• Current Photovoltaic Research
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• v.9 no.4
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• pp.111-122
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• 2021

Silicon heterojunction technology (HJT) solar cells have received considerable attention due to advantages that include high efficiency over 26%, good performance in the real world environment, and easy application to bifacial power generation using symmetric device structure. Furthermore, ultra-highly efficient perovskite/c-Si tandem devices using the HJT bottom cells have been reported. In this paper, we discuss the unique feature of the HJT solar cells, the fabrication processes and the current status of technology development. We also investigate practical challenges and key technologies of the HJT solar cell manufacturers for reducing fabrication cost and increasing productivity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.444-445
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• 2009

The metallic contact system of silicon solar cell must have several properties, such as low contact resistance, easy application and good adhesion. Ni is shown to be a suitable barrier to Cu diffusion as well as desirable contact metal to silicon. Nickel monosilicide(NiSi) has been suggested as a suitable silicide due to its lower resistivity, lower sintering temperature and lower layer stress than $TiSi_2$. Copper and Silver can be plated by electro & light-induced plating method. Light-induced plating makes use the photovoltaic effect of solar cell to deposit the metal on the front contact. The cell is immersed into the electrolytic plating bath and irradiated at the front side by light source, which leads to a current density in the front side grid. Electroless plated Ni/ Electro&light-induced plated Cu/ Light-induced plated Ag contact solar cells result in an energy conversion efficiency of 16.446 % on $0.2\sim0.6\;{\Omega}{\cdot}cm$, $20\;\times\;20\;mm^2$, CZ(Czochralski) wafer.

• Electrical & Electronic Materials
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• v.10 no.9
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• pp.930-937
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• 1997

Polycrystalline CdTe thin films have been studied for photovoltaic application because of their high absorption coefficient and optimal band energy(1.45 eV) for solar energy conversion. In this study CdTe thin films were deposited on CdS(chemical bath deposition)/ITO(indium tin oxide) substrate by rf-magnetron sputtering under various conditions. Structural optical and electrical properties are investigated with XRD UV-Visible spectrophotometer SEM and solar simulator respectively. The fabricated CdTe/CdS solar cell exhibited open circuit voltage( $V_{oc}$ ) of 610 mV short circuit current density( $J_{sc}$ ) of 17.2 mA/c $m^2$and conversion efficiency of about 5% at optimal sputtering conditions.

• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2269-2279
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• 2009

Six metal-free organic dyes having thiophene (1), benzene-thiophene (2), thiophene-benzene (3), thiophene-pyridine (4), thiophene-thiophene (5), and pyridine (6) linkers between 9,9-dimethylfluorenyl terminal group and $\alpha$-cyanoacrylic acid anchor were synthesized. Among them, organic dye 5 showed the longest ${\lambda}_{max}$ value (424 nm) in UV-Vis absorption spectrum, better incident monochromatic photon-to-current conversion efficiency (IPCE), highest short circuit photocurrent density ($J_{SC},\;9.33\;mA^2/cm^2$), and highest overall conversion efficiency ($\eta$, 3.91%).

• Current Photovoltaic Research
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• v.5 no.4
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• pp.135-139
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• 2017

We fabricated two different transparent conducting oxide thin films of ZnO doped with Ga ($Ga_2O_3$ 0.9 wt%) as well as Al ($Al_2O_3$ 2.1 wt%) (GAZO) and ZnO doped only with Al ($Al_2O_3$ 3 wt%) (AZO). It was investigated how it affects the moisture resistance of the transparent electrode. In addition, $Cu(In,Ga)Se_2$ thin film solar cells with two transparent oxides as front electrodes were fabricated, and the correlation between humidity resistance of transparent electrodes and device performance of solar cells was examined. When both transparent electrodes were exposed to high temperature distilled water, they showed a rapid increase in sheet resistance and a decrease in the fill factor of the solar cell. However, AZO showed a drastic decrease in efficiency at the beginning of exposure, while GAZO showed that the deterioration of efficiency occurred over a long period of time and that the long term moisture resistance of GAZO was better.

• Bulletin of the Korean Chemical Society
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• v.31 no.10
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• pp.2909-2912
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• 2010

Hydrogenated microcrystalline silicon (${\mu}c$-Si:H) thin film for solar cells is prepared by plasma-enhanced chemical vapor deposition and physical properties of the ${\mu}c$-Si:H p-layer has been investigated. With respect to stable efficiency, this film is expected to surpass the performance of conventional amorphous silicon based solar cells and very soon be a close competitor to other thin film photovoltaic materials. Silicon in various structural forms has a direct effect on the efficiency of solar cell devices with different electron mobility and photon conversion. A Raman microscope is adopted to study the degree of crystallinity of Si film by analyzing the integrated intensity peaks at 480, 510 and $520\;cm^{-1}$, which corresponds to the amorphous phase (a-Si:H), microcrystalline (${\mu}c$-Si:H) and large crystals (c-Si), respectively. The crystal volume fraction is calculated from the ratio of the crystalline and the amorphous phase. The results are compared with high-resolution transmission electron microscopy (HR-TEM) for the determination of crystallinity factor. Optical properties such as refractive index, extinction coefficient, and band gap are studied with reflectance spectra.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.2
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• pp.178-181
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• 2008

A solar cell based on dye-sensitized photoelectric conversion was studied by investigating the effects of the amount of polyethylene glycol(PEG), added to the $TiO_2$ paste, on surface morphology of the $TiO_2$ films and on the solar cell performance. Energy conversion efficiency was found to increase with PEG addition up to 20 % by weight of $TiO_2$ and then decrease with further addition due to the aggregation of $TiO_2$ nano particles in the $TiO_2$ film. In this study, the best result of dye-sensitized solar cell was the short circuit current(Isc) of $22.6mAcm^{-2}$, the open circuit voltage (Voc) of 0.73 V, the fill factor (ff) of 0.55 and the overall energy conversion efficiency (${\eta}$) of 9.1 % under illumination with AM 1.5 simulated sunlight.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.383-387
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• 2009

Multi-crystalline silicon surface etching without grain-boundary delineation is a challenging task for the fabrication of high efficiency solar cell. The use of sodium hydroxide - sodium hypochlorite (NaOH40% + NaOCl 12%) solution for texturing multi-crystalline silicon wafer surface in solar cell fabrication line is reported in this article. in light current-voltage results, the cells etched in NaOH 40% + NaOCl 12% = 1:2 exhibited higher short circuit current and open circuit voltage than those of the cells etched in NaOH 40% + NaOCl 12% = 1:1 solution. we have obtained 15.19% conversion efficiency in large area(156cm2) multi-Si solar cells etched in NaOH 40% + NaOCl 12% = 1:1 solution.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.100-106
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• 2009

A novel 8 V DC power source with an external series-parallel connection of 50 Dye-sensitized Solar Cells (DSCs) has been proposed. One DSC has the optimized length to width ratio of $5.2{\times}2.6\;cm$ and an active area $8\;cm^2$ ($4.62{\times}1.73\;cm$) which attained a conversion efficiency of 4.02%. From the electrochemical impedance spectroscopic analysis, it was found that the resistance elements related to the Pt electrode and electrolyte interface behave like that of diode and the series resistance corresponds to the sum of the other resistance elements. Surface morphology and sheet resistance of Pt counter electrode did not degrade the performance of the cell. This novel 8V-0.33A DC power source shows stable performance with an energy conversion efficiency of 4.24% under 1 sun illumination (AM 1.5, Pin of $100\;mW/cm^2$).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.1
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• pp.18-21
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• 2013

$SiO_2$ layer grown by rapid thermal oxidation and $SiN_x$ layer were used for passivating the surface of n-type silicon solar cell, instead of only $SiN_x$ layer generally used in photovoltaic industry. The rapid thermal oxidation provides the reduction of processing time and avoids bulk life time degradation during the processing. Improvement of 30 mV in Voc and $2.7mA/cm^2$ in Jsc was obtained by applying these two layers. This improvement led to fabrication of a large area ($239cm^2$) n-type solar cell with 17.34% efficiency. Internal quantum efficiency measurement indicates that the improvement comes from the front side passivation, but not the rear side, by using $SiO_2/SiN_x$ stack.