Cr/Pt 촉매층 도입에 따른 고효율 염료감응태양전지의 특성 개선

노윤영 ( Yun Young Noh ),송오성 ( Oh Sung Song ) 대한금속재료학회(구 대한금속학회) 2014 대한금속·재료학회지 Vol.52 No.8

Abstract: In order to improve energy conversion efficiency by applying a Cr/Pt bilayer on a flat glass substrate of a counter electrode (CE), we prepared a 0.45 cm2 dye-sensitized solar cell (DSSC) device with glass/FTO/blocking layer/TiO2/N719 (dye)/electrolyte/50 nm Pt/50 nm Cr/FTO/glass. For comparison, a 100 nmthick Pt counter electrode on a FTO substrate was also prepared using the same procedure. The photovoltaic properties, the short circuit current density, open circuit voltage, fill factor, energy conversion efficiency, and impedance, were characterized using a solar simulator and potentiostat. The phase and microstructure of the bilayer were examined by X-ray diffraction and transmission electron microscopy. The measured energy conversion efficiencies of the dye-sensitized solar cell devices with Pt only and Cr/Pt bilayer counter electrodes were 6.33% and 8.66%, respectively. The increase in the efficiency of Cr/Pt was attributed to the enhanced catalytic activated Pt layer by the compressive strain field due to the introduction of a Cr layer. This suggests that the use of a Cr/Pt bilayered catalytic layer improves the efficiency of dye-sensitized solar cells over those with a conventional Pt only layer.

나노급 Mo/Pt 이중 촉매층 도입에 따른 염료감응태양전지의 물성

노윤영 ( Yun Young Noh ),송오성 ( Oh Sung Song ) 대한금속재료학회(구 대한금속학회) 2014 대한금속·재료학회지 Vol.52 No.3

A Mo/Pt bilayered catalytic layer on a flat glass substrate was used as a counter electrode to improve the energy conversion efficiency of a dye-sensitized solar cell device with the structure of effective area of 0.45 cm2 glass/FTO/blocking layer/TiO2/N719(dye)/electrolyte/50 nm Pt/50 nm Mo/glass. For comparison, 100 nm-thick Pt and Mo counter electrodes on flat glass substrates were also prepared using the same procedure. The photovoltaic properties, such as the short circuit current density, open circuit voltage, fill factor, energy conversion efficiency, and impedance, were characterized using a solar simulator and poten-tiostat. The phases and microstructures of the catalytic layers were examined by X-ray diffraction and field emission electron microscopy. The measured energy conversion efficiency of the dye-sensitized solar cell devices with only Pt and Mo/Pt bilayer counter electrodes was 4.60% and 6.30%, respectively. The interface resistance at the interface between the counter electrode and electrolyte decreased when a Mo/Pt bilayer thin film was used. The new phase of Pt3Mo led to an increase in catalytic activity. This suggests that the Mo/Pt bilayered catalytic layers may provide better efficiency in the dye-sensitized solar cells than the conventional Pt layers.

나노급 Cr/Pt 이중 촉매층 도입에 따른 염료감응태양전지의 물성

노윤영 ( Yun Young Noh ),송오성 ( Oh Sung Song ) 대한금속재료학회(구 대한금속학회) 2014 대한금속·재료학회지 Vol.52 No.4

A Cr/Pt bilayered catalytic layer on a flat glass substrate is used as a counter electrode in order to improve the energy conversion efficiency of a dye-sensitized solar cell device with an effective structure area of 0.45 cm2 glass/FTO/blocking layer/TiO2/N719(dye)/electrolyte/50 nm Pt/50 nm Cr/glass. For comparison, 100 nm-thick Pt and Cr counter electrodes on flat glass substrates are also prepared using the same procedure. The sheet resistance is examined using a four-point probe. The photovoltaic properties, such as the short circuit current density, open circuit voltage, fill factor, energy conversion efficiency, and impedance, are characterized using a solar simulator and potentiostat. The phases of the bilayered films are examined using X-ray diffraction. Furthermore, the microstructure of the bilayered films is characterized via field emission electron microscopy. The measured energy conversion efficiencies of the dye-sensitized solar cell devices with only Pt and Cr/Pt bilayer counter electrodes are 4.60% and 6.68%, respectively. The interface resistance at the interface between the counter electrode and electrolyte decreases when a Cr/Pt bilayer thin film is applied. The new phases of Pt3Cr enable an increase in the catalytic activity. This suggests that the Cr/Pt bilayer catalytic layers might improve the efficiency of dye-sensitized solar cells compared with the conventional Pt layers.

나노급 Al/Pt 또는 Ti/Pt 이중 촉매층 도입에 따른 염료감응태양전지의 물성

노윤영 ( Yun Young Noh ),송오성 ( Oh Sung Song ) 대한금속재료학회(구 대한금속학회) 2014 대한금속·재료학회지 Vol.52 No.1

Al/Pt and Ti/Pt bilayers to a flat glass substrate were employed as a counter electrode to improve the energy conversion efficiency of a dye-sensitized solar cell device with a structure of glass/FTO/blocking layer/TiO2/N719(dye)/electrolyte/(50 nmPt-50 nmAl) or (50 nmPt-50 nmTi)/glass. For comparison, a 100 nmthick Pt counter electrode on a flat glass substrate was also prepared using the same method. The sheet resistance was examined by a four point probe. The photovoltaic properties, such as the short circuit current density, open circuit voltage, fill factor, energy conversion efficiency, and impedance, were characterized using a solar simulator and potentiostat. The phases of the bilayered films were identified by X-ray diffraction. The measured energy conversion efficiencies of the dye-sensitized solar cell devices with Al/Pt and Ti/Pt bilayer counter electrodes were 5.36% and 5.03%, respectively. The interface resistance at the interface between the counter electrode and electrolyte decreased when the Al/Pt and Ti/Pt bilayer thin films were applied. The new phases of AlPt3 and Pt3Ti led to a decrease in resistivity and an increase in catalytic activity. This suggests that Al/Pt and Ti/Pt bilayer thin films might improve the efficiency of dye-sensitized solar cells.

투명전도층이 없는 염료감응형 태양전지의 Ru 상대전극 연구

노윤영 ( Yun Young Noh ),유기천 ( Ki Cheon Yoo ),유병관 ( Byung Kwan Yu ),한정조 ( Jeung Jo Han ),고민재 ( Min Jae Ko ),송오성 ( Oh Sung Song ) 대한금속재료학회 ( 구 대한금속학회 ) 2012 대한금속·재료학회지 Vol.50 No.2

A TCO-less ruthenium (Ru) catalytic layer on glass substrate instead of conventional Ru/TCO/glass substrate was assessed as counter electrode (CE) material in dye sensitized solar cells (DSSCs) by examining the effect of the Ru thickness on the DSSC performance. Ru films with different thicknesses (34, 46, 69, and 90 nm) were deposited by atomic layer deposition (ALD) on glass substrates to replace both existing catalyst and electrode layer. In order to make our comparison, we also prepared an Ru catalytic layer by a similar method on FTO/glass substrate. Finally, we prepared the 0.45 cm2 DSSC device the properties of the DSSCs were examined by cyclic voltammetry (CV), impedance spectroscopy (EIS), and current-voltage (I-V) method. CV measurementsrevealed an increase in catalytic activity with increasing film thickness. The charge transfer resistance at the interface between the electrolyte and Rudecreased with increasing Ru thickness. I-V resultsshowed that the energy conversion efficiency increased up to 1.96%. Our results imply that TCO-less Ru/glass might perform as both catalyst and electrode layer when it is used in counter electrodes in DSSCs.

염료감응태양전지의 Cu/Pt 이중 촉매층의 전해질과의 반응에 따른 열화

노윤영 ( Yun Young Noh ),송오성 ( Oh Sung Song ) 대한금속재료학회(구 대한금속학회) 2014 대한금속·재료학회지 Vol.52 No.9

This study examined the stability of a Cu/Pt bilayered counter electrode (CE) with the electrolyte and the energy conversion efficiency of dye-sensitized solar cells using a 0.45 cm2 dye-sensitized solar cell (DSSC) device with a glass/FTO/blocking layer/TiO2/N719 (dye)/electrolyte/50 nm-Pt/50 nm-Cu/FTO/glass. For comparison, a 100 nm-thick Pt only CE DSSC was also prepared using the same method. The photovoltaic properties, such as the short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF), energy conversion efficiency (ECE), and impedance, were checked using a solar simulator and potentiostat with time after assembling the DSSC. The microstructure of the Cu/Pt bilayer was examined by optical microscopy after 0~30 minutes and 3 weeks. The ECE of the DSSC using the Pt only CE was 4.60 %, which did not show any time dependence. On the other hand, for the Cu/Pt CE DSSC, the ECEs after 0 minutes, 30 minutes, and 3 weeks were 5.72%, 5.03%, and 1.36%, respectively. Moreover, the interface resistance increased; 6, 7, and 40 Ω at 0 minutes, 30 minutes, and 3 weeks, respectively. The corrosion area of the Cu/Pt CE determined by an optical microscopy after 0 minutes, 30 minutes, and 3 weeks was 0, 23.40, and 51.35%, respectively. These results confirmed that the ECE and catalytic activity of Cu/Pt CE decreased drastically with time. Therefore, a DSSC using a Cu/Pt CE may be superior to the Pt only CE immediately after integrating of the device, but the performance of the former degrades drastically with time. †(Received September 30, 2013)

Cu/Pt 이층 상대전극을 채용한 염료감응 태양전지의 물성

노윤영 ( Yun Young Noh ),송오성 ( Oh Sung Song ) 대한금속재료학회(구 대한금속학회) 2014 대한금속·재료학회지 Vol.52 No.7

In order to improve energy-conversion efficiency using a Cu/Pt bilayer on a flat-glass substrate of a counter electrode (CE), a 0.45 cm2 dye-sensitized solar-cell (DSSC) device (with glass/FTO/blocking layer/ TiO2/N719 (dye)/electrolyte/50 nm-Pt/50 nm-Cu/glass) was prepared. For comparison, 100-nm thick Cu and Pt CEs were also prepared on flat-glass substrates using the same method. The photovoltaic properties of the DSSC device, such as short-circuit current-density (Jsc), open-circuit voltage (Voc), fill factor (FF), energy-conversion efficiency (ECE), and impedance, were checked using a solar simulator and potentiostat. The sheet resistance was examined using a four point probe. The phases of the bi-layered films were examined using X-ray diffraction. The measured energy-conversion efficiency of the DSSC devices with only Pt and Cu/Pt bilayer counter electrodes was 4.60% and 5.72%, respectively. The sheet resistance and interface (CE/electrolyte) resistance of a Cu/Pt bilayer were smaller than those of a Pt-only layer. The phases of the Cu/Pt bi-layered films were identified in pure Cu and Pt without any intermetallic layer. We concluded that the increase in the efficiency of DSSCs employing Cu/Pt, resulted from employing the low-resistive Cu layer. †(Received August 20, 2013)

폴리스틸렌 비드와 ZnO를 이용한 표면적이 증가된 Ru 염료감응형 태양전지 상대전극 물성 평가

노윤영 ( Yun Young Noh ),송오성 ( Oh Sung Song ) 대한금속재료학회(구 대한금속학회) 2013 대한금속·재료학회지 Vol.51 No.12

In order to improve the energy conversion efficiency (ECE) by increasing the surface area of counter electrode (CE), we prepared 500 nm-polystyrene (PS) beads on a flat glass substrate, deposited with 100 nm-thick ZnO and 34 nm-thick Ru nano thin film using ALD. A 34 nm-thick Ru CE on a flat glass substrate was also prepared using the same method for a comparison. Finally, a 0.45 cm2 dye-sensitized solar cell (DSSC) device with a glass/FTO/blocking layer/TiO2/N719(dye)/electrolyte/34 nm-Ru/100 nm-ZnO/ 500 nm-PS bead/glass structure was fabricated. The microstructure of the CE was examined by field emission scanning electron microscopy (FE-SEM). The photovoltaic properties, such as the short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF), energy conversion efficiency (ECE) and impedance, were characterized using a solar simulator and potentiostat. The microstructure examined using a FE-SEM confirmed that 100 nm-ZnO/34 nm-Ru on 500 nm-PS beads increases the surface area by 70% compared to a glass substrate. The ECE of the device with the CE, the glass/Ru and 500 vnm-beads/100 vnm-ZnO/Ru, was 1.81%, and 2.91%, respectively. These results suggest that the surface area of the CE contributed to the increase in efficiency. Moreover, increasing of surface area through ZnO coating on PS beads was more suitable for increasing efficiency than the conventional flat glass substrates.

저온 원자층증착법으로 제조된 ZnO/TiO2 나노이층박막의 물성 연구

노윤영 ( Yun Young Noh ),한정조 ( Jeung Jo Han ),유병관 ( Byung Kwan Yu ),송오성 ( Oh Sung Song ) 대한금속재료학회(구 대한금속학회) 2011 대한금속·재료학회지 Vol.49 No.6

We examined the microstructure and optical properties of crystallized ~30 nm-ZnO/~10 nm amorphous TiO2 nano bilayered films as nano electrodes were deposited at extremely low substrate temperatures of 150-210℃. The bilayered films were deposited on silicon substrates with 10 cm diameters by ALD (atomic layer deposition) using DEZn (diethyl zinc(Zn(C2H5)2)) and TDMAT (tetrakis dimethyl-amid titanium(Ti(N(CH3)2)4) as the ZnO and TiO2 precursors, respectively, and H2O as the oxidant. The microstructure, phase, and optical properties of the bilayered films were examined by FE-SEM, TEM, XRD, AES, and UV-VIS-NIR spectroscopy. FE-SEM and TEM showed that all bilayered films were deposited very uniformly and showed crystallized ZnO and amorphous TiO2 layers. AES depth profiling showed that the ZnO and TiO2 films had a stoichiometric composition of 1:1 and 1:2, respectively. These bilayered films have optical absorption properties in a wide range of ultraviolet wavelengths, 250-390 nm, whereas the single ZnO and TiO2 films showed an absorption range of 350-380nm.

스캐터링층 도입에 따른 염료감응태양전지의 물성평가

노윤영 ( Yun Young Noh ),송오성 ( Oh Sung Song ) 대한금속재료학회(구 대한금속학회) 2013 대한금속·재료학회지 Vol.51 No.10

We propose a working electrode with a scattering layer inserted for dye-sensitized solar cells (DSSCs) with the following structure: glass/FTO/blocking layer/TiO2/scattering layer/dye/electrolyte/Pt/ FTO/glass. A working electrode without a scattering layer was also prepared using a similar method for comparison. The microstructure was examined by optical microscopy and field emission scanning electron microscopy (FE-SEM). The photovoltaic properties, such as the short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF), energy conversion efficiency (ECE) and impedance were characterized using a solar simulator and potentiostat. FE-SEM confirmed that the blocking layer with 20 nm grains and the scattering layer with 350-450 nm grains had been prepared. The Jsc and Voc increased, and impedance analysis revealed a decrease in the electron transfer resistance and electron recombination resistance at the TiO2/electrolye interface. The ECE with the scattering layer was 6.35%, which was 20% higher than that observed in the ECE without the scattering layer. (Received January 3, 2013)