SnO2:F with Very High Haze Value and Transmittance in Near Infrared Wavelength for Use as Front Transparent Conductive Oxide Films in Thin-Film Silicon Solar Cells

2013 ◽  
Vol 1536 ◽  
pp. 63-69 ◽  
Author(s):  
Masanobu Isshiki ◽  
Yasuko Ishikawa ◽  
Toru Ikeda ◽  
Takuji Oyama ◽  
Hidefumi Odaka ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Carrier Concentration ◽  
Near Infrared ◽  
Light Trapping ◽  
Flat Glass ◽  
High Mobility ◽  
Transparent Conductive Oxide ◽  
Infrared Wavelength ◽  
Novel Approach

ABSTRACTLow sheet resistance (high mobility) with high transmittance in all wavelength is required for front TCO. High haze value is also required for effective light trapping. For this purpose, we have combined F-doped SnO2 (FTO) with high mobility deposited by LPCVD and reactive ion etching (RIE) processed glass substrate. However, two problems have been found. (1) The mobility of FTO on RIE substrate dropped from that on flat glass (75 to 36 cm2/Vs). To avoid this drop, thicker film is needed. (2) To keep high transmittance with thicker film, lower carrier concentration is needed. But the mobility dropped with lower carrier concentration. In order to solve these constrains, we have adopted a stacked structure using thick non-doped layer of 2700 nm and thin F-doped layer of 500 nm. With this novel approach, we have successfully achieved the high mobility (80 cm2/Vs), low carrier concentration (2.2x1019 /cm3) and high haze value (77% at wavelength of 1000 nm) at the same time. This new developed high-haze SnO2 is a new promising TCO for thin-film Si solar cells.

Photonic and plasmonic crystal based enhancement of solar cells- overcoming the Lambertian classical 4n2 limit

2012 ◽  
Vol 1426 ◽  
pp. 137-147
Author(s):  
Rana Biswas ◽  
Chun Xu ◽  
Sambit Pattnaik ◽  
Joydeep Bhattacharya ◽  
Nayan Chakravarty ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Near Infrared ◽  
Light Trapping ◽  
Infrared Region ◽  
Plasmonic Crystal ◽  
Device Architecture ◽  
Back Reflectors ◽  
Trapping Methods ◽  
Normal Light

ABSTRACTLong wavelength photons in the red and near infrared region of the spectrum are poorly absorbed in thin film silicon cells, due to their long absorption lengths. Advanced light trapping methods are necessary to harvest these photons. The basic physical mechanisms underlying the enhanced light trapping in thin film solar cells using periodic back reflectors include strong diffraction coupled with light concentration. These will be contrasted with the scattering mechanisms involved in randomly textured back reflectors, which are commonly used for light trapping. A special class of conformal solar cells with plasmonic nano-pillar back reflectors will be described, that generates absorption beyond the classical 4n2 limit (the Lambertian limit) averaged over the entire wavelength range for nc-Si:H. The absorption beyond the classical limit exists for common 1 micron thick nc-Si:H cells, and is further enhanced for non-normal light. Predicted currents exceed 31 mA/cm2 for nc-Si:H. The nano-pillars are tapered into conical protrusions that enhance plasmonic effects. Such conformal nc-Si:H solar cells with the same device architecture were grown on periodic nano-hole, periodic nano-pillar substrates and compared with randomly textured substrates, formed by annealing Ag/ZnO or etched Ag/ZnO. The periodic back reflector solar cells with nano-pillars demonstrated higher quantum efficiency and higher photo-currents that were 1 mA/cm2higher than those for the randomly textured back reflectors. Losses within the experimental solar architectures are discussed.

Realization of Significant Absorption Enhancement in Thin Film Silicon Solar Cells with Textured Photonic Crystal Backside Reflector

2008 ◽  
Vol 1123 ◽  
Author(s):  
Lirong Zeng ◽  
Peter Bermel ◽  
Yasha Yi ◽  
Bernard A. Alamariu ◽  
Kurt A. Broderick ◽  
...  
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Photonic Crystal ◽  
Near Infrared ◽  
Light Trapping ◽  
Short Circuit ◽  
Large Angle ◽  
Bragg Reflector ◽  
Absorption Enhancement ◽  
Si Solar Cells

AbstractThe major factor limiting the efficiencies of thin film Si solar cells is their weak absorption of red and near-infrared photons due to short optical path length and indirect bandgap. Powerful light trapping is essential to confine light inside the cell for sufficient absorption. Here we report the first experimental application of a new light trapping scheme, the textured photonic crystal (TPC) backside reflector, to monocrystalline thin film Si solar cells. TPC combines a onedimensional photonic crystal, i.e., a distributed Bragg reflector (DBR), with a reflection grating. The near unity reflectivity of DBR in a wide omnidirectional bandgap and the large angle diffraction by the grating ensures a strong enhancement in the absorption of red and near-infrared photons, leading to significant improvements in cell efficiencies. Measured short circuit current density Jsc was increased by 19% for 5 μm thick cells, and 11% for 20 μm thick cells, compared to theoretical predictions of 28% and 14%, respectively.

Laser Scribing of W-textured ZnO Substrates Using Green Laser

2013 ◽  
Vol 1493 ◽  
pp. 207-212
Author(s):  
Ryousuke Ishikawa ◽  
Hidetoshi Wada ◽  
Yasuyoshi Kurokawa ◽  
Porponth Sichanugrist ◽  
Makoto Konagai
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Low Cost ◽  
Light Trapping ◽  
Silicon Layer ◽  
Transparent Conductive Oxide ◽  
Green Laser ◽  
Laser Scribing ◽  
Thin Film Silicon ◽  
532 Nm

ABSTRACTThin-film silicon solar cells have been attracted a lot of intention as low-cost solar cells. One of the most important technologies for improving their performances is light trapping. We have demonstrated the high potential of double-textured zinc oxide (ZnO) thin films used as front transparent conductive oxide (TCO) films due to further enhancement of their light-trapping effects. Although the laser scribing method has already been well established for low-cost thin-film silicon solar cell module manufacturing, laser scribing technique on double-textured ZnO is new and still a challenging issue. In this study, we firstly demonstrated the availability of laser scribing for amorphous silicon (a-Si) solar cells fabricated on double-textured ZnO substrates. It is general to utilize lasers with wavelength of 1.06 μm and 532 nm for scribing of TCO and silicon layer, respectively. Here we attempted to scribe both of TCO and silicon layers using a 532 nm wavelength laser (green laser) for process simplifying.

scholarly journals Improve the Properties of p-i-nα-Si:H Thin-Film Solar Cells Using the Diluted Hydrochloric Acid-Etched GZO Thin Films

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Fang-Hsing Wang ◽  
Ming-Yue Fu ◽  
Chean-Cheng Su ◽  
Cheng-Fu Yang ◽  
Hua-Tz Tzeng ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Solar Cells ◽  
Substrate Temperature ◽  
Carrier Concentration ◽  
Carrier Mobility ◽  
Transmission Rate ◽  
Light Trapping ◽  
Thin Film Solar Cells ◽  
Working Pressure

Gallium-doped zinc oxide (GZO) thin films were deposited on glass, and the process parameters are RF power of 50 W and working pressure of 5 mTorr, and the substrate temperature was changed from room temperature to 300°C. At first, the thickness was around 300 nm by controlling the deposition time. The effects of substrate temperature on the crystallinity, lattice constant (c), carrier mobility, carrier concentration, resistivity, and optical transmission rate of the GZO thin films were studied. The 200°C-deposited GZO thin films had the best crystallinity, the larger carrier concentration and carrier mobility, and the lowest resistivity. For that, the thickness of the GZO thin films was extended to around 1000 nm. Hydrochloric (HCl) acid solutions with different concentrations (0.1%, 0.2%, and 0.5%) were used to etch the surfaces of the GZO thin films, which were then used as the substrate electrodes to fabricate the p-i-nα-Si:H thin-film solar cells. The haze ratio of the GZO thin films increased with increasing HCl concentration, and that would effectively enhance light trapping inside the absorber material of solar cells and then improve the efficiency of the fabricated thin-film solar cells.

scholarly journals Plasmon-Enhanced Sunlight Harvesting in Thin-Film Solar Cell by Randomly Distributed Nanoparticle Array

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1380
Author(s):  
Marwa M. Tharwat ◽  
Ashwag Almalki ◽  
Amr M. Mahros
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Solar Cell ◽  
Near Infrared ◽  
Structural Parameters ◽  
Visible Region ◽  
Nanoparticle Array ◽  
Solar Energy Harvesting ◽  
Infra Red ◽  
Crucial Parameter

In this paper, a randomly distributed plasmonic aluminum nanoparticle array is introduced on the top surface of conventional GaAs thin-film solar cells to improve sunlight harvesting. The performance of such photovoltaic structures is determined through monitoring the modification of its absorbance due to changing its structural parameters. A single Al nanoparticle array is integrated over the antireflective layer to boost the absorption spectra in both visible and near-infra-red regimes. Furthermore, the planar density of the plasmonic layer is presented as a crucial parameter in studying and investigating the performance of the solar cells. Then, we have introduced a double Al nanoparticle array as an imperfection from the regular uniform single array as it has different size particles and various spatial distributions. The comparison of performances was established using the enhancement percentage in the absorption. The findings illustrate that the structural parameters of the reported solar cell, especially the planar density of the plasmonic layer, have significant impacts on tuning solar energy harvesting. Additionally, increasing the plasmonic planar density enhances the absorption in the visible region. On the other hand, the absorption in the near-infrared regime becomes worse, and vice versa.

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