DOI: 10.17863/cam.113061
title: Research data supporting "Multilayer Films for Photon Upconversion-Driven Photoswitching"

description: UV-Vis absorption/transmittance spectra were measured with a Cary-60 spectrophotometer using wavelength scan from 290-800 nm with a resolution of 1 nm at a scan speed of 600 nm∙min-1 and an average time of 0.1 s. Solid-state samples (with glass substrate) were directly mounted to the sample holder. Conversion spectra of NBD@PVAc film with and without TTA-UC@PVAc film were collected using an Ocean Optics Flame spectrometer (integration time 100 ms), together with an Ocean Optics DH-2000 white light source. The upconversion (UC) emission spectra, phosphorescence spectra, UC quantum yield (UCQY) and UC fluorescence lifetime and phosphorescence lifetimes of all samples were measured with an FLS 1000 TCSPC spectrometer (Edinburgh Instruments Ltd.). Samples were excited with a 532 nm laser (MGL-III-532, 200 mW), with a short-pass filter (cut-off 500 nm, Thorlabs) applied in front of the detector for upconversion measurements. The laser power was adjusted using Thorlabs PM100A Power Meter Console combined with a S120VC Si photodiode power sensor (range: 200-1100 nm). Unless otherwise stated all measurements were performed in air at room temperature. For measurements under N2 atmosphere, N2 was purged for 2.5 hours. The threshold intensity, Ith, of the TTA-UC@PVAc film samples were measured with an FLS 1000 TCSPC spectrometer (Edinburgh Instruments Ltd.). Samples were excited with a 532 nm laser, with a short-pass filter (cut-off 500 nm, Thorlabs) applied in front of the detector for upconversion measurements. The power was chosen between 9 mW∙cm-2 to 9091 mW∙cm-2. Emission decay (UC fluorescence or phosphorescence) measurements were performed using the multi-channel scaling (MCS) method on the FLS1000 PL spectrometer. The emission decay was recorded using a highspeed photomultiplier tube (PMT -980) equipped with TCC2 counting electronics. The UC fluorescence decay profile was measured using 532 nm laser excitation (MGL-III-532 laser), with a short-pass filter (cut-off 500 nm, Thorlabs) applied in front of the detector. The pulse repetition rate was12.5 kHz (80 μs), the laser power was set to its maximum, and the pulse width was gradually increased until more than 1000 counts/s was observed at 440 nm. For phosphorescence lifetimes at 665 nm, a long-pass 590 nm filter was used in place of the 500 nm cut off filter and the repetition rate increased to 1 kHz (1 ms) for TTA-UC film, and 500 Hz (2 ms) for PtOEP only film. The instrument response function (IRF) was measured using with a SiO2 particle suspension solution (Ludox® colloidal silica) using a neutral density filter (OD=3) in front of the excitation source, and with no emission filter. Individual tail-fits were applied to each emission decay curve using the FAST software package (Edinburgh Instruments) using a multiexponential decay function. The goodness of fit was assessed using the reduced chi-square statistics, χ2, and the randomness of the residuals. UV-Vis absorbance spectra of the photoisomerisation kinetics were measured using a Perkin Elmer Lambda 750 spectrometer with a slit width of 1 nm and a scan speed of 266.75 nm min-1. Measurements were taken at 1 nm intervals from 500 – 290 nm. Temperature control was achieved using Perkin Elmer Peltier temperature controller 201 with water cooling. Solid film samples were sandwiched between two quartz slides, and a background of the empty slides subtracted. The UV-Vis absorbance spectrum in the native state was first taken at 25 °C. The sample was irradiated for 10 minutes under UV light (Thorlabs 340 nm, minimum 53 mW Mounted LED, 700 mA). Spectra were then taken every 2 minutes for 52 measurements at temperatures of 25, 35 and 45 °C. Please see README file for more details.