Photoinduced Carrier Generation and Decay Dynamics in Intercalated and Non-intercalated Polymer:Fullerene Bulk Heterojunctions
- 17 June 2011
- journal article
- research article
- Published by American Chemical Society (ACS) in ACS Nano
- Vol. 5 (7), 5635-5646
- https://doi.org/10.1021/nn201251v
Abstract
The dependence of photoinduced carrier generation and decay on donor–acceptor nanomorphology is reported as a function of composition for blends of the polymer poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene) (pBTTT-C₁₄) with two electron-accepting fullerenes: phenyl-C₇₁-butyric acid methyl ester (PC₇₁BM) or the bisadduct of phenyl-C₆₁-butyric acid methyl ester (bis-PC₆₁BM). The formation of partially or fully intercalated bimolecular crystals at weight ratios up to 1:1 for pBTTT-C₁₄:PC₇₁BM blends leads to efficient exciton quenching due to a combination of static and dynamic mechanisms. At higher fullerene loadings, pure PC₇₁BM domains are formed that result in an enhanced free carrier lifetime, as a consequence of spatial separation of the electron and hole into different phases, and the dominant contribution to the photoconductance comes from the high-frequency electron mobility in the fullerene clusters. In the pBTTT-C₁₄:bis-PC₆₁BM system, phase separation results in a non-intercalated structure, independent of composition, which is characterized by exciton quenching that is dominated by a dynamic process, an enhanced carrier lifetime and a hole-dominated photoconductance signal. The results indicate that intercalation of fullerene into crystalline polymer domains is not detrimental to the density of long-lived carriers, suggesting that efficient organic photovoltaic devices could be fabricated that incorporate intercalated structures, provided that an additional pure fullerene phase is present for charge extraction.12 page(sKeywords
This publication has 63 references indexed in Scilit:
- Influence of Phase Segregation on Recombination Dynamics in Organic Bulk‐Heterojunction Solar CellsAdvanced Functional Materials, 2011
- Photoinduced Charge Carrier Generation in Blends of Poly(Thienothiophene) Derivatives and [6,6]-Phenyl-C61-butyric Acid Methyl Ester: Phase Segregation versus IntercalationThe Journal of Physical Chemistry C, 2010
- Photoinduced Energy and Charge Transfer in P3HT:SWNT CompositesThe Journal of Physical Chemistry Letters, 2010
- The Effect of Nanoparticle Shape on the Photocarrier Dynamics and Photovoltaic Device Performance of Poly(3‐hexylthiophene):CdSe Nanoparticle Bulk Heterojunction Solar CellsAdvanced Functional Materials, 2010
- Measuring the Extent of Phase Separation in Poly-3-Hexylthiophene/Phenyl-C61-Butyric Acid Methyl Ester Photovoltaic Blends with 1H Spin Diffusion NMR SpectroscopyChemistry of Materials, 2010
- Efficient generation of charges via below-gap photoexcitation of polymer-fullerene blend films investigated by terahertz spectroscopyPhysical Review B, 2008
- The Locus of Free Charge‐Carrier Generation in Solution‐Cast Zn1–xMgxO/Poly(3‐hexylthiophene) Bilayers for Photovoltaic ApplicationsAdvanced Functional Materials, 2007
- The Mobility and Decay Kinetics of Charge Carriers in Pulse-Ionized Microcrystalline PCBM PowderAdvanced Functional Materials, 2006
- Electrodeless time-resolved microwave conductivity study of charge-carrier photogeneration in regioregular poly(3-hexylthiophene) thin filmsPhysical Review B, 2004
- Mobility and decay kinetics of charge carriers in photoexcited PCBM/PPV blendsPhysical Review B, 2004