Nanostructures for plasmonic effects in solar cells and LEDs

Solar cells and light-emitting diodes (LEDs) have made significant progress, with rapid development of high- quality materials and novel device structures. However, the unsatisfactory uptake of light remains a challenge due to multiple light loss channels in sandwich-like device structures, and this demands effective photon management in order to improve performance. Plasmonic nanostructures allow the manipulation of light-trapping or extraction in optoelectronic devices. Plasmonic effects are considered to be competent light-absorbing assistants to break through the light-trapping limit in solar cells. Similarly, plasmonic nanostructures are good light scatters in LEDs, which outcouple emitted light over a wide range of wavelengths. This chapter introduces the fundamentals of surface plasmons either propagating at planar metallic surfaces or localized at metallic nanostructures. Then, optical techniques for the excitation of surface plasmon polaritons (SPPs), as well as the resonance condition for localized surface plasmon resonance (LSPR), are reviewed. Next, fabrication and simulation methods of various plasmonic nanostructures to create plasmonic effects to enhance light-trapping or light emission in solar cells and LEDs are discussed. Finally, the prospects for the future development of plasmonic nanostructures based on the strategy of light manipulation are given.