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Title: Diffusion length in nanoporous TiO{sub 2} films under above-band-gap illumination

We determined the carrier diffusion lengths in TiO{sub 2} nanoporous layers of dye-sensitized solar cells by using scanning photocurrent microscopy using an ultraviolet laser. Here, we excited the carrier directly in the nanoporous layers where the diffusion lengths were found to 140 μm as compared to that of visible illumination measured at 90 μm. The diffusion length decreased with increasing laser modulation frequency, in which we determined the electron lifetimes and the diffusion coefficients for both visible and UV illuminations. The diffusion lengths have been studied in terms of the sintering temperatures for both cells with and without binding molecules. We found a strong correlation between the diffusion length and the overall light-to-current conversion efficiency, proving that improving the diffusion length and hence the interparticle connections, is key to improving cell efficiency.
Authors:
; ; ; ; ; ;  [1]
  1. Department of Physics and Division of Energy Systems Research, Ajou University, Suwon 443-749 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22300095
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 4; Journal Issue: 6; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; DIFFUSION; DIFFUSION LENGTH; EFFICIENCY; FILMS; MICROSCOPY; MODULATION; SOLAR CELLS; TITANIUM OXIDES