title: Nanoparticle-assisted high photoconductive gain in composites of polymer and fullerene.
abstract: Polymer-inorganic nanocrystal composites offer an attractive means to combine the merits of organic and inorganic materials into novel electronic and photonic systems. However, many applications of these composites are limited by the solubility and distribution of the nanocrystals in the polymer matrices. Here we show that blending CdTe nanoparticles into a polymer-fullerene matrix followed by solvent annealing can achieve high photoconductive gain under low applied voltages. The surface capping ligand renders the nanoparticles highly soluble in the polymer blend, thereby enabling high CdTe loadings. An external quantum efficiency as high as approximately 8,000% at 350 nm was achieved at -4.5 V. Hole-dominant devices coupled with atomic force microscopy images show a higher concentration of nanoparticles near the cathode-polymer interface. The nanoparticles and trapped electrons assist hole injection into the polymer under reverse bias, contributing to efficiency values in excess of 100%.
authors.forename: Hsiang-Yu
authors.initials: HY
authors.lastname: Chen
authors.forename: Michael K F
authors.initials: MK
authors.lastname: Lo
authors.forename: Guanwen
authors.initials: G
authors.lastname: Yang
authors.forename: Harold G
authors.initials: HG
authors.lastname: Monbouquette
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
mesh_terms: D004553:Electric Conductivity; D037741:Fullerenes / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D010777:Photochemistry / Q000379:methods; D011108:Polymers / Q000737:chemistry*
chemical_list: D037741:Fullerenes; D011108:Polymers
references.citation: Nanotechnology. 2006 Aug 28;17(16):4041-7
references.pmid: 21727535
references.citation: Phys Chem Chem Phys. 2006 Aug 14;8(30):3557-60
references.pmid: 16871346
references.citation: Nano Lett. 2008 Feb;8(2):678-84
references.pmid: 18179278
references.citation: Phys Rev B Condens Matter. 1996 Dec 15;54(24):17628-17637
references.pmid: 9985889
references.citation: Nanotechnology. 2006 Sep 28;17(18):4736-42
references.pmid: 21727606
references.citation: Nature. 2002 Dec 19-26;420(6917):800-3
references.pmid: 12490945
references.citation: Science. 2002 Mar 29;295(5564):2425-7
references.pmid: 11923531
references.citation: Nat Mater. 2005 Feb;4(2):138-42
references.pmid: 15640806