The self-assembly and self-organization of porphyrins and related macrocycles enables the bottomup fabrication of photonic materials for fundamental studies of the photophysics of these materials and for diverse applications. This rapidly developing field encompasses a broad range of disciplines including molecular design and synthesis, materials formation and characterization, and the design and evaluation of devices. Since the self-assembly of porphyrins by electrostatic interactions in the late 1980s to the present, there has been an ever increasing degree of sophistication in the design of porphyrins that self-assemble into discrete arrays or self-organize into polymeric systems. These strategies exploit ionic interactions, hydrogen bonding, coordination chemistry, and dispersion forces to form supramolecular systems with varying degrees of hierarchical order. This review concentrates on the methods to form supramolecular porphyrinic systems by intermolecular interactions other than coordination chemistry, the characterization and properties of these photonic materials, and the prospects for using these in devices. The review is heuristically organized by the predominant intermolecular interactions used and emphasizes how the organization affects properties and potential performance in devices.

The improvement of the power conversion efficiency (PCE) of polymer bulk heterojunction (BHJ) solar cells has generally been achieved through synthetic design to control frontier molecular orbital energies and molecular ordering of the electron-donating polymer. An alternate approach to control the PCE of a BHJ is to tune the miscibility of the fullerene and a semiconducting polymer by varying the structure of the fullerene. The miscibility of a series of 1,4-fullerene adducts in the semiconducting polymer, poly(3-hexylselenophene), P3HS, was measured by dynamic secondary ion mass spectrometry using a model bilayer structure. The microstructure of the bilayer was investigated using high-angle annular dark-field scanning transmission microscopy and linked to the polymer-fullerene miscibility. Finally, P3HS:fullerene BHJ solar cells were fabricated from each fullerene derivative, enabling the correlation of the active layer microstructure to the charge collection efficiency and resulting PCE of each system. The volume fraction of polymer-rich, fullerene-rich, and polymer-fullerene mixed domains can be tuned using the miscibility leading to improvement in the charge collection efficiency and PCE in P3HS:fullerene BHJ solar cells. These results suggest a rational approach to the design of fullerenes for improved BHJ solar cells.

A core phthalocyanine platform allows engineering the solubility properties the band gap; shifting the maximum absorption toward the red. A simple method to increase the efficiency of heterojunction solar cells uses a self-organized blend of the phthalocyanine chromophores fabricated by solution processing.Low-cost photovoltaic (PV) devices may derive performance benefits from the light-absorbing properties of phthalocyanine organic dyes because of their high extinction coefficients, stability, and energy band gaps well-matched to the incident solar spectrum. [1][2][3][4] Despite these desirable attributes, use of phthalocyanines in low-cost solar cells is complicated by their poor solubility in organic solvents (necessitating vacuum deposition processing) 2,5,6 and narrow absorption bandwidths at red (Q-band) and ultraviolet (B-band) wavelengths. 7 Bulk heterojunction (BHJ) solar cells with dyes such as phthalocyanine 5,7,8 and polymer blends have been reported. 9,10 There are a several solar cell designs that contain phthalocyanines, especially the zinc and copper complexes, and those that also contain various C 60 derivatives wherein the layers are vapor-deposited in specified layers. [11][12][13] Other soluble dye systems have been incorporated into layered devices, or into BHJ solar cells. 4,[14][15][16] We demonstrate a new blend-type parallel tandem solar cell device architecture with several innovative features. (1) Click-type alkyation chemistry on a single commercially available phthalocyanine platform allows design of a series of robust, chemically compatible dyes with tunable optical band gaps and energy levels. (2) The family of soluble phthalocyanine dyes permits solution-based processing of molecular BHJ solar cells. (3) In these devices, the semiconductor active layer is composed of a blend of three phthalocyanine derivatives having The ca. 70 nm thick blended phthalocyanine active layer provides a disordered tandem device architecture wherein light can be absorbed by materials with successively smaller band gaps and photogenerated charges are collected with a common complementary organic semiconductor. This demonstrates that a hierarchical organization of dyes, wherein the lowest band gap (red) dye is at the surface and higher band gap (blue) dyes are layered or assembled on top, is not a priori necessary to assure vectoral charge migration between the electrodes. 2, 17 A standard, reproducible, solution-processed device architecture is used to illustrate these points. 9,11We achieve both improved phthalocyanine solubility and control over the optical properties using high yield substitution of peripheral fluoro groups on hexadecafluorophthalocyanato zinc (ZnPcF 16 ) by thio-alkanes (CH 3 (CH 2 ) 11 SH) (Scheme 1). 18,19 Because the frontier molecular orbitals (HOMO and LUMO) are primarily delocalized on the ring periphery, substitution of electron withdrawing groups with electron-donating groups affects the orbital energy levels. 5,7 The HOMO is destabilized more than the LUMO, resultin...

Tune me up: The increasing number of new donor materials for organic solar cells requires compatible electron acceptors. A series of 1,4‐fullerene adducts with tunable chemical, electronic, and material properties is introduced to effectively influence the photovoltaic characteristics of solar cells.

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The highly fluorinated alkyl moieties of a new porphyrin drive the self-organization of thin films with C60 on ITO electrodes.

A new method for synthesizing gold, nickel, and cobalt metal nanoparticles at room temperature from metal salts employing plasmid DNA in a toroidal topology as a sacrificial mold is presented. The diameter of the toroidal DNA drives the formation and size of the nanoparticle, and UV light initiates the oxidation of the DNA and concomitant reduction of the DNA bound metal ions. The nanoparticles were characterized by atomic force microscopy (AFM), transmission electron microscopy (TEM), and electron diffraction (ED).

Dimeric metalloporphyrin hosts with tweezer-like structures have been synthesized by reacting the cyanuric chloride scaffold, CC, with 5-(4-aminophenyl)-10,15,20-triphenylporphyrin, P, and 5-(4-aminophenyl)-10,15,20-trimesitylporphyrin, M, to yield the homoconjugates free bases PP and MM and the heterodyad PM. Metalation with Zn(II), gives three structurally related ditopic receptors P(Zn)P(Zn), P(Zn)M(Zn), and M(Zn)M(Zn) with differential steric hindrance and conformational rigidity. The solution structure and supramolecular properties of these porphyrin dimers have been investigated as isolated molecules and in the presence of aliphatic alpha,omega-diamines of general formula H(2)N-(CH(2))(n)-NH(2) (n = 4-8) by spectroscopic and theoretical studies including multidimensional NMR, UV-vis, molecular modeling, and computational NMR methods. Binding constants in the range 4.2 x 10(6) to 3.4 x 10(7) M(-1) are observed in dichloromethane at 298 K, with a 3 orders of magnitude increase as compared to monodentate nBuNH(2), thus indicating the occurrence of a host-guest ditopic interaction. Linear correlation graphs are obtained by plotting the Soret band shift (Delta nu, cm(-1)) of the complex as a function of the diamine chain length. Combined NMR evidence and OPLS 2005 Force Field conformational analysis point to a mutual adaptation of both the binding partners in the host-guest complex, whose geometry is mainly dictated by the steric impact of the bulky substituents at the porphyrin periphery.