Glass might soon face competition from an unlikely contender: bamboo. Scientists in China have transformed regular bamboo into a transparent material that is also resistant to fire and water and suppresses smoke.

Traditionally, silica glass, made from sand, is the preferred building material for applications requiring transparency and strength, such as windows. However, it is not particularly sustainable and can be heavy and brittle. Transparent wood has emerged as a viable alternative in recent years. By chemically removing lignin from wood fibers and treating the remaining material with plexiglass or epoxy, researchers have created a transparent, renewable material that rivals or exceeds the strength of glass while being lighter and a better thermal insulator.

Despite these advantages, transparent wood has some drawbacks. It is more flammable than glass and is already in high demand, with slow replenishment rates. To address these issues, researchers at Central South University of Forestry and Technology (CSUFT) in China turned to bamboo.

“Bamboo, often referred to as ‘the second forest,’ boasts a fast growth and regeneration rate, allowing it to reach maturity and be utilized as a building material within four to seven years of growth,” said Caichao Wan, the study’s corresponding author. “With an output four times higher than wood per acre, bamboo is recognized for its exceptional efficiency.”

Bamboo’s internal structure and chemical composition are very similar to wood, so the team used a similar method to make it transparent. After removing the lignin, the bamboo is infused with inorganic liquid sodium silicate, altering the light refraction of the fibers to make them clear. The material is then treated to become hydrophobic, or water-repellent.

The final product consists of a three-layered structure: silane on the top, silicon dioxide in the middle, and sodium silicate on the bottom. The transparent bamboo exhibits a light transmittance of 71.6%, is flame retardant, water-repellent, and blocks smoke and carbon monoxide. Mechanically, it boasts a bending modulus of 7.6 GPa and a tensile modulus of 6.7 GPa.

This innovative transparent bamboo can be used as a building material and as a substrate for perovskite solar cells. When used in solar cells, it acts as a light management layer, boosting the cells’ power conversion efficiency by 15.29%.

“In future research, we will focus on the large-scale fabrication and multi-functionalization of this transparent bamboo,” said Wan.

The development of transparent bamboo presents a sustainable and efficient alternative to traditional glass and transparent wood, promising significant advancements in construction and renewable energy applications.

By Impact Lab