Twisting semiconductors enhances clean fuel generation efficiency

Twisting semiconductors enhances clean fuel generation efficiency
by Sophie Jenkins
London, UK (SPX) Apr 26, 2024

In a significant advancement for sustainable fuel generation, University of Cambridge researchers have enhanced the performance of copper oxide semiconductors. These semiconductors are crucial for devices that convert water into hydrogen fuel using solar power. Despite their low cost and non-toxic nature, copper oxides generally lag behind silicon in efficiency. By orienting copper oxide crystal growth diagonally, researchers achieved a dramatic improvement in electric charge movement, enhancing performance by 70% over previous models.

This novel approach also resulted in increased stability of the photocathodes, crucial for practical applications. Copper (I) oxide, known for its potential as a silicon alternative, captures sunlight efficiently but struggles with charge retention. "Like other oxide semiconductors, cuprous oxide has its intrinsic challenges," explained Dr. Linfeng Pan, co-first author. He highlighted the typical depth of light absorption versus charge travel as a limiting factor.

Professor Sam Stranks, leading the research, pointed out the importance of crystal growth orientation to material performance. "The way the crystals are grown is vital to their performance," Stranks noted, indicating that defects typically reduce solar cell material efficiency. The team used thin film deposition at room temperature, simplifying the production process and allowing for precise control over crystal orientation, which significantly improved charge mobility.

"These crystals are basically cubes, and we found that when the electrons move through the cube at a body diagonal, rather than along the face or edge of the cube, they move an order of magnitude further," said Pan. "The further the electrons move, the better the performance." Stranks added, "Something about that diagonal direction in these materials is magic. We need to carry out further work to fully understand why and optimize it further, but it has so far resulted in a huge jump in performance."

While more research is needed, the findings suggest a promising direction for energy transition materials. "There's still a long way to go, but we're on an exciting trajectory," concluded Stranks.

Research Report:High carrier mobility along the [111] orientation in Cu2O photoelectrodes