Device Physics of Dye Solar Cells

Abstract

Design of new materials for nanostructured dye solar cells (DSC) requires understanding the link between the material properties and cell efficiency. This paper gives an overview of the fundamental and practical aspects of the modeling and characterization of DSCs, and integrates the knowledge into a user-friendly DSC device model. Starting from basic physical and electrochemical concepts, mathematical expressions for the IV curve and differential resistance of all resistive cell components are derived and their relation to electrochemical impedance spectroscopy (EIS) is explained. The current understanding of the associated physics is discussed in detail and clarified. It is shown how the model parameters can be determined from complete DSCs by current dependent EIS and incident-photon-to-collected-electron (IPCE) measurements, supplemented by optical characterization, and used to quantify performance losses in DSCs. The paper aims to give a necessary theoretical background and practical guidelines for establishing an effective feedback-loop for DSC testing and development.

A review on applications of Cu2ZnSnS4 as alternative counter electrodes in dye-sensitized solar cells

“…A smaller series resistance (R S ) will give a higher FF, which results in a high conversion efficiency. [59][60][61] …”

Alternate redox electrolytes in dye-sensitized solar cells

“…An ideal redox shuttle with the redox level closer to the D + /D redox level is critical so as to increase the V oc while still maintaining rapid regeneration of the dye to prevent degradation. Furthermore, those performance can also be affected by non-electroactive species applied in different electrolytes, for example some small cations (such as protons, Li + ), organic cations (such as dialkylimidazolium), or additives (such as 4-tert-butylpyridine tBP) [21][22][23][24]. While several previous studies have explained the effect of the electrolyte composition on the photovoltaic performance of the DSC, many questions still remain open to date.…”

Effect of Diffuse Light Scattering Designs on the Efficiency of Dye Solar Cells: An Integral Optical and Electrical Description

“…The average collection efficiency thus tells us how many percent of the all electrons generated into the is the collection efficiency of electrons if they were generated uniformly in the film, k B is the Boltzman constant, T is the absolute temperature, m is the ideality factor, 28,29 and i REC,0 is the "dark" recombination current density at the equilibrium, given by …”

“…To derive the IV curve of the complete DSC, the voltage losses in the other cell components should be taken into account, 28 but here, we omit these voltage losses and investigate the photoelectrode performance only. The power output (Wm -2 ) of the photoelectrode is simply P TiO2 = V TiO2 i CELL , the maximum of which devided by the standard total solar irradiance of trapping.…”

“…The spectral dependence of the dye and the electrolyte extinction coefficients is extracted from reported absorptance data of standard transparent cells. 28 In all cases, the thickness of the absorbing electrode is taken to be d=7.0 microns. We neglected the specular reflectance arising from the interface between the transparent conducting oxide coating and the supporting glass plate to simplify the calculation.…”