Impact of Particle Shape on Optical and Electrical Properties of Ultrathin Silicon Solar Cells

We study the effect of particle shape on the optical and electrical response of ultrathin silicon solar cells. In a particle-based cell, wherein nanoparticles form the cell absorber, the electrical operation of the cell is subjected to geometrical limitations. Assuming that doped silicon nanoparticles with predefined shapes are distributed on a silicon layer to form the cell junction, it is shown that existing a sufficiently large contact area between the nanoparticle and its adjacent layer has a significant effect on transport of the photo-generated carriers. We show that despite having interesting absorption, a cell comprising pure spherical silicon particles has a relatively weak power conversion efficiency. We see that imperfect nanospheres as well as particles with other shapes but larger contact areas in the junction can propose higher cell efficiencies.