Photo and electroluminescence properties in Zns: (Cu, La) and Zns: (Ag, La) phosphors

ACS Appl. Mater. Interfaces

et al. 2020

A stretchable alternating current electroluminescent display seamlessly combines the light-emitting capabilities with mechanical compliance, which offers exciting opportunities for applications in wearable gadgets, soft robots, and fashion designs. The widespread adaption to deformable forms of optoelectronics is currently impeded by the tedious and labor-intensive fabrication process. This study reports an efficient and scalable procedure to create a fully screen-printed, multicolor, and stretchable electroluminescent display. The as-prepared device exhibits excellent deformability and low-voltage operation. The practical implementation is demonstrated by creating a wearable sound-synchronized sensing system with an epidermal display responsive to the rhythm of music. The ink formulation and printing procedure developed here pave the way for convenient fabrication of stretchable electronic devices.

Section: Resultsmentioning

confidence: 99%

Fully Screen-Printed, Multicolor, and Stretchable Electroluminescent Displays for Epidermal Electronics

Zhao

ACS Appl. Mater. Interfaces

et al. 2020

“…A maximum is obtained at an intermediate frequency of 17 kHz, which represents the optimal conditions to achieve bright emission. The luminance initially rises with voltage frequency, as a result of increased injection of accelerated electrons to activate luminescent centers. − The brightness rapidly decreases by further increasing the excitation frequency due to retrapping of electrons in donor levels. − In addition, the device shows noticeable blue-shifted emissions by increasing the voltage frequency (see Figure S8 in the Supporting Information). Light emission of Cu-doped ZnS phosphors comes from blue and green EL emitters, showing increased contribution from deep energy levels with blue color under high voltage frequencies. , …”

mentioning

confidence: 99%

Stretchable High-Permittivity Nanocomposites for Epidermal Alternating-Current Electroluminescent Displays

Zhao

Wang

et al. 2019

ACS Materials Lett.

Stretchable alternating current electroluminescent display is an emerging form of light-emitting device by combining elasticity with optoelectronic properties. The practical implementations are currently impeded by the high operating voltages required to achieve sufficient brightness. In this study, we report the development of dielectric nanocomposites by filling surface-modified ceramic nanoparticles into polar elastomers, which exhibit a series of desirable attributes, in terms of high permittivity, mechanical deformability, and solution processability. Dielectric nanocomposite effectively concentrates electric fields onto phosphor to enable low-voltage operation of stretchable electroluminescent display, thereby alleviating safety concerns toward wearable applications. The practical feasibility is demonstrated by an epidermal stopwatch that allows intimate integration with the human body. The high-permittivity nanocomposites reported here represent an attractive building block for stretchable electronic systems, which may find broad range of applications in intrinsically stretchable transistors, sensors, light-emitting devices, and energy-harvesting devices.

“…The emission intensity initially increases with the frequency until 30 kHz as a result of increased injection of accelerated electrons to activate the luminance centers [ 64 – 66 ]. The luminance decreases by further raising the frequency due to the capture of injected electrons at donors [ 67 – 69 ].…”

Section: Resultsmentioning

confidence: 99%

A Printable and Conductive Yield-Stress Fluid as an Ultrastretchable Transparent Conductor

Yin

et al. 2021

Research

In contrast to ionically conductive liquids and gels, a new type of yield-stress fluid featuring reversible transitions between solid and liquid states is introduced in this study as a printable, ultrastretchable, and transparent conductor. The fluid is formulated by dispersing silica nanoparticles into the concentrated aqueous electrolyte. The as-printed features show solid-state appearances to allow facile encapsulation with elastomers. The transition into liquid-like behavior upon tensile deformations is the enabler for ultrahigh stretchability up to the fracture strain of the elastomer. Successful integrations of yield-stress fluid electrodes in highly stretchable strain sensors and light-emitting devices illustrate the practical suitability. The yield-stress fluid represents an attractive building block for stretchable electronic devices and systems in terms of giant deformability, high ionic conductivity, excellent optical transmittance, and compatibility with various elastomers.