Ferroelectric Polymer Matrix for Probing Molecular Organization in Perylene Diimides

Chellappan, Kishore V.; Kandappa, Sunil Kumar; Rajaram, Sridhar; Narayan, K. S.

doi:10.1021/jz5023976

Cited by 11 publications

(7 citation statements)

References 28 publications

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“…16 Due to their tendency for π−π interactions, PDIs are known to form self-organized aggregates, 17 a property that in principle can support long-range electron transport. 18−21 PDI organization in OPV blends adapts the structural motif of Htype columnar aggregates, 22 although cases of J-aggregate formation 23 or slip-stacked packing 24 are also possible. In comparison to the fullerene-based OPV devices, the limited mobility of photogenerated charges in PDI-based photoactive layers results in increased nongeminate recombination losses of charges that limit device performance.…”

Section: ■ Introductionmentioning

confidence: 99%

“…In this regard, other electron-accepting molecules can be useful for OPV applications. − One class of emerging electron-acceptor materials is the family of low-cost perylene dimide derivatives (PDIs). − PDIs hold great promise as n-type components in OPV bulk heterojunctions since they exhibit strong absorption in the visible while retaining high thermal, chemical, and photostability properties . Due to their tendency for π–π interactions, PDIs are known to form self-organized aggregates, a property that in principle can support long-range electron transport. − PDI organization in OPV blends adapts the structural motif of H-type columnar aggregates, although cases of J-aggregate formation or slip-stacked packing are also possible. In comparison to the fullerene-based OPV devices, the limited mobility of photogenerated charges in PDI-based photoactive layers results in increased nongeminate recombination losses of charges that limit device performance .…”

Section: Introductionmentioning

confidence: 99%

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Charge versus Energy Transfer Effects in High-Performance Perylene Diimide Photovoltaic Blend Films

Singh

Shivanna

Iosifidis

et al. 2015

ACS Appl. Mater. Interfaces

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Perylene diimide (PDI)-based organic photovoltaic devices can potentially deliver high power conversion efficiency values provided the photon energy absorbed is utilized efficiently in charge transfer (CT) reactions instead of being consumed in nonradiative energy transfer (ET) steps. Hitherto, it remains unclear whether ET or CT primarily drives the photoluminescence (PL) quenching of the PDI excimer state in PDI-based blend films. Here, we affirm the key role of the thermally assisted PDI excimer diffusion and subsequent CT reaction in the process of PDI excimer PL deactivation. For our study we perform PL quenching experiments in the model PDI-based composite made of poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b']dithiophene-2,6-diyl-alt-(4-(2-ethylhexanoyl)-thieno[3,4-b]thiophene)-2-6-diyl] (PBDTTT-CT) polymeric donor mixed with the N,N'-bis(1-ethylpropyl)-perylene-3,4,9,10-tetracarboxylic diimide (PDI) acceptor. Despite the strong spectral overlap between the PDI excimer PL emission and UV-vis absorption of PBDTTT-CT, two main observations indicate that no significant ET component operates in the overall PL quenching: the PL intensity of the PDI excimer (i) increases with decreasing temperature and (ii) remains unaffected even in the presence of 10 wt % content of the PBDTTT-CT quencher. Temperature-dependent wide-angle X-ray scattering experiments further indicate that nonradiative resonance ET is highly improbable due to the large size of PDI domains. The dominance of the CT over the ET process is verified by the high performance of devices with an optimum composition of 30:70 PBDTTT-CT:PDI. By adding 0.4 vol % of 1,8-diiodooctane we verify the plasticization of the polymer side chains that balances the charge transport properties of the PBDTTT-CT:PDI composite and results in additional improvement in the device efficiency. The temperature-dependent spectral width of the PDI excimer PL band suggests the presence of energetic disorder in the PDI excimer excited state manifold.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Charge versus Energy Transfer Effects in High-Performance Perylene Diimide Photovoltaic Blend Films

Singh

Shivanna

Iosifidis

et al. 2015

ACS Appl. Mater. Interfaces

Self Cite

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“…In the low concentration regime, the dye is expected to be filled in the amorphous regions of the polymer film, resulting in the dominance of the monomeric emission over the dimeric emission. [ 14 ] The cavity effect induced in the dielectric region between two hemispheroidal structures can be attributed to the narrowing of the emission spectra and the increased emission intensity in the patterned films. The crystallinity to amorphous ratio is calculated by X‐ray diffraction measurements, as shown in Figure S6 (Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

Self‐Assembled Patterns in Ferroelectric Polymer Thin Films: Formation and Implications

Behera

Narayan

2022

Macro Materials & Eng

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Patterned piezoelectric polymer films serve as a suitable template for exploring various applications based on the characteristic electrical and optical properties. Here, the large‐area spontaneous pattern formation in relaxor terpolymer, poly(vinylidene difluoride‐trifluoroethylene‐chlorofluoroethelene) (P(VDF‐TrFE‐CFE)) films, is demonstrated using the cost‐effective breath‐figure technique. The experimental parameters allowed for controlling the hemispheroidal patterns, with pore dimensions varying from a few ≈100 nm to ≈ mm range. Due to the increased charge accumulation region, these porous structures exhibit enhanced ferroelectric and piezoelectric responses. Additionally, the refractive index contrast in the patterned structures leads to improved diffused reflection and thermal emittance. Furthermore, in the presence of guest‐dye molecules, the dominant amorphous phase of the patterned films results in higher photoluminescence yield. These features enable patterned films for high‐efficiency piezoelectric generators and passive daytime radiators.

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“…Syntheses of TP and PER-PDA are reported elsewhere. 27,28 They were >99% pure according to HPLC analyses.…”

Section: Synthesismentioning

confidence: 99%

Effects of temperature and CO2 pressure on the emission of N,N′-dialkylated perylene diimides in poly(alkyl methacrylate) films. Are guest-host alkyl group interactions important?

2016

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Static and dynamic fluorescence measurements have been made on four N, N −dialkylated perylene diimides in films of poly(alkyl methacrylate)s (PAMAs) with 5 different alkyl groups and in a 'model solvent', n-butyl acetate, over wide temperature ranges. The results indicate that the excited singlet states of the perylene guest molecules are controlled primarily by chain relaxations rather than hole free volumes in the polymer matrixes. The short singlet lifetimes of the perylene molecules require that the guest molecules respond primarily to the environments experienced by their ground states within the PAMA matrixes; each of the PAMAs offers slightly different locations in which the guest molecules can reside as a result of interactions between the N −alkyl substituents on the imide groups of the perylenes and the alkyl groups on the PAMA side chains. PAMAs with branched side chains were found to have a larger influence than PAMAs with linear side chains on the fluorescence properties of the guest molecules. The results are compared to those employing pyrenyl derivatives (with much longer excited singlet lifetimes) in the same PAMA films. The overall results indicate that the perylenes can be used as a complementary probe of local polymer chain dynamics, but they are less sensitive to their environments than are pyrenyl groups. However, they offer some distinct advantages: (1) a much wider range of N, N −disubstituted perylene diimides can be synthesized easily; (2) those substituents can be designed to allow a greater or lesser interaction with an anisotropic host matrix. Also, rapid conformational changes of a bis-perylene derivative appear to be restricted in the polymer matrixes. Those restrictions appear reduced when the polymer films are placed under high pressures of the plasticizing gas, CO 2 , but not when they are under equal pressures of a much less intervening gas, N 2 .

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Ferroelectric Polymer Matrix for Probing Molecular Organization in Perylene Diimides

Cited by 11 publications

References 28 publications

Charge versus Energy Transfer Effects in High-Performance Perylene Diimide Photovoltaic Blend Films

Charge versus Energy Transfer Effects in High-Performance Perylene Diimide Photovoltaic Blend Films

Self‐Assembled Patterns in Ferroelectric Polymer Thin Films: Formation and Implications

Effects of temperature and CO2 pressure on the emission of N,N′-dialkylated perylene diimides in poly(alkyl methacrylate) films. Are guest-host alkyl group interactions important?

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