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.

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...