• Bulletin of the Korean Chemical Society
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• 제32권8호
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• pp.2743-2750
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• 2011

Lanthanide(III)-cored complex as a wavelength conversion material has been successfully designed and synthesized for highly efficient dye-sensitized solar cells, for the first time, since light with a short wavelength has not been effectively used for generating electric power owing to the limited absorption of these DSSCs in the UV region. A black dye (BD) was chosen and used as a sensitizer, because BD has a relatively weak light absorption at shorter wavelengths. The overall conversion efficiency of the BD/WCM device was remarkably increased, even with the relatively small amount of WCM added to the device. The enhancement in $V_{oc}$ by WCM, like DCA, could be correlated with the suppression of electron recombination between the injected electrons and $I_3{^-}$ ions. Furthermore, the short-circuit current density was significantly increased by WCM with a strong UV light-harvesting effect. The energy transfer from the Eu(III)-cored complex to the $TiO_2$ film occurred via the dye, so the number of electrons injected into the $TiO_2$ surface increased, i.e., the short-circuit current density was increased. As a result, BD/WCM-sensitized solar cells exhibit superior device performance with the enhanced conversion efficiency by a factor of 1.22 under AM 1.5 sunlight: The photovoltaic performance of the BD/WCM-based DSSC exhibited remarkably high values, $J_{sc}$ of 17.72 mA/$cm^2$, $V_{oc}$ of 720 mV, and a conversion efficiency of 9.28% at 100 mW $cm^{-2}$, compared to a standard DSSC with $J_{sc}$ of 15.53 mA/$cm^2$, $V_{oc}$ of 689 mV, and a conversion efficiency of 7.58% at 100 mW $cm^{-2}$. Therefore, the Eu(III)-cored complex is a promising candidate as a new wavelength conversion coadsorbent for highly efficient dye-sensitized solar cells to improve UV light harvesting through energy transfer processes. The abstract should be a single paragraph which summaries the content of the article.

• Current Photovoltaic Research
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• 제2권2호
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• pp.73-77
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• 2014

To investigate the effect of metal back-reflective layers (MBLs) on the performance of GaAs solar cells, we fabricated GaAs solar cells on Al and Ag metal layers using the transfer printing technique. We also investigated the effect of MBL texturing on the performance of transfer printed GaAs solar cells. Transfer printed solar cells with MBLs exhibited improved photovoltaic performance compared to solar cells without MBLs due to light trapping. We demonstrated GaAs solar cells with MBLs on a flexible substrate and performed systematic bending tests. All the measured characteristics of solar cells showed little change in performance.

• Current Photovoltaic Research
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• 제10권4호
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• pp.111-115
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• 2022

For the high efficiency of the photovoltaic module, a high-output solar cell, which is the basis of photovoltaic power generation, is required. As the light receiving area of the solar cell increases, the light receiving area of the photovoltaic module also increases. Accordingly, recent trend is to use large-area solar cells such as M6 and M8 instead of M2-based solar cells for manufacturing the photovoltaic module and a study on the mechanical stiffness of the module with increased size is required. In this study, a mechanical load test corresponding to IEC-61215 was performed among the reliability tests of large-area photovoltaic modules. In order to confirm the degree to which the mechanical load test affects the photovoltaic module, the output and EL images were checked by sequentially increasing the pressure by 600 Pa at a pressure of 2400 Pa. Also, factors such as output and efficiency of large-area photovoltaic modules were verified through mechanical load testing of actual large-area photovoltaic modules and the rate of change was very small at 1%.

• Current Photovoltaic Research
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• 제6권1호
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• pp.1-11
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• 2018

Current major photovoltaic (PV) market share (> 60%) is being occupied by the multicrystalline (mc)-silicon solar cells despite of low efficiency compared to single crystalline silicon solar cells. The diamond wire sawing technology reduces the production cost of crystalline silicon solar cells, it increases the optical loss for the existing mc-silicon solar cells and hence its efficiency is low in the current mass production line. To overcome the optical loss in the mc-crystalline silicon, caused by the diamond wire sawing, next generation texturing process is being investigated by various research groups for the PV industry. In this review, the limitation of surface structure and optical loss due to the reflectivity of conventional mc-silicon solar cells are explained by the typical texturing mechanism. Various texturing technologies that could minimize the optical loss of mc-silicon solar cells are explained. Finally, next generation texturing technology to survive in the fierce cost competition of photovoltaic market is discussed.

• Current Photovoltaic Research
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• 제6권2호
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• pp.31-38
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• 2018

Multijunction solar cells present a practical solution towards a better photovoltaic conversion for a wider spectral range. In this review, we compare different types of multi-ijunction solar cell. First, we introduce thin film multijunction solar cell include to the thin film silicon, III-V material and chalcopyrite material. Until now the maximum reported power conversion efficiencies (PCE) of solar cells having different component sub-cells are 14.0% (thin film silicon), 46% (III-V material), 4.4% (chalcopyrite material) respectively. We then discuss the development of multijunction solar cell in which c-Si is used as bottom sub-cell while III-V material, thin film silicon, chalcopyrite material or perovskite material is used as top sub-cells.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2007년도 추계학술발표대회 및
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• pp.130.1-130.1
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• 2007

• Current Photovoltaic Research
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• 제2권3호
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• pp.103-109
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• 2014

Highly efficient hydrogenated nanocrystalline silicon (nc-Si:H) thin-film solar cells were prepared on flexible stainless steel substrates using plasma-enhanced chemical vapor deposition. To enhance the performance of solar cells, material properties of back reflectors, n-doped seed layers and wide bandgap nc-SiC:H window layers were optimized. The light scattering efficiency of Ag back reflectors was improved by increasing the surface roughness of the films deposited at elevated substrate temperatures. Using the n-doped seed layers with high crystallinity, the initial crystal growth of intrinsic nc-Si:H absorber layers was improved, resulting in the elimination of the defect-dense amorphous regions at the n/i interfaces. The nc-SiC:H window layers with high bandgap over 2.2 eV were deposited under high hydrogen dilution conditions. The vertical current flow of the films was enhanced by the formation of Si nanocrystallites in the amorphous SiC:H matrix. Under optimized conditions, a high conversion efficiency of 9.13% ($V_{oc}=0.52$, $J_{sc}=25.45mA/cm^2$, FF = 0.69) was achieved for the flexible nc-Si:H thin-film solar cells.

• 전기학회논문지
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• 제60권1호
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• pp.100-104
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• 2011

In this work, an optimum condition of electrolytes preparation for photovoltaic cells application was investigated experimentally in terms of impedance and conversion efficiency of the cells. 3-methoxyppropionitrie and redox pairs with LiI and $I_2$ were used as stable solvents for fabrication of electrolyte. Efficiency comparison of the prepared cells carried out for various additives and ionic liquids. From the results, there was an optimum concentration (about 0.3 M) of ionic liquids for efficient cell fabrication. For case of electrolyte using single DMAp additive, the maximum conversion efficiency of the cell was 6.4%($V_{oc}$: 0.78V, $J_{sc}$: 14.4 mA/$cm^2$, ff: 0.57). For case of electrolyte using both DMAp and CEMim additives, the maximum conversion efficiency of the cell was 7.2%($V_{oc}$: 0.79V, $J_{sc}$: 16 mA/$cm^2$, ff: 0.57). From the result of electrochemical impedance measurement, both Z1 and Z3 values of binary additives-based cell decreased compared to those of single additive-based. This is due to the decreased in internal and charge transfer resistivities of the cells.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.175-178
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• 2006

Solid-state dye-sensitized solar cells were fabricated using a polymer matrix in electrolyte in the purpose of the improvement of the durability in the dye-sensitized solar cell. In these dye-sensitized solar cells, the polymer electrolyte consisting of $I_2$, LiI, ionic liquid, ethylene carbonate/propylene carbonate and polymer matrix was casted onto $TiO_2$ electrode impregnated Ruthenium complex dye as a photosensitizer. Photovoltaic properties of solid-state dye-sensitized solar cells using polymer matrix (PMMA, PEG, or PAN) were investigated. Comparing photovoltaic effects of cells using hole conducting polymers (BE or 6P) instead of polymer matrix, we investigated the availability of the solid-state polymer electrolyte in dye-sensitized solar cells.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.313-313
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• 2010

The performance of polymer photovoltaic cells based on blends of poly(3-hexylyhiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) is strongly influenced by blend composition and thickness. Polymer photovoltaic cells based on bulk-heterojunction have been fabricated with a structure of ITO/poly(3, 4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS)-pentacene/poly (3-hexylthiophene) (P3HT):phenyl-C61-butyric acid methyl ester (PCBM)/Al. We have prepared PEDOT:PSS by dissolving pentacene in N-methylpyrrolidine (NMP) and mixing with PEDOT:PSS. Pentacene was added a maximum concentration of approximately 5.5mg to the PEDOT:PSS solution and sonicated for 10 min. Active layer (P3HT:PCBM) (1:1) was strongly influenced by PEDOT:PSS-pentacene. We have investigated the performance of photovoltaic device with different concentration of P3HT:PCBM (1:1) 2.0wt%, 2.2wt%, 2.4wt% and 2.6wt%, respectively. The photocurrent and power conversion efficiency (PCE) showed a maximum between 2.0wt% and 2.2wt% concentration of P3HT:PCBM. This implied that both morphology and electron transport properties of the layer influenced the performance of the present photovoltaic cells. As the concentration of P3HT:PCBM blends as an active layer was increased, the power conversion efficiency was decreased. P3HT:PCBM layer and PEDOT:PSS-pentacene layer were characterized by work function, UV-visible absorption, atomic force microscopy (AFM), X-ray diffraction (XRD) and scanning electron microscope (SEM).