Efficiency enhancement in thin-film silicon solar cells by plasmonic nanodiscs array Neda Ahmadi* Department of Basic Sciences, Garmsar Branch, Islamic Azad University, Garmsar, Iran Abstract. Plasmonic nanoparticles are promising ways for the efficiency enhancement of thin- film solar cells. We have taken into account the bare silicon wafer and the embedded thin-film silicon solar cells with Au nanodiscs array. We study these geometries of thin-film silicon solar cells and find the effect of Au nanoparticles on light transmission and reflection spectrum, power absorption, generation rate, power electric, and short-circuit current density; and for this, we have used finite difference time domain, FDTD software. We also consider the near-field electric intensity in the vicinity of nanoparticles with different sizes, which are known as a solar cells efficiency enhancement mechanism. Our study can be useful for new perspectives for antire- flection coating applications and light management in silicon solar cells. © 2021 Society of Photo-Optical Instrumentation Engineers (SPIE) [DOI: 10.1117/1.JNP.15.036010] Keywords: thin-film silicon solar cell; plasmonic nanodiscs array; electric power; generation rate; electric field; magnetic field. Paper 21040 received May 1, 2021; accepted for publication Sep. 2, 2021; published online Sep. 20, 2021. 1 Introduction Photovoltaic cells are a promising way for solving the problems of climate change as a very important problem in the world. The first challenge for using photovoltaic technology is price, because comparing with fossil fuel technology is more expensive. 1 Currently, the most solar cells market is based on the crystalline silicon wafer with 200 to 300 nm thickness, whereas 40% cost of these cells is due to silicon wafers. For this reason, the researchers start the wide research about thin-film solar cells. The main constraint of using thin-film technology is the ineffective absorption of near-bandgap light of these solar cells, specially for indirect-bandgap semicon- ductors such as silicon. Therefore, finding new ways for light trapping in these solar cells for absorption enhancement is very important. There are different methods for increasing absorp- tion, such as surface texturing or creating the texture on the substrate, 2,3 but these methods have problems and they are not suitable for thin-film solar cells. 4 Using the metal nanoparticles is a useful way for the absorption enhancement in thin-film solar cells due to surface plasmon resonance. For this, there is a great amount of work in fun- damental properties and application of plasmonic resonance specially in integrated optics and biosensing. 5,6 The first works in the plasmonic field and efficiency enhancement of solar cells have been done by Stuart and Hall. 7 They reported the increasing photocurrent for the thick silicon surface using Ag nanoparticles at the wavelength of 800 nm. After that, Schaadt et al. used Au nanoparticles on highly doped wafer-based solar cells. They showed the increase of photocurrent up to 80% around 500 nm. 8 Moreover, Derkacs et al. 9 used the Au nanoparticles on thin-film amorphous silicon solar cells, and they achieved 8% overall enhancement in conversion efficiency. One year later, Piallai et al. reported new results about the effect of Ag nanoparticles on photocurrent of thick silicon-on-insulator and planar wafer-based cells. They showed an increase of photocurrent 33% and 19%, respectively. 10 Subsequently, metal nanoparticles have been used to increase the light extraction efficiency of light-emitting diodes by Pillai et al. They also reported an overall electroluminescence enhancement of a factor of 7 for thin silicon-on- insulator light-emitting diodes. 10,11 These nanoparticles have intensive interaction with incident *Address all correspondence to Neda Ahmadi, ahmadiphysic@gmail.com or n.ahmadi@srbiau.ac.ir 1934-2608/2021/$28.00 © 2021 SPIE Journal of Nanophotonics 036010-1 Jul–Sep 2021 • Vol. 15(3)