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, chemistry and photochemistry science to design and produce glow powder, ink and paint 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 with high luminous intensity.
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 presence of light following an absorption of light.
Phosphorescence is a process of de-excitation between two states of different multiplicity (between the excited state and the ground state) 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 (glow property) 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 glow powder and pigment, day and night
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 science allows us to develop your customized glow powder. It's a whole scientific work on the scale of the glow 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 glow property
Today, there is a wide variety of commercial glow pigments, which are essentially green or blue. It is therefore easy to obtain a phosphorescent material. The mixture of a commercial glow pigment in an ink and/or paint allows to obtain easily a phosphorescent solution.
The difficulty is if you wish a strong glow intensity in the dark 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 glow pigmentary charge can irremediably reduce the luminous intensity in the dark from several hours to a few minutes.
Controlling color of a glow powder and pigment
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 glow 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
To be able to offer this performance, we develop our glow powder pigments but only deliver our inks (screen printing, pad printing,...). This allows us to control all the steps from the preparation of the pigment powder mixture to the formulation of inks and paints.
All our glow materials 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 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. Glow in the dark 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...