Bulk heterojunction organic photovoltaic (OPV) devices are multilayer organic devices that can be fabricated using low-cost and scalable solution processing methods, but current devices exhibit poor mechanical stability and degrade under deformation due to cracking and delamination. Recent approaches to improve mechanical durability involve modifying the side-chain or main-chain structures of conjugated polymers in the active layer, but in general it is difficult to simultaneously optimize electronic properties, morphology, and mechanical stability. Here, we present a general approach to improve the mechanical stability of bulk heterojunction active layers through incorporation of an internal elastic network. Network-stabilized bulk heterojunction OPVs are prepared using reactive small molecular additives that are rapidly cross-linked through thiol−ene coupling after processing the active layer. Thiol−ene reactions catalyzed by a base or initiated through short exposure to UV light produce insoluble, elastic thiol−ene networks in the active layer. We show through a combination of crack onset strain measurements, morphological analysis, and OPV device testing that network-stabilized OPVs with up to 20% thiol−ene network exhibit improved deformability with no loss in PCE, and we implement networkstabilized bulk heterojunction OPVs to produce stretchable photovoltaic devices. This work represents a simple approach for improving the mechanical durability of bulk heterojunction OPVs.
Metal organic frameworks (MOFs) have recently been used as precursors of the catalysts for the combustion of volatile organic compounds (VOCs). In the present work, three kinds of CeO 2 catalysts were successfully synthesized from Ce-MOF-808, Ce-BTC, and Ce-UiO-66, with specific topological structures and coordinate environments. Catalysts with small particle size, stacking mode, and structural defects could be created by pyrolysis of Ce-MOFs, which affects the activity in the toluene combustion significantly. Raman spectra, XPS, and OSC studies were performed to reveal the formation of defect sites. The thermal redox properties were determined by H 2 -TPR. Catalytic activity tests were conducted on the toluene combustion, and CeO 2 -MOF-808 showed the best catalytic performance (T90 = 278 • C) due to its having the largest specific surface area, abundant active surface oxygen species, and low-temperature reducibility.
initiated by decarbonylation, which occurs at a significant rate at 80 °C. The product 2 was the first of several that were formed. It was formed by decarbonylation and the activation of one of the CH bonds on the C-methyl group. The ynamine ligand was transformed into a /iV-aminoallenyl ligand and a bridging hydride ligand. A triply bridging aminoallenyl ligand was formed by a decarbonylation and CH activation at the C-methyl group of the ynamine ligand in the osmium complex Os3(CO)10(/u-MeC2NMe2) to yield the complex Os3(CO)10(^-H2CCNMe2)(M-H) (eq 2).2c Compound 2 was found to add CO at room temperature to form compound 4 by converting the M-7j1 23-aminoallenyl ligand to a g-T;2-aminoallenyl ligand. At 75 °C, 4 lost CO to re-form 2. However, at 75 °C in a closed system, compound 4 was slowly converted to 3. This is believed to occur by decarbonylation to 2 and a slow readdition of CO to yield 3, which is simply a more stable isomer of 4. With prolonged heating 3 was converted to the even more stable isomer 5, which can be decarbonylated to yield 6. However, we also found that substantial amounts of 6 were formed by heating 2 to 100 °C for 10 min in the absence of CO. Since compound 5 was not significantly converted to 6 and 6 does not add CO to yield 5 under these conditions, we believe that 2 can probably also be converted to 6 without the intermediacy of 5.We have shown previously that the manganese complex Mn2(CO)80t-MeC2NEt2), which is structurally very similar to 1, also undergoes a series of hydrogen-shift transformations to yield an isomer containing a bridging aminoallene ligand, an isomer similar to 5 that contains a bridging ?;2-metalated aminoallyl ligand, and a decarbonylated complex containing a bridging t;4 *-metalated aminoallyl ligand similar to that proposed for 6.12 In the present study, we have characterized yet another isomeric form of the ynamine ligand, namely, the vinyl(amino)carbene as found in compound 3. In contrast to the manganese study, we have also demonstrated that hydride-containing intermediates are involved in the hydrogen-shift processes.Acknowledgment. These studies were supported by the Office of Basic Energy Sciences of the U.S. Department of Energy. Supplementary Material Available: Tables of hydrogen atom positional parameters and anisotropic thermal parameters for 2-4 (11 pages); listings of structure factor amplitudes (47 pages). Ordering information is given on any current masthead page.
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