Electronic Processes in Organic Solids

Pope, Martin; Swenberg, Charles E.

doi:10.1146/annurev.pc.35.100184.003145

Cited by 490 publications

(798 citation statements)

References 3 publications

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“…3.5 Å with strong π-π stacking by the involvements of 14 carbons in π-π interactions. 23 As shown of the ladder-like arrays. Interestingly, the intermolecular distances between the pyrenyl planes of two adjacent molecules in 7b, 7c and 9 are ca.…”

Section: X-ray Molecular Structures and Crystal Packingmentioning

confidence: 99%

Pyrene-cored blue-light emitting [4]helicenes: synthesis, crystal structures, and photophysical properties

Paudel

Seto

et al. 2013

Org. Biomol. Chem.

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Section: X-ray Molecular Structures and Crystal Packingmentioning

confidence: 99%

Pyrene-cored blue-light emitting [4]helicenes: synthesis, crystal structures, and photophysical properties

Paudel

Seto

et al. 2013

Org. Biomol. Chem.

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“…The electronic structure of organic molecular crystals is strikingly different from the conventional inorganic semiconductors, such as Si, in that the electronic polarization of the dielectric medium by charge carriers constitutes a major effect, with energy scale greater than transfer integrals or temperature [1,2]. The transport gap E t for creating a separated electron-hole pair has a substantial (1-2 eV) polarization energy contribution [3] and exceeds the optical gap by ∼ 1 eV.…”

Section: Transport Gapmentioning

confidence: 99%

“…We focus here on the electronic polarization of crystalline thin films near surfaces and interfaces. We find that electronic polarization, and hence E t , in a prototypical organic crystal is significantly different at a free surface, near a metal-organic interface, in thin organic layers, and in the bulk.Weak intermolecular forces characterize organic molecular crystals, whose electronic and vibrational spectra are readily related to gas-phase transitions [1,2]. Due to small transfer integrals, charge carriers are molecular ions embedded in the lattice of neutral molecules.…”

mentioning

confidence: 99%

Electronic polarization at surfaces and thin films of organic molecular crystals: PTCDA

Tsiper

Soos

Gao

et al. 2002

Chemical Physics Letters

270

166

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The electronic polarization energies, P = P+ + P−, of a PTCDA (perylenetetracarboxylic acid dianhydride) cation and anion in a crystalline thin film on a metallic substrate are computed and compared with measurements of the PTCDA transport gap on gold and silver. Both experiments and theory show that P is 500 meV larger in a PTCDA monolayer than in 50Å films. Electronic polarization in systems with surfaces and interfaces are obtained self-consistently in terms of charge redistribution within molecules. I. TRANSPORT GAPThe electronic structure of organic molecular crystals is strikingly different from the conventional inorganic semiconductors, such as Si, in that the electronic polarization of the dielectric medium by charge carriers constitutes a major effect, with energy scale greater than transfer integrals or temperature [1,2]. The transport gap E t for creating a separated electron-hole pair has a substantial (1-2 eV) polarization energy contribution [3] and exceeds the optical gap by ∼ 1 eV. Limited overlap rationalizes the modest mobilities of organic molecular solids. Devices such as light-emitting diodes, thin film transistors, or photovoltaic cells require charge transport and are consequently based on thin films, quite often deposited on metallic substrates [4,5]. Organic electronics relies heavily on controlling films with monolayer precision, on forming structures with several thin films, and on characterizing the interfaces. The positions of transport states and mechanisms for charge injection are among the outstanding issues for exploiting organic devices. We focus here on the electronic polarization of crystalline thin films near surfaces and interfaces. We find that electronic polarization, and hence E t , in a prototypical organic crystal is significantly different at a free surface, near a metal-organic interface, in thin organic layers, and in the bulk.Weak intermolecular forces characterize organic molecular crystals, whose electronic and vibrational spectra are readily related to gas-phase transitions [1,2]. Due to small transfer integrals, charge carriers are molecular ions embedded in the lattice of neutral molecules. The transport gap E t in the crystal is derived from the charge gap for electron transfer in the gas phase, I(g) − A(g), which is the difference between the ionization potential and the electron affinity. But crystals have electrostatic interactions even in the limit of no overlap, and charge carriers are surrounded by self-consistent polarization clouds. In contrast to polaronic effects, electronic polarization is instantaneous and directly affects the positions of energy levels. Formation of polarization clouds is associated with stabilization energy P + for cations (the "holes") and P − for anions (the "electrons"). The combination P = P + + P − occurs in E t = I(g) − A(g) − P . Since Coulomb interactions are long-ranged, polarization clouds extend over many lattice constants and P depends on the proximity to surfaces and interfaces.

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“…Rebane, and others. (Exhaustive references cannot be included here, but for a comprehensive text covering many aspects, see (10).) Beginning at room temperature, let us consider the optical absorption spectrum of terrylene molecules dispersed at low concentration (say 10 -6 mol/mol) in a solid transparent host of p-terphenyl (see Fig.…”

Section: Low Temperature Spectroscopy Of Molecules In Solids: Inhomogmentioning

confidence: 99%

Nobel Lecture: Single-molecule spectroscopy, imaging, and photocontrol: Foundations for super-resolution microscopy

Moerner

2015

Rev. Mod. Phys.

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The initial steps toward optical detection and spectroscopy of single molecules in condensed matter arose out of the study of inhomogeneously broadened optical absorption profiles of molecular impurities in solids at low temperatures. Spectral signatures relating to the fluctuations of the number of molecules in resonance led to the attainment of the single-molecule limit in 1989 using frequency-modulation laser spectroscopy. In the early 90's, many fascinating physical effects were observed for individual molecules, and the imaging of single molecules as well as observations of spectral diffusion, optical switching and the ability to select different single molecules in the same focal volume simply by tuning the pumping laser frequency provided important forerunners of the later superresolution microscopy with single molecules. In the room temperature regime, imaging of single copies of the green fluorescent protein also uncovered surprises, especially the blinking and photoinduced recovery of emitters, which stimulated further development of photoswitchable fluorescent protein labels. Because each single fluorophore acts a light source roughly 1 nm in size, microscopic observation and localization of individual fluorophores is a key ingredient to imaging beyond the optical diffraction limit. Combining this with active control of the number of emitting molecules in the pumped volume led to the super-resolution imaging of Eric Betzig and others, a new frontier for optical microscopy beyond the diffraction limit. The background leading up to these observations is described and current developments are summarized. The early days Introduction and early inspirationsI want to thank the Nobel Committee for Chemistry, the Royal Swedish Academy of Sciences, and the Nobel Foundation for selecting me for this prize recognizing the development of super-resolved fluorescence microscopy. I am truly honored to share the prize with my two esteemed colleagues, Stefan Hell and Eric Betzig. My primary contributions center on the first optical detection and spectroscopy of single molecules in the condensed phase(1), and on the observations of imaging, blinking and photocontrol not only for single molecules at low temperatures in solids, but also for useful variants of the green fluorescent protein at room temperature (2). This lecture describes the context of the events leading up to these advances as well as a portion of the subsequent developments both around the world and in my laboratory.In the mid-1980's, I derived much early inspiration from amazing advances that were occurring around the world where single nanoscale quantum systems were detected and explored for both scientific and technological reasons. Some of these were (i) the spectroscopy of single electrons or ions confined in vacuum electromagnetic traps (3-5), (ii) scanning tunneling microscopy (STM) (6) and atomic force microscopy (AFM) (7), and (iii) the study of ion currents in single membrane-embedded ion channels (8). But why not optical detection and ...

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Electronic Processes in Organic Solids

Cited by 490 publications

References 3 publications

Pyrene-cored blue-light emitting [4]helicenes: synthesis, crystal structures, and photophysical properties

Pyrene-cored blue-light emitting [4]helicenes: synthesis, crystal structures, and photophysical properties

Electronic polarization at surfaces and thin films of organic molecular crystals: PTCDA

Nobel Lecture: Single-molecule spectroscopy, imaging, and photocontrol: Foundations for super-resolution microscopy

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