This work describes systematic studies of shoulder-by-shoulder electrochromic devices to reveal their special characteristics and specific applications.

Lately, the color-changeable electrochromic technology has been applied onto mobile phones to shield the cameras, where special demands for the electrochromic working unit are a fast bleaching response time, a high transmittance in the bleached state when cameras work, a long-lasting memory effect in the colored state when cameras are in the standby mode, and excellent cyclic stability and safety. However, in electrochromic films, long-lasting memory effect always means a slow response time. And a traditional electrochromic device contains at least five functional layers, which limits its transmittance in the bleached state on a large scale. Herein, we designed a three-layered all-solid-state camera shielding device (ITO/WO3/electrolyte) with necessary WO3 electrochromic working units and a lateral WO3 storage unit which is known as the shoulder-by-shoulder electrochromic structure. Owing to the high-performance WO3 film and the special characteristics of the shoulder-by-shoulder electrochromic technology, our greatly simplified device perfectly met all the above-mentioned requirements. This research will be a strong push for the applications of electrochromic technology onto all kinds of mobile devices.

Ge1−xSnx film with Sn content (at%) as high as 13% was grown on Si (100) substrate with Ge buffer layer by magnetron sputtering epitaxy. According to the analysis of HRXRD and Raman spectrum, the quality of the Ge1−xSnx crystal was strongly dependent on the growth temperature. Among them, the GeSn (400) diffraction peak of the Ge1−xSnx film grown at 240 °C was the lowest, which is consistent with the Raman result. According to the transmission electron microscope image, some dislocations appeared at the interface between the Ge buffer layer and the Si substrate due to the large lattice mismatch, but a highly ordered atomic arrangement was observed at the interface between the Ge buffer layer and the Ge1−xSnx layer. The Ge1−xSnx film prepared by magnetron sputtering is expected to be a cost-effective fabrication method for Si-based infrared devices.