Color printing enabled by phase change materials on paper substrate

Abstract

We have coated phase change materials (PCMs) on rough and flexible substrates to achieve multicolor changeable devices. The principle of the device is based on an earlier discovery that lights have strong interference effect in PCM films, leading to various colors by reflection. In this work, paper substrates are laminated by parylene layers to protect the device from water before coated with functional PCM films. The PCM-based color printing (PCP) on paper is not affected by rough surfaces and shows a similar color appearance as that on smooth surfaces. In particular, the color-printed device can be patterned by UV lithography to display a clear and tunable optical image, and it exhibits a low sensitivity to the angle of view. Such PCP has potential applications for low-cost, disposable, and flexible displays.

Rewritable color nanoprints in antimony trisulfide films

“…Specifically, the refractive index of the extraordinary crystalline state (blue line) increased by a maximum of 1.0 across the entire visible range, which is larger than that of most widely studied typical PCMs, e.g., GST (see fig. S3) ( 11 , 13 ), Sb 2 Te 3 ( 34 ), and Ag 3 In 4 Sb 76 Te 17 (AIST) ( 12 ). We also compared the measured optical constants of the completely reamorphized square area with the as-deposited amorphous Sb 2 S 3 film.…”

“…Of particular interest are subwavelength thin films of optically lossy materials on metals whose colors are sensitive to the thickness and optical properties of these films alone (9,10). Chalcogenide phase-change materials (PCMs) (11)(12)(13)(14) can achieve reversible color switching in these systems using an ultrathin form factor. With reversible subnanosecond structural phase transitions causing large changes in their optical constants, PCMs offer fast and stable color changes between amorphous and crystalline states.…”

“…Moreover, the switching can be repeated billions of times without damaging the materials (15)(16)(17). However, most PCMs, including the widely used Ge 2 Sb 2 Te 5 (GST), exhibit only small refractive index changes and correspondingly small spectral shift of ~35 nm in the visible spectrum when switched between states (12)(13)(14). In contrast, wide-bandgap PCMs, such as antimony trisulfide (Sb 2 S 3 ), provide larger refractive index changes in the visible spectrum (18) and are, therefore, desirable for color-changing devices.…”

Dynamic control of mode modulation and spatial multiplexing using hybrid metasurfaces

“…PCMs, such as germanium antimony telluride (GST), indium antimonide (InSb), gallium lanthanum sulfide (GLS), and vanadium oxide (VO2), are used for data storage, integrated optical circuits, color printing, optical display and so on, by employing their unique reversible, nonvolatile properties [33,34].…”

“…While other methods may suffer from relatively huge loss and may not be very feasible for the integration of metadevices. Using the PCMs can achieve dynamic functionalities with high efficiency, feasibility, and larger working bandwidth, which makes PCMs a promising choice for reconfigurable metasurfaces.PCMs, such as germanium antimony telluride (GST), indium antimonide (InSb), gallium lanthanum sulfide (GLS), and vanadium oxide (VO2), are used for data storage, integrated optical circuits, color printing, optical display and so on, by employing their unique reversible, nonvolatile properties [33,34].Upon an appropriate stimulus like thermal, optical, or electrical, PCMs offer a flexible control of optical parameters during the phase transition of the composite atom array between crystal and amorphous states or insulator-to-conductor states [35]. Such atomic rearrangements remain stable at room temperature and come with an abrupt change in the physical properties (e.g., complex refractive index and resistivity) after phase transition [36].…”