Supporting Information for. Photon Upconversion in Supramolecular Gel Matrixes: Spontaneous Accumulation of Light-Harvesting Donor Acceptor

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1 Supporting Information for Photon Upconversion in Supramolecular Gel Matrixes: Spontaneous Accumulation of Light-Harvesting Donor Acceptor Arrays in Nanofibers and Acquired Air Stability Pengfei Duan, Nobuhiro Yanai,*,, Hisanori Nagatomi and Nobuo Kimizuka*, Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka , Japan. PRESTO, JST, Honcho 4-1-8, Kawaguchi, Saitama , Japan. S1

2 Figure S1 Outline of the TTA-UC process, showing the energy levels involved in the TTA-UC (S = singlet, T = triplet). The TTA-UC involves a sensitizer (donor) with high intersystem crossing (ISC) efficiency and an emitter (acceptor) with high fluorescence quantum yield. First, the sensitizer absorbs the low energy light to produce the excited singlet state (S 1 ). Second, the triplet state (T 1 ) is populated through ISC. Third, triplet-triplet energy transfer (TTET) from donor T 1 to the triplet state of the acceptor via the Dexter mechanism. Finally, the collision and annihilation (TTA) between two acceptor triplets produce a high-energy singlet excited state of the acceptor S 1 which radiates upconverted photons. PtOEP/DPA/LBG Figure S2. Time dependence of UC emission intensity at λ max = 435 nm of the ternary PtOEP/DPA/LBG gel in DMF (red, [PtOEP] = 33 M, [DPA] = 6.7 mm, [LBG] = 13.3 mm, λ ex = 532 nm) and PtOEP/DPA in DMF solution (black, [PtOEP] = 33 M, [DPA] = 6.7 mm, λ ex = 532 nm). All the samples were kept and measured in air at room temperature. S2

3 Figure S3. DSC heating curves of the LBG gel ([LBG] = 10 mg ml -1 = 13.3 mm in DMF) and DPA/LBG binary gels with different DPA concentration ([DPA] = 6.7 mm or 13.3 mm, [LBG] = 13.3 mm in DMF). Heating rate, 2 ºC/min UCPL quantum yield DPA concentration (mm) Figure S4. TTA-UC quantum yield of PtOEP/DPA/LBG ternary gel in aerated DMF at room temperature as a function of DPA concentration ([PtOEP] = 33 mm, [LBG] = 13.3 mm, λ ex = 532 nm, excitation power density = 774 mw cm -2 ). S3

4 Figure S5. (a) Phosphorescence spectra of the PtOEP/LBG binary gel (red; [PtOEP] = 33 M, [LBG] = 13.3 mm) and the PtOEP/DPA/LBG ternary gel (black; [PtOEP] = 33 M, [DPA] = 6.7 mm, [LBG] = 13.3 mm) in aerated DMF at 77 K (λ ex = 532 nm). (b) Phosphorescence spectra of the PtOEP/LBG binary gel (red; [PtOEP] = 33 M, [LBG] = 13.3 mm) and the PtOEP/DPA/LBG ternary gel (black; [PtOEP] = 33 M, [DPA] = 6.7 mm, [LBG] = 13.3 mm) in deaerated DMF at room temperature (λ ex = 532 nm). Figure S6. Phosphorescence spectra of the PtOEP/LBG binary gels in deaerated (red) and airsaturated (black) DMF at room temperature ([PtOEP] = 33 M, [LBG] = 13.3 mm; λ ex = 532 nm). S4

5 Figure S7. Time dependence of upconverted emission intensity at 437 nm upon continuous excitation at 532 nm of the PtOEP/DPA/LBG ternary gel. Black: in air-saturated DMF with a laser power density of 19 mw cm -2 ; red: in air-saturated DMF with a laser power density of 145 mw cm -2 ; green: in deaerated DMF with a laser power density of 145 mw cm -2. [PtOEP] = 33 M, [DPA] = 6.7 mm, [LBG] = 13.3 mm, at room temperature. The slight decrease observed right after the excitation of 145 mw cm -2 laser (red) is not due to the oxygen quenching, since the similar behavior was observed in deaerated gel (green), and the upconverted emission intensity in airsaturated gel (red) is close to that in deaerated gel (green) under the identical excitation power. It might be due to the local heating and following structural rearrangements. Note that no gradual increment of UC emission intensity was observed during these time course measurements, suggesting that the oxygen consumption by chemical reaction is not the reason for the in-air TTA- UC. Figure S8. Temperature-dependence of UC emission intensity at λ max = 435 nm on the heatingcooling process cycle for the ternary PtOEP/DPA/LBG gel in air-saturated DMF ([PtOEP] = 33 M, [DPA] = 6.7 mm, [LBG] = 13.3 mm; λ ex = 532 nm). S5

6 Figure S9. TTA-UC emission intensity observed for PtOEP/DPA/LBG ternary gel as a function of the 532 nm excitation power density in air-saturated DMF at room temperature ([PtOEP] = 33 M, [DPA] = 6.7 mm, and [LBG] = 13.3 mm). The data was first collected by increasing the excitation power density (black squares), and then by decreasing the excitation power density (red circles). Figure S10. Photoluminescence spectra of PtOEP/DPA/LBG in aerated DMF at 77 K with different incident power density of 532 nm laser with a short pass filter ([PtOEP] = 33 M, [DPA] = 6.7 mm, [LBG] = 13.3 mm; λ ex = 532 nm). S6

7 Figure S11. (a) Normalized absorption and emission spectra of DBP (black line) and Ir(C6) 2 (acac) (red line) in DMF gels; (b) photoluminescence spectra of the ternary gel Ir(Cs) 2 (acac)/dbp/lbg ([Ir(C6) 2 (acac)] = 67 M, [DBP] = 6.7 mm, [LBG] = 13.3 mm) in DMF with different incident power density of 445 nm laser in air at room temperature (short-pass filter 425 nm); (c) dependence of the integration of UC emission on the incident power density. The dashed lines are fitting results with slopes of 1.93 (blue) and 1.12 (red) in the low- and high-power regimes respectively with a threshold I th = 28 mw cm -2. (d) Normalized absorption and emission spectra of BPEA (black line) and PtTPBP (red line) in DMF gels; (e) photoluminescence spectra of the ternary gel PtTPBP/BPEA/LBG ([PtTPBP] = 67 M, [BPEA] = 6.7 Mm, [LBG] 13.3 mm) in DMF with different incident power density of 635 nm laser in air at room temperature (short-pass filter 625 nm); (f) dependence of the integration of UC emission on the incident power density. The dashed lines are fitting results with slopes of 1.89 (blue) and 1.06 (red) in the low- and high-power regimes respectively with a threshold I th = 4.1 mw cm -2 ; (g) Normalized absorption and emission spectra of rubrene (black line) and PdPc(OBu) 8 (red line) in DMF gels; (h) photoluminescence spectra of the ternary gel PdPc(OBu) 8 /rubrene/lbg ([PdPc(OBu) 8 ] = 67 M, [rubrene] = 6.7 mm, [LBG] =13.3 mm) in DMF with different incident power density of 725 nm laser in air at room temperature (short-pass filter 710 nm); (i) dependence of the integration of UC emission on the incident power density. The dashed lines are fitting results with slopes of 1.95 (blue) and 1.02 (red) in the low- and high-power regimes respectively with a threshold I th = 20 mw cm -2. [LBG] = 10 mg ml -1. S7

8 Table S1. Upconversion properties of PtOEP/DPA/LBG ternary gel systems in various mixing molar ratios. The LBG concentration was fixed as 10 mg ml -1 = 13.3 mm. Q = quench, UC = upconversion, N= no upconversion, WUC = weak upconversion. The concentration ratio was optimized as [LBG]/[DPA] = 1/0.5 and [DPA]/[PtOEP] = 200/1 based on the UC emission intensity ([PtOEP] = 33 mm, [DPA] = 6.7 mm). [LBG] /[DPA] [DPA]/ 1/1 1/0.5 1/0.3 1/0.1 [PtOEP] 50/1 Q Q Q Q 100/1 UC UC WUC WUC 200/1 UC UC WUC WUC 300/1 WUC WUC N N 500/1 N N N N S8