Porphyrin-sensitized solar cells

Abstract

Nature has chosen chlorophylls in plants as antennae to harvest light for the conversion of solar energy in complicated photosynthetic processes. Inspired by natural photosynthesis, scientists utilized artificial chlorophylls - the porphyrins - as efficient centres to harvest light for solar cells sensitized with a porphyrin (PSSC). After the first example appeared in 1993 of a porphyrin of type copper chlorophyll as a photosensitizer for PSSC that achieved a power conversion efficiency of 2.6%, no significant advance of PSSC was reported until 2005; beta-linked zinc porphyrins were then reported to show promising device performances with a benchmark efficiency of 7.1% reported in 2007. Meso-linked zinc porphyrin sensitizers in the first series with a push-pull framework appeared in 2009; the best cell performed comparably to that of a N3-based device, and a benchmark 11% was reported for a porphyrin sensitizer of this type in 2010. With a structural design involving long alkoxyl chains to envelop the porphyrin core to suppress the dye aggregation for a push-pull zinc porphyrin, the PSSC achieved a record 12.3% in 2011 with co-sensitization of an organic dye and a cobalt-based electrolyte. The best PSSC system exhibited a panchromatic feature for light harvesting covering the visible spectral region to 700 nm, giving opportunities to many other porphyrins, such as fused and dimeric porphyrins, with near-infrared absorption spectral features, together with the approach of molecular co-sensitization, to enhance the device performance of PSSC. According to this historical trend for the development of prospective porphyrin sensitizers used in PSSC, we review systematically the progress of porphyrins of varied kinds, and their derivatives, applied in PSSC with a focus on reports during 2007-2012 from the point of view of molecular design correlated with photovoltaic performance.

Metal-free organic sensitizers for use in water-splitting dye-sensitized photoelectrochemical cells

“…The core of chlorophyll-a is a substituted chlorin (4), a porphyrin ring with a reduced exo double bond (5). Because porphyrins are synthetically more accessible than chlorins and bacteriochlorins, many groups have studied them as light-harvesting molecules in dye-sensitized solar cells (DSSCs) (6,7). Unlike ruthenium polypyridyl dyes, porphyrins contain only abundant elements and strongly absorb across most of the visible spectrum (8).…”

Bottom-Up Hierarchical Self-Assembly of Chiral Porphyrins through Coordination and Hydrogen Bonds

“…To understand the role of metal ions and self-organization of porphyrins, enzymes and light-harvesting systems mimicking the natural pigments have been synthesized and studied, confirming the importance of the supramolecular structure on the light harvesting ability. [8][9][10][11][12] Self-assembled chiral systems based on synthetic porphyrins present a broad range of potential applications in areas such as photovoltaic cells, 13 sensors, 14 optoelectronics 15 and nanoelectronic devices 16 and also non-linear optical materials. 17 The number and position of the stereogenic centers in molecules united by covalent or non-covalent bonds directly affect the chiral transfer from the molecular level up to the supramolecular aggregates that they form in solution and consequently their optical activity can be modified.…”

Formation of Au and tetrapyridyl porphyrin complexes in superfluid helium

“…As a result these molecules and their derivatives have long attracted the interest of biologists and biochemists. [1,2] Porphyrins have good thermal stability and versatile chemical properties, making them candidates for a wide variety of applications such as catalysis, [3,4] solar energy conversion, [5,6] and the development of metal-organic frameworks. [7][8][9] Among the porphyrins, 5,10,15,20-Tetra(4-pyridyl)porphyrin (H2TPyP) is one of the meso-substituted prophyrins that have been widely used in various chemical and photochemical studies.…”