Nonlinear Band Gap Tunability in Selenium-Tellurium Alloys and Its Utilization in Solar Cells

Ido Hadar, Xiaobing Hu, Zhong Zhen Luo, Vinayak P. Dravid, Mercouri G. Kanatzidis

Research output: Contribution to journalArticle

Abstract

In this Letter, we report the alloying of the high-band-gap photovoltaic elemental absorber selenium with the isomorphic low-band-gap semiconductor tellurium to tune the band gap energy of Se1-xTex to the optimal value for photovoltaic absorber. Photovoltaic devices based on crystalline Se1-xTex alloys are promising candidates for extremely cheap and highly scalable solar cells, offering simple low-temperature fabrication and intrinsic stability. We explore the electro-optical properties of Se1-xTex alloys and show that the tellurium red shifts the band gap in a nonlinear manner, faster than expected, due to significantly nonlinear change of the conduction band energy, allowing them to easily reach the desired band gap of 1.2-1.4 eV. On the basis of these results, we rationally design and demonstrate the fabrication of simple Se1-xTex photovoltaic devices, showing significantly improved current density in comparison to pure selenium. Furthermore, we identify and analyze the main factors limiting the device efficiency and suggest a few approaches for future improvements of such photovoltaic devices.

Original languageEnglish
Pages (from-to)2137-2143
Number of pages7
JournalACS Energy Letters
Volume4
Issue number9
DOIs
Publication statusPublished - Sep 13 2019

    Fingerprint

ASJC Scopus subject areas

  • Chemistry (miscellaneous)
  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Materials Chemistry

Cite this