世界上最难的数学题

智能窗户是一种有前途的绿色技术，其在外部刺激下具有可调节的透明度以管理光传输和太阳能。但是，需要将基于太阳光谱智能管理的更多功能集成到当前的智能窗口中。在这项工作中，通过将发光开关与电致变色窗配对来制造双功能智能窗。双重功能基于用氧化钨和铜纳米簇功能化的单个掺杂氟的氧化锡涂层玻璃，其中氧化钨用作电致变色材料，而铜纳米簇提供光致发光。除了基于窗口的电致变色对可见光的调节之外，还可以精细地打开和关闭发光，从而为双功能智能窗口建立了一对可逆状态（“打开”和“关闭”）。两种状态之间的对比度达到88％。此外，双功能智能窗口的操作高度可逆，响应时间仅为12.6 s。这款双功能智能窗户原型通过在合理管理太阳光谱的基础上将不同功能材料集成到一个智能窗户中，为开发多功能智能窗户铺平了道路。

Two cyclometalated ruthenium complexes 2 and 4 containing a redox-active amine substituent and three carboxylic acid groups were synthesized, where the ruthenium ion and the amine site were separated by a phenyl or biphenyl bridge for 2 and 4, respectively. Nanocrystalline TiO2 films on fluorine doped SnO2 (FTO)/glass substrates anchored with 2 or 4 were prepared. These films display two consecutive anodic waves in the potential region between +0.1 and +1.0 V vs Ag/AgCl. Among four organic solvents examined, the FTO/TiO2/2 film displays the best cyclic electrochemical stability in ClCH2CH2Cl. Both films exhibit promising two-step electrochromism in the near infrared region. A contrast ratio (ΔT%) of 42% at 1000 nm and 40% at 680 nm was achieved for the FTO/TiO2/2 film in the single- and double-oxidation process, respectively. In contrast, the FTO/TiO2/4 film shows electrochromism at 1300 nm (ΔT% = 58%) and 780 nm (ΔT% = 59%) in the single- and double-oxidation process, respectively. The coloration efficiency of these processes varies in a range of 150–270 cm2/C. These films are potentially useful as variable optical attenuators for telecommunications.

We report fabrication of photoinduced-electrochromic (or photochromic) organic nanoparticles that can be regarded as a new class of photoswitchable nanomaterials. Ion association between dicationic benzyl viologen (BzV2+) and tetraphenylborate anion (TPB–) in water produces organic ion-pair charge-transfer-type (IPCT) nanoparticles with a mean diameter of 15–20 nm. Electrostatic binding of BzV2+ with TPB– results in the prominent appearance of a new broad absorption band at 400–550 nm, which can be assign to the CT transition between these species. The IPCT nanoparticles show an interesting photoinduced electrochromic behavior caused by the electron transfer (ET) from TPB– to BzV2+, giving an intense blue-color dispersion. The feed charge stoichiometry (= [TPB–]/(2 × [BzV2+])) does not influence the kinetics of the photoinduced electrochromism, but it remarkably controls the reverse ET reaction (or retention time) in the nanoparticles; in the case of neutral stoichiometry, a very long-lived ET state can be observed, which is mainly due to decomposition of the oxidized TPB (sacrificial donor) and the resultant absence of the counterpart of benzyl viologen radical cations (BzV+?) for back ET reaction. On the other hand, the excess presence of TPB– does not cause the decomposition of oxidized TPB in the nanoparticle, making the reverse ET reaction faster, but a moderately long-lived ET state is still observable, which is probably originated from efficient electron diffusion or transport between molecules inside the nanoparticle.

A series of electrochromic metal complex nanosheets comprising 1,3,5-tris(4-(2,2′:6′,2″-terpyridyl)phenyl)benzene or 1,3,5-tris((2,2′:6′,2″-terpyridyl)ethynyl)benzene and Fe2+ or Co2+ was synthesized. The preparation of multilayered nanosheets was achieved by liquid/liquid interfacial synthesis using an organic ligand solution and an aqueous metal–ion solution. The resultant nanosheet had a flat, smooth morphology and was several hundreds of nanometers thick. Upon its deposition on an indium tin oxide (ITO) electrode, the nanosheet underwent a reversible and robust redox reaction (Fe3+/Fe2+ or Co2+/Co+) accompanied by a distinctive color change. Electrochromism was achieved in a solidified device composed of the nanosheet, a pair of ITO electrodes, and a polymer-supported electrolyte. The combination of Fe2+ and Co2+ nanosheets in one device—deposited on each ITO electrode—demonstrated dual-electrochromic behavior.

首次观察到涉及光致变色二噻吩基环戊烯（DTE）电化学开环的关键中间体的动力学过程，其中DTE的电子性质是决定电致变色反应速率决定步骤的重要因素。双色性已实现为单分子荧光记忆。

Reductive electropolymerization of the biscyclometalated ruthenium complex [(vtpy)Ru(tpb)Ru(vtpy)]2+ [vtpy = 4′-vinyl-2,2′:6′,2″-terpyridine; tpb = 1,2,4,5-tetra(2-pyridyl)benzene] proceeded smoothly on electrode surfaces. Thanks to the strong electron coupling between the ruthenium centers of the individual monomeric units and strong intervalence charge-transfer absorption in the mixed valence state, the produced adherent metallopolymeric films exhibited near-IR electrochromism with tricolor switching, good contrast ratio (40% at 1165 nm), short response time, low-switching voltage, and long memory time.

设计并制备了基于双间苯二甲酸酯的新型电致变色系统。他们通过两电子还原显示出电致变色行为。所显示的颜色显示出大大增强的双稳性，并且取决于两个间苯二甲酸酯基团之间共轭桥的长度。我们认为，使用共轭桥连接两个电致变色系统是获得新的双稳态电致变色系统的良好基本策略。

设计并合成了由π-共轭和离子部分组成的新型电致变色分子。它形成了纳米分离的近晶相，其中咪唑鎓盐的离子导电层位于苯并噻吩基部分的空穴传输层之间。在没有电解质溶液的情况下，在该化合物的整体液晶状态下观察到电致变色。在该纳米分离的近晶相中，在电极处迅速形成双电层。因此，空穴从电极注入，导致π共轭部分的氧化。

苯胺和吡咯的电化学聚合，以及电致变色和聚合物电池效应的论证，是适合大学水平的高中和入门化学的论证。这些演示激发了学生对导电聚合物的电化学制备的兴趣，从这两种聚合物显示的生动的电致变色可以很容易地理解掺杂和去掺杂过程。