Rare-Earth Doped Forsterite: Anti-reflection Coating with Upconversion Properties as Solar Capture Solution

Solar energy is a renewable power source that is harnessable nearly everywhere in the world. The investments in solar devices increase each year. Silicon is the dominant material in the production of commercial solar cells. More than 80% of world production is based on monocrystalline and polycrystalline silicon. Efficiency record commercial silicon solar panels convert about 25% of the sunlight into energy while the vast majority of conventional panels convert between 15 and 16%. The main factors of energy loss are the loss by light reflection on the cell surface and the loss by the energy emitted in the ultraviolet (UV) and infrared (IR) ranges which is directly transmitted and converted to heat without being harnessed by the cell. To overcome these losses, usually anti-reflective materials are applied on solar devices. In this chapter, the use of forsterite (Mg2SiO4) as an anti-reflective coating (ARC) is explored. Besides the antireflection property, forsterite is easily doped with several rare-earths (REs). Some elements of these group are capable of upconverting energy from de IR to the visible (Vis) spectral range. The theory behind the upconversion (UC) phenomenon is also presented here. Studies indicate that the use of forsterite ARC doped with UC REs on commercial silicon solar cells might be a low-cost solution to increase the efficiency of commercial devices.