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Title: Solution-processed air-stable mesoscopic selenium solar cells

Crystalline selenium (c-Se) is a direct band gap semiconductor and has been developed for detector applications for more than 30 years. While most advances have been made using vacuum deposition processes, it remains a challenge to prepare efficient c-Se devices directly from solution. We demonstrate a simple solution process leading to uniform and high-crystallinity selenium films under ambient conditions. A combination of ethylenediamine (EDA) and hydrazine solvents was found to be effective in dissolving selenium powder and forming highly concentrated solutions. These can be used to infiltrate a mesoporous titanium dioxide layer and form a smooth and pinhole-free capping overlayer. Efficient light-induced charge injection from the crystalline selenium to TiO2 was observed using transient absorption spectroscopy. A small amount of EDA addition in the hydrazine solution was found to improve the film coverage significantly, and on the basis of the finding, we are able to achieve up to 3.52% power conversion efficiency solar cells with a fill factor of 57%. Lastly, these results provide a method to control the crystalline selenium film and represent significant progress in developing low-cost selenium-based solar cells.
Authors:
 [1] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2] ;  [3] ;  [2]
  1. Harbin Institute of Technology, Harbin (China); Northwestern Univ., Evanston, IL (United States)
  2. Northwestern Univ., Evanston, IL (United States)
  3. Harbin Institute of Technology, Harbin (China)
Publication Date:
Grant/Contract Number:
SC0001059
Type:
Published Article
Journal Name:
ACS Energy Letters
Additional Journal Information:
Journal Volume: 1; Journal Issue: 2; Journal ID: ISSN 2380-8195
Publisher:
American Chemical Society (ACS)
Research Org:
Northwestern Univ., Evanston, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE
OSTI Identifier:
1282423
Alternate Identifier(s):
OSTI ID: 1314039