Spatial Distribution of Light Scattering and Absorption Interactions with TiO2- Nanoparticles from Monte Carlo and Generalized-Multiparticle-Mie based Simulations for Dye-Sensitized Solar Cell Analysis and Optimization

TiO2-based dye-sensitized solar cells (DSSCs) are a promising light harvesting technology that attracts tremendous research interest. The bulk of research however by far focuses on the light absorber and other components of the cell configuration through mostly experimental investigations [1,2]. The structure of DSSCs’ photosensitive component, the photoelectrode, is based on a randomly organized network of TiO2-nanoparticles (NPs). This highly complex structure has made the theoretical studies difficult. Currently, optical models proposed in the literature have been limited to an oversimplified study of isolated spherical nanoparticles [3]. The underlying theory relating the photoelectrode structure with its light harvesting capacity remains unclear. In this research, a computer simulation program is presented for modeling the optical response of DSSCs’ photoelectrode, and developing fundamental understanding of light interactions with TiO2-NPs. The light harvesting capacity of the photoelectrode is examined through simulated transmittance, reflectance, and absorptance spectra for different configurations. Unlike currently used models for similar applications, this C++ program is based on generalized-multiparticle-Mie (GMM) rigorous electromagnetic scattering solutions for aggregated spherical nanoparticles (SNPs) [4]. A Monte Carlo algorithm was coupled to GMM calculations to simulate light propagation within the photoelectrode. Using scanning electron microscope (SEM) micrograph to have realistic TiO2-NP configurations, the simulation results were compared to experimental spectra.