Limits...
Synthesis, structure, and opto-electronic properties of organic-based nanoscale heterojunctions.

Rezek B, Cermák J, Kromka A, Ledinský M, Hubík P, Mareš JJ, Purkrt A, Cimrová V, Fejfar A, Kočka J - Nanoscale Res Lett (2011)

Bottom Line: We show that employing and combining advanced scanning probe techniques can provide us significant insight into the correlation of these properties.These data are further correlated with local material composition detected using micro-Raman spectroscopy and with other electronic transport data.We demonstrate benefits of this multi-dimensional characterizations on (i) bulk heterojunction of fully organic composite films, indicating differences in blend quality and component segregation leading to local shunts of photovoltaic cell, and (ii) thin-film heterojunction of polypyrrole (PPy) electropolymerized on hydrogen-terminated diamond, indicating covalent bonding and transfer of charge carriers from PPy to diamond.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Physics ASCR, v,v,i,, Cukrovarnická 10, 16200 Prague 6, Czech Republic. rezek@fzu.cz.

ABSTRACT
Enormous research effort has been put into optimizing organic-based opto-electronic systems for efficient generation of free charge carriers. This optimization is mainly due to typically high dissociation energy (0.1-1 eV) and short diffusion length (10 nm) of excitons in organic materials. Inherently, interplay of microscopic structural, chemical, and opto-electronic properties plays crucial role. We show that employing and combining advanced scanning probe techniques can provide us significant insight into the correlation of these properties. By adjusting parameters of contact- and tapping-mode atomic force microscopy (AFM), we perform morphologic and mechanical characterizations (nanoshaving) of organic layers, measure their electrical conductivity by current-sensing AFM, and deduce work functions and surface photovoltage (SPV) effects by Kelvin force microscopy using high spatial resolution. These data are further correlated with local material composition detected using micro-Raman spectroscopy and with other electronic transport data. We demonstrate benefits of this multi-dimensional characterizations on (i) bulk heterojunction of fully organic composite films, indicating differences in blend quality and component segregation leading to local shunts of photovoltaic cell, and (ii) thin-film heterojunction of polypyrrole (PPy) electropolymerized on hydrogen-terminated diamond, indicating covalent bonding and transfer of charge carriers from PPy to diamond.

No MeSH data available.


Related in: MedlinePlus

Design and electrochemical synthesis of PPy-diamond heterojunction: (a) Schematic cross-sectional drawing of experimental setup for electrochemical synthesis of PPy on diamond device structure. (b) Schematic top view of PPy-diamond device connected for electrical measurements. (c) Voltage as a function of time as detected during the electrochemical synthesis in galvanostatic regime.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3211298&req=5

Figure 4: Design and electrochemical synthesis of PPy-diamond heterojunction: (a) Schematic cross-sectional drawing of experimental setup for electrochemical synthesis of PPy on diamond device structure. (b) Schematic top view of PPy-diamond device connected for electrical measurements. (c) Voltage as a function of time as detected during the electrochemical synthesis in galvanostatic regime.

Mentions: For creating organic-inorganic junction, we synthesized and grafted the PPy on diamond electrochemically from pyrrole (0.24 M) and NaCl (0.1 M) aqueous solution by the application of a constant current (current density -0.3 mA/cm2) and the employment of a hydrogen-terminated intrinsic monocrystalline diamond (synthetic IIIa CVD diamond) with conductive surface as a working electrode [44]. For the electronic transport measurements, we defined H-terminated conductive narrow channel (5 μm wide) on a monocrystalline diamond surface by selective oxygen plasma discharge treatment through a photolithographic mask. PPy was electrochemically synthesized on the channel. Synthesis and electronic measurement setups are shown schematically in Figure 4. Typical PPy growth curve is shown there as well.


Synthesis, structure, and opto-electronic properties of organic-based nanoscale heterojunctions.

Rezek B, Cermák J, Kromka A, Ledinský M, Hubík P, Mareš JJ, Purkrt A, Cimrová V, Fejfar A, Kočka J - Nanoscale Res Lett (2011)

Design and electrochemical synthesis of PPy-diamond heterojunction: (a) Schematic cross-sectional drawing of experimental setup for electrochemical synthesis of PPy on diamond device structure. (b) Schematic top view of PPy-diamond device connected for electrical measurements. (c) Voltage as a function of time as detected during the electrochemical synthesis in galvanostatic regime.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211298&req=5

Figure 4: Design and electrochemical synthesis of PPy-diamond heterojunction: (a) Schematic cross-sectional drawing of experimental setup for electrochemical synthesis of PPy on diamond device structure. (b) Schematic top view of PPy-diamond device connected for electrical measurements. (c) Voltage as a function of time as detected during the electrochemical synthesis in galvanostatic regime.
Mentions: For creating organic-inorganic junction, we synthesized and grafted the PPy on diamond electrochemically from pyrrole (0.24 M) and NaCl (0.1 M) aqueous solution by the application of a constant current (current density -0.3 mA/cm2) and the employment of a hydrogen-terminated intrinsic monocrystalline diamond (synthetic IIIa CVD diamond) with conductive surface as a working electrode [44]. For the electronic transport measurements, we defined H-terminated conductive narrow channel (5 μm wide) on a monocrystalline diamond surface by selective oxygen plasma discharge treatment through a photolithographic mask. PPy was electrochemically synthesized on the channel. Synthesis and electronic measurement setups are shown schematically in Figure 4. Typical PPy growth curve is shown there as well.

Bottom Line: We show that employing and combining advanced scanning probe techniques can provide us significant insight into the correlation of these properties.These data are further correlated with local material composition detected using micro-Raman spectroscopy and with other electronic transport data.We demonstrate benefits of this multi-dimensional characterizations on (i) bulk heterojunction of fully organic composite films, indicating differences in blend quality and component segregation leading to local shunts of photovoltaic cell, and (ii) thin-film heterojunction of polypyrrole (PPy) electropolymerized on hydrogen-terminated diamond, indicating covalent bonding and transfer of charge carriers from PPy to diamond.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Physics ASCR, v,v,i,, Cukrovarnická 10, 16200 Prague 6, Czech Republic. rezek@fzu.cz.

ABSTRACT
Enormous research effort has been put into optimizing organic-based opto-electronic systems for efficient generation of free charge carriers. This optimization is mainly due to typically high dissociation energy (0.1-1 eV) and short diffusion length (10 nm) of excitons in organic materials. Inherently, interplay of microscopic structural, chemical, and opto-electronic properties plays crucial role. We show that employing and combining advanced scanning probe techniques can provide us significant insight into the correlation of these properties. By adjusting parameters of contact- and tapping-mode atomic force microscopy (AFM), we perform morphologic and mechanical characterizations (nanoshaving) of organic layers, measure their electrical conductivity by current-sensing AFM, and deduce work functions and surface photovoltage (SPV) effects by Kelvin force microscopy using high spatial resolution. These data are further correlated with local material composition detected using micro-Raman spectroscopy and with other electronic transport data. We demonstrate benefits of this multi-dimensional characterizations on (i) bulk heterojunction of fully organic composite films, indicating differences in blend quality and component segregation leading to local shunts of photovoltaic cell, and (ii) thin-film heterojunction of polypyrrole (PPy) electropolymerized on hydrogen-terminated diamond, indicating covalent bonding and transfer of charge carriers from PPy to diamond.

No MeSH data available.


Related in: MedlinePlus