Ge Solar Cells with Micro-Rod Arrays: Structural and Optical Properties

Ge single-junction solar cell structures are grown on micro-patterned Ge substrates using lowpressure metalorganic chemical vapor deposition. 300 nm high micro-rod arrays are formed on the p-Ge substrates using photolithography and dry etching techniques. The micro-rod arrays are designed with rod diameter varying from 5 to 15 μm and arranged in a hexagonal geometry with rod spacing varying from 2 to 12 μm. Ge p–n junction structures are fabricated by phosphorus atomic diffusion process on the micro-patterned Ge substrates. 100 nm thick InGaP window and 300 nm thick GaAs cap layers are grown to reduce the surface recombination and the ohmic contact resistivity, respectively. Our results indicate that the micro-rod structures improve the performance of the Ge solar cells. An improvement of 16.1% in the photocurrent of the Ge micro-rod solar cell is observed compared to that of a reference Ge solar cell with planar surface. The improvement in the short circuit current density can be attributed to the light trapping effect, enlarged p–n junction area, and enhanced carrier collection efficiency. As a result, the conversion efficiency of the Ge solar cell with micro-rod arrays (5 μm diameter, 2 μm spacing, and 300 nm height) is improved from 3.84 to 4.78% under 1 sun AM 1.5G conditions.

Download Full-text

Numerical Simulation of Single Junction InGaN Solar Cell by SCAPS

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.821.407 ◽

2019 ◽

Vol 821 ◽

pp. 407-413 ◽

Cited By ~ 2

Author(s):

Mohamed Orabi Moustafa ◽

Tariq Alzoubi

Keyword(s):

Solar Cells ◽

Solar Cell ◽

Collection Efficiency ◽

Short Circuit ◽

Photovoltaic Performance ◽

Surface Recombination ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Bandgap Energy ◽

Single Junction

The performance of the InGaN single-junction thin film solar cells has been analyzed numerically employing the Solar Cell Capacitance Simulator (SCAPS-1D). The electrical properties and the photovoltaic performance of the InGaN solar cells were studied by changing the doping concentrations and the bandgap energy along with each layer, i.e. n-and p-InGaN layers. The results reveal an optimum efficiency of the InGaN solar cell of ~ 15.32 % at a band gap value of 1.32 eV. It has been observed that lowering the doping concentration NA leads to an improvement of the short circuit current density (Jsc) (34 mA/cm2 at NA of 1016 cm−3). This might be attributed to the increase of the carrier mobility and hence an enhancement in the minority carrier diffusion length leading to a better collection efficiency. Additionally, the results show that increasing the front layer thickness of the InGaN leads to an increase in the Jsc and to the conversion efficiency (η). This has been referred to the increase in the photogenerated current, as well as to the less surface recombination rate.

Download Full-text

CdTe-Based Thin Film Solar Cells: Past, Present and Future

Energies ◽

10.3390/en14061684 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1684

Author(s):

Alessandro Romeo ◽

Elisa Artegiani

Keyword(s):

Thin Film ◽

Solar Cells ◽

Solar Cell ◽

Short Circuit ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Open Circuit ◽

Early Years ◽

Solar Cell Efficiency ◽

Cell Efficiency

CdTe is a very robust and chemically stable material and for this reason its related solar cell thin film photovoltaic technology is now the only thin film technology in the first 10 top producers in the world. CdTe has an optimum band gap for the Schockley-Queisser limit and could deliver very high efficiencies as single junction device of more than 32%, with an open circuit voltage of 1 V and a short circuit current density exceeding 30 mA/cm2. CdTe solar cells were introduced at the beginning of the 70s and they have been studied and implemented particularly in the last 30 years. The strong improvement in efficiency in the last 5 years was obtained by a new redesign of the CdTe solar cell device reaching a single solar cell efficiency of 22.1% and a module efficiency of 19%. In this paper we describe the fabrication process following the history of the solar cell as it was developed in the early years up to the latest development and changes. Moreover the paper also presents future possible alternative absorbers and discusses the only apparently controversial environmental impacts of this fantastic technology.

Download Full-text

Silicon Substrate Treated with Diluted NaOH Aqueous for Si/PEDOT: PSS Heterojunction Solar Cell with Performance Enhancement

Energies ◽

10.3390/en13184659 ◽

2020 ◽

Vol 13 (18) ◽

pp. 4659

Author(s):

Tao Chen ◽

Hao Guo ◽

Leiming Yu ◽

Tao Sun ◽

Yu Yang

Keyword(s):

Aqueous Solution ◽

Solar Cell ◽

Silicon Substrate ◽

High Performance ◽

Immersion Time ◽

Performance Enhancement ◽

Light Trapping ◽

Short Circuit ◽

Short Circuit Current ◽

Short Circuit Current Density

Si/PEDOT: PSS solar cell is an important alternative for photovoltaic device due to its anticipated high theoretical efficiency and simple manufacturing process. In this study, processing silicon substrate with diluted NaOH aqueous solution was found to be an effective method for improving device performance, one that notably improves junction quality and light trapping ability. When immersed in diluted NaOH aqueous solution, the junction quality was improved according to the enlarged fill factor, reduced series resistance, and enhanced minor carrier lifetime. The diluted NaOH aqueous solution immersion etched the silicon surface and helped with the enhancement of light trapping ability, further improving the short-circuit current density. Although diluted NaOH aqueous solution immersion for bare silicon could improve the performance of devices, proper immersion time was needed. The influence of immersion time on device performances was investigated. The photovoltaic conversion efficiency easily increased from 10.01% to 12.05% when silicon substrate was immersed in diluted NaOH aqueous for 15 min. This study contributes to providing efficient and convenient methods for preparing high performance Si/PEDOT: PSS solar cells.

Download Full-text

Donor-π-Conjugated Spacer-Acceptor Dye-Sensitized Solid-State Solar Cell Using CuI as the Hole Collector

International Journal of Photoenergy ◽

10.1155/2019/1653027 ◽

2019 ◽

Vol 2019 ◽

pp. 1-5

Author(s):

D. N. Liyanage ◽

K. D. M. S. P. K. Kumarasinghe ◽

G. R. A. Kumara ◽

A. C. A. Jayasundera ◽

K. Tennakone ◽

...

Keyword(s):

Solar Cells ◽

Solar Cell ◽

Solid State ◽

Short Circuit ◽

Electrical Power ◽

Short Circuit Current ◽

Liquid Electrolyte ◽

Short Circuit Current Density ◽

Dye Sensitized ◽

Type Semiconductor

Dye-sensitized solid-state solar cells (DSSCs) replacing the liquid electrolyte with a p-type semiconductor have been extensively examined to solve the practical problems associated with wet-type solar cells. Here, we report the fabrication of a solid-state solar cell using copper iodide (CuI) as the hole conductor and alkyl-functionalized carbazole dye (MK-2) as the sensitizer. A DSSC sensitized with MK-2 showed a solar-to-electrical power conversion efficiency of 3.33% with a Voc of 496 mV and a Jsc of 16.14 mA cm-2 under AM 1.5 simulated sunlight. The long alkyl chains act as a barrier for charge recombination, and the strong accepting and donating abilities of the cyanoacrylic and carbazole groups, respectively, enhance the absorption of light at a longer wavelength, increasing the short-circuit current density. The efficiency recorded in this work is higher than similar DSSCs based on other hole collectors.

Download Full-text

Nanoimprint Photonic Crystal Film Enhanced Light-Trapping in a-Si Thin Film Solar Cells

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.110-116.497 ◽

2011 ◽

Vol 110-116 ◽

pp. 497-502

Author(s):

Wei Ping Chu ◽

Fuh Shyang Juang ◽

Jian Shian Lin ◽

Tien Chai Lin ◽

Chen Wei Kuo

Keyword(s):

Thin Film ◽

Solar Cells ◽

Photonic Crystals ◽

Current Density ◽

Light Trapping ◽

Short Circuit ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Thin Film Solar Cells ◽

Uv Lamp

We utilize photonic crystals to enhanced lighttrapping in a-Si:H thin film solar cells. The photonic crystals effectively increase Haze ratio of glass and decrease reflectance of a-Si:H solar cells. Therefore, increase the photon path length to obtain maximum absorption of the absorber layer. The photonic crystals can effective in harvesting weakly absorbing photons with energies just above the band edge. We were spin coated UV glue on the glass, and then nanoimprint of photonic crystals pattern. Finally, used UV lamp was curing of UV glue on the glass. When the 45∘composite photonic crystals structures, the haze was increase to 87.9 %, resulting the short circuit current density and efficiency increasing to 13.96 mA/cm2 and 7.39 %, respectively. Because 45∘composite photonic crystals easy to focus on the point of light lead to the effect of scattering can’t achieve. So, we designs 90∘V-shaped photonic crystals structures to increase scattering. When the 90∘V-shaped photonic crystals structures, the Haze was increase to 93.9 %. Therefore, the short circuit current density and Efficiency increasing to 15.62 mA/cm2 and 8.09 %, respectively. We observed ~35 % enhancement of the short-circuit current density and ~31 % enhancement of the conversion efficiency.

Download Full-text

Preparation of the Three Main Layers of CdS/CdTe Thin Film Solar Cells Using a Single Vacuum System

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.378-379.601 ◽

2011 ◽

Vol 378-379 ◽

pp. 601-605 ◽

Cited By ~ 1

Author(s):

Saleh N. Alamri ◽

M. S. Benghanem ◽

A. A. Joraid

Keyword(s):

Thin Film ◽

Solar Cells ◽

Solar Cell ◽

Short Circuit ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Open Circuit ◽

Fused Silica ◽

Vacuum System ◽

Cdte Thin Film

This study investigates the preparation of the three main layers of a CdS/CdTe thin film solar cell using a single vacuum system. A Close Space Sublimation System was constructed to deposit CdS, CdTe and CdCl2 solar cell layers. Two hot plates were used to heat the source and the substrate. Three fused silica melting dishes were used as containers for the sources. The properties of the deposited CdS and CdTe films were determined via Atomic force microscopy, scanning electron microscopy, X-ray diffraction and optical transmission spectroscopy. An J-V characterization of the fabricated CdS/CdTe solar cells was performed under solar radiation. The short-circuit current density, Jsc, the open-circuit voltage, Voc, fill factor, FF and conversion efficiency, η, were measured and yielded values of 27 mA/cm2, 0.619 V, 58% and 9.8%, respectively.

Download Full-text

Silicon nanowires solar cell

MRS Proceedings ◽

10.1557/opl.2011.330 ◽

2011 ◽

Vol 1305 ◽

Author(s):

Xiaobing Xie ◽

Xiangbo Zeng ◽

Wenjie Yao ◽

Ping Yang ◽

Shiyong Liu ◽

...

Keyword(s):

Solar Cell ◽

Silicon Nanowires ◽

Short Circuit ◽

Nanowire Array ◽

Chemical Vapor ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Open Circuit ◽

Type Layer ◽

Si Nanowire Array

ABSTRACTWe made an amorphous-silicon (a-Si) solar cell with a nanowire-array structure on stainless steel(SS) by plasma enhanced chemical vapor (PECVD) deposition. This nanowire structure has an n-type Si nanowire array in which a-Si intrinsic layer and p type layer are sequentially grown on the surface of the nanowire. The highest open-circuit voltage (Voc) and short-circuit current density (Jsc) for AM 1.5 illumination were 620 mV and 13.4 mA/cm2, respectively at a maximum power conversion efficiency of 3.57%.

Download Full-text

Novel Photonic Crystal Based Polycrystalline CdTe/Silicon Solar Cells

SRPH Journal of Fundamental Sciences and Technology ◽

10.47176/sjfst.3.1.5 ◽

2020 ◽

Keyword(s):

Solar Cells ◽

Solar Cell ◽

Photonic Crystal ◽

Conversion Efficiency ◽

Current Density ◽

Cell Structure ◽

Short Circuit ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Silicon Solar Cells

In this paper, a novel photonic crystal (PhC) polycrystalline CdTe/Silicon solar cells are theoretically explained that increase their short circuit current density and conversion efficiency. The proposed structure consist of a polycrystalline CdTe/Silicon solar cell that a photonic crystal is formed in the upper cell. The optical confinement is achieved by means of photonic crystal that can adjust the propagation and distribution of photons in solar cells. For validation of modeling, the electrical properties of the experimentally-fabricated based CdS/CdTe solar cell is modeled and compared that there is good agreement between the modeling results and experimental results from the litterature. The results of this study showed that the solar cell efficiency is increased by about 25% compared to the reference cell by using photonic crystal. The open circuit voltage, short circuit current density, fill factor and conversion efficiency of proposed solar cell structure are 1.01 V, 40.7 mA/cm2, 0.95 and 27% under global AM 1.5 conditions, respectively. Furthermore, the influence of carrier lifetime variation in the absorber layer of proposed solar cell on the electrical characteristics was theoretically considered and investigated.

Download Full-text

Numerical study of a highly efficient light trapping nanostructure of perovskite solar cell on a textured silicon substrate

Scientific Reports ◽

10.1038/s41598-020-75630-4 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Alireza Tooghi ◽

Davood Fathi ◽

Mehdi Eskandari

Keyword(s):

Solar Cell ◽

Silicon Substrate ◽

Numerical Study ◽

Light Trapping ◽

Short Circuit ◽

Short Circuit Current ◽

Perovskite Solar Cell ◽

Short Circuit Current Density ◽

Planar Structure ◽

Plasmonic Enhancement

Abstract In this paper, a nanostructured perovskite solar cell (PSC) on a textured silicon substrate is examined, and its performance is analyzed. First, its configuration and the simulated unit cell are discussed, and its fabrication method is explained. In this proposed structure, poly-dimethylsiloxane (PDMS) is used instead of glass. It is shown that the use of PDMS dramatically reduces the reflection from the cell surface. Furthermore, the light absorption is found to be greatly increased due to the light trapping and plasmonic enhancement of the electric field in the active layer. Then, three different structures, are compared with the main proposed structure in terms of absorption, considering the imperfect fabrication conditions and the characteristics of the built PSC. The findings show that in the worst fabrication conditions considered structure (FCCS), short-circuit current density (Jsc) is 22.28 mA/cm2, which is 27% higher than that of the planar structure with a value of 17.51 mA/cm2. As a result, the efficiencies of these FCCSs are significant as well. In the main proposed structure, the power conversion efficiency (PCE) is observed to be improved by 32%, from 13.86% for the planar structure to 18.29%.

Download Full-text

Analysis of Back Surface Field (BSF) Performance in P-Type And N-Type Monocrystalline Silicon Wafer

E3S Web of Conferences ◽

10.1051/e3sconf/20184301006 ◽

2018 ◽

Vol 43 ◽

pp. 01006 ◽

Cited By ~ 3

Author(s):

Ferdiansjah ◽

Faridah ◽

Kelvian Tirtakusuma Mularso

Keyword(s):

Solar Cell ◽

Doping Level ◽

Short Circuit ◽

Surface Recombination ◽

Short Circuit Current ◽

Short Circuit Current Density ◽

Surface Recombination Velocity ◽

Back Surface ◽

Solar Cell Performance ◽

P Type

Back Surface Field (BSF) has been used as one of means to enhance solar cell performance by reducing surface recombination velocity (SRV). One of methods to produce BSF is by introducing highly doped layer on rear surface of the wafer. Depending on the type of the dopant in wafer, the BSF layer could be either p+ or n+. This research aims to compare the performance of BSF layer both in p-type and n-type wafer in order to understand the effect of BSF on both wafer types. Monociystalline silicon wafer with thickness of 300 μm. area of 1 cm2, bulk doping level NB = 1.5×1016/cm3 both for p-type wafer and n-type wafer are used. Both wafer then converted into solar cell by adding emitter layer with concentration NE =7.5×1018/cm3 both for p-type wafer and n-type wafer. Doping profile that is used for emitter layer is following complementary error function (erfc) distribution profile. BSF concentration is varied from 1×1017/cm3 to 1×1020/cm3 for each of the cell. Solar cell performance is tested under standard condition, with AM1.5G spectrum at 1000 W/m2. Its output is measured based on its open circuit voltage (Voc). short circuit current density (JSC), efficiency (η). and fill factor (FF). The result shows that the value of VOC is relatively constant along the range of BSF concentration, which is 0.694 V – 0.702 V. The same pattern is also observed in FF value which is between 0.828 – 0.831. On the other hand, value of JSC and efficiency will drop against the increase of BSF concentration. Highest JSC which is 0.033 A/cm2 and highest efficiency which is 18.6% is achieved when BSF concentration is slightly higher than bulk doping level. The best efficiency can be produced when BSF concentration is around 1×1017cm-3.. This result confirms that surface recombination velocity has been reduced due to the increase in cell’s short circuit current density and its efficiency. In general both p-type and n-type wafer will produce higher efficiency when BSF is applied. However, the increase is larger in p-type wafer than in n-type wafer. Better performance for solar cell is achieved when BSF concentration is slightly higher that bulk doping level because at very high BSF concentration the cell’s efficiency will be decreased.

Download Full-text