The photophysical properties of a series of ruthenium trisbipyridine complexes covalently linked to aromatic chromophores of the type [Ru(bpy)2(4-methyl-4‘-(2-arylethyl)-2,2‘-bipyridine)]2+(ClO4)2, where aryl = 2-naphthyl ([Ru]-naphthalene), 1-pyrenyl ([Ru]-pyrene), and 9-anthryl ([Ru]-anthracene) have been investigated at room temperature and at 77 K. The photophysical properties of these bichromophores are determined by intramolecular energy-transfer processes that are governed by the relative positions of the various singlet and triplet energy levels. As a result, fluorescence from each of the pendant aromatic chromophores is completely quenched following their photoexcitation. For [Ru]-naphthalene the initial excitation energy is localized on the [Ru]-centered 3MLCT state, whereas for [Ru]-anthracene the energy is localized on the anthracene triplet state. Since the [Ru]-centered 3MLCT state and the lowest energy pyrene triplet state are isoenergetic, an equilibrium is established resulting in a long-lived room-temperature 3MLCT emission from [Ru]-pyrene (τ = 5.23 μs). At 77 K dual emission is observed from this bichromophore comprising pyrene phosphorescence and 3MLCT emission, the relative proportions of which vary with time after the laser pulse.

A 3D printer based slot‐die coater is developed as a lab‐to‐fab translation tool for solution‐processed solar cells. The modified 3D printer is used to develop the printing process for potential use in large scale roll‐to‐roll production. Fabrication of a 47.3 cm2 organic solar cell module with 4.56% efficiency and printed perovskite solar cells with 11.6% efficiency are demonstrated.

A high molecular weight donor-acceptor conjugated polymer is synthesized using the Suzuki polycondensation method. Using this polymer, a single-junction bulk-heterojunction solar cell is fabricated giving a power conversion efficiency of 9.4% using a fullerene-modified ZnO interlayer at the cathode contact.

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Polarized images have been prepared using simple laser‐induced melting of aligned nanorods in a polymer film. The technique is easy‐to‐use, cost‐effective, and may be used to render the read‐out either legible or illegible (see Figure). The information content could be increased by creating ordered nanoparticles with different angles of polarization, thereby permitting readout from different layers within the film, which might lead to 3D applications.

The syntheses of linear and star-shaped light harvesting polymers with well defined structure and narrow molecular weight distribution are described. These polymers have ruthenium polybipyridine moieties as the energy trap cores and styrene functionalized coumarin monomers as the light absorbing antenna chromophores. The polymers have been made by reversible addition-fragmentation chain transfer (RAFT) polymerisation using di-or hexafunctional ruthenium-containing RAFT agents. The resulting ruthenium-containing polymers have narrow molecular weight distribution (polydispersity v 1.1) and exhibit energy transfer efficiencies of up to 60% between the coumarin donor dyes and the ruthenium acceptor chromophores.

With the rapid development of nanotechnology, methodologies that will enable the cost-effective, controlled assembly of nanostructures in a routine manner are in high demand. Photoactive polymers are promising candidates to fulfill the materials requirements for energy storage and conversion devices, molecular sensors, and photonic materials. 1 Of particular interest is the utilization of efficient energy transfer processes in a polymer chain containing sequences of donor chromophores that absorb the incident light and the subsequent trapping of the energy in suitably placed acceptor species. 2 Such "antenna" polymers simulate the efficient light harvesting process of pigment arrays in the photosynthetic apparatus of green plants and can act to effectively increase the light absorption cross section of components in photomolecular devices.The synthesis of photoactive polymers with welldefined architectures has long been of great interest to photochemists but is difficult to achieve by conventional free radical polymerization methods. Living radical polymerization has made great progress in recent years and emerged as one of the most effective synthetic routes to make well-defined polymers. 3 Among them, reversible addition-fragmentation chain transfer (RAFT) polymerization appears particularly useful and, in principle, could be applied to all classical radical polymerization systems.The RAFT process involves performing a conventional free radical polymerization in the presence of certain thiocarbonylthio compounds SdC(Z)-SR that act as highly efficient reversible addition-fragmentation chain transfer agents and provide the polymerization with living characteristics. Following RAFT polymerization, nearly all polymer chains will have the thiocarbonylthio and R as end groups. RAFT polymerization thus provides a means of introducing specifically placed photoactive moieties into polymer chains using appropriately functionalized RAFT agents.We have previously incorporated chromophores into RAFT agents by the coupling reaction of 4-cyano-4-((thiobenzoyl)sulfanyl)pentanoic acid (RAFT-acid) with the required hydroxy-functionalized chromophores. 4 However, the stability of the resulting ester linkage can limit the applications in a number of circumstances, such as in the presence of acid or base. Although the ester linkage could be replaced by a more stable amide linkage, this general method is limited by the low yield of the coupling reaction between RAFT-acid and aminefunctionalized chromophores due to the competing aminolysis reaction of the thiocarbonylthio group by the amine.We describe here a novel alternative method to introduce suitable chromophores into a RAFT agent. The overall process and mechanism are outlined in Scheme 1. This procedure involves performing a RAFTlike polymerization reaction, except the molar ratio of monomer to RAFT agent is kept at unity. A small amount (1-2% molar equivalent) of free radical initiator is used to initiate the reaction. In our work 2-cyanoprop-2-yl dithiobenzoate 5 and 2,2′-az...

Polymers prepared by RAFT polymerisation containing acenaphthyl energy donors and a terminal anthryl energy acceptor have a narrow molecular weight distribution and exhibit excitation energy transfer efficiencies up to 70%.