Plants rely on sunlight for photosynthesis, but not all sunlight is equally useful to them. Notably, plants use red and orange light much more efficiently than blue and ultraviolet (UV) light. Some advanced greenhouse films like UbiQD’s UbiGro film are designed to fix that. These films contain tiny particles called quantum dots that absorb the less-useful UV and blue light and re-emit it as red light — the kind plants love (Figure 1).
Figure 1: Diagram comparing clear greenhouse films (A) to quantum-dot greenhouse films (B), which result in larger plants due to the conversion of blue light to red light.
The films are already making a difference for growers, but there’s a problem: much of the newly created red light gets stuck bouncing around inside the plastic film instead of reaching the crops below, where it can be used. That’s where Smart Material Solutions comes in. We use nanocoining and roll-to-roll processes to create microscopic patterns on the surface of the greenhouse films to help more light escape the film and reach the plants, providing more energy to grow.
How Nanopatterns Extract Light
The light emitted by the quantum dots can become trapped inside the plastic film due to a phenomenon called total internal reflection. This occurs when light traveling within a material (such as glass or plastic) strikes the boundary with a less dense material (like air) at certain angles, causing it to reflect entirely back into the original material rather than passing through. Figure 2 shows a photo of total internal reflection of a laser beam inside a piece of glass. In some applications, total internal reflection is desirable — for instance, fiber optic cables rely on this effect to transmit light, and the information it carries, over long distances without loss.
Figure 2: Photo showing total internal reflection of a laser beam inside a glass slide.
In greenhouse films, total internal reflection is undesirable because it prevents some of the light emitted by the quantum dots from escaping the film and reaching the plants. One way to overcome this issue is to add a micropattern to the film’s surface to disrupt the light’s path and encourage it to escape (Figure 3). In smooth spectral-shifting greenhouse films, up to 87% of the light emitted from the quantum dots never reaches the plants they’re intended to illuminate. About 75% of this light becomes trapped inside the film by total internal reflection, and of the remaining 25%, only half is emitted toward the plants while the other half escapes in the opposite direction. Micropatterning the films can reduce total internal reflection and preferentially direct the light toward the plants.
Figure 3: Much of the light emitted by quantum dots gets trapped inside smooth films (A). Micropatterning helps this light escape in the direction of the plants, resulting in more plant growth (B).
Bonus Benefits of Surface Patterning
These tiny patterns don’t just help with light delivery — they offer other advantages too:
Even Light Distribution: Micropatterns spread incoming sunlight more evenly across the greenhouse, increasing crop yields by preventing bright spots and shadows.
Cleaner, Clearer Films: Some of our nano-sized patterns mimic natural surfaces like lotus leaves, making greenhouse films repel water and dust. This keeps them cleaner and clearer, so more sunlight gets in.
Less Glare, More Growth: Certain patterns can also reduce reflection from the film’s surface, helping maximize the total amount of sunlight that enters the greenhouse.
Preliminary Work at Smart Material Solutions
SMS and UbiQD have conducted preliminary experiments in which SMS micropatterned the surface of UbiQD’s greenhouse films. The most effective patterns produced a significant increase in the light emitted toward the plants compared to smooth, unpatterned films. These results highlight the potential of combining light-converting greenhouse films with Smart Material Solutions’ surface patterning technology, helping growers get even more from the sunlight they already have. It’s a simple, effective upgrade that could lead to bigger harvests, healthier plants, and a smarter way to meet the world’s growing food demands.
SMS can generate a wide array of nano and micropatterns for applications including enhanced light capture for solar panels, anti-dust coatings, structural color, or superhydrophobicity. We’d love to chat about how highly scalable engineered surface textures can add value to your products!