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Assessment of Luminescent Downshifting Layers for the Improvement of Light‐Harvesting Efficiency in Dye‐Sensitized Solar Cells
Author(s) -
Hosseini Zahra,
Diau Eric WeiGuang,
Mehrany Khashayar,
Taghavinia Nima
Publication year - 2014
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201402505
Subject(s) - dye sensitized solar cell , luminescence , materials science , absorption (acoustics) , optoelectronics , molar absorptivity , quantum efficiency , attenuation coefficient , energy conversion efficiency , electrolyte , optics , chemistry , electrode , physics , composite material
Abstract Luminescence downshifting (LDS) of light can be a practical photon management technique to compensate the narrow absorption band of high‐extinction‐coefficient dyes in dye‐sensitized solar cells (DSSCs). Herein, an optical analysis on the loss mechanisms in a reflective LDS (R‐LDS)/DSSC configuration is reported. For squaraine dye (550–700 nm absorption band) and CaAlSiN 3 :Eu 2+ LDS material (550–700 nm emission band), the major loss channels are found to be non‐unity luminescence quantum efficiency (QE) and electrolyte absorption. By using an ideal LDS layer (QE=100 %), a less absorbing electrolyte (Co‐based), and antireflection coatings, approximately 20 % better light harvesting is obtained. If the absorption/emission band of dye/LDS is shifted to 800 nm, a maximal short‐circuit current density ( J sc ) of 22.1 mA cm −2 can be achieved. By putting the LDS layer in front of the DSSC (transmissive mode), more significant loss channels are observed, and hence a lower overall efficiency than the R‐LDS configuration.