29/11/2022
Reading time 10 minutes
The expert's eye

Are you looking for a phosphorescent material?

OliKrom has acquired a unique expertise in the field of phosphorescent materials. Our team masters the most advanced concepts in materials science and photochemistry to design and produce phosphorescent inks and paints with high luminous intensity and a varied color palette.

 

What is phosphorescence ?

A phosphorescent material has the ability to store light and restore it in the dark.

It is important to distinguish fluorescence which stops as soon as the illumination stops, from phosphorescence which persists. Fluorescence and phosphorescence are two forms of photoluminescence, that is to say an emission of light following an absorption of light.

Phosphorescence is a process of de-excitation between two states of different multiplicity which is not allowed by the quantum model, but which is made possible by the spin-orbit coupling. The transition is consequently slow to take place. In molecular chemistry, the phosphorescence process is generally encountered during the relaxation between an excited state T1 (triplet state) and the ground state S=0 (singlet state), involving a change of multiplicity.

Optimal phosphorescence, day and night

color-intelligence

If you are looking to develop a collection, a product, a targeted color with intense phosphorescent intensity, OliKrom is your partner.

Our unique know-how in materials science and photochemistry allows us to develop your customized photoluminescent product. It's a whole scientific work on the scale of the pigment and the matrix (paint, ink) that allows us to control the photochemical cascade to confer optimal phosphorescent properties.

The main difficulties observed to obtain a phosphorescent material

Stabilize the property

Today, there is a wide variety of commercial phosphorescent pigments, which are essentially green or blue. It is therefore easy to obtain a phosphorescent material. The mixture of a commercial pigment in an ink and/or paint allows to obtain easily a phosphorescent solution.

The difficulty is if you wish a strong phosphorescent intensity with a stability of the property throughout the production, with a recurrence. By experience, we know that phosphorescent materials are extremely sensitive to shear forces, that an uncontrolled addition of an additive, a dye, a pigmentary charge can irremediably reduce the luminous intensity.

 

Controlling color

Another major challenge is to achieve color control by day and night. Our teams use photochemical cascade to optimize :

  • the color: violet, blue, green, red, orange, yellow, black... ;
  • the luminous intensity ;
  • the duration of emission in time;
  • the matrix and deposition method: ink (screen printing, pad printing, syringe filling), paint (high or low pressure pneumatic spray, aerosol can), composite, plastic...

 

The process from start to finish

olikrom-process

To be able to offer this performance, we develop our pigments but only deliver our inks (screen printing, pad printing,...). This allows us to control all the steps from the preparation of the pigment mixture to the formulation of inks and paints.

All our products are produced in our factory (33, France) and controlled by our quality department. The phosphorescence properties of our products are characterized by :

  • the emission spectrum which gives access to the variation of the intensity of the emitted light according to the wavelength;
  • the quantum yield which informs on the luminescent performance of the material. It varies from 1 (all the absorbed photons are re-emitted) to 0 (the compound is not luminescent);
  • the lifetime which is the characteristic time of the emission. In most cases, the fluorescence emission follows an exponential probability law in exp (- t/τ), where τ is the lifetime. The order of magnitude of the lifetime of many fluorescent substances is the nanosecond (billionth of a second). In phosphorescence, the lifetime can reach several hours.

Some applications examples of phosphorescent and photoluminescent materials

Phosphorescent materials with optimized properties, in intensity and variety of color, have many applications today. Photoluminescent products are marketed in the form of paint, ink, aerosol cans, adhesives...

 

On the road

As an example, OliKrom has developed LuminoKrom® photoluminescent paint that captures light during the day and lights up in the dark for 10 hours without consuming any electricity or emitting any CO2. It is now widely deployed in the field of road markings (ground paints and signs) to increase safety in places without public lighting in France and abroad.

 

For industrial sites

In the industrial sector, the uses are emergency signage, safety clothing. The issue for some sensitive industries is to ensure the continuity of an activity in case of power outage: locating switches, valves, stairs, corridors, danger zones...

 

In everyday life

Other projects are related to sobriety, eco-design to create autonomous advertising signs, create new architectural concepts, or even playful: decoration (stars, garlands), clothing, make-up, adhesive, clocks...

photoluminescente-technology-bike-path

Improve bike path visibility

secure-stairs-phosphorescent

Staircase security

terra-nocta-phosphorescent

Artistic creation - Parc Terra Botanica (Angers (49) in France)

Do you have a project ?

Need to develop a phosphorescent/photoluminescent material, an ink, a paint? Our experts are at your side.