Effect of crystalline domain size on the photophysical properties of thin organic molecular films

Mäkinen, Antti; Melnyk, Andrew R.; Schoemann, S.; Headrick, Randall L.; Gao, Yongli

doi:10.1103/physrevb.60.14683

Cited by 26 publications

(14 citation statements)

References 16 publications

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“…Since the position and the intensities of the reflection in the XRD of films on OTS versus the other substrates remains similar, the redshifted absorption spectrum of films grown on OTS can likely be attributed to delocalized excitons in vapor-deposited perylene diimide thin films. [15] This characteristic absorption spectrum has been shown to accompany substantially increased crystal grain size, [15] which is consistent with the present AFM data for the PDI-FCN 2 films grown on OTS-treated substrates versus the other surface treatments. …”

Section: Optical Spectra Of Dicyano Pdi Films On Various Substratessupporting

confidence: 79%

Effects of Arylene Diimide Thin Film Growth Conditions on n‐Channel OFET Performance

Jones

Facchetti

Wasielewski

et al. 2008

Adv Funct Materials

205

183

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A series of eight perylene diimide (PDI)‐ and naphthalene diimide (NDI)‐based organic semiconductors was used to fabricate organic field‐effect transistors (OFETs) on bare SiO2 substrates, with the substrate temperature during film deposition (Td) varied from 70–130 °C. For the N,N′‐n‐octyl materials that form highly ordered films, the mobility (µ) and current on‐off ratio (Ion/Ioff) increase slightly from 70 to 90 °C, and remain relatively constant between 90 and 130 °C. Ion/Ioff and µ of dibromo‐PDI‐based OFETs decrease with increasing Td, while films of N,N′‐1H,1H‐perfluorobutyl dicyanoperylenediimide (PDI‐FCN2) exhibit dramatic Ion/Ioff and µ enhancements with increasing Td. Increased OFET mobility can be correlated with higher levels of molecular ordering and minimization of film morphology surface irregularities. Additionally, the effects of SiO2 surface modification with trimethylsilyl and octadecyltrichlorosilyl monolayers, as well as with polystyrene, are investigated for N,N′‐n‐octyl dicyanoperylenediimide (PDI‐8CN2) and PDI‐FCN2 films deposited at Td = 130 °C. The SiO2 surface treatments have modest effects on PDI‐8CN2 OFET mobilities, but modulate the mobility and morphology of PDI‐FCN2 films substantially. Most importantly, the surface treatments result in substantially increased Vth and decreased Ioff values for the dicyanoperylenediimide films relative to those grown on SiO2, resulting in Vth > 0.0 V and Ion/Ioff ratios as high as 108. Enhancements in current modulation for these high‐mobility, air‐stable, and solution‐processable n‐type semiconductors, should prove useful in noise‐margin enhancement and further improvements in organic electronics.

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Section: Optical Spectra Of Dicyano Pdi Films On Various Substratessupporting

confidence: 79%

Effects of Arylene Diimide Thin Film Growth Conditions on n‐Channel OFET Performance

Jones

Facchetti

Wasielewski

et al. 2008

Adv Funct Materials

205

183

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“…In addition to the in situ measurements, the absorption spectra were recorded in the ambient conditions for a separate set of pristine film samples 3. RESULTS AND ANALYSIS DPEP films produced through fast thermal evaporation have been shown to be mostly amorphous in their 12 Hence the absorption spectrum in Figure 1 shows three distinct peaks above 400 nm, which are assigned to the vibrational levels of S1 state. The low-intensity peak at 375 nm (3.30 eV) is assigned to S2 state.…”

Section: Methodsmentioning

confidence: 99%

<title>Femtosecond photoemission study of excited state dynamics in organic photoreceptors</title>

et al. 2000

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The charge transfer (CT) process in organic semiconductor thin film structures is an important problem for applications such as photoreceptors and light-emitting devices. The operation of a photoreceptor structure is based on a CT process between a donor molecule and an acceptor transport molecule. We have investigated such a structure formed by vacuum-grown thin films of two organic molecules, N,N'-diphenethyl-3,4,9,1O-perylenetetracarboxylic-diimide (DPEP) and N,N'-diphenyl-N,N'-(3-methylphenyl)-1,1 '-biphenyl-4,4'-diamine (TPD), with femtosecond time-resolved photoemission spectroscopy (TR-PES). By measuring the lifetimes of the excited electron states in the mixtures of these molecules we are able to determine the timescale for the electron transfer (ET) between the excited states of the TPD and DPEP molecules. We show that the biexponential ET dynamics consist of a short component of less than 100 fs and a long component of several hundreds fs in length.

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“…The aggregation and self-assembly of PDI systems have been the subject of significant investigation. , Typically, the dominant driving force for aggregation in these systems is π–π interactions between perylene cores, often leading to highly ordered column-like structures . On one hand, thin films of PDI aggregates have been reported to exhibit very long exciton migration length scales (>2 μm), suggesting that PDI aggregates should effectively transport excitons to charge separation sites; on the other hand, formation of these extended structures can have deleterious effects due to increased charge carrier trapping. , …”

Section: Introductionmentioning

confidence: 99%

Elucidating Structural Evolution of Perylene Diimide Aggregates Using Vibrational Spectroscopy and Molecular Dynamics Simulations

et al. 2018

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Perylene diimides (PDIs) are a family of molecules that have potential applications to organic photovoltaics. These systems typically aggregate cofacially due to π-stacking interactions between the aromatic perylene cores. In this study, the structure and characteristics of aggregated N, N'-bis(2,6-diisopropylphenyl)-3,4,9,10-perylenetetracarboxylic diimide (common name lumogen orange), a perylene diimide (PDI) with sterically bulky imide functional groups, were investigated using both experimental vibrational spectroscopy and molecular dynamics (MD) simulations. Samples of lumogen orange dispersed in chloroform exhibited complex aggregation behavior, as evidenced by the evolution of the FTIR spectrum over a period of several hours. While for many PDI systems with less bulky imide functional groups aggregation is dominated by π-stacking interactions between perylene cores, MD simulations of lumogen orange dimers indicated a second, more energetically favorable aggregate structure mediated by "edge-to-edge" interactions between PDI units. Two-dimensional infrared spectroscopy together with orientational statistics obtained from MD simulations were employed to identify and rationalize aggregation-induced coupling between vibrational modes.

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Effect of crystalline domain size on the photophysical properties of thin organic molecular films

Cited by 26 publications

References 16 publications

Effects of Arylene Diimide Thin Film Growth Conditions on n‐Channel OFET Performance

Effects of Arylene Diimide Thin Film Growth Conditions on n‐Channel OFET Performance

<title>Femtosecond photoemission study of excited state dynamics in organic photoreceptors</title>

Elucidating Structural Evolution of Perylene Diimide Aggregates Using Vibrational Spectroscopy and Molecular Dynamics Simulations

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