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29 Jan 02:54

Forest management in southern China generates short term extensive carbon sequestration

by Xiaowei Tong

Nature Communications, Published online: 08 January 2020; doi:10.1038/s41467-019-13798-8

Forest management may play an important role in climate change mitigation. Here, Tong et al. combine remote sensing and machine learning modelling to map forest cover dynamics in southern China during 2002–2017, showing effects on carbon sequestration that are extensive but of uncertain longevity and possible negative impact on soil water.
17 Oct 15:28

Excitation‐Dependent Long‐Life Luminescent Polymeric Systems under Ambient Conditions

by Yanli Zhao, Yan Su, Yongfeng Zhang, Zhonghao Wang, Weichen Gao, Peng Jia, Dan Zhang, Chaolong Yang, Youbing Li
Excitation‐Dependent Long‐Life Luminescent Polymeric Systems under Ambient Conditions

Lucky blue‐red clovers : A strategy for achieving excitation‐dependent long‐life luminescent polymer systems under ambient conditions by tuning the aggregation state of phosphors in polyvinyl alcohol films is developed. The developed polymers show promise in multicolor patterning for anti‐counterfeiting applications.


Abstract

Organic room temperature luminescent materials present a unique phosphorescence emission with a long lifetime. However, many of these materials only emit single blue or green color in spite of external stimulation, and their color tunability is limited. Herein, we report a rational design to extend the emission color range from blue to red by controlling the doping of simple pyrene derivatives into a robust polymer matrix. The integration of these pyrene molecules into the polymer films enhances the intersystem crossing pathway, decreases the first triplet level of the system, and ensures the films show a sensitive response to excitation energy, finally yielding excitation‐dependent long‐life luminescent polymeric systems under ambient conditions. These materials were used to construct anti‐counterfeiting patterns with multicolor interconversion, presenting a promising application potential in the field of information security.