In inverted perovskite solar cells (PSCs), the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) is a widely used electron transport material. However, a high degree of energy disorder and inadequate passivation of PCBM limit the efficiency of devices, and severe self-aggregation and unstable morphology limit the lifespan of devices. Here, we design a series of fullerene dyads FP-Cn (n = 4, 8, 12) to replace PCBM as an electron transport layer, where [60]­fullerene is linked with a terpyridine chelating group via a flexible alkyl chain of different lengths as a spacer. Among three fullerene dyads, FP-C8 shows the most enhanced molecule ordering and adhesion with the perovskite surface due to the balanced decoupling between the chelation effect from terpyridine and the self-assembly of fullerene, leading to lower energy disorder and higher morphological stability relative to PCBM. The FP-C8/C60-based devices using Cs0.05FA0.90MA0.05PbI2.85Br0.15 as a light absorber show a power conversion efficiency of 21.69%, higher than that of PCBM/C60 (20.09%), benefiting from improved electron extraction and transport as well as reduced charge recombination loss. When employing FAPbI3 as a light absorber, the FP-C8/C60-based devices exhibit an efficiency of 23.08%, which is the champion value of inverted PSCs with solution-processed fullerene derivatives. Moreover, the FP-C8/C60-based devices show better moisture and thermal stability than PCBM/C60-based devices and maintain 96% of their original efficiency after 1200 h of operation, while their counterpart PCBM/C60 maintains 60% after 670 h.

The first single-diamond cubic phase in al iquid crystal is reported. This skeletal structure with the Fd " 3mspace group is formed by self-assembly of bolaamphiphiles with swallow-tailed lateral chains.I tc onsists of bundles of pconjugated p-terphenyl rods fused into an infinite network by hydrogen-bonded spheres at tetrahedral four-way junctions. We also present aq uantitative model relating molecular architecture to the space-filling requirements of six possible bicontinuous cubic phases,t hat is,t he single-and doublenetwork versions of gyroid, diamond, and "plumber'sn ightmare".Among the most intriguing self-assembled nano-and mesoscale soft-matter structures are the cubic phases formed by lyotropic and thermotropic liquid crystals (LCs), by block copolymers, [1,2] and by nanoparticle arrays. [3][4][5] Tw o classes of cubic phases can be distinguished, the "bicontinuous" and the "micellar" types. [6,7] Them icellar phases represent periodic arrays of spheres on ac ubic lattice, whereas the bicontinuous phases are more complex and usually formed by two networks divided by aminimal surface with aconstant mean curvature.Depending on the symmetry, the double gyroid (DG, Ia " 3d,Q 230 ), the double diamond (DD; Pn " 3m,Q 224 ), and the body-centered plumber'sn ightmare ("double primitive") cubic phases (DP; Im3 m,Q 229 )w ith junction valencies of n = 3, 4, and 6, respectively,c an be distinguished (Figure 1a-c). Figure 6. Models showing a) the micellar Fd " 3m cubic phase [27,28] and b) the new SD bicontinuous cubic phase of compounds 1/18-11/22.

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The so-called smectic-Q (SmQ) liquid crystal phase was discovered in 1983 in rod-like molecules, but its structure remain unclear in spite of numerous attempts to solve it. Herein, we report what we believe to be the solution: A unique bicontinuous phase that is non-cubic and is made up of orthogonal twisted columns with planar 4-way junctions. While SmQ had only been observed in chiral compounds, we show that this chiral phase forms also in achiral materials through spontaneous symmetry breaking. The results strongly support the idea of a helical substructure of bicontinuous phases and long-range homochirality being sustained by helicity-matching at network junctions. The model also explains the triangular shape of double-gyroid domains growing within a SmQ environment. SmQ-forming materials hold potential for applications such as circularly polarized light emitters that require no alignment or asymmetric synthesis.

Bicontinuous cubic liquid crystalline phases of π-conjugated molecules, representing self-assembled 3D-ordered interpenetrating networks with cubic symmetry, are receiving increasing attention due to their capacity for charge transport in all three dimensions and their inherent spontaneous helicity. Herein, a robust general design concept for creating bicontinuous cubic phases is reported. It is based on a nonsymmetric-substituted π-conjugated 5,5′-diphenyl-2,2′-bithiophene platform with one end containing three outfanning flexible chains and with a range of substituents at the other end (the apex). The cubic phases are stable over broad temperature ranges, often down to ambient temperature, and tolerate a wide range of apex substitution patterns, allowing structural diversity and tailoring of the cubic phase type and application-relevant properties. With an increasing number and size of apex substituents, a sequence of three different modes of cubic self-assembly is observed, following an increasing helical twist. Thus, two ranges of the achiral double network Ia3d phase range can be distinguished, a long pitch and a short pitch, with the chiral triple network I23 cubic phase in the intermediate pitch range. The findings provide a new prospect for the directed design of cubic phase-forming functional materials based on spontaneously formed helical network liquid crystals with tunable application specific properties.

Ultrafine nickel particles have intriguing physical and chemical properties, which are interesting both in fundamental and applied research. The size of the particle was controlled by gas pressure. X-ray diffraction studies showed that fine Ni particles have fcc crystal structure and are coated with thin Ni oxide on the surface. Electron micrographs showed a spherical particle shape, forming a long chain. Size dependence of magnetic properties were studied. The specific magnetic moment drastically decreases when reducing the diameter d of particles <15 nm. The coercivity Hc also approaches zero when d is about 15 nm. Therefore, we can suppose that the critical size for superparamagnetism at room temperature is about 15 nm. According to the superparamagnetic formula KV=25 kT, the value of the magnetic anisotropy constant can be determined, K = −5.8 × 105 (erg/cc). It is found to be larger than bulk Ni [K=−3.4–5.1 × 104 (erg/cc)], the same as Fe particles. The maximum of coercivity at room temperature is about 250 Oe, that is less than the theory value for the coherent rotation model, Hc = 4 K/3Ms=1600 Oe. The mechanism of reversal magnetization can be understood by the sphere chain model. The critical diameter of the single domain is about 65 nm. Curie temperature Tc obviously decreases for 9-nm average diameter particles rather than bulk. It may be in connection with the lattice contraction.

Here we reported a hierarchical self-assembly approach toward welldefined superlattices in supramolecular liquid crystals by fullerene-based sphere−cone block molecules. The fullerenes crystallize to form monolayer nanosheets intercalated by the attached soft hydrocarbon cones. The frustration caused by cross-sectional area mismatch between the spheres and the somewhat oversize cones leads to a unique lamellar superlattice whereby each stack of six pairs of alternating sphere−cone sublayers is followed by a cone double layer. While such areal mismatch problems in soft matter are usually solved by interface curvature, the lamellar superlattice solution is best suited to systems with rigid layers. Meanwhile, formation of the superlattice significantly improves the material's transient electron conductivity, with the maximum value being among the highest for π-conjugated organic materials. The design principle of solving steric frustration by forming a superlattice opens a new avenue toward self-assembled optoelectronic materials.