New 3D supramolecular networks S1 and S2 were prepared by Zn(II) coordination of the tetraphenylmethane-based p-type and n-type molecules bearing four terpyridine ligands. XRD and BET results indicate they are relatively amorphous and non-porous with a high degree of interpenetration within the networks. These could be disassembled by adding more Zn(II) ions and reassembled to form extended 3D networks S3-6 by inserting linear n-type or p-type linking units. BET data suggests that these expanded networks are more porous than the original networks S1-2, but the low porosity and surface area suggest a high degree of interpenetration remains within the expanded networks. The optical properties of these materials were compared to the linear polymers P1-3 made by Zn(II)-mediated assembly of the same linear linking units. The emission spectra of both the 3-D and 1-D cases with the same linking unit matched each other, confirming the incorporation of the linker units into the expanded assemblies. This shows that metal-ligand mediated self-assembly can be used to make two component systems in which the optical properties can be tuned by selection of the units. The assembly was also performed in the presence of CdSe nanocrystals to form nanocomposites.

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Alkoxysubstituted benzo[c] [1,2,5]thiadiazole electron accepting units were prepared and copolymerized with various thiophene-based electron donating monomers to produce new low bandgap polymers P1-4. The materials showed broad absorption in the range from 300 to 700 nm with bandgaps below 2 eV in solution. Efficiencies of over 1% were obtained from pho-tovoltaic cells using P4 with PCBM as acceptor.

Multiphoton excited fluorescence of organic molecules is promising in the applications of efficient nonlinear optical devices and bioimaging. However, they usually have disadvantages of poor photostability and serious fluorescence quenching in aqueous media or solid state, which seriously limit their related applications. In this work, for the first time, the two‐photon excited Förster resonance energy transfer (FRET) process is used to enhance the solid‐state fluorescence of the supramolecular centre (acceptor) in an artificial 3D metal–organic complex (MLC), in which a 3D Zn (II)‐coordinated tetrahedral core is utilized as the donor. More interestingly, the two‐photon light harvesting system, which can be pumped with an optical intensity as low as 1 MW/cm2, exhibits an ultrafast energy transfer rate (∼6.9 × 108 s−1) and ultrahigh photostability. The underlying physical mechanisms are revealed through comprehensive steady‐state and time‐resolved spectroscopic analysis. This work demonstrates that the 3D MLC can be directly used in two‐photon bioimaging and also sheds light on developing other multiphoton harvesting systems, such as metal–organic frameworks.

Methylene Blue (MB) has been found to be one of the most common dyes used in the industries. Adsorption process using Activated Carbon (AC) has been proven to be able to remove MB effectively but the treatment cost using the adsorbent is considered expensive due to its high energy cost. Sugarcane Bagasse (SGB) is an agricultural by-product and abundantly available material in many developing countries. FTIR and XRD were used to confirm the existence of ligno-cellulose content of SGB after experiencing various chemical treatments. SGB had 5 -40 folds higher MB removal capability than commercial activated carbon, depending on the pH of water medium and the type of SGB. SGB showed a much better performance in adsorbing MB in alkaline environment than in acidic environment. Langmuir adsorption isotherm model was able to estimate the removal capacity of non-chemical treated SGB (NSGB) and CaCl2 treated SGB (CSGB) at 84.7458 mg/g and 35.2113 mg/g respectively. An extremely higher MB removal capacity was found for BSGB due to the complexity of the surface site after chemical treatment. NaOH treated SGB (BSGB) with low lignin residue content was the most favourable adsorbent for MB adsorption.

Developing organic chromophores with large two-photon absorption (TPA) in both organic solvents and aqueous media is crucial owing to their applications in solid-state photonic devices and biological imaging. Herein, a series of novel terpyridine-based quadrupolar derivatives have been synthesized. The influences of electron-donating group, type of conjugated bridge, as well as solvent polarity on the molecular TPA properties have been investigated in detail. In contrast to the case in organic solvents, bis(thienyl)-benzothiadiazole as a rigid conjugated bridge will completely quench molecular two-photon emission in aqueous media. However, the combination of alkylcarbazole as the donor and bis(styryl)benzene as a conjugation bridge can enlarge molecular TPA cross-sections in both organic solvent and aqueous media. The reasonable two-photon emission brightness for the organic nanoparticles of chromophores 3-5 in the aqueous media, prepared by the reprecipitation method, enables them to be used as probes for in vivo biological imaging.

Discharging wastewater containing heavy metals of Cu, Pb, Zn and Cd into water bodies can cause toxicity in plants and aquatic animals and some of them will be unable to survive except algae. Wastewater treatment method to remove heavy metal contaminants includes chemical precipitation, ion exchange, membrane, filtration, adsorption using activated carbon. However, these methods are either expensive or have other disadvantages such as high energy consumption and inefficiencies when existing heavy metals are at trace concentration. Biosorption using algae biomass can be an alternative method to eliminate heavy metals. The objective of the project is to investigate the capability of Marine Algae (MA) and Freshwater Algae (FA) biomass in adsorbing heavy metals of Cu, Pb, Zn and Cd from water medium using synthetic water and industrial water. MA and FA were obtained from the eastern coast of Pulau Ubin and local fish farm respectively. After being fully washed with deionised water, dried in a furnace for 105˚C, they are grinded to pass 1 mm 2 of siever. MA and FA were characterised using FTIR to determine their functional groups. An industrial water was collected from industrial discharge from metal factories in northern side of Singapore. Effect of adsorption time, adsorbent concentration, and pH were studied. The result showed that FA and MA had a higher capability in adsorbing a total metal of about 40 ppm level from an industrial water, or 4 times than synthetic water concentration, at the same adsorbent dosage of 50 mg. In conclusion, the presence of various functional groups, hydroxyl, carboxylic and amine groups, in all MA and FA samples had enabled the algae biomass to adsorb heavy metals of Cu, Pb, Cd and Zn from synthetic and industrial water. Due to their biosorptive properties and fast adsorption capability, algae could be a potential method for cleaning up surface water or post-treatment of wastewater and minimise the cost of eutrophication.

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