Fluorescence enhancement induced by quadratic electric-field effects on singlet exciton dynamics in poly(3-hexylthiophene) dispersed in poly(methyl methacrylate)

Iimori, Toshifumi; Awasthi, Kamlesh; Chiou, Chuang-Chun; Diau, Eric Wei‐Guang; Ohta, Nobuhiro

doi:10.1039/c8cp07801g

Cited by 10 publications

(13 citation statements)

References 67 publications

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“…The magnitudes of Δ I PL / I PL , evaluated for G1 and G2 lines of P3HT are similar;

\frac{∆ I_{PL}}{I_{italicPL}}

~0.012. This value is slightly smaller than that estimated earlier, [ 32,34 ] which might be due to the difference of P3HT sample morphology or conditions of device preparation.…”

Section: Resultscontrasting

confidence: 73%

“…[ 37 ] Time‐resolved E‐PL measurements are instrumental in disentangling the processes affected by an applied electric field. [ 31–34,37 ] As the strength of applied field and wavelength of excitation in the PL decay measurements were similar to those in the steady‐state PL and E‐PL measurements, the results correlated with each other. PL decay profiles were measured with field strengths 0 and 0.3 MV/cm; the results appear in Figure 4, with the difference and ratio between these two decay profiles.…”

Section: Resultssupporting

confidence: 61%

“…The fitted results appear in Tables S1. The assignments of the three components are torsional relaxation, exciton diffusion to low energy states (down‐hill relaxation), and exciton decay from lowest emitting state for pristine P3HT sample, [ 32 ] while the sub‐picosecond component involves rapid injection of electron to PCBM in the case of mixture samples. Figure 2a,b clearly indicates that the change of lifetime followed the change of PL intensity shown in Figure 1.…”

Section: Resultsmentioning

confidence: 99%

“…[ 30 ] Electric‐field effects on the fluorescence of π‐conjugated polymers such as poly[2‐(phenyl)‐3‐(4′‐(3,7‐dimethyloctyloxy)phenyl)‐1,4‐phenylenevinylene‐ co ‐2‐(11′‐decylsulfanylundecanyloxy)‐5‐methoxy‐1,4‐phenylene vinylene] (S3‐PPV) and rr‐P3HT were similarly examined. [ 31–34 ] Upon application of an electric field S3‐PPV showed an enhanced or quenched PL dependent on the excitation wavelength. [ 31 ] The effects of electric field on fluorescence for rr‐P3HT were measured for various configurations, namely P3HT embedded in a PMMA polymer matrix, junction structures of P3HT (FTO/TiO 2 /Sb 2 S 3 /P3HT/PMMA/Ag, FTO/TiO 2 /P3HT/PMMA/Ag and FTO/P3HT/PMMA/Ag).…”

Section: Introductionmentioning

confidence: 99%

“…[ 31 ] The effects of electric field on fluorescence for rr‐P3HT were measured for various configurations, namely P3HT embedded in a PMMA polymer matrix, junction structures of P3HT (FTO/TiO 2 /Sb 2 S 3 /P3HT/PMMA/Ag, FTO/TiO 2 /P3HT/PMMA/Ag and FTO/P3HT/PMMA/Ag). Non‐radiative processes were affected in those films, depending on the direction of the applied field in P3HT films having a junction structure, [ 32,34 ] but the effects of an electric field on the dynamics of P3HT having a bulk heterojunction with electron acceptors were not studied. In the present work, we investigated the effect of an external electric field on the PL intensity and decay of P3HT:PCBM mixture films using steady‐state and time‐resolved electrophotoluminescence (E‐PL).…”

Section: Introductionmentioning

confidence: 99%

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Photoluminescence of P3HT:PCBM bulk heterojunction thin films and effect of external electric field

Narra

Tsai

Awasthi

et al. 2021

J Chinese Chemical Soc

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Steady‐state and time‐resolved photoluminescence (PL) and electrophotoluminescence (E‐PL) have been recorded for bulk heterojunction samples of thin films of regio‐regular poly(3‐hexylthiophene) (P3HT) and methyl [6,6]‐phenyl‐C61‐butanoate (PCBM). The PL spectra of the bulk heterojunction samples showed a monotonic decrease of PL quantum yield with increased PCBM content in the film. The PL decay was measured with both a femtosecond up‐conversion technique and a time‐correlated single‐photon‐counting technique. The mechanism of PL quenching deviated from a simple Stern‐Volmer equation, explained in terms of an apparent static quenching with a sphere‐of‐action model and dynamic quenching. With increased content of PCBM, the static quenching played a dominant role. Upon application of an electric field, the E‐PL spectra of both P3HT and bulk heterojunction samples showed an enhanced quantum yield and incremented lifetime of PL of P3HT. The long‐range electron transfer from P3HT to PCBM was retarded upon application of an electric field; the field‐induced change increased with increasing PCBM content.

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“…The magnitudes of Δ I PL / I PL , evaluated for G1 and G2 lines of P3HT are similar;

\frac{∆ I_{PL}}{I_{italicPL}}

~0.012. This value is slightly smaller than that estimated earlier, [ 32,34 ] which might be due to the difference of P3HT sample morphology or conditions of device preparation.…”

Section: Resultscontrasting

confidence: 73%

Section: Resultssupporting

confidence: 61%

Section: Resultsmentioning

confidence: 99%