单组份有机太阳能电池纳米相分离调控新策略

<正>有机太阳能电池因其质轻、柔性、结构可调、可溶液加工等特点具有潜在的应用前景,近年来成为研究热点。其中,双组份或多组分的本体异质结型太阳能电池的研究最为深入,其能量转换效率已超过13%~(1,2);然而这类器件存在优化步骤多、稳定性差等缺点,不利于大面积制备。单组份太阳能电池中电子给体与受体通过共价键连接组成单     

α-Cu_2Se有序起伏结构的原子级分辨率表征

<正>微观结构与性能的关联是如今材料物理化学研究的核心问题之一。自从德国物理学家Knoll和Ruska~1在1932年成功制成了世界上第一台实用化的透射电子显微镜(TEM),电镜就成为了分析材料微观结构不可或缺的有力工具。由于电磁透镜仅具有凸透镜的特性,无法通过和凹透镜的组合来消除像差,尤其是由于电磁透镜中近轴和远轴磁场对电子束会聚能力不同导致的球差难以消     

马兰戈尼效应在有机半导体成膜中的应用

<正>1背景介绍以有机发光二极管、有机太阳能电池和有机场效应晶体管为主的有机半导体薄膜器件,因在便携、可穿戴电子器件领域有巨大的应用前景,而逐渐成为无机半导体器件的一个重要补充。溶液法生长有机半导体薄膜工艺更使有机半导体器件的低成本、可在柔性基底上大面积制备的优点得到体现,因而受到广泛关注。但是,溶液法制备工艺也存在着诸多不足,比如被称为"咖啡环"效应的溶剂自然挥发造成的薄     

硼烯化合物的合成及应用

In most cases, borylenes containing boron (I) are unstable. In this article, we proceed from the electron configuration of borylene and review the common methods of stabilizing this category of compounds through a series of borylenes in literature. In addition, the article briefly introduces the metallic borylenes and non-metallic borylenes and their properties. Some of these properties have been applied in nitrogen fixation.     

天然产物生物合成:探索大自然合成次生代谢产物的奥秘

天然产物(次生代谢产物)是大自然馈赠给人类的礼物,由于其复杂的骨架结构和良好的药用价值,吸引着化学家们对其进行结构鉴定以及化学合成。尽管人们在天然产物全合成中取得了巨大的成就,但仍然面临着合成路线长、产率低、缺乏选择性等问题。大自然是最伟大的化学家,它利用酶作为催化剂,往往能够高效地合成天然产物。在基因水平上探索大自然合成复杂多样的天然产物的奥秘不仅有助于人们进一步理解和认知有机化学,还为人们开发和利用大自然高效催化化学反应的工具——酶奠定了基础。     

注重基础促进交叉尊重选择培育英才 ——北京大学化学学科"拔尖计划"十年

北京大学化学与分子工程学院在实施基础学科拔尖学生培养计划过程中,实行动态管理制度,低年级统一培养,高年级通过制定个性化教学方案和参加科研训练的办法遴选拔尖学生,探索"扎根课堂打好基础,依托科研提高能力,着眼交流开阔眼界"的培养模式,实现"以高水平科研带动创新人才培养"的目标。在基础核心课程中设置平行的英文班和阅读讨论班以适应不同学生的需求。2016年,随着北京大学综合改革计划的推进,进一步明确了"一体化、多层次、开放式、重基础、求创新"的教学指导思想,在注重化学基础理论知识和基本实验方法培养、注重数学和物理基础知识学习的基础上,构建多样化和多模式的立体课程体系,为学生提供适合的课程学习和个性化学术发展途径。     

钆离子:周期表中最高自旋的离子

钆离子是元素周期表中自旋值最大的离子,其轨道角动量被完全淬灭,具有十分特殊的电子结构。本文以核磁共振造影剂以及分子自旋量子比特为例介绍了钆离子在前沿科技中的应用。     

元素周期表实物展窗:元素化学性质的形象化展示

以展示元素单质、化合物和矿物样品为形式制作的元素周期表实物展窗能够形象化地展示各种元素的化学特性。元素周期表实物展窗将实物样品展示度与样品背后的化学内涵相结合,可以展示元素和化学学科的风貌。     

Direct Observation of Aggregation-Induced Emission Mechanism

The mechanism of aggregation-induced emission, which overcomes the common aggregation-caused quenching problem in organic optoelectronics, is revealed by monitoring the real time structural evolution and dynamics of electronic excited state with frequency and polarization resolved ultrafast UV/IR spectroscopy and theoretical calculations. The formation of Woodward–Hoffmann cyclic intermediates upon ultraviolet excitation is observed in dilute solutions of tetraphenylethylene and its derivatives but not in their respective solid. The ultrafast cyclization provides an efficient nonradiative relaxation pathway through crossing a conical intersection. Without such a reaction mechanism, the electronic excitation is preserved in the molecular solids and the molecule fluoresces efficiently, aided by the very slow intermolecular charge and energy transfers due to the well separated molecular packing arrangement. The mechanisms can be general for tuning the properties of chromophores in different phases for various important applications.     

Hydration-Facilitated Fine-Tuning of the AIE Amphiphile Color and Application as Erasable Materials with Hot/Cold Dual Writing Modes

Hydration water greatly impacts the color of inorganic crystals, but it is still unknown whether hydration water can be utilized to systematically manipulate the emission color of organic luminescent groups. Now, metal ions with different hydration ability allow fine-tuning the emission color of a fluorescent group displaying aggregation induced emission (AIE). Because the hydration water can be removed easily by gentle heating or mechanical grinding and re-gained by solvent fuming, rewritable materials can be fabricated both in the hot-writing and cold-writing modes. This hydration-facilitated strategy will open up a new vista in fine-tuning the emission color of AIE molecules based on one synthesis and in the design of smart luminescent devices.