Cu2ZnSnS4 Solar Cells with Over 10% Power Conversion Efficiency Enabled by Heterojunction Heat Treatment

Steven Johnston, Chang Yan, Jialiang Huang, Kaiwen Sun, Yuanfang Zhang, Heng Sun, Aobo Pu, Mingrui He, Fangyang Liu, Katja Eder, Limei Yang, Julie Cairney, N. Ekins-Daukes, Ziv Hameiri, John Stride, Shiyou Chen, Martin Green, Xiaojing Hao

Research output: Contribution to journalArticlepeer-review

643 Scopus Citations


Sulfide kesterite Cu2ZnSnS4 provides an attractive low-cost, environmentally benign and stable photovoltaic material, yet the record power conversion efficiency for such solar cells has been stagnant at around 9% for years. Severe non-radiative recombination within the heterojunction region is a major cause limiting voltage output and overall performance. Here we report a certified 11% efficiency Cu2ZnSnS4 solar cell with a high 730 mV open-circuit voltage using heat treatment to reduce heterojunction recombination. This heat treatment facilitates elemental inter-diffusion, directly inducing Cd atoms to occupy Zn or Cu lattice sites, and promotes Na accumulation accompanied by local Cu deficiency within the heterojunction region. Consequently, new phases are formed near the hetero-interface and more favourable conduction band alignment is obtained, contributing to reduced non-radiative recombination. Using this approach, we also demonstrate a certified centimetre-scale (1.11 cm2) 10% efficiency Cu2ZnSnS4 photovoltaic device; the first kesterite cell (including selenium-containing) of standard centimetre-size to exceed 10%.

Original languageAmerican English
Pages (from-to)764-772
Number of pages9
JournalNature Energy
Issue number9
StatePublished - 2018

Bibliographical note

Publisher Copyright:
© 2018, The Author(s).

NREL Publication Number

  • NREL/JA-5K00-72245


  • conversion efficiency
  • copper
  • copper compounds
  • efficiency
  • energy efficiency
  • heat treatment
  • heterojunctions
  • open circuit voltage
  • solar cells
  • solar power generation
  • tin compounds zinc compounds


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