title: Efficient CdSe quantum dot-sensitized solar cells prepared by an improved successive ionic layer adsorption and reaction process.
abstract: In pursuit of efficient quantum dot (QD)-sensitized solar cells based on mesoporous TiO(2) photoanodes, a new procedure for preparing selenide (Se(2-)) was developed and used for depositing CdSe QDs in situ over TiO(2) mesopores by the successive ionic layer adsorption and reaction (SILAR) process in ethanol. The sizes and density of CdSe QDs over TiO(2) were controlled by the number of SILAR cycles applied. After some optimization of these QD-sensitized TiO(2) films in regenerative photoelectrochemical cells using a cobalt redox couple [Co(o-phen)(3)(2+/3+)], including addition of a final layer of CdTe, over 4% overall efficiencies were achieved at 100 W/m(2) with about 50% IPCE at its maximum. Light-harvesting properties and transient voltage decay/impedance measurements confirmed that CdTe-terminated CdSe QD cells gave better charge-collection efficiencies and kinetic parameters than corresponding CdSe QD cells. In a preliminary study, a CdSe(Te) QD-sensitized TiO(2) film was combined with an organic hole conductor, spiro-OMeTAD, and shown to exhibit a promising efficiency of 1.6% at 100 W/m(2) in inorganic/organic hybrid all-solid-state cells.
authors.affiliation: Laboratory for Photonics and Interfaces, Institute of Chemical Sciences and Engineering, School of Basic Sciences, Swiss Federal Institute of Technology, CH-1015 Lausanne, Switzerland. hyojoong.lee@epfl.ch
authors.forename: Hyojoong
authors.initials: H
authors.lastname: Lee
authors.forename: Mingkui
authors.initials: M
authors.lastname: Wang
authors.forename: Peter
authors.initials: P
authors.lastname: Chen
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Gamelin
authors.forename: Shaik M
authors.initials: SM
authors.lastname: Zakeeruddin
authors.forename: Michael
authors.initials: M
authors.lastname: Grätzel
authors.forename: Md K
authors.initials: MK
authors.lastname: Nazeeruddin
mesh_terms: D000327:Adsorption; D019187:Cadmium Compounds / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D011211:Electric Power Supplies; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007477:Ions; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000295:instrumentation; D010316:Particle Size; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry*; D012993:Solar Energy; D013499:Surface Properties
chemical_list: D019187:Cadmium Compounds; D007477:Ions; D046911:Macromolecular Substances; D018036:Selenium Compounds; C058667:cadmium selenide