Keyword Suggestions

E6.03 - Temperature Dependence of Photoluminescence Dynamics in CuZnSnS Single Crystals 
April 23, 2014   9:00am - 9:15am

CuZnSnS (CZTS) is considering as an important light absorber for next generation low-cost thin-film solar cells because of its optimal band gap energy for solar conversion efficiency and its high absorption coefficient [1-2]. The power conversion efficiency of CZTS-based solar cells, which currently obtained a maximum value of ~8.4% [3], is believed to relate essentially to the defect states existing intrinsically in quaternary compound CZTS [1,4-7]. Our recent results have pointed out the significant roles of the band tail states which cause picosecond-scaled localization of photocarriers as well as a sub-nanosecond multiple trapping processes in recombination dynamics of CZTS single crystals at room temperature (RT) [1]. In addition to knowledge obtained at RT, for some particularly practical uses of CZTS-based solar cells such as in aerospace industry, fundamental physical understandings of temperature dependent photocarrier dynamics in CZTS are also of importance.In this study, we determined the temperature dependence of photocarrier recombination dynamics in CZTS singles crystals. The observed microsecond-scaled photoluminescence (PL) decay times at low temperatures indicate localization of photogenerated carriers at spatially separated band tails. A good consistency was observed for the temperature dependence of the decay rate and that of the PL intensity. As the temperature is increased, nonradiative recombination becomes dominant, leading to a considerable enhancement of the decay rate as well as a significant decrease of the PL intensity. A large change of about three orders in magnitude of the decay time, from microsecond to sub-nanosecond, indicates very efficient nonradiative recombination at high temperatures in CZTS, which might be one of the main reasons that limit the power conversion efficiency of the CTZS-based solar cells.This work was supported by JST-CREST and the Sumitomo Electric Industries Group CSR Foundation.References[1]. L. Q. Phuong et al., Appl. Phys. Lett. 103 (2013) in press.[2]. K. Ito et al., Jpn. J. Appl. Phys. 27, 2094 (1988).[3]. B. Shin et al., Prog. Photovoltaics 21, 72 (2013).[4]. K. Tanaka et al., Phys. Status Solidi A 203, 2891 (2006).[5]. M. J. Romero et al., Phys. Rev. B 84, 165324 (2011).[6]. S. Levcenko et al., Phys. Rev. B 86, 045206 (2012).[7]. A. Nagaoka et al., Appl. Phys. Lett. 103, 112107 (2013).

Average Rating: (No Ratings)
  Was great, surpassed expectations, and I would recommend this
  Was good, met expectations, and I would recommend this
  Was okay, met most expectations
  Was okay but did not meet expectations
  Was bad and I would not recommend this

Keynote Address
Panel Discussion - Different Approaches to Commercializing Materials Research
Business Challenges to Starting a Materials-Based Company
Fred Kavli Distinguished Lectureship in Nanoscience
Application of In-situ X-ray Absorption, Emission and Powder Diffraction Studies in Nanomaterials Research - From the Design of an In-situ Experiment to Data Analysis