Epl 470

Excitation
of the Pdots samples was performed with pump pulses generated via
an optical parametric amplifier from 800 nm pulses, which were converted
to 740 nm and subsequently doubled to attain 370 nm with an OPO crystal.
Aqueous solutions of Pdots were measured using a 1 cm quartz cuvette
and an excitation power at the sample of 300 μW. Fluorescence
at a right angle to the excitation was passed through a Bruker SPEC
250IS spectrograph (ca. 200 nm observation window) and onto the streak
camera (Hamamatsu streak camera and blanking unit C5680 in combination
with a Synchroscan Unit M5675). A charge-coupled device (CCD) camera
(Hamamatsu Orca-ER C4742–95) was used in the binning mode (2
× 2 pixels) to give a 512 × 512 pixel matrix. The observed
time window in time range 2 was 700 ps, while in time range 4, it
was 2000 ps with FWHM instrument response functions of 30 or 45 ps.
For the decay curves obtained from the streak camera, the procedure
written in Matlab was employed assuming a Gaussian instrument response
function. Time-correlated single photon counting (TCSPC) measurements
were carried out in a time window of 50 ns using a pulsed diode laser
source (Edinburgh Instruments EPL470, λ_exc. = 405
nm).^{32 (link)}

Absorption spectra were measured by using a Jasco V-670 spectrophotometer. Fluorescence spectra and time-resolved fluorescence were recorded with a Edinburgh-F900 (Edinburgh Instruments) fluorimeter. A WhiteLase Micro (Fianium) laser was used as an excitation source together with bandpass filters (Thorlabs), with 10 nm bandwidth centred at 520 nm (BP-PH-8M) and 570 nm (BP-PH, BP-PH-CF₃, BP-PH-OMe). Excitation of the previously reported BODIPY-C₁₀ was performed by using a picosecond pulsed diode laser EPL-470 (Edinburgh Instruments), emitting at 473 nm at 1 MHz frequency. Fluorescence decays were measured using the time-correlated single-photon counting technique. Fluorescence decays had 5000 counts at the peak of the decay, with 20 ns (BP-PH, BP-PH-CF₃, BP-PH-OMe, BP-PH-8M) and 50 ns (BODIPY-C₁₀) windows being used with 4096 channels. Absorption and fluorescence measurements were performed using quartz cuvettes (10 mm). QY measurements were obtained by a comparative method using fluorescein (QY_F = 0.95 in 0.1 M NaOH_aq; used for BODIPY-C₁₀) [51 (link)], Rhodamine-6G (QY_F = 0.94 in EtOH; used for BP-PH-8M) [52 (link)], and Rhodamine-101 (QY_F = 0.91 in EtOH; used for BP-PH-CF₃, BP-PH, BP-PH-OMe) [52 (link)] as a standard. The concentration of dyes was 2–6 $$\mathsf{\mu }$$ M.

A solution of photosensitizer was degassed by N₂ for 15 min in a sealed quartz cuvette with a septum cap. Different concentrations of BIH or catalyst were added to the solution of photosensitizer under N₂. The steady-state fluorescence for solution samples was measured by Duetta fluorescence and absorbance spectrometer. The excited-state lifetime (τ₀) of CuPP and PP was measured with an FLS 920 fluorescence spectrometer (Edinburgh instruments), in which a picosecond pulsed diode laser (λ = 472 nm) (Edinburgh instruments EPL-470) was used as the excitation source. The quenching rate constant (k_q) was calculated by Stern–Volmer equation: $I_0/I\mathrm{or}{\tau }_0/\tau =1+k_q\times {\tau }_0\times \left[Q\right]$ where $I_0$ and $I$ represent the fluorescence intensity of photosensitizer in the absence and presence of quencher, $k_q$ is the quenching rate constant, ${\tau }_0$ is the lifetime of the photosensitizer, and $\left[Q\right]$ is the concentration of quencher.