Carrier Transport and Recombination In A-SI:H P-I-N Solar Cells in Dark and Under Illumination

2003 ◽  
Vol 762 ◽  
Author(s):  
J. Deng ◽  
J.M. Pearce ◽  
V. Vlahos ◽  
R.J. Koval ◽  
R.W. Collins ◽  
...  

AbstractA study has been carried out on the forward bias dark current and the short circuit current -open circuit voltage characteristics of a-Si:H p-i-n solar cells over wide range of illumination intensities. Results are presented with superposition of these characteristics over extended current voltage regimes. This and the observed separation between these characteristics are consistent with the arguments presented based on first principle arguments. The conclusions drawn about the role of photo-generated carrier lifetimes, the densities of defects and the potential barriers in the i-layers adjacent to the n and p contacts are confirmed by numerical simulations. The key role of these potential barriers to the split in the characteristics offer new insight into both why the lack of superposition has been observed and the erroneous conclusions drawn about carrier transport for a-Si:H solar cells in the dark and under illumination.

2012 ◽  
Vol 486 ◽  
pp. 140-144 ◽  
Author(s):  
Zulkhair A. Mansurov ◽  
M. Aueylkhankyzy ◽  
Bakhytzhan T. Lesbaye ◽  
Dmitriy I. Chenchik ◽  
K.K. Dikhanbaev ◽  
...  

The present work is devoted to studying photoelectrical properties of the solar cells covered with nickel oxide nanoparticles synthesized in counter flow propane flame. In the given case, the nanoparticles of oxides play the role of quantum points on the surface of the solar cells and promotes effective absorption of light energy. The applying of silicon solar cells of nickel oxide nanoparticles to the surface caused the increase of output open circuit voltage of 4-7 %, the increase of short - circuit current of 20 - 28 %, that in total caused the increase of efficiency of the solar cells by 2-3%.


2010 ◽  
Vol 1245 ◽  
Author(s):  
Steve Reynolds ◽  
Vladimir Smirnov

AbstractAn equivalent-circuit electrical model is used to simulate the photovoltaic properties of mixed-phase thin-film silicon solar cells. Microcrystalline and amorphous phases are represented as separate parallel-connected photodiode equivalent circuits, scaled by assuming that the photodiode area is directly proportional to the volume fraction of each phase. A reasonable correspondence between experiment and simulation is obtained for short-circuit current and open-circuit voltage vs. volume fraction. However the large dip in fill-factor and reduced PV efficiency measured for cells prepared in the low-crystalline region is inadequately reproduced. It is concluded that poor PV performance in this region is not due solely to shunting by more highly-crystalline filaments, which supports the view that the low-crystalline material has transport properties inferior to either microcrystalline or amorphous silicon.


2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Hongtao Cui ◽  
Chang-Yeh Lee ◽  
Wei Li ◽  
Xiaolei Liu ◽  
Xiaoming Wen ◽  
...  

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.


1985 ◽  
Vol 49 ◽  
Author(s):  
Z E. Smith ◽  
S. Wagner

AbstractThe light-induced performance degradation of amorphous silicon solar cells is described well by a model in which the carrier lifetimes are determined by the dangling bond density. The kinetics of the defect generation follow the model in which band-to-band recombination provides the energy for the creation of dangling bonds, which in turn introduce gap states that reduce carrier lifetime. Degradation will be slower in solar cells operating at lower excess carrier concentrations. This is documented with a comparison of degradation data for cells of different i-layer thickness, cells operating at open circuit vs. load, and for single vs. cascade cells. The model also correctly predicts the relation between short circuit current and fill factor degradation. At sufficiently long times, the efficiency will decrease at approximately the same rate for all cell structures and dimensions, with an offset in time between different device types which can be calculated.


2000 ◽  
Vol 609 ◽  
Author(s):  
Nils Jensen ◽  
Uwe Rau ◽  
Jürgen H. Werner

ABSTRACTThis contribution investigates the electronic properties of a-Si:H/c-Si solar cells and explains their electrical output parameters open circuit voltage, short circuit current, and fill factor. Our device analysis is based on measurements of the internal quantum efficiency, of current/voltage and capacitance/voltage curves. We find carrier recombination within the crystalline silicon absorber material to be responsible for the limitation of the open circuit voltage. The short circuit current is restricted by collection losses in the absorber material and by absorption in the electrically inactive a-Si:H emitter. Resistive losses affecting the fill factor originate from the transport of minority carriers across the interface. The I/V curves measured at low temperatures reveal a characteristic S-shaped behavior. This effect increases with decrasing temperature and stems from the minority carrier transport, which is hindered by the band offset between a-Si:H and c-Si. We propose a new analytical model to describe this anomalous behavior.


Author(s):  
М.Н. Солован ◽  
Г.О. Андрущак ◽  
А.И. Мостовой ◽  
Т.Т. Ковалюк ◽  
В.В. Брус ◽  
...  

AbstractGraphite/ p -SiC Schottky diodes are fabricated using the recently suggested technique of transferring drawn graphite films onto p -SiC single-crystal substrates. The current–voltage and capacitance–voltage characteristics are measured at different temperatures and at different frequencies of a small-signal AC signal, respectively. The temperature dependences of the potential-barrier height and of the series resistance of the graphite/ p -SiC junctions are measured and analyzed. The dominant mechanisms of the charge–carrier transport through the diodes are determined. It is shown that the dominant mechanisms of the transport of charge carriers through the graphite/ p -Si Schottky diodes at a forward bias are multi-step tunneling recombination and tunneling described by the Newman formula (at high bias voltages). At reverse biases, the dominant mechanisms of charge transport are the Frenkel–Poole emission and tunneling. It is shown that the graphite/ p -SiC Schottky diodes can be used as detectors of ultraviolet radiation since they have the open-circuit voltage V _oc = 1.84 V and the short-circuit current density I _sc = 2.9 mA/cm^2 under illumination from a DRL 250-3 mercury–quartz lamp located 3 cm from the sample.


Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1684
Author(s):  
Alessandro Romeo ◽  
Elisa Artegiani

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.


Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 726
Author(s):  
Ray-Hua Horng ◽  
Yu-Cheng Kao ◽  
Apoorva Sood ◽  
Po-Liang Liu ◽  
Wei-Cheng Wang ◽  
...  

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.


Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4268
Author(s):  
Jessica de Wild ◽  
Gizem Birant ◽  
Guy Brammertz ◽  
Marc Meuris ◽  
Jef Poortmans ◽  
...  

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.


2020 ◽  
Vol 92 (2) ◽  
pp. 20901
Author(s):  
Abdul Kuddus ◽  
Md. Ferdous Rahman ◽  
Jaker Hossain ◽  
Abu Bakar Md. Ismail

This article presents the role of Bi-layer anti-reflection coating (ARC) of TiO2/ZnO and back surface field (BSF) of V2O5 for improving the photovoltaic performance of Cadmium Sulfide (CdS) and Cadmium Telluride (CdTe) based heterojunction solar cells (HJSCs). The simulation was performed at different concentrations, thickness, defect densities of each active materials and working temperatures to optimize the most excellent structure and working conditions for achieving the highest cell performance using obtained optical and electrical parameters value from the experimental investigation on spin-coated CdS, CdTe, ZnO, TiO2 and V2O5 thin films deposited on the glass substrate. The simulation results reveal that the designed CdS/CdTe based heterojunction cell offers the highest efficiency, η of ∼25% with an enhanced open-circuit voltage, Voc of 0.811 V, short circuit current density, Jsc of 38.51 mA cm−2, fill factor, FF of 80% with bi-layer ARC and BSF. Moreover, it appears that the TiO2/ZnO bi-layer ARC, as well as ETL and V2O5 as BSF, could be highly promising materials of choice for CdS/CdTe based heterojunction solar cell.


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