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 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.

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 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.

High short-circuit current density CdTe solar cells using all-electrodeposited semiconductors

2014 ◽  
Vol 556 ◽  
pp. 529-534 ◽  
Author(s):  
O.K. Echendu ◽  
F. Fauzi ◽  
A.R. Weerasinghe ◽  
I.M. Dharmadasa
Keyword(s):  
Solar Cells ◽  
Current Density ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Cdte Solar Cells

Ultrathin CdTe solar cells with absorber layer thinner than 0.2 microns

2018 ◽  
Vol 83 (2) ◽  
pp. 20101 ◽  
Author(s):  
Min Wang ◽  
Xun Li ◽  
Deliang Wang
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Absorber Layer ◽  
Cdte Solar Cell ◽  
Cdte Solar Cells ◽  
Different Temperatures ◽  
Total Leakage

In this study, ultrathin Cadmium telluride (CdTe) solar cells with absorber thickness from 50 to 200 nm were fabricated. The short-circuit current (JSC) and open-circuit voltage (VOC) were found to decrease significantly with the thickness of absorber layer decreasing. The decrease of the JSC was mainly because of the insufficient light absorption. Even so, the JSC was still found to be 8.2 mA/cm2, which was about 32% of that of a normal CdTe solar cell when the thickness of absorber layer was reduced to ∼1% of that of a normal CdS/CdTe solar cell, i.e. 50 nm. The reasons, which caused the decrease of VOC, were also discussed in this study. The dark current–voltage characteristics were analyzed and the contribution of ohmic shunting current to the total leakage current was found to increase with the thickness of CdTe absorber layer decreasing. The device characteristics of the ultrathin CdTe solar cells under weak light irradiance and at different temperatures were also investigated. This study provides a guideline for the fabrication of ultrathin CdTe solar cells in the future.

Determining the exciton diffusion length of copper phthalocyanine in operating planar-heterojunction organic solar cells

2020 ◽  
Vol 89 (3) ◽  
pp. 30201 ◽  
Author(s):  
Xi Guan ◽  
Shiyu Wang ◽  
Wenxing Liu ◽  
Dashan Qin ◽  
Dayan Ban
Keyword(s):  
Solar Cells ◽  
Organic Solar Cells ◽  
Diffusion Length ◽  
Copper Phthalocyanine ◽  
Short Circuit ◽  
Thick Layer ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Exciton Diffusion ◽  
Exciton Diffusion Length

Organic solar cells based on planar copper phthalocyanine (CuPc)/C60 heterojunction have been characterized, in which a 2 nm-thick layer of bathocuproine (BCP) is inserted into the CuPc layer. The thin layer of BCP allows hole current to tunnel it through but blocks the exciton diffusion, thereby altering the steady-state exciton profile in the CuPc zone (zone 1) sandwiched between BCP and C60. The short-circuit current density (JSC) of device is limited by the hole-exciton scattering effect at the BCP/CuPc (zone 1) interface. Based on the variation of JSC with the width of zone 1, the exciton diffusion length of CuPc is deduced to be 12.5–15 nm. The current research provides an easy and helpful method to determine the exciton diffusion lengths of organic electron donors.

scholarly journals Numerical Investigation of Graphene as a Back Surface Field Layer on the Performance of Cadmium Telluride Solar Cell

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3275
Author(s):  
Devendra KC ◽  
Deb Kumar Shah ◽  
M. Shaheer Akhtar ◽  
Mira Park ◽  
Chong Yeal Kim ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Doping Concentration ◽  
Carrier Lifetime ◽  
Short Circuit ◽  
Back Surface ◽  
Back Surface Field ◽  
Cdte Solar Cell ◽  
Cdte Solar Cells ◽  
Surface Field

This paper numerically explores the possibility of ultrathin layering and high efficiency of graphene as a back surface field (BSF) based on a CdTe solar cell by Personal computer one-dimensional (PC1D) simulation. CdTe solar cells have been characterized and studied by varying the carrier lifetime, doping concentration, thickness, and bandgap of the graphene layer. With simulation results, the highest short-circuit current (Isc = 2.09 A), power conversion efficiency (h = 15%), and quantum efficiency (QE ~ 85%) were achieved at a carrier lifetime of 1 × 103 ms and a doping concentration of 1 × 1017 cm−3 of graphene as a BSF layer-based CdTe solar cell. The thickness of the graphene BSF layer (1 mm) was proven the ultrathin, optimal, and obtainable for the fabrication of high-performance CdTe solar cells, confirming the suitability of graphene material as a BSF. This simulation confirmed that a CdTe solar cell with the proposed graphene as the BSF layer might be highly efficient with optimized parameters for fabrication.

scholarly journals The Influence of the Thickness of Compact TiO2 Electron Transport Layer on the Performance of Planar CH3NH3PbI3 Perovskite Solar Cells

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3295
Author(s):  
Andrzej Sławek ◽  
Zbigniew Starowicz ◽  
Marek Lipiński
Keyword(s):  
Solar Cells ◽  
Electron Transport ◽  
Short Circuit ◽  
Photovoltaic Performance ◽  
Perovskite Solar Cells ◽  
Precursor Solution ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Transport Layer ◽  
Electron Transport Layer

In recent years, lead halide perovskites have attracted considerable attention from the scientific community due to their exceptional properties and fast-growing enhancement for solar energy harvesting efficiency. One of the fundamental aspects of the architecture of perovskite-based solar cells (PSCs) is the electron transport layer (ETL), which also acts as a barrier for holes. In this work, the influence of compact TiO2 ETL on the performance of planar heterojunction solar cells based on CH3NH3PbI3 perovskite was investigated. ETLs were deposited on fluorine-doped tin oxide (FTO) substrates from a titanium diisopropoxide bis(acetylacetonate) precursor solution using the spin-coating method with changing precursor concentration and centrifugation speed. It was found that the thickness and continuity of ETLs, investigated between 0 and 124 nm, strongly affect the photovoltaic performance of PSCs, in particular short-circuit current density (JSC). Optical and topographic properties of the compact TiO2 layers were investigated as well.

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