title: Supersensitization of CdS quantum dots with a near-infrared organic dye: toward the design of panchromatic hybrid-sensitized solar cells.
abstract: The photoresponse of quantum dot solar cells (QDSCs) has been successfully extended to the near-IR (NIR) region by sensitizing nanostructured TiO(2)-CdS films with a squaraine dye (JK-216). CdS nanoparticles anchored on mesoscopic TiO(2) films obtained by successive ionic layer adsorption and reaction (SILAR) exhibit limited absorption below 500 nm with a net power conversion efficiency of ~1% when employed as a photoanode in QDSC. By depositing a thin barrier layer of Al(2)O(3), the TiO(2)-CdS films were further modified with a NIR absorbing squaraine dye. Quantum dot sensitized solar cells supersensitized with a squariand dye (JK-216) showed good stability during illumination with standard global AM 1.5 solar conditions, delivering a maximum overall power conversion efficiency (η) of 3.14%. Transient absorption and pulse radiolysis measurements provide further insight into the excited state interactions of squaraine dye with SiO(2), TiO(2), and TiO(2)/CdS/Al(2)O(3) films and interfacial electron transfer processes. The synergy of combining semiconductor quantum dots and NIR absorbing dye provides new opportunities to harvest photons from different regions of the solar spectrum.
authors.affiliation: Radiation Laboratory and Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA.
authors.forename: Hyunbong
authors.initials: H
authors.lastname: Choi
authors.forename: Roxana
authors.initials: R
authors.lastname: Nicolaescu
authors.forename: Sanghyun
authors.initials: S
authors.lastname: Paek
authors.forename: Jaejung
authors.initials: J
authors.lastname: Ko
authors.forename: Prashant V
authors.initials: PV
authors.lastname: Kamat
mesh_terms: D000042:Absorption; D019187:Cadmium Compounds / Q000737:chemistry*; D003116:Color; D004396:Coloring Agents / Q000737:chemistry*; D003503:Cyclobutanes / Q000737:chemistry*; D011211:Electric Power Supplies; D007259:Infrared Rays; D010636:Phenols / Q000737:chemistry*; D045663:Quantum Dots; D012993:Solar Energy; D013440:Sulfides / Q000737:chemistry*
chemical_list: D019187:Cadmium Compounds; D004396:Coloring Agents; D003503:Cyclobutanes; D010636:Phenols; D013440:Sulfides; C480596:squaraine; C034939:cadmium sulfide