Identification of both bipolaron and electron-hole pair contributions to organic magnetoresistance in a regioregular polythiophene device

Sahin-Tiras, Kevser; Riedl, Austin D.; Wohlgenannt, M.; Rybicki, James

doi:10.1016/j.orgel.2017.05.051

Cited by 7 publications

(7 citation statements)

References 33 publications

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“…Also, the MFEs may occur via particular magneto-responsive species. Indeed, many species, such as an e-h pair ( polaron pair), 3,4,6,[8][9][10][11][12][13][14][15] a triplet exciton (TE), [16][17][18] a trap carrier, and a doubly-charged spinless bipolaron, [19][20][21] have been considered as the main species of MFEs. Due to such many factors to be considered, multiple mechanisms and explanations on MFEs have been proposed.…”

Section: Introductionmentioning

confidence: 99%

Correlation between bias-dependent ESR signals and magnetic field effects in organic light emitting diodes

Kanemoto

Hatanaka

Suzuki

2019

Journal of Applied Physics

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The bias dependent behaviors in magnetic field effects (MFEs) of the current and the electroluminescence (EL) intensity in organic light emitting diodes (OLEDs) have been investigated from electrically-detected and EL-detected magnetic resonance (EDMR and ELDMR) techniques. An EDMR signal was not detected from the electron-only device, and the hole-only device gave only a much smaller EDMR signal than the OLED device. Both the EDMR and ELDMR signals observed from the OLED are concluded to primarily arise from the spin-dependent reaction of electron-hole (e-h) pairs. Both the normalized EDMR and ELDMR signal intensities decrease by increasing the operation bias of OLED, because the increased bias enhances the dissociation and recombination of e-h pairs beyond the increase in the pair-density by the bias. The bias-dependence curves of magneto-conductances and magneto-EL intensities are demonstrated to be very similar to those of the normalized EDMR and ELDMR, respectively. This similarity gives direct evidence that e-h pairs determine the MFEs of the present OLEDs at room temperature and that the MFEs are reduced by bias-dependent dissociation and recombination of e-h pairs. The bias-dependent EDMR and ELDMR experiments are thus effective as probing methods to examine the magnetic field properties via e-h pairs of OLEDs.

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Section: Introductionmentioning

confidence: 99%

Correlation between bias-dependent ESR signals and magnetic field effects in organic light emitting diodes

Kanemoto

Hatanaka

Suzuki

2019

Journal of Applied Physics

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“…Reference Alq 3 +25 13 100 298 [13] PFO +16 5 100 300 [14] m-MTDATA :3TPYMB > +1000 30 300 294 [15] RR-P3HT +1.8 5.4 100 298 [16] −3.9 and 160 °C, and a highest mobility of 0.033 cm 2 V −1 s −1 was observed when the thin films were thermal annealed at 150 °C.…”

Section: Ofet Characterizationmentioning

confidence: 99%

“…[ 10 ] Many common organic semiconductors have been investigated as OMAR device active layers, including tris(8‐hydroxyquinoline)aluminum (Alq 3 ), poly(9,9‐di‐n‐octylfluorenyl‐2,7‐diyl) (PFO), 4,4,4‐tris[3‐methylphenyl(phenyl)amino]triphenylamine (m‐MTDATA), tris‐[3‐(3‐pyridyl)mesityl]borane (3TPYMB), poly(3‐hexylthiophene) (P3HT), poly[2‐methoxy‐5‐(3’,7’‐dimethyloctyloxy)‐1,4‐phenylenevinylene] (MDMO‐PPV), phenyl‐C 61 ‐butyric acid methyl ester (PCBM), poly[2‐methoxy‐5‐(2’‐ethylhexyloxy)‐1,4‐phenylenevinylene] (MEH‐PPV), poly( N ‐vinyl carbazole) (PVK), and pentacene. [ 11–22 ]…”

Section: Introductionmentioning

confidence: 99%

“…[10] Many common organic semiconductors have been investigated as OMAR device active layers, including tris(8-hydroxyquinoline)aluminum (Alq 3 ), poly(9,9-di-noctylfluorenyl-2,7-diyl) (PFO), 4,4,4-tris [3-methylphenyl(phenyl) amino]triphenylamine (m-MTDATA), tris-[3-(3-pyridyl)mesityl] borane (3TPYMB), poly(3-hexylthiophene) (P3HT), poly[2methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV), phenyl-C 61 -butyric acid methyl ester (PCBM), poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), poly(N-vinyl carbazole) (PVK), and pentacene. [11][12][13][14][15][16][17][18][19][20][21][22] 𝜋-Conjugated diradicaloid molecules are attracting interest because of their potentially unique electronic properties originating from their diradical character. [23][24][25][26][27][28][29] Diradicaloids have resonance structures between open-shell diradicals and closed-shell quinoids, the stabilities of which depend strongly on the molecular structures.…”

Section: Introductionmentioning

confidence: 99%

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Essential Role of Triplet Diradical Character for Large Magnetoresistance in Quinoidal Organic Semiconductor with High Electron Mobility

2022

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A diradicaloid molecule with high semiconducting performance is synthesized based on the quinoidal benzo[1,2-b:4,5-b′]dithiophene structure. The diradical character is investigated by quantum chemical calculations and variable temperature electron spin resonance. The diode devices based on this molecule show a large change in electric current in magnetic fields below 100 mT with a strong dependence on the measurement temperatures; as the population of the triplet diradicals increases at high temperatures, the magnetoconductance (MC) values increase. As a result, a MC of −19.4% is achieved at 120 °C, which is the largest negative MC observed for organic molecules to date. In contrast, a smaller diradicaloid molecule based on quinoidal thieno[3,2-b]thiophene without thermally accessible triplet state shows no MC, indicating the essential role of the triplet diradicals. The strong correlation between the MC and the triplet diradical concentrations suggests that the charge conduction in the diradicaloid is suppressed through a spin-blocking mechanism, which can be controlled through the magnetic modulation of the hyperfine fields. The compound forms high-crystallinity thin films and has high monopolar electron transport in organic field-effect transistors, with an average mobility of 1.01 cm 2 V −1 s −1 for edge-cast films.

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“…The results of this study were published as a journal article[63]. Some parts of this chapter were included from this publication.…”

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confidence: 99%

Magnetic field effect and other spectroscopies of organic semiconductor and hybrid organic-inorganic perovskite devices

Tiras¹

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Identification of both bipolaron and electron-hole pair contributions to organic magnetoresistance in a regioregular polythiophene device

Cited by 7 publications

References 33 publications

Correlation between bias-dependent ESR signals and magnetic field effects in organic light emitting diodes

Correlation between bias-dependent ESR signals and magnetic field effects in organic light emitting diodes

Essential Role of Triplet Diradical Character for Large Magnetoresistance in Quinoidal Organic Semiconductor with High Electron Mobility

Magnetic field effect and other spectroscopies of organic semiconductor and hybrid organic-inorganic perovskite devices

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