We improve the energy conversion efficiency (ECE) of a dye sensitized solar cell (DSSC) by preparing a working electrode (WE) with localized surface plasmon resonance (LSPR) by inducing Au thin films with thickness of 0.0 to 5.0 nm, deposited via sputtering. Field emission scanning electron microscopy and atomic force microscopy were used to characterize the microstructure of the blocking layer (BL) of the Au thin films. Micro-Raman measurement was employed to confirm the LSPR effect, and a solar simulator and potentiostat were used to evaluate the photovoltaic properties, including the impedance and the I-V of the DSSC of the Au thin films. The results of the microstructural analysis confirmed that nano-sized Au agglomerates were present at certain thicknesses. The photovoltaic results show that the ECE reached a value of 5.34% with a 1-nm thick-Au thin film compared to the value of 5.15 % without the Au thin film. This improvement was a result of the increase in the LSPR of the TiO2 layer that resulted from the Au thin film coating. Our results imply that the ECE of a DSSC may be improved by coating with a proper thickness of Au thin film on the BL.

The cobalt silicides were investigated for employment as a catalytic layer for a DSSC. Using an E-gun evaporation process, we prepared a sample of 100 nm-thick cobalt on a p-type Si (100) wafer. To form cobalt silicides, the samples were annealed at temperatures of 300 oC, 500 oC, and 700 oC for 30 minutes in a vacuum. Four-point probe, XRD, FE-SEM, and CV analyses were used to determine the sheet resistance, phase, microstructure, and catalytic activity of the cobalt silicides. To confirm the corrosion stability, we also checked the microstructure change of the cobalt silicides after dipping into iodide electrolyte. Through the sheet resistance and XRD results, we determined that Co2Si, CoSi, and CoSi2 were formed successfully by annealing at 300 oC, 500 oC, and 700 oC, respectively. The microstructure analysis results showed that all the cobalt silicides were formed uniformly, and CoSi and CoSi2 layers were very stable even after dipping in the iodide electrolyte. The CV result showed that CoSi and CoSi2 exhibit catalytic activities 67 % and 54 % that of Pt. Our results for Co2Si, CoSi, and CoSi2 revealed that CoSi and CoSi2 could be employed as catalyst for a DSSC.

Mo-based thin films are frequently used as back electrode materials because of their low resistivity and high crystallinity in CIGS chalcopyrite solar cells. Mo:Na/Mo bilayer thin films with 1μm thickness were deposited on soda lime glass by varying the thickness of each layer using dc-magnetron sputtering. The effects of the Mo:Na layer on morphology and electrical property in terms of resistivity were systematically investigated. The resistivity increased from 159μΩcm to 944μΩcm; this seemed to be caused by increased surface defects and low crystallinity as the thickness of Mo:Na layer increased from 100 nm to 500 nm. The surface morphologies of the Mo thin films changed from a somewhat coarse fibrous structures to irregular and fine celled structures with increased surface cracks along the cell boundaries as the thickness of Mo:Na layer increased. Na contents varied drastically from 0.03 % to 0.52 % according to the variation of Mo:Na layer thickness. The change in Na content may be ascribed to changes in surface morphology and crystallinity of the thin films.

The effect of a sputter deposition sequence of Cu, Zn, and Sn metal layers on the properties of Cu2ZnSnS4 (CZTS) was systematically studied for solar cell applications. The set of Cu/Sn/Zn/Cu multi metal films was deposited on a Mo/SiO2/Si wafer using dc sputtering. CZTS films were prepared through a sulfurization process of the Cu/Sn/Zn/Cu metal layers at 500˚C in a H2S gas environment. H2S (0.1%) gas of 200 standard cubic centimeters per minute was supplied in the cold-wall sulfurization reactor. The metal film prepared by one-cycle deposition of Cu(360 nm)/Sn(400 nm)/Zn(400 nm)/Cu(440 nm) had a relatively rough surface due to a well-developed columnar structure growth. A dense and smooth metal surface was achieved for two- or three-cycle deposition of Cu/Sn/Zn/Cu, in which each metal layer thickness was decreased to 200 nm. Moreover, the three-cycle deposition sample showed the best CZTS kesterite structures after 5 hr sulfurization treatment. The two- and three-cycle Cu/Sn/Zn/Cu samples showed high-efficient photoluminescence (PL) spectra after a 3 hr sulfurization treatment, wheres the one-cycle sample yielded poor PL efficiency. The PL spectra of the three-cycle sample showed a broad peak in the range of 700-1000 nm, peaked at 870 nm (1.425 eV). This result is in good agreement with the reported bandgap energy of CZTS.

스크린 인쇄공법을 이용하여 구형 실리콘 태양전지용 전면 전극을 제작하였고 그 물성을 검토하였다.집광형 구형 실리콘 태양전지는 종래의 결정질 실리콘 태양전지 발전 시스템 설치비용 중 21%를 차지하는 실리콘 소재의 사용량을 줄이기 위해 볼 형태의 구형 실리콘을 사용하였고, 입사되는 태양광을 최대한 활용하기위해 알루미늄으로 된 집광판을 사용하는 것을 특징으로 한다. 전도성 필러로써 Flake 형태의 Ag 파우더를 사용하였고, 기재와의 접착력을 부여하기 위한 유기 바인더로서 에폭시수지, 폴리에스테르수지,아크릴수지 등을 비교 검토한 결과, 에폭시수지 고형분 12%를 첨가한 paste가 기재와의 접착성, 태양전지 광전변환효율, 내구성에서 가장 우수함을 알 수 있었다.

요오드화수은은 우수한 엑스선 민감도 특성을 가진 광도전체로 비정질 셀레늄을 대체할 수 있는 후보물 질로 많은 연구가 진행되고 있지만 높은 누설전류로 인해 상용화에 많은 한계점을 나타내고 있다. 본 연구 에서는 요오드화수은의 높은 누설전류를 저감하기 위해 요오드화수은에 비해 입자가 작은 이산화규소 및 이산화티타늄을 물리적으로 혼합하여 단위시편을 제작하였으며 제작된 단위시편의 전기적 특성을 비교·분석하였다. 그 결과 혼합한 두 물질 모두 요오드화수은의 높은 누설전류를 저감하는데 효과가 있었으며 요오드화수은-이산화티타늄 혼합물에서는 방사선 민감도 특성이 상당히 높아짐을 확인하였다.