• 한국신재생에너지학회:학술대회논문집
• /
• 2006.06a
• /
• pp.174-174
• /
• 2006

• 한국태양에너지학회:학술대회논문집
• /
• 2012.03a
• /
• pp.397-399
• /
• 2012

Dye-sensitized solar cells (DSSCs) have received considerable attention as the most promising candidates for renewable energy systems in recent years. Among these, organic dyes which have many advantages such as large absorption coefficients, customized molecular design for desired photophysical and photochemical properties, inexpensiveness and environment-friendliness, are suitable as photosensitizers for DSSCs. We have studied on the design and synthesis of two organic dyes (BECZ 1 and BECZ 2) with a 9-ethyl-9H-carbazole core for dye-sensitized solar cells (DSSCs). Two organic dyes comprised of two 9-ethyl-9H-carbazole moiety as electron-donor, two types of cyanoacrylic acid moiety acting as acceptor. In addition, n-ethyl unit introduced for increasing the solubility and the donating power. The obtained organic dyes were comprehensively characterized by NMR, GC-MS, FAB-MS and UV/Vis spectroscopies. DSSCs sensitized by the dyes BECZ1 and BECZ2 produced ${\eta}$ value 3.31% and a ${\eta}$ value 3.21%.

• Journal of Ceramic Processing Research
• /
• v.22 no.5
• /
• pp.584-589
• /
• 2021

TiO2 photoelectrodes for dye-sensitized solar cells (DSSCs) were fabricated by changing the thickness using screen printingmethod. The amount of dye adsorbed on TiO2 increases as the thickness of the TiO2 photoelectrode increases because of theincrease in the dye molecule adsorption site. The performance of DSSCs increases up to a TiO2 thickness of approximately12 ㎛, indicating a tendency of dye adsorption that enables photocurrent generation. However, when TiO2 is thicker than 12㎛, the TiO2 films start to break, resulting in a decrease in the performance. The optimum thickness of the TiO2photoelectrode was 12 ㎛, which has a low charge transfer resistance.

• Applied Chemistry for Engineering
• /
• v.22 no.5
• /
• pp.461-466
• /
• 2011

In this study, the fluorine doped $TiO_2$ was prepared as a photoelectrode in order to improve the efficiency of dye-sensitized solar cells and estimated the electrochemical characterizations. The energy conversion efficiency of the prepared dye-sensitized solar cells using fluorine doped $TiO_2$ was calculated from a current-voltage curve. The efficiency of prepared dye-sensitized solar cells was improved by about maximum three times by F-doping on $TiO_2$. It was suggested that the efficiency of dye-sensitized solar cells was improved by hybrid semiconductors of $TiO_2/TiOF_2$ in photoelectrode based on reduced $TiOF_2$ energy level via fluorine doping. It can be confirmed that the electron transport was faster but the electron recombination was slower by doping fluorine on $TiO_2$ in photoelectrode through intensity-modulated photocurrent spectroscopy and intensity-modulated photovoltage spectroscopy analysis.

• ETRI Journal
• /
• v.26 no.6
• /
• pp.647-652
• /
• 2004

A new ionic liquid, 1-vinyl-3-heptylimidazolium iodide (VHpII), was synthesized and applied as a redox electrolyte for dye-sensitized solar cells. The chemical structure of the synthesized VHpII was confirmed using $^1H$ NMR. Thermogravimetric analysis showed that the VHpII was stable for thermal stress of up to $250^{\circ}C$. The energy conversion efficiencies of the VHpII-based dye-sensitized solar cells were investigated in terms of the effect of a lithium iodide addition. A solar cell containing the redox couple of VHpII and iodine showed a conversion efficiency of 2.63% under 1 sun light intensity at AM 1.5. Adding 0.4 M LiI results in a conversion efficiency of 3.63%, which was an improvement of about 40%. The increased conversion efficiency was ascribed to an increase in external quantum efficiency.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.12
• /
• pp.2436-2440
• /
• 2009

In this work, TCO-less dye-sensitized solar cells (DSCs) using Ti-mesh layer is fabricated for high-efficient low-cost solar cell application. The Ti-mesh metal can replace TCO in the photo-electrode part of DSCs, thus the cell structure is composed of a glass/dye sensitized TiO2 particle/ Ti-mesh layer/electrolyte/Pt sputtered counter electrode/ glass. The Ti-mesh electrode with high conductivity can collect electrons from the $TiO_2$ layer and allows the ionic diffusion of $I^-/I_3^-$ through the mesh hole. Thin Ti-mesh ($\sim40{\mu}m$ in thickness) electrode material is processed using rapid prototype method. The efficiency of prepared TCO-less DSCs sample is about 1.45 % ((ff: 0.5, Voc: 0.52V, Jsc: 5.55 $mA/cm^2$).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.24 no.5
• /
• pp.427-431
• /
• 2011

Hybrid $SiO_2-TiO_2$ photoelectrode with different type of layers was investigated in dye-sensitized solar cells (DSSC). Use of a thin layer of nanocrystalline $TiO_2$ would imply reduction in the amount of dye coverage, however, lower amount of dye in the thin films would imply fewer electron generation upon illumination. So, thus, it becomes necessary to include a $SiO_2-TiO_2$ layer for increase light harvesting effect such that the lower photon conversion due to thin layer could be compensated. In this paper reports the use of transparent high surface area $TiO_2$ layer and an additional $SiO_2-TiO_2$ layer, thus ensuring adequate light harvesting in these devices. The best solar conversion efficiency 6.6% under AM 1.5 was attained with a multi-layer structure using $TiO_2$ layer/$SiO_2-TiO_2$ layer/$TiO_2$ layer for the light harvesting and this had resulted to about 44% increase in photocurrent density of dye-sensitized solar cells.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.1
• /
• pp.144-151
• /
• 2010

The shadowing effects lead to the serious power losses of the PV module. The shadowing effects are caused by several factors such as leafs, dust, antenna and clouds. The dye-sensitized solar cells are more economical than the conventional silicon solar cell that's why the dye-sensitized solar cells are recently focused on. We carried out research on the efficiency of the dye-sensitized solar cell depending on the level of shadow changing the formula of the circuit. The research on the efficiency of the large dye-sensitized solar cell depending on the level of shadow focused on commercialization was carried out. As the results, it is known that the series and parallel connection method is the best choice for the least losses of PV module assemblies. It is especially known that one more series connection is the best choice for the least losses about shadowing effects and current losses in the series and parallel connection.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.87-87
• /
• 2010

Photoelectrochemical (PEC) systems are promising methods of producing H2 gas using solar energy in an aqueous solution. The photoelectrochemical properties of numerous metal oxides have been studied. Among them, the PEC systems based on TiO2 have been extensively studied. However, the drawback of a PEC system with TiO2 is that only ultraviolet (UV) light can be absorbed because of its large band gap (3.2 - 3.4 eV). Two approaches have been introduced in order to use PEC cells in the visible light region. The first method includes doping impurities, such as nitrogen, into TiO2, and this technique has been extensively studied in an attempt to narrow the band gap. In comparison, research on the second method, which includes visible light water splitting in molecular photosystems, has been slow. Mallouk et al. recently developed electrochemical water-splitting cells using the Ru(II) complex as the visible light photosensitizer. the dye-sensitized PEC cell consisted of a dye-sensitized TiO2 layer, a Pt counter electrode, and an aqueous solution between them. Under a visible light (< 3 eV) illumination, only the dye molecule absorbed the light and became excited because TiO2 had the wide band gap. The light absorption of the dye was followed by the transfer of an electron from the excited state (S*) of the dye to the conduction band (CB) of TiO2 and its subsequent transfer to the transparent conducting oxide (TCO). The electrons moved through the wire to the Pt, where the water reduction (or H2 evolution) occurred. The oxidized dye molecules caused the water oxidation because their HOMO level was below the H2O/O2 level. Organic dyes have been developed as metal-free alternatives to the Ru(II) complexes because of their tunable optical and electronic properties and low-cost manufacturing. Recently, organic dye molecules containing multi-branched, multi-anchoring groups have received a great deal of interest. In this work, tri-branched tri-anchoring organic dyes (Dye 2) were designed and applied to visible light water-splitting cells based on dye-sensitized TiO2 electrodes. Dye 2 had a molecular structure containing one donor (D) and three acceptor (A) groups, and each ended with an anchoring functionality. In comparison, mono-anchoring dyes (Dye 1) were also synthesized. The PEC response of the Dye 2-sensitized TiO2 film was much better than the Dye 1-sensitized or unsensitized TiO2 films.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.05a
• /
• pp.412-415
• /
• 2008

In a research on the practical dye-sensitized solar cell, a study on a large module have preference because module must be able to generate the proper current that is possible to convert electrically. So the parallel connection of dye-sensitized solar cells which outputs a large current easily is essential. However, there is a current loss in a paralle connection of dye-sensitized solar cells and the loss becomes larger according to increasing the number of parallel connection. In this study, we analyzed the cause of the current loss in the parallel connection by using the equivalent circuit analysis. One DSC used in this experiment had an active area $8cm^2$(4.62cm$\times$1.73cm) and it attained a conversion efficiency of 5.43% under 1 sun illumination ($P_{in}$ of 100 mW/$cm^2$) using a solar simulator.