Phthalocyanines: From outstanding electronic properties to emerging applications

Abstract

This review paper gives a brief overview on how the outstanding chemical and physical properties of phthalocyanines and phthalocyanine derivatives are being studied and employed in order to construct state-of-the-art technological devices. In a first instance, a short account on how the nature of the phthalocyanine structure and its organization in condensed phases play an important role in their conducting and ultraviolet-visible absorption properties is presented. Consequently, these basic electronic and photophysical features of phthalocyanines allow us to explain why phthalocyanine-based multicomponent covalent or noncovalent donor-acceptor systems may give rise to very interesting photophysical properties, in particular in terms of their ability to generate very long-lived photoinduced charge-separated states. A concise survey on the organization of these multifunctional systems shows how a profound understanding of the morphology at the nanometer-scale of these phthalocyanine-based molecular materials is needed in order to control their physical properties in condensed phases. All the previously mentioned chemical and physical features combined together led us to the description of the latest attempts at incorporating phthalocyanines into photovoltaic devices for solar energy conversion and onto quantum dots for photodynamic therapy or quantum computing.

Exciton Dynamics in Phthalocyanine Molecular Crystals

“…[9][10][11][12] Inspired by their photosynthetic homologous (e.g., bacteriochlorophyll chromophores), different representative examples of self-assembled molecular materials based on Pc building blocks have been synthesized to investigate their exciton transport properties. 13 In contrast to the field of photosynthesis, 2,14,15 in the field of organic electronics a hopping (incoherent) mechanism is generally assumed when the exciton/charge dynamics in Pcbased self-assembled materials is investigated.…”

“…16,18 A few examples in related self-assembled systems (porphyrins) have shown that exciton diffusion can efficiently occur by means of a coherent mechanism. 19 Recently, an octa(butyl)-substituted metal-free phthalocyanine, H2-OBPc (1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine, see Figure 1a) has been synthesized and exhibited good crystallinity properties (1D π-stacked arrangements, see Figure 1b) in thin films. 20,21 The high degree of crystallinity of the solution-processed thin films allowed Rawat et al to investigate the correlation between long-range order and the nature of the lowest exciton states of the aggregate.…”

Investigation of ground and excited state photophysical properties of gadolinium phthalocyanine

“…Phthalocyanines can be modified and analyzed in solid state as thin films, in solution or in the powder state [6,7]. Due to its structural flexibility, the synthesis and structure-property relationship of phthalocyanines continue attracting attention from the scientific community.…”

Mechanism of the Zn(II)Phthalocyanines’ Photochemical Reactions Depending on the Number of Substituents and Geometry

“…α pt, λq " N rn S0 ptq σ 01 pλq`n S1 ptq σ 1n pλq`n T1 ptq σ TT pλqs (1) in which N is the number of molecules per cm 3 .…”

“…Phthalocyanines are organic molecules and remarkable molecular materials [1][2][3] whose structures and properties are similar to porphyrins [4]. Especially, in symmetric and asymmetric substituted phthalocyanines [5][6][7], the ability to tailor their properties by varying the metal center or by modifying the peripheral substituent allows large flexibility [8] from the applications point of view, such as in photodynamic therapy [9][10][11][12] and organic solar cells [13][14][15].…”