Solar Cell Contacts Using Nano-Sized Dispersions

1999 ◽  
Vol 581 ◽  
Author(s):  
Doug Schulz ◽  
R. Ribelin ◽  
X. Wu ◽  
K.M. Jones ◽  
R.J. Matson ◽  
...  
Keyword(s):  
Solar Cells ◽  
Spray Deposition ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Cdte Layer ◽  
Open Circuit ◽  
Alloy Formation ◽  
Current Densities ◽  
P Type ◽  
Open Circuit Voltages

ABSTRACTNano-sized dispersions have been employed as precursor inks for the spray deposition of contacts to both Si and CdTe materials. In the case of Si, nano-sized Al particles (nano-Al) were dispersed and spray deposited onto p-type Si. Annealing above the eutectic temperature causes alloy formation yielding a p+ layer with p ∼ 10−4 Ω•cm. For CdTe, nano-sized Te particles (nano-Te) were dispersed and sprayed onto CdTe/CdS/SnO2/glass heterostructures. Contact to the CdTe layer occurred during a 30 min anneal in He (T = 215 to 255 °C). These solar cells were finished by spin-coating the Te layer with Ag paint and subsequently annealing in air (100 °C / 1 h). This approach produces solar cells with open circuit voltages (Voc) from 720 to 800 mV, short circuit current densities (Jsc) from 18 to 20 mA/cm2 and efficiencies up to 10.3%. The performance of these cells was similar to those produced using the standard NREL contact.

A NEW APPROACH TO IDEAL AlGaAs MQW SOLAR CELLS

2001 ◽  
Vol 15 (17n19) ◽  
pp. 778-781 ◽  
Author(s):  
J. C. RIMADA ◽  
L. HERNÁNDEZ
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Quantum Wells ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Depletion Region ◽  
Open Circuit ◽  
Current Densities ◽  
Conversion Efficiencies ◽  
Open Circuit Voltages

A theoretical model has been developed which shows that the insertion of multi-quantum wells into the depletion region of a p-i(MQW)-n Al x Ga 1-x As solar cell can significantly enhance the conversion efficiencies. Open-circuit voltages, short-circuit current densities, I-V curves and conversion efficiencies have been calculated as functions of the well and barrier band gaps, width and depth of the wells, number of wells in the intrinsic region and the recombination rate in the interfaces. Particular emphasis is placed on calculation of absorption of the Al x Ga 1-x As quantum wells. These results are matched with p-i-n solar cells which are identical in all respects except that they do not have quantum wells. We demonstrated that for determined values of the studied parameters the conversion efficiencies of the quantum well solar cell is higher to corresponding cell without quantum wells.

scholarly journals Chalcogenide glass-ceramic with self-organized heterojunctions: application to photovoltaic solar cells

2018 ◽  
Vol 9 ◽  
pp. 3 ◽  
Author(s):  
Xianghua Zhang ◽  
Ilia Korolkov ◽  
Bo Fan ◽  
Michel Cathelinaud ◽  
Hongli Ma ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Cells ◽  
Chalcogenide Glass ◽  
Glass Ceramic ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Iodine Doping ◽  
P Type ◽  
Photovoltaic Solar Cells

In this work, we present for the first time the concept of chalcogenide glass-ceramic for photovoltaic applications with the GeSe2–Sb2Se3–CuI system. It has been demonstrated that thin films, deposited with the sputtering technique, are amorphous and can be crystallized with appropriate heat treatment. The thin film glass-ceramic behaves as a p-type semiconductor, even if it contains p-type Cu2GeSe3and n-type Sb2Se3. The conductivity of Sb2Se3has been greatly improved by appropriate iodine doping. The first photovoltaic solar cells based on the association of iodine-doped Sb2Se3and the glass-ceramic thin films give a short-circuit current density JSCof 10 mA/cm2and an open-circuit voltage VOCof 255 mV, with a power conversion efficiency of about 0.9%.

Simulation of Symmetrically Doped Silicon Nanowire Solar Cells

2011 ◽  
Vol 1322 ◽  
Author(s):  
Felix Voigt ◽  
Thomas Stelzner ◽  
Silke H. Christiansen
Keyword(s):  
Solar Cells ◽  
Short Circuit ◽  
Silicon Nanowire ◽  
Short Circuit Current ◽  
Cylindrical Symmetry ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Back Surface ◽  
Cell Efficiency ◽  
P Type

ABSTRACTSilicon nanowire solar cells were simulated using the Silvaco TCAD software kit. For optimization of speed the simulations were performed in cylinder coordinates with cylindrical symmetry. Symmetric doping was assumed with a dopant density of 1018 cm-3 in the p-type core and inside the n-type shell. In the implementation a cathode contact was wrapped around the semiconductor nanorod and an anode was assumed at the bottom of the rod. Optimization of cell efficiency was performed with regard to the rod radius and the rod length. In both optimization processes clear maxima in efficiency were visible, resulting in an optimal radius of 66 nm with the pn junction at 43.5 nm and an optimal rod length of about 48 μm. The maximum of efficiency with respect to the rod radius is due to a decrease of short-circuit current density (Jsc) and an increase of open-circuit voltage (Uoc) with radius, while the maximum with respect to the rod length is explained by the combination of an increase of Jsc and a decrease of Uoc. Fill factors stay rather constant at values between 0.6 and 0.8. Further, the influence of a back surface field (BSF) layer was surveyed in simulations. Positioning the BSF next to the cathode contact considerably improved cell efficiency. In addition, simulations with a cathode contact on top of the nanowire structure were undertaken. No severe deterioration of cell performance with increasing radius was observed so far in this configuration. Hence, nanorods with much larger radii can be used for solar cells using this contact scheme. In comparison to simulations with wrapped cathode contacts, Jsc and Uoc and therefore efficiency is considerably improved.

Effect of Location of Sodium Precursor on the Morphological and Device Properties of CIGS Solar Cells

2013 ◽  
Vol 1538 ◽  
pp. 51-60 ◽  
Author(s):  
Neelkanth G. Dhere ◽  
Ashwani Kaul ◽  
Helio Moutinho
Keyword(s):  
Thin Film ◽  
Surface Roughness ◽  
Solar Cells ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Thin Film Solar Cells ◽  
Cigs Solar Cells ◽  
Device Properties ◽  
Open Circuit Voltages

ABSTRACTSodium plays an important role in the development of device quality CIGS (Cu-In-Ga-Se) and CIGSeS (Cu-In-Ga-Se-S) chalcopyrite thin film solar cells. In this study the effect of location of sodium precursor on the device properties of CIGS solar cells was studied. Reduction in the surface roughness and improvement in the crystallinity and morphology of the absorber films was observed with increase in sodium quantity from 0 Å to 40 Å and to 80 Å NaF. It was found that absorber films with 40 Å and 80 Å NaF in the front of the metallic precursors formed better devices compared to those with sodium at the back. Higher open circuit voltages and short circuit current values were achieved for devices made with these absorber films as well.

The Influence of Nanoparticle Fillers on the Effectiveness of Phosphorus Diffusion Pastes

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Rudolf Nüssl ◽  
Josef Biba ◽  
David Britton
Keyword(s):  
Doping Level ◽  
Silicon Nanoparticles ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Functional Additives ◽  
Current Voltage ◽  
Current Densities ◽  
P Type

A phosphosilicate polymer spin-on glass dopant has been adapted to produce a screen printable N-type diffusion pastes using different types of nanoparticles as functional additives to quantitatively change the doping strength of the paste. Strong qualitative and quantitative differences in the resulting phosphorous concentration profiles after diffusion have been found between different compositions. Not only is an intermediate doping level obtainable if silicon nanoparticles are used instead of silica but also a shallower dopant depth is also achieved. The electrical quality of the layer formed by diffusing phosphorus into the surface of a P-type silicon wafer has been investigated by the fabrication and testing of P-N junction solar cells. The devices exhibit diodelike current–voltage (IV) characteristics with open-circuit voltages of 0.437 V and 0.523 V and short-circuit current densities of 1.88 mA/cm2 and 4.78 mA/cm2 indicating a low doping level of the cell emitter and a relatively high series resistance of the junction.

scholarly journals Improving Efficiency of Evaporated Cu2ZnSnS4Thin Film Solar Cells by a Thin Ag Intermediate Layer between Absorber and Back Contact

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Hongtao Cui ◽  
Chang-Yeh Lee ◽  
Wei Li ◽  
Xiaolei Liu ◽  
Xiaoming Wen ◽  
...  
Keyword(s):  
Solar Cells ◽  
Carrier Transport ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Depletion Region ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Back Contact ◽  
Secondary Phases ◽  
P Type

A 20 nm Ag coating on Mo back contact was adopted to improve the back contact of evaporated Cu2ZnSnS4(CZTS) solar cells. The Ag layer helped reduce the thickness of MoS2which improves fill factor (FF) significantly; additionally, it reduced secondary phases ZnS and SnS2−x, which may help carrier transport; it was also involved in the doping of the absorber layer, which compensated the intrinsic p-type doping and therefore drags down the doping level. The doping involvement may enlarge the depletion region and improve lifetime of the absorber, which led to enhancing open circuit voltage (VOC), short circuit current density (JSC), and efficiency significantly. However, it degrades the crystallinity of the material slightly.

Highly and Rapidly Stabilized Protocrystalline Silicon Multilayer Solar Cells

2005 ◽  
Vol 862 ◽  
Author(s):  
Koeng Su Lim ◽  
Joong Hwan Kwak ◽  
Seong Won Kwon ◽  
Seung Yeop Myong
Keyword(s):  
Solar Cells ◽  
Room Temperature ◽  
Open Circuit Voltage ◽  
Layer Structure ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Current Voltage ◽  
Back Reflector ◽  
P Type

AbstractWe have developed highly stabilized (p-i-n)-type protocrystalline silicon (pc-Si:H) multilayer solar cells. However, the source of the superior light-induced stability of the pc-Si:H multilayer absorbers compared to conventional amorphous silicon (a-Si:H) absorbers remains unclear. Photoluminescence (PL) and Fourier transform infrared (FTIR) spectroscopy measured at room temperature produce strong evidence that nano-sized silicon grains embedded in regularly arranged highly H2-diluted sublayers suppress the photocreation of dangling bonds. To achieve a high conversion efficiency, we applied a double-layer p-type amorphous siliconcarbon alloy (p-a-Si1-xCx:H) structure to the pc-Si:H multilayer solar cells. The less pronounced initial short wavelength quantum efficiency variation as a function of bias voltage, and the wide overlap of dark current - voltage (JD-V) and short-circuit current - open-circuit voltage (Jsc-Voc) characteristics prove that the double p-a-Si1-xCx:H layer structure successfully reduces recombination at the p/i interface. Thus, we achieved a highly stabilized efficiency of 9.0 % without any back reflector.

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

Energies ◽  
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.

scholarly journals GaInP/GaAs/poly-Si Multi-Junction Solar Cells by in Metal Balls Bonding

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 726
Author(s):  
Ray-Hua Horng ◽  
Yu-Cheng Kao ◽  
Apoorva Sood ◽  
Po-Liang Liu ◽  
Wei-Cheng Wang ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Low Temperature ◽  
Triple Junction ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Metal Line ◽  
Solar Simulator ◽  
Junction Solar Cell

In this study, a mechanical stacking technique has been used to bond together the GaInP/GaAs and poly-silicon (Si) solar wafers. A GaInP/GaAs/poly-Si triple-junction solar cell has mechanically stacked using a low-temperature bonding process which involves micro metal In balls on a metal line using a high-optical-transmission spin-coated glue material. Current–voltage measurements of the GaInP/GaAs/poly-Si triple-junction solar cells have carried out at room temperature both in the dark and under 1 sun with 100 mW/cm2 power density using a solar simulator. The GaInP/GaAs/poly-Si triple-junction solar cell has reached an efficiency of 24.5% with an open-circuit voltage of 2.68 V, a short-circuit current density of 12.39 mA/cm2, and a fill-factor of 73.8%. This study demonstrates a great potential for the low-temperature micro-metal-ball mechanical stacking technique to achieve high conversion efficiency for solar cells with three or more junctions.

scholarly journals Ultrathin Cu(In,Ga)Se2 Solar Cells with Ag/AlOx Passivating Back Reflector

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4268
Author(s):  
Jessica de Wild ◽  
Gizem Birant ◽  
Guy Brammertz ◽  
Marc Meuris ◽  
Jef Poortmans ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Solar Cells ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Electron Microscopic ◽  
Current Increase ◽  
Time Resolved ◽  
Cigs Solar Cells

Ultrathin Cu(In,Ga)Se2 (CIGS) absorber layers of 550 nm were grown on Ag/AlOx stacks. The addition of the stack resulted in solar cells with improved fill factor, open circuit voltage and short circuit current density. The efficiency was increased from 7% to almost 12%. Photoluminescence (PL) and time resolved PL were improved, which was attributed to the passivating properties of AlOx. A current increase of almost 2 mA/cm2 was measured, due to increased light scattering and surface roughness. With time of flight—secondary ion mass spectroscopy, the elemental profiles were measured. It was found that the Ag is incorporated through the whole CIGS layer. Secondary electron microscopic images of the Mo back revealed residuals of the Ag/AlOx stack, which was confirmed by energy dispersive X-ray spectroscopy measurements. It is assumed to induce the increased surface roughness and scattering properties. At the front, large stains are visible for the cells with the Ag/AlOx back contact. An ammonia sulfide etching step was therefore applied on the bare absorber improving the efficiency further to 11.7%. It shows the potential of utilizing an Ag/AlOx stack at the back to improve both electrical and optical properties of ultrathin CIGS solar cells.

Sign in / Sign up

Export Citation Format

Share Document