Near Infrared Absorbers

INFRARED LIGHT

Sunlight consists not only of the visible light but also of ultraviolet (UV) and infrared light (IR). The visible part of the spectrum (400 to 700 nm) makes up for 43 % of the sun’s energy, whereas the ultraviolet (250 to 400 nm) makes up only 5%. Infrared light (700 to 2500 nm) accounts for the majority of the sun’s energy, at 52%.

Infrared light cannot be seen by the human eye, but it is noticed as heat. On sunny days the heat builds up in buildings and vehicles and can be a serious issue, which can require extensive air conditioning to keep temperatures at a pleasant level. The high energy costs and environmental impact associated with the climate control make alternative solutions for a reduction of the heat build-up interesting. This is the point where infrared absorbing materials come into the picture.

Infrared light also plays an important role in technical applications. Heating and drying processes in thermoplastic polymers, coating and printing applications are often accelerated by IR light.

Materials designed to absorb infrared light have special chemical properties. In order to interact with infrared light, molecules must have a suitable structure, which allows the excitation of electrons, and thus the absorption of infrared light. The chemistry of inorganic metallic oxides offers numerous options to create materials with the required sensitivity to infrared light. The introduction of additional elements into the crystal structure, or processes to generate mixed – valence oxides are only a few options which we use to create efficient infrared absorbing materials.