3D Photonic Crystals as Diffractive and Energy Selective Filter for Tandem Thin Film Solar Cells

2007 ◽  
Vol 1014 ◽  
Author(s):  
Ralf B. Wehrspohn ◽  
Andreas Bielawny ◽  
Carsten Rockstuhl ◽  
Falk Lederer

AbstractWe suggest a photonic structure with energy selective and diffractive properties to be incorporated in thin-film tandem solar cells. Our device enhances the pathway of incident light within a amorphous silicon photovoltaic (PV) top cell in its spectral region of low optical absorption. This leads to an increase in the short-circuit current of the top cell. For a conductive inverted opal structure as intermiediate layer, we numerically determine an current increase of 1.44mA/cm2 for an a-Si:H / c-Si thin-film tandem cell corresponding to an increase in the absolute efficiency from 11.1% to 12.4%.

2009 ◽  
Vol 1153 ◽  
Author(s):  
Rahul Dewan ◽  
Darin Madzharov ◽  
Andrey Raykov ◽  
Dietmar Knipp

AbstractLight trapping in microcrystalline silicon thin-film solar cells with integrated lamellar gratings was investigated. The influence of the grating dimensions on the short circuit current and quantum efficiency was investigated by numerical simulation of Maxwell’s equations by a Finite Difference Time Domain approach. For the red and infrared part of the optical spectrum, the grating structure leads to scattering and higher order diffraction resulting in an increased absorption of the incident light in the silicon thin-film solar cell. By studying the diffracted waves arising from lamellar gratings, simple design rules for optimal grating dimensions were derived.


2008 ◽  
Vol 1101 ◽  
Author(s):  
Hitoshi Sai ◽  
Hiroyuki Fujiwara ◽  
Michio Kondo

AbstractBack surface reflectors (BSRs) with grating structures have been developed to enhance light trapping in thin-film microcrystalline Si (μc-Si:H) solar cells. As a grating structure, a periodic honeycomb-like dimple pattern with periods of 100 ˜ 450 nm has been fabricated on Al substrates by a self-ordering process using anodic oxidation of Al. A clear diffraction effect by the grating structure has been confirmed on the patterned Al using angle-dependent reflection measurement. From quantum efficiency measurements, we found that the periodically patterned BSR can confine the incident light effectively, especially at longer wavelengths. Nevertheless, short circuit current densities obtained from the patterned BSRs are rather comparable to that obtained from the random textured substrate. For further improvement of the light-trapping effect by the grating structure, it is necessary to realize higher diffraction efficiencies while maintaining high total reflectivity on the BSR structure.


2021 ◽  
Author(s):  
Atul Kumar

Abstract Kesterite CZTSxSe1−x has a band gap range from 1 to 1.5eV depending upon S/Se ration. The tandem of kieserite solar cell is proposed and simulated in SCAPS-1D for device configuration and analysis of the performance. CZTS of bandgap 1.5eV as top cell and CZTSSe of bandgap 1.1eV as bottom cell are stacked in tandem for the structure. The thickness of the two layer are optimized for matching the short circuit current JSC in the tandem. This study shines light on alternative technique of thin film multijunction for enhancing the efficiency of CZTSxSe1−x solar cells.


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.


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.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Nils Neugebohrn ◽  
Norbert Osterthun ◽  
Maximilian Götz-Köhler ◽  
Kai Gehrke ◽  
Carsten Agert

AbstractOxide/metal/oxide (OMO) layer stacks are used to replace transparent conductive oxides as front contact of thin-film solar cells. These multilayer structures not only reduce the overall thickness of the contact, but can be used for colouring of the cells utilizing interference effects. However, sheet resistance and parasitic absorption, both of which depend heavily on the metal layer, should be further reduced to reach higher efficiencies in the solar cells. In this publication, AgOX wetting layers were applied to OMO electrodes to improve the performance of Cu(In,Ga)Se2 (CIGS) thin-film solar cells. We show that an AgOX wetting layer is an effective measure to increase transmission and conductivity of the multilayer electrode. With the presented approach, we were able to improve the short-circuit current density by 18% from 28.8 to 33.9 mA/cm2 with a metal (Ag) film thickness as low as 6 nm. Our results highlight that OMO electrodes can be an effective replacement for conventional transparent conductive oxides like aluminium-doped zinc oxide on thin-film solar cells.


Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3397 ◽  
Author(s):  
Jong Lim ◽  
Woo Shin ◽  
Hyemi Hwang ◽  
Young-Chul Ju ◽  
Suk Ko ◽  
...  

Cut solar cells have received considerable attention recently as they can reduce electrical output degradation when the c-Si solar cells (crystalline-silicon solar cells) are shaded. Cut c-Si solar cells have a lower short-circuit current than normal solar cells and the decrease in short-circuit currents is similar to the shading effect of c-Si solar cells. However, the results of this study’s experiment show that the shadow effect of a c-Si solar cell reduces the V o c (open circuit voltage) in the c-Si solar cell but the V o c does not change when the c-Si solar cell is cut because the amount of incident light does not change. In this paper, the limitations of the electrical power analysis of the cut solar cells were identified when only photo current was considered and the analysis of the electric output of the cut c-Si solar cells was interpreted with a method different from that used in previous analyses. Electrical output was measured when the shaded and cut rates of c-Si solar cells were increased from 0% to 25, 50 and 75%, and a new theoretical model was compared with the experimental results using MATLAB.


2011 ◽  
Vol 110-116 ◽  
pp. 497-502
Author(s):  
Wei Ping Chu ◽  
Fuh Shyang Juang ◽  
Jian Shian Lin ◽  
Tien Chai Lin ◽  
Chen Wei Kuo

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.


2011 ◽  
Vol 378-379 ◽  
pp. 601-605 ◽  
Author(s):  
Saleh N. Alamri ◽  
M. S. Benghanem ◽  
A. A. Joraid

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.


2013 ◽  
Vol 114 ◽  
pp. 59-64 ◽  
Author(s):  
Yang-Eun Lee ◽  
Sei-Yong Kim ◽  
Won-Ik Jeong ◽  
Jang-Joo Kim

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