An alloy-like model based on Y6 and its derivative BTP-M is constructed to fabricate ternary organic solar cells, leading to a best efficiency of 17.03%.

Morphology control is critical to achieve high efficiency CH3NH3PbI3 perovskite solar cells (PSC). The surface properties of the substrates on which crystalline perovskite thin films form are expected to affect greatly the crystallization and, thus, the resulting morphology. However, this topic is seldom examined in PSC. Here we developed a facile but efficient method of modifying the ZnO-coated substrates with 3-aminopropanioc acid (C3-SAM) to direct the crystalline evolution and achieve the optimal morphology of CH3NH3PbI3 perovskite film. With incorporation of the C3-SAM, highly crystalline CH3NH3PbI3 films were formed with reduced pin-holes and trap states density. In addition, the work function of the cathode was better aligned with the conduction band minimum of perovskite for efficient charge extraction and electronic coupling. As a result, the PSC performance remarkably increased from 9.81(±0.99)% (best 11.96%) to 14.25(±0.61)% (best 15.67%). We stress the importance of morphology control through substrate surface modification to obtain the optimal morphology and device performance of PSC, which should generate an impact on developing highly efficient PSC and future commercialization.

Field-effect transistors based on single crystals of organic semiconductors have the highest reported charge carrier mobility among organic materials, demonstrating great potential of organic semiconductors for electronic applications. However, single-crystal devices are difficult to fabricate. One of the biggest challenges is to prepare dense arrays of single crystals over large-area substrates with controlled alignment. Here, we describe a solution processing method to grow large arrays of aligned C(60) single crystals. Our well-aligned C(60) single-crystal needles and ribbons show electron mobility as high as 11 cm(2)V(-1)s(-1) (average mobility: 5.2 ± 2.1 cm(2)V(-1)s(-1) from needles; 3.0 ± 0.87 cm(2)V(-1)s(-1) from ribbons). This observed mobility is ~8-fold higher than the maximum reported mobility for solution-grown n-channel organic materials (1.5 cm(2)V(-1)s(-1)) and is ~2-fold higher than the highest mobility of any n-channel organic material (~6 cm(2)V(-1)s(-1)). Furthermore, our deposition method is scalable to a 100 mm wafer substrate, with around 50% of the wafer surface covered by aligned crystals. Hence, our method facilitates the fabrication of large amounts of high-quality semiconductor crystals for fundamental studies, and with substantial improvement on the surface coverage of crystals, this method might be suitable for large-area applications based on single crystals of organic semiconductors.

A gel is defi ned as a two-component (solid and liquid), continuous, solid-like material with viscoelastic rheological Crystal Growth of Calcium Carbonate in Hydrogels as a Model of BiomineralizationIn recent years, the prevalence of hydrogel-like organic matrices in biomineralization has gained attention as a route to synthesizing a diverse range of crystalline structures. Here, examples of hydrogels in biological, as well as synthetic, bio-inspired systems are discussed. Particular attention is given to understanding the physical versus chemical effects of a broad range of hydrogel matrices and their role in directing polymorph selectivity and morphological control in the calcium carbonate system. Finally, recent data regarding hydrogel-matrix incorporation into the growing crystals is discussed and a mechanism for the formation of these single-crystal composite materials is presented. Future and is researching crystal growth in gels as a means to form nanocomposites.chains form helices (double or single helices) that subsequently aggregate into three-dimensional (3D) bundles, forming a porous network with fi brous characteristics (Figure 1 a,b). [ 82 , 83 ] Both the gelling and melting temperatures can be tailored by chemical modifi cation such as partial hydroxyethylation. [ 84 ] The mechanical behavior of agarose gels is sensitive to molecular weight and concentration [ 85 ] as well as chemical modifi cation.

Single crystals are usually faceted solids with homogeneous chemical compositions. Biogenic and synthetic calcite single crystals, however, have been found to incorporate macromolecules, spurring investigations of how large molecules are distributed within the crystals without substantially disrupting the crystalline lattice. Here, electron tomography reveals how random, three-dimensional networks of agarose nanofibers are incorporated into single crystals of synthetic calcite by allowing both high- and low-energy fiber/crystal interface facets to satisfy network curvatures. These results suggest that physical entrapment of polymer aggregates is a viable mechanism by which macromolecules can become incorporated inside inorganic single crystals. As such, this work has implications for understanding the structure and formation of biominerals as well as toward the development of new high-surface area, single-crystal composite materials.

Recent years have witnessed substantial advances in the use of DNA as a smart material to construct periodically patterned structures. 1 DNA also has been designed to direct the assembly of other functional molecules by the use of appropriate attachment chemistries. 2 The diversity of materials which can be chemically attached to DNA considerably enhances the attractiveness of DNA nanostructures for assembly of other materials. Self-assembling DNA tiling lattices represent a versatile system for nanoscale construction. The methodology of DNA lattice self-assembly begins with the chemical synthesis of single-stranded DNA molecules, which self-assemble into DNA branched motif complexes, known as tiles. 1b-1f DNA tiles can carry sticky-ends that preferentially match the sticky-ends of other particular DNA tiles, thereby facilitating the further assembly into lattices. Self-assembled twodimensional DNA tiling lattices composed of tens of thousands of tiles have been demonstrated. 1b-1f Self-assembled DNA arrays provide an excellent template for spatially positioning other molecules with increased relative precision and programmability.Here we report an experiment using a linear array of DNA triple crossover molecules (TX) to controllably template the self-assembly of two forms (single-layer or double-layer) of streptavidin linear arrays through biotin-streptavidin interaction. Figure 1 illustrates the design. The TX molecule used here was derived from the DNA motif described elsewhere, 1c and it consists of seven oligonucleotides hybridized to form three double-stranded helices lying in a plane and linked by strand exchange at four immobile crossover points. The TX molecule shown in Figure 1a is designed such that it contains two stem loops protruding, one each out of the upper and the lower helices. A linear array of the TX molecules can be obtained by designing three pairs of sticky ends where their complementarity is represented by matching color and geometric shape ( Figure 1b). To template the assembly of streptavidin molecules, the hairpin loops were modified to incorporate two biotin groups per loop, indicated by the small blue dots. Formation of single-layer or double-layer streptavidin linear arrays was controlled using two different templates which are illustrated in Figure 1b. In the first template (left panel), only one stem loop in each TX molecule was modified with biotin groups. However, in the second template (right panel), both stem loops were modified to incorporate biotins. The binding of streptavidin molecules, which is represented as yellow dots, to the two different templates resulted in singlelayer or double-layer streptavidin linear arrays, as shown in Figure 1b.Streptavidin has a diameter of ∼4 nm. Its binding to the selfassembled TX array generates bumps at biotinylated locations on hairpin loops of the TX tiles which can be detected by atomic force microscopy imaging (AFM). Figure 2a shows an AFM image of a sample containing only streptavidin, demonstrating that the streptavidin molecule...

Synthetic and biogenic calcite (CaCO 3 ) crystals are known to incorporate biomacromolecules [1] and other organic molecules [2] while still diffracting x-rays as single crystals. This work evaluates the parameters that control the incorporation of polymer networks during calcite-crystal growth in agarose hydrogels. We find that the crystallization pressure promotes the exclusion of the gel network, while faster growth rates favor the incorporation. These two competing factors determine how much of the gel network is incorporated into the calcite crystals.

We present a DNA nanostructure, the three-helix bundle (3HB), which consists of three double helical DNA domains connected by six immobile crossover junctions such that the helix axes are not coplanar. The 3HB motif presents a triangular cross-section with one helix lying in the groove formed by the other two. By differential programming of sticky-ends, 3HB tiles can be arrayed in two distinct lattice conformations: one-dimensional filaments and two-dimensional lattices. Filaments and lattices have been visualized by high-resolution, tapping mode atomic force microscopy (AFM) under buffer. Their dimensions are shown to be in excellent agreement with designed structures. We also demonstrate an electroless chemical deposition for fabricating metallic nanowires templated on self-assembled filaments. The metallized nanowires have diameters down to 20 nm and display Ohmic current-voltage characteristic.