image: Schematic illustration of self-healing stretchable polymer semiconductors based on single-strength vs. hierarchical hydrogen bonds
Credit: ©Science China Press
Foldable phones are old news. But imagine this: a future phone that doesn't just bend, but stretches like a rubber band — and even fixes its own cracks.
Sounds like a sci-fi movie, right? The key to making it happen? A semiconductor that can both stretch and self-heal.
Nice idea, but reality bites. Why is it so hard? Because it's a built-in contradiction:
- Charge transport wants the molecular chains to stand like soldiers: rigid, orderly, highly crystalline.
- Stretching and self-healing want them to act like playdough: soft, disordered, dynamic, and reversible.
Trying to get both from the same material is like asking someone to be a tough guy and a softie at the same time. Not easy.
Enter hydrogen bonds. Think of them as little "dynamic repair masters" — they can break and reform on their own, which makes them great for stretchability and healing. But most semiconductor materials so far rely on single-strength hydrogen bonds. One level of strength just isn't enough to deliver both good stretchability and healing.
So scientists came up with a new trick: hierarchical hydrogen bonds.
Imagine a mix of Velcro and a zipper: some bonds are super strong anchors; others are weak and reversible. Together, they create a network that stays stable overall, but can break step by step under stress, dissipating energy along the way. This teamwork finally nails the three-way balancing act: charge transport, stretchability, and self-healing.
Using this idea, the researchers grafted a hierarchical hydrogen-bonding unit into a classic polymer semiconductor backbone. The results are as follows:
- Tighter molecular packing → better charge transport
- Dynamic, reversible networks → better stretchability and self-healing
The numbers speak for themselves:
- Crack onset strain: 150%
- Electrical healing efficiency: 90%
- Fully flexible transistor array: even at 150% strain, it still delivers a high mobility of 1.01 cm² V⁻¹ s⁻¹
That's a new record for self-healing, stretchable semiconductors.
This study is the first to use a hierarchical hydrogen bond strategy to solve the long-standing trade-off between charge transport, stretchability, and self-healing — achieving all three at once. It opens a new path toward truly stretchable, self-healing electronics in the future.
This work was led by Professor Zhen's group at Beijing University of Chemical Technology (https://www.x-mol.com/groups/zhen_yonggang?lang=en).