Dye-Sensitized Solar Cells with Electrospun Nanofiber Mat-Based Counter Electrodes

Abstract

Textile-based dye-sensitized solar cells (DSSCs) can be created by building the necessary layers on a textile fabric or around fibers which are afterwards used to prepare a textile layer, typically by weaving. Another approach is using electrospun nanofiber mats as one or more layers. In this work, electrospun polyacrylonitrile (PAN) nanofiber mats coated by a conductive polymer poly(3,4-ethylenedioxythiopene) polystyrene sulfonate (PEDOT:PSS) were used to produce the counter electrodes for half-textile DSSCs. The obtained efficiencies were comparable with the efficiencies of pure glass-based DSSCs and significantly higher than the efficiencies of DSSCs with cotton based counter electrodes. The efficiency could be further increased by increasing the number of PEDOT:PSS layers on the counter electrode. Additionally, the effect of the post treatment of the conductive layers by HCl, acetic acid, or dimethyl sulfoxide (DMSO) on the DSSC efficiencies was investigated. Only the treatment by HCl resulted in a slight improvement of the energy-conversion efficiency.

Spectral Analysis and Parameter Identification of Textile-Based Dye-Sensitized Solar Cells

“…The DSSC with five layers of PEDOT: PSS has, however an increased resistance related to the four-layer one. This is in agreement with the results in [11], where the efficiency of the cells with five layers of S V 4 is slightly decreased when compared to the efficiency of cells with four layers of S V 4, and furthermore the I-U curve of the cells with five layers of S V 4 lies lower than the I-U characteristics of cells with four layers. The reason for the increase of the resistance of cells with five S V 4 layers is, however, unclear.…”

“…The proposed identification method was tested while using a standard DSSC with glass electrodes prepared as described in [11]. The sine-sweep signal with range of (1 Hz–50,000 Hz) was added to the constant steady-state voltage.…”

“…The both electrodes were put together and fixed by an adhesive tape, and the cells were filled with an iodine/triiodide based electrolyte (type 016 purchased from Man Solar). The detailed description of the cell preparation is given in [11]. …”

Electrospinning a Dye-Sensitized Solar Cell

“…For this, the PAN/graphite nanofiber mat with the additional PAN layer and the PAN/TiO 2 /dye nanofiber mat were dip-coated in poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and left for drying on glass plates. Generally, this process leads to fully conductive nanofiber mats which would produce a short-circuit if put together in the form of a DSSC [31]. However, Reference [29] also indicates that the conductivity of nonconductive PAN nanofiber mats dip-coated in PEDOT:PSS significantly depends on the number of dip-coating cycles, suggesting that a thin layer of a not too highly viscous PEDOT:PSS may sink inside the nanofiber mat and in this way possibly reduce conductivity along the upper surface.…”

“…Typically, the transmission through an electrospun nanofiber mat, produced either from pure PAN or from PAN/TiO 2 , is in the range of 5-15%, depending on the wavelength [32]. Coating the nanofiber mat even with a thin PEDOT:PSS layer reduces the transmission further [31]. This indicates that while it is generally possible to prepare fully electrospun DSSCs, further research is necessary to improve the optical properties, especially the transmission through one of the electrodes, e.g., by preparing one electrode as a combination of nanofibrous mat and nanomembrane which is possible by tailoring the electrospinning parameters correspondingly [33].…”