Turning waste into treasure! Huang Academy team \”ACS Nano\”: made with scraped scale flexible electroluminescent device!

In the past few decades, a variety of electroluminescent device, in particular a flexible electroluminescent device is widely used in flat panel displays, a large decoration, display flag field illumination, the optical signals. Alternating current type electroluminescent device (ACEL), compared with the current light-emitting device with low power consumption, light uniformity, the advantages of easy production. And energy conversion efficiency is very high, much less heat is generated, so that it is expected to be integrated into wearable electronic devices (e.g., electronic skin) in. In order to realize the demand wearable electronic device, the device for preparing a flexible ACEL need to develop a flexible, transparent substrate, and integrated with the light emitting material. Most electroluminescent device using the electronic display and a smooth surface, high optical transparency as a plastic flexible substrate. But with the widespread use of plastics, a large plastic garbage landfill and incineration, causing serious pollution of groundwater and air, tremendous damage to our environment. Therefore, look for a green, economic and environmentally friendly materials instead of transparent plastic is imminent. Scale as inedible waste, accounting for about 3% of the annual output of 70.5 million tons of fish. Isinglass can be extracted from fish scales, is biodegradable macromolecules produced by the hydrolysis of collagen composition, about 40-55% of the scale, it has a sustainable, low cost and eco-friendliness. Further, since the presence of isinglass internal myofibrillar protein, fish gelatin having a good film, and the manufacturing process of green. Therefore, these benefits are expected to promote isinglass used in flexible electronics. Recently, Huang Fellow Institute of Advanced Materials, Nanjing University of Technology, Professor Liu Juqing and Professor Haidong team developed a flexible transient ACEL device is based on a transparent film of isinglass. Obtained fish gelatin film has good flexibility, a visible light transmittance of 91.1% at 24 days and can be completely degraded in the soil. OF by fish gelatin silver nanowire film deposited successfully a flexible transparent film electrode was prepared. low sheet resistance electrode 22.4Ω / sq, and 82.3% transmittance retention. Based on silver nanowires – a flexible thin film electrode isinglass ACEL device the emission intensity at a voltage of 300 V (frequency of 400 Hz) for the working conditions 56.0 cd m-2, and showed good flexibility and biodegradability. The work entitled \”Sustainable and Transparent Fish Gelatin Films for Flexible Electroluminescent Devices \”published in the\” ACS Nano \”. ​变废为宝!黄维院士团队《ACS Nano》:用刮下来的鱼鳞做柔性电致发光器件! [explain] Photo

​变废为宝!黄维院士团队《ACS Nano》:用刮下来的鱼鳞做柔性电致发光器件!
FIG. 1 is the preparation of fish gelatin film

Figure 1 , isinglass film prepared by solution casting method is mainly: pH scale cleaned and pretreated to form a film solution; then the solution was poured into a petri dish, after the dry film, and the thickness of the fish and the flexible film prepared by the process of easily adjusted.

​变废为宝!黄维院士团队《ACS Nano》:用刮下来的鱼鳞做柔性电致发光器件!
2 isinglass translucency and surface roughness of the film of FIG.

in this work, fish gelatin is used as the flexible substrate film is a transparent electrode, either visually identifying transparency, ultraviolet or visible spectral studies, indicate that PET and transparency isinglass flexible film, cellophane film are quite even more UV-vis spectroscopy results showed that fish gelatin film transmittance throughout the visible spectral range up to 91.1% It is slightly greater than the light transmittance of PET film and cellophane. surface roughness of the substrate is another important parameter particularly a flexible electronic device of high performance ACEL. found by atomic force microscopy, fish gelatin film surface roughness (0.5 nm) and PET (0.4 nm) considerably, while much lower than cellophane film (3.2 nm), is a potential of the electronics are integrated flexible material (FIG. 2).

​变废为宝!黄维院士团队《ACS Nano》:用刮下来的鱼鳞做柔性电致发光器件! 3 fish gelatin film
FIG. folding properties and resistance to organic solvent

in addition to high transparency, low roughness, excellent fish gelatin film is flexible and applicable to high chemical stability ACEL provide advantageous protection device. curvature a case where a radius of 0.9 mm, the film may be bent, and the film easily recover after bending, even the film may be folded into a complicated shape. Further, isinglass film was immersed in various organic solvents for 24 hours, maintains its original shape without any damage, exhibits good chemical stability (FIG. 3).

​变废为宝!黄维院士团队《ACS Nano》:用刮下来的鱼鳞做柔性电致发光器件!
FIG 4 isinglass film recyclability and biodegradability

isinglass the film also has excellent recyclability and biodegradability can (FIG. 4). the preparation of goodFish film was redissolved in water, the film can be prepared with the same new solution casting method. Redissolution and deposition process can be repeated a number of cycles, and no significant change in light transmittance, the described thin film having high recyclability. Further, as compared with non-degradable polymers prior to use of the flexible device ACEL, isinglass film is a biodegradable collagen derivatives, having excellent biodegradability, can reduce environmental pollution and waste disposal costs, in line with modern society, the pursuit of sustainable development.

​变废为宝!黄维院士团队《ACS Nano》:用刮下来的鱼鳞做柔性电致发光器件!
FIG 5 Preparation of fish gelatin based film device structure and properties of flexible ACEL

Analysis by spraying silver nanowire film composite and isinglass prepared silver nanowire – Fish rubber film electrode. Based on silver nanowires – isinglass highly flexible thin film electrode, the advantages of biodegradable properties, good transparency and good conductivity and stability, this work will be applied to the flexible ACEL device (FIG. 5). When the voltage is 300 V, a frequency of 400 Hz, the brightness of the device up to 56 cd m-2. Meanwhile, the device has good flexibility, is bent even when having a high emission stability. Bending cycles and after 1000, the emission intensity was not significantly reduced. More interesting is that, due to their high transparency, flexible device may be emitted from both sides of the electrode, the light emitting device which allows only one side of the conventional transmission are very different. Different phosphors selected, adjusting the mixing ratio of phosphor by weight, it is reasonable to realize a bright multi-color emission. Furthermore, the device can be completely dissolved in water, provides a description of the policy photoelectric products which does not contain environmentally harmful by-products and electronic waste. [Summary] isinglass highly transparent film presented herein not only environmentally friendly preparation process is simple, low cost, while the film has good flexibility, good transparency, biodegradability and good chemical stability. And the film in the flexible electroluminescence light-emitting device application exhibit excellent properties, it has a broad application prospect. At the same time, this work also shows great potential as a film isinglass flexible material, is expected to be applied to other applications in the field of flexible electronics. Original link: https://dx.doi.org/10.1021/acsnano.9b09880