PHOTOINDUCED CHARGE SEPARATION AND RECOMBINATION IN A CONJUGATED POLYMER-SEMICONDUCTOR NANOCRYSTAL COMPOSITE

Citation
Js. Salafsky et al., PHOTOINDUCED CHARGE SEPARATION AND RECOMBINATION IN A CONJUGATED POLYMER-SEMICONDUCTOR NANOCRYSTAL COMPOSITE, Chemical physics letters, 290(4-6), 1998, pp. 297-303
Citations number
18
Categorie Soggetti
Physics, Atomic, Molecular & Chemical
Journal title
ISSN journal
00092614
Volume
290
Issue
4-6
Year of publication
1998
Pages
297 - 303
Database
ISI
SICI code
0009-2614(1998)290:4-6<297:PCSARI>2.0.ZU;2-2
Abstract
Semiconductor nanocrystals and conjugated polymers are classes of well -known materials with optoelectronic properties. We demonstrate that i n a nanocrystalline TiO2/poly(p-phenylene vinylene) (PPV) composite, e xcitons photogenerated in the polymer can be dissociated at the interf ace between the components, with electrons transferred to the nanocrys tals. We show this and also follow the subsequent recombination using a time-resolved microwave conductivity technique. Recombination procee ds in a complex manner with roughly half of the initial amplitude deca ying in 600 ns and the remainder in a biexponential process with time constants and relative amplitudes of 4.3 (0.7) and 80 mu s (0.3). Phot ovoltaic devices were made from the composite films and their properti es are discussed in light of the measured recombination rate and a sim ple carrier transport model. (C) 1998 Elsevier Science B.V. All rights reserved.