Free-carrier dynamics and band tails in C u2ZnSn(Sx S e1-x)4: Evaluation of factors determining solar cell efficiency

Le Quang Phuong, Makoto Okano, Genki Yamashita, Masaya Nagai, Masaaki Ashida, Akira Nagaoka, Kenji Yoshino, Yoshihiko Kanemitsu

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

We investigated the composition-dependent photocarrier dynamics in Cu2ZnSn(SxSe1-x)4 (CZTSSe) single crystals using various types of steady-state and time-resolved optical spectroscopy. Photoluminescence spectroscopy shows that the band-tail states formed below the band edge decrease monotonically with increasing Se content. THz time-resolved spectroscopy clarifies that an increase in the Se content leads to a shorter lifetime of the free photocarriers. A trade-off between the composition-dependent band-tail density and the free-carrier lifetime occurs in CZTSSe single crystals. Our experimental results provide insights into the physics behind the low and composition-dependent conversion efficiency of CZTSSe-based solar cells.

Original languageEnglish
Article number115204
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume92
Issue number11
DOIs
Publication statusPublished - 2015 Sep 9
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

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