%0 Journal Article %T Piperidine-Substituted Perylene Sensitizer for Dye-Sensitized Solar Cells %A Joe Otsuki %A Yusho Takaguchi %A Daichi Takahashi %A Palanisamy Kalimuthu %A Surya Prakash Singh %A Ashraful Islam %A Liyuan Han %J Advances in OptoElectronics %D 2011 %I Hindawi Publishing Corporation %R 10.1155/2011/860486 %X We have prepared a novel piperidine-donor-substituted perylene sensitizer, PK0002, and studied the photovoltaic performance in dye-sensitized solar cells (DSSCs). Physical properties and photovoltaic performance of this new perylene derivative PK0002 are reported and compared with those of unsubstituted perylene sensitizer, PK0003. PK0002, when anchored to nanocrystalline TiO2 films, achieves very efficient sensitization across the whole visible range extending up to 800£¿nm. The incident photon-to-current conversion efficiency (IPCE) spectrum was consistent with the absorption spectrum and resulted in a high short-circuit photocurrent density ( ) of 8.8£¿mA£¿cm£¿2. PK0002 showed higher IPCE values than PK0003 in the 520¨C800£¿nm region. Under standard AM 1.5 irradiation (100£¿mW£¿cm£¿2) and using an electrolyte consisting of 0.6£¿M dimethylpropyl-imidazolium iodide, 0.05£¿M£¿I2, 0.1£¿M£¿LiI, and 0.5£¿M tert-butylpyridine in acetonitrile, a solar cell containing sensitizer PK0002 yielded a short-circuit photocurrent density of 7.7£¿mA£¿cm£¿2, an open-circuit photovoltage of 0.57£¿V, and a fill factor of 0.70, corresponding to an overall conversion efficiency of 3.1%. 1. Introduction Dye-sensitized solar cells (DSSCs) have been widely investigated because of their simple structure and potential for low-cost production [1¨C3]. In this solar cell, a monolayer of dyes is attached to the surface of nanocrystalline TiO2 film to absorb solar light. The molecular design of dye-sensitizers that can absorb visible light of all colors for nanocrystalline oxide semiconductor solar cells is a challenging task as several requirements have to be fulfilled by the dye which are very difficult to be met simultaneously. Most of current research concerns development of panchromatic sensitizers based on organic dyes and transition metal complexes. Towards this goal, a number of transition metal complexes are used as effective sensitizers, due to their intense charge-transfer absorption over the whole visible range and highly efficient metal-to-ligand charge-transfer in a dye-sensitized solar cell device. DSSCs with dyes based on ruthenium complexes have achieved energy conversion efficiencies over 11% [4, 5]. In recent years, there has been much effort in replacing the ruthenium complexes with fully organic photosensitizers for environmental reasons, lower cost, and the possibility to obtain very high extinction coefficients, which could also allow application in thinner solar cells as demanded in, for example, solid-state DSSCs. Derivatives of perylene have been widely applied in various %U http://www.hindawi.com/journals/aoe/2011/860486/