Soft, even foldable, flexible electronic devices, such as flexible cell phone screens, and even soft mobile phones, are new devices that many people have been waiting for. However, limited by the brittleness of semiconductor materials, it may bring about a revolution in the electronic technology. Electronic technology and production processes are also facing enormous challenges. Chinese scientists have also attacked a city a few days ago: Their latest research results are expected to break this bottleneck.
Prof. Shi Xun, researcher of the Shanghai Institute of Ceramics, Chinese Academy of Sciences and researcher Chen Lidong collaborated with Prof. Yuri Grin of the German Maps Institute to find the first kind of semiconductor material that is 'soft' like metal: it is a typical semiconductor, but However, it has very unusual mechanical properties similar to that of metal—good ductility and bendability, or it can be widely used in flexible electronic devices. The chemical composition of this magical material contains silver atoms, which is α-Ag2S.
Schematic. Magical Flexible Semiconductor Material α-Ag2S
The relevant research paper was published on April 9th in the international academic journal Nature Materials.
For a long time, people have assumed that semiconductor materials are as brittle as ceramics. However, Chinese scientists recently discovered that α-Ag2S materials have surprising performance.
The processing fragments of ceramics and semiconductors are usually fine particles or powders, but α-Ag2S will not be broken under external forces and large strains. The processing fragments of the material are similar to metal, and are a kind of elongated winding filaments.
Rapidly developing flexible electronic materials in recent years simply make organic/inorganic material electronic devices on flexible substrates. Even so, their unique deformability and efficient, low-cost manufacturing processes in information, energy, medical, defense, etc. The field has a wide range of application prospects.
However, current inorganic materials, especially semiconductors, are brittle materials, and they are prone to cracks under large bending and large deformation, or under tensile conditions, and lead to device failure. In addition, organic semiconductors have relatively low mobility compared to inorganic semiconductors, and electrical The range of adjustable performance is small and it cannot meet the vigorous development demand of the semiconductor industry.
Photograph by Respondents for the mysterious semiconductor material α-Ag2S.
For the application of flexible electrons, researchers such as Shi Xun and others prepared α-Ag2S films, which have greater deformability than bulk materials. Moreover, after tens or hundreds of bends, their electrical conductivity remained unchanged or changed. Very small.
Know it, know why.
The researchers found that during the deformation and slippage of α-Ag2S, the two S atoms move along the slides formed by six Ag atoms. At this time, the old Ag-S bonds are constantly weakened or even broken, and there are new ones. The Ag-S bond strengthens or even generates. Therefore, the force between the sliding surfaces is always maintained in the Ag-S bond state, and the energy fluctuation during the slip is small, resulting in a small sliding energy barrier. At the same time, the keying state ensures a strong force between these sliding surfaces, avoiding the occurrence of cracks or even the dissociation of materials during the sliding process.
This property is obviously different from other materials. The barrier of diamond material in sliding is too large. Therefore, there is no slip surface and it cannot be extended. However, the interaction between NaCl and the sliding surface of graphite is too small. In the slip process, cracks are easily generated, dissociating and losing their integrity.
According to the researchers, a material with good sliding properties and ductility must meet two basic conditions: First, there is a slip surface with a small energy barrier, which can slip under the action of external forces; and secondly, during the slip process. There is no decomposition in it, and the integrity and integrity of the material are still maintained.
They are looking for other semiconductor materials similar to α-Ag2S.
