary point defects can be altered.

Substrate geometry CdTe solar cells with catalytically-grown nano-rough surfaces

MRS Advances ◽  
2016 ◽  
Vol 1 (14) ◽  
pp. 985-990
Author(s):  
G. Papageorgiou ◽  
J.D. Major ◽  
K. Durose
Keyword(s):  
Solar Cells ◽  
Indium Tin Oxide ◽  
Optical Transmission ◽  
Photovoltaic Performance ◽  
Open Circuit ◽  
Glass Substrates ◽  
Cdte Solar Cells ◽  
Nano Structures ◽  
Cdte Films ◽  
Open Circuit Voltages

ABSTRACTSubstrate geometry CdTe solar cells have been modified with the addition of metal-catalysed nano-structures in order to influence their efficiency. Conditions for the growth of Au- and Bi-catalysed nanostructures were explored. The substrate devices themselves comprised indium tin oxide/CdS/CdTe/Mo foil and were developed using the MgCl2 alternative to the usual CdCl2 processing – this yielded open circuit voltages of up to 740 mV. It was demonstrated that the addition of Au-catalysed nanowires to 200 nm thick CdTe films on glass substrates decreased their optical transmission by 10%, this being significantly higher than for thick films. However, reproducibility issues with forming Bi nanostructures limited the device modification tests to the use of Au-catalysed wires, and these always acted to depress photovoltaic performance.

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.

scholarly journals Degradation of Mg-doped zinc oxide buffer layers in thin film CdTe solar cells

2019 ◽  
Vol 691 ◽  
pp. 137556 ◽  
Author(s):  
Francesco Bittau ◽  
Shridhar Jagdale ◽  
Christos Potamialis ◽  
Jake W. Bowers ◽  
John M. Walls ◽  
...  
Keyword(s):  
Thin Film ◽  
Zinc Oxide ◽  
Solar Cells ◽  
Buffer Layers ◽  
Cdte Solar Cells ◽  
Mg Doped

Controlling Band Alignment at the Back Interface of Cadmium Telluride Solar Cells using ZnTe and Te Buffer Layers

MRS Advances ◽  
2019 ◽  
Vol 4 (16) ◽  
pp. 913-919 ◽  
Author(s):  
Fadhil K. Alfadhili ◽  
Adam B. Phillips ◽  
Geethika K. Liyanage ◽  
Jacob M. Gibbs ◽  
Manoj K. Jamarkattel ◽  
...  
Keyword(s):  
Solar Cells ◽  
Fill Factor ◽  
Critical Role ◽  
Open Circuit ◽  
Band Alignment ◽  
Buffer Layers ◽  
Device Performance ◽  
Band Bending ◽  
Cdte Solar Cells ◽  
Hole Current

ABSTRACTFormation of a low barrier back contact plays a critical role in improving the photoconversion efficiency of the CdTe solar cells. Incorporating a buffer layer to minimize the band bending at the back of the CdTe device can significantly lower the barrier for the hole current, improving open circuit voltage (VOC) and the fill factor. Over the past years, researchers have incorporated the both ZnTe and Te as buffer layers to improve CdTe device performance. Here we compare device performance using these two materials as buffer layers at the back of CdTe devices. We show that using Te in contact to CdTe results in higher performance than using ZnTe in contact to the CdTe. Low temperature current density-voltage measurements show that Te results is a lower barrier with CdTe than ZnTe, indicating that Te has better band alignment, resulting in less downward bending in the CdTe at the back interface, than ZnTe does.

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