Photovoltaic device with an anti-reflective coating and anti-reflective coating for photovoltaic devices

A photovoltaic device comprising an anti-reflective coating on a light incident side of a transparent cover layer, the anti-reflective coating comprising a layer of diatom frustules, each of the frustules comprising two adjacent and connected porous silica layers,

• the first porous silica layer having a pore diameter and pore pitch defining a first layer porosity, the second porous silicon layer having a pore diameter and pore pitch defining a second layer porosity, the second layer porosity being less than the first layer porosity,
• the layer of diatom frustules being arranged such that the first porous silica layer is light incident with respect to the second porous silica layer.

An anti-reflective coating for a photovoltaic device, the anti-reflective coating comprising a layer of diatom frustules, each of the frustules comprising two adjacent and connected porous silica layers,

• the first porous silica layer having a pore diameter and pore pitch defining a first porosity,
• the second porous silicon layer having a pore diameter and pore pitch defining a second porosity, the second porosity being less than the first porosity,
• the layer of diatom frustules being arranged such that the first porous silica layer is the light incident layer of the anti-reflective coating.