Ma Lanchao

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04 Jan 14:27

High‐Performance Ambipolar Polymers Based on Electron‐Withdrawing Group Substituted Bay‐Annulated Indigo

by Jie Yang, Yaqian Jiang, Zeyi Tu, Zhiyuan Zhao, Jinyang Chen, Zhengran Yi, Yifan Li, Shuai Wang, Yuanping Yi, Yunlong Guo, Yunqi Liu
Advanced Functional Materials High‐Performance Ambipolar Polymers Based on Electron‐Withdrawing Group Substituted Bay‐Annulated Indigo

Here, an effective two‐step method is developed to obtain an electron‐withdrawing group (EWG) substituted bay‐annulated indigo (BAI) units. Four polymers, PBAI‐V, P2FBAI‐V, P2ClBAI‐V, and P4OBAI‐V, are developed by this method. Particularly, P2ClBAI‐V exhibits remarkable hole and electron mobilities of 4.04 and 1.46 cm2 V−1 s−1, respectively. These mobilities are among the highest values for BAI‐based polymers.


Abstract

For donor–acceptor conjugated polymers, it is an effective strategy to improve their electron mobilities by introducing electron‐withdrawing groups (EWGs, such as F, Cl, or CF3) into the polymer backbone. However, the introduction of different EWGs always requires a different synthetic approach, leading to additional arduous work. Here, an effective two‐step method is developed to obtain EWG substituted bay‐annulated indigo (BAI) units. This method is effective to introduce various EWGs (F, Cl, or CF3) into BAI at different substituted positions. Based on this method, EWG substituted BAI acceptors, including 2FBAI, 2ClBAI, and 2CF3BAI, are reported for the first time. Furthermore, four polymers of PBAI‐V, P2FBAI‐V, P2ClBAI‐V, and P4OBAI‐V are developed. All the polymers show ambipolar transport properties. Particularly, P2ClBAI‐V exhibits remarkable hole and electron mobilities of 4.04 and 1.46 cm2 V−1 s−1, respectively. These mobilities are among the highest values for BAI‐based polymers.

26 Jan 23:33

Stable White Light-Emitting Biocomposite Films

by Julia Gotta, Tal Ben Shalom, Stella Aslanoglou, Anna Cifuentes-Rius, Nicolas H. Voelcker, Roey Elnathan, Oded Shoseyov, Shachar Richter

Abstract

The demonstration of reliable and stable white light-emitting diodes (LEDs) is one of the main technological challenges of the LED industry. This is usually accomplished by incorporation of light-emitting rare-earth elements (REEs) compounds within an external polymeric coating of a blue LED allowing the generation of white light. However, due to both environmental and cost issues, the development of low-cost REE-free coatings, which exhibit competitive performance compared to conventional white LED is of great importance. In this work, the formation of an REE-free white LED coating is demonstrated. This biocomposite material, composed of biological (crystalline nanocellulose and porcine gastric mucin) and organic (light-emitting dyes) compounds, exhibits excellent optical and mechanical properties as well as resistance to heat, humidity, and UV radiation. The coating is further used to demonstrate a working white LED by incorporating it within a commercial blue LED.

Thumbnail image of graphical abstract

Light-emitting films made out of biocomposite materials are demonstrated. These comprise of dyes incorporated in proteins, hosted in a crystalline nanocellulose matrix. The films do not contain rare-earth materials and exhibit excellent optical and mechanical properties as well as resistance to heat, humidity, and UV radiation. The biocomposite is utilized to form a stable working white light-emitting diode.