Time-resolved measurement system of electrofluorescence spectra

Abstract

Instrument response standard in time-resolved fluorescence Rev. Sci. Instrum. 80, 033109 (2009); 10.1063/1.3095677Alkali-helium exciplex formation on the surface of helium nanodroplets. II. A time-resolved study A time-resolved measurement system for electrofluorescence spectra ͑plots of electric-field-induced change in fluorescence intensity as a function of wavelength͒ has been constructed by combining the time-correlated single-photon-counting system for emission decay measurement with modulated electric field as a sample bias. Four fluorescence decays, which correspond to positive, zero, negative, and zero sample bias, respectively, can be measured simultaneously, and a small field-induced change in decay profile can be detected precisely by using the constructed system. Measurements of time-resolved electrofluorescence spectra have been performed in electron donoracceptor compounds which show a photoinduced electron transfer.

Electric Field Effects on Photoluminescence of CdSe Nanoparticles in a PMMA Film

“…Time-resolved PL measurements in the presence and absence of F were carried out by a single-photon counting lifetime measurement system combined with a pulse generator supplying a bipolar square wave [37]. Briefly, the excitation light source was a second harmonic of the output from a mode-locked femtosecond Ti:sapphire laser (Tsunami, Spectra Physics, Santa Clara, CA, USA).…”

“…Figure 9a shows the representative PL decays of the CdSe nanoparticles with a diameter of 6.6 nm in PMMA in the presence and absence of F. The monitoring PL wavelength was 640 nm, which arises from the exciton-emitting state. As mentioned in the Experimental Section, these decays were stored in turn with time duration of 30 ms and the accumulation time was several hours, so that the field-induced change in absolute intensity as well as the decay constant could be properly evaluated [37]. It is shown in Figure 9a that the PL decay is different between the presence and absence of F. Figure 9b,c show the difference between the decays observed at zero field (I 0 (t)) and at 0.5 MV· cm −1 (I PL (t)), i.e., I PL (t) − I 0 (t), referred to as ∆I PL (t), and the ratio I PL (t)/I 0 (t), respectively.…”

Electric-Field-Induced Enhancement/Quenching of Photoluminescence of π-Conjugated Polymer S3-PPV: Excitation Energy Dependence

“…Fluorescence decays were obtained with a multichannel pulse-height analyzer (MCA). To measure the effect of electric field on the decay profile, we applied a modulated voltage to the sample; 15 this voltage was a rectangular wave of positive, zero, negative, and zero bias in sequence. The duration of each segment was 30 ms, of which the first 3 ms was a dead time to avoid an overshooting effect immediately after the alteration of the applied voltage.…”

Photo- and field-induced charge-separation and phosphorescence quenching in organometallic complex Ir(ppy)3

“…3͒. 9 All the decay profiles were simulated by assuming a bi-exponential decay, i.e., A 1 exp͑−t / 1 ͒ + A 2 exp͑−t / 2 ͒, and lifetimes and pre-exponential factors were determined, as given in Table I ͑ 1 and 2 are the lifetimes and A 1 and A 2 are the pre-exponential factors͒.…”

“…Electroabsorption ͑E-A͒, electrophotoluminescence ͑E-PL͒, E-PL-excitation ͑E-PL-Ex͒ spectra as well as field-induced change in emission decay profile were measured as described elsewhere. [7][8][9] Figure 1 shows absorption, E-A, PL, and E-PL spectra of Ir͑ppy͒ 3 . E-A spectra were measured with = 54.7°.…”