Holographic lenses for building integrated concentrating photovoltaics

• A holographic solar concentrator has been designed, constructed and characterised.
• The system configuration is suitable for building integration.
• The holographic lens diffracts in the bandwidth to which the cell is more sensitive.
• The system prevents the cell overheating.
• The use of the holographic element increases the electrical efficiency of the system.

A volume transmission phase holographic element was designed and constructed to perform as a building integrated photovoltaic concentrator. The holographic lens diffracts light in the spectral bandwidth to which the cell presents the highest sensitivity with a concentration factor of 3.6X. In this way, the cell is protected from overheating because the infrared for which the solar cell is not sensitive is not concentrated. In addition, based on the asymmetric angular selectivity of the volume hologram and based on the linear concentration, only single-axis tracking is needed. The use of the holographic element increases the efficiency of the PV cell by 3% and the fill factor by 8%.