Supersized CDs and DVDs with extra storage space are a step closer, thanks to researchers in China.

Fangfang Jian and colleagues, from the Qingdao University of Science and Technology, have synthesised metal cluster complexes capable of absorbing two photons simultaneously in an excited state. Materials with this property can be used to make precise laser beams.

CDs and DVDs consist of a single layer onto which data is written using laser beams. Multiple closely spaced layers stacked one on top of the other allows more storage space on each disc. But a very precisely focused laser beam is required to do this.

Jian said that using organic materials for this purpose is well explored, with fairly poor results, and metal cluster complexes have not been considered until now. These complexes with a core of four metal atoms and one oxygen atom, surrounded by six organic ligands, are better at absorbing the photons than the organic materials, he said.

Research continues to find the perfect metal complex for this purpose, as Jian said that materials with even better properties can be found based on his metal complex design.

Nina Athey-Pollard