Evaluation of the recombination processes in DSSC by measuring the open circuit voltage over a wide illumination intensity range

Authors

  • Marko Berginc,

    Corresponding author
    • Laboratory of Photovoltaics and Optoelectronics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
    Search for more papers by this author
  • Urša Opara Krašovec,

    1. Laboratory of Photovoltaics and Optoelectronics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
    Search for more papers by this author
  • Marko Topič

    1. Laboratory of Photovoltaics and Optoelectronics, Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
    Search for more papers by this author

Corresponding author: e-mail marko.berginc@fe.uni-lj.si, Phone: +386 1 4768 276, Fax: +386 1 4264 630

Abstract

The many recombination paths in the dye-sensitized solar cells (DSSCs) differently affect the open circuit voltage (VOC) vs. illumination intensity (G) dependence. In the literature contradictive results concerning the dVOC/dlog(G) gradient ranging from 60 to 120 mV decade−1 exist. To resolve this we have studied the effects of the active layer thickness (d), cell temperature (TC), and, math formula concentration ([math formula]) of ionic liquid (IL) based DSSCs on the dVOC/dlog(G) gradient. The results confirmed that d has only a small effect on the dVOC/dlog(G) gradient, while it is strongly dependent on TC and [math formula]. The dVOC/dlog(G) gradient could be as low as 60 mV decade−1 at low [math formula] and low TC, while it may exceed 130 mV decade−1 at higher [math formula] and higher TC. In addition, comparison of theoretical models with experimental results indicates that between 1–100 mW cm−2 the recombination path between the electrons in a tail of shallow traps in TiO2 and the math formula ions prevails.

Ancillary