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Electrical Conduction Mechanism of AZO Thin Film and Photo-Electric Conversion Efficiency of Film-Typed Dye Sensitized Solar Cell

AZO 박막의 전기전도특성 및 필름형 염료 태양전지의 광전 변환 특성

  • Received : 2009.12.03
  • Accepted : 2010.02.23
  • Published : 2010.04.30

Abstract

In this paper, AZO thin film was deposited on polyethylene terephthalate(PET) substrate by r. f. magnetron sputtering method from a ZnO target mixed with 2[wt%] Al2O3. The flexible film-typed dye sensitized solar cell(F-DSC) was fabricated and photo-electric conversion efficiency was investigated. The results showed that the minimum resistivity and the maximum deposition rate of AZO conducting film were recorded as $1.8{\times}10^{-3}[{\Omega}{\cdot}cm]$ and 25.5[nm/min], respectively at r.f. power of 220[W]. From the analysis of XPS data an improvement of electrical resistivity or an increase in carrier concentration with increasing sputtering power may be related to the generation of lattice imperfections as a result of increasing component ratio of O1s/Zn2p, which generates donor carriers or active growth of crystalline grain. The photo-electric conversion efficiency of F-DSC with AZO conducting electrode was over 2.79[%], which was comparable as that with commercially available ITO electrode.

본 연구에서는 플렉시블 염료감응 태양전지(F-DSC)의 투명전도막으로서의 적용 가능성을 평가하기 위하여 PET 기판위에 AZO 박막을 증착하였다. 또한 ITO와 AZO 박막을 이용하여 동일한 조건하에서 F-DSC를 제작하여 광변환효율을 조사하였다. AZO의 경우 체적저항율 및 증착율은 220[W]의 전력조건하에서 각각 $1.8{\times}10^{-3}[{\Omega}{\cdot}cm]$와 25.5[nm/min] 정도였으며, 광투과율은 약 87[%]였다. AZO 박막의 전기전도 메카니즘의 방전전력 의존성은 XPS 분석결과 방전전력이 증가함에 따라 O1s/Zn2p의 성분비가 증가하여 산소성분에 의한 도너 제공에 크게 영향을 받는 것으로 나타났다. 한편, AZO 투명전도막으로 제작된 F-DSC의 변환효율은 약 2.79[%] 정도였으며, 이는 상용 ITO의 2.94[%]에 거의 필적되는 값으로 AZO의 F-DSC에의 응용 가능성이 충분함을 알 수 있었다.

Keywords

References

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