Hydrogen-Bonding-Induced H-Aggregation of Charge-Transfer Complexes for Ultra-Efficient Second Near-Infrared Region Photothermal Conversion

Abstract

Open AccessCCS ChemistryRESEARCH ARTICLE14 Jul 2022Hydrogen-Bonding-Induced H-Aggregation of Charge-Transfer Complexes for Ultra-Efficient Second Near-Infrared Region Photothermal Conversion Jieqiong Xu†, Zhiwei Yin†, Liang Zhang, Qian Dong, Xinqi Cai, Shengkai Li, Qian Chen, Phouphien Keoingthong, Zhaoqian Li, Long Chen, Zhuo Chen and Weihong Tan Jieqiong Xu† Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology, Hunan University, Changsha, Hunan 410082 , Zhiwei Yin† Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology, Hunan University, Changsha, Hunan 410082 , Liang Zhang Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology, Hunan University, Changsha, Hunan 410082 , Qian Dong Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology, Hunan University, Changsha, Hunan 410082 , Xinqi Cai Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology, Hunan University, Changsha, Hunan 410082 , Shengkai Li Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology, Hunan University, Changsha, Hunan 410082 , Qian Chen Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology, Hunan University, Changsha, Hunan 410082 , Phouphien Keoingthong Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology, Hunan University, Changsha, Hunan 410082 , Zhaoqian Li Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology, Hunan University, Changsha, Hunan 410082 , Long Chen Faculty of Science and Technology, University of Macau, Avenida da Universidade, Taipa 999078 , Zhuo Chen *Corresponding author: E-mail Address: [email protected] Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology, Hunan University, Changsha, Hunan 410082 and Weihong Tan Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, College of Life Sciences, Hunan Provincial Key Laboratory of Biomacromolecular Chemical Biology, Hunan University, Changsha, Hunan 410082 The Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital), Institute of Basic Medicine and Cancer (IBMC), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022 https://doi.org/10.31635/ccschem.021.202101058 SectionsSupplemental MaterialAboutAbstractPDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareFacebookTwitterLinked InEmail Aggregation plays a critical role in modulating the photophysical process of organic molecules. However, the rational control of the construction of a function-oriented stacking mode for efficient photothermal (PT) conversion in the second near-infrared region (NIR-II; 1000–1700 nm) remains a challenge. Herein, an H-aggregation of 3,3′,5,5′-Tetramethylbenzidine (TMB)–TMB dication (TMB++) complexes in linear agarose (H-TTC/LAG) with narrowed band gap (0.96 eV) was fabricated through intermolecular hydrogen-bonding interactions between the amino groups of TTC and the peripheral hydroxyl groups of LAG. Charge-transfer mechanism and H-aggregation ensured NIR-II absorption of the complex at >1400 nm. The H-aggregation also promoted a non-radiation relaxation pathway and improved the thermal stability of TTC, which together favored the constructed H-TTC/LAG with ultra-efficient PT conversion that increased rapidly to 140 °C in 15 s under the NIR-II laser (1064 nm, 1.0 W cm−2) irradiation. Such a unique H-TTC/LAG with good biocompatibility was used to demonstrate a superior PT therapy via high-efficiency tumor growth inhibition in mouse mammary carcinoma (4T1) the BALB/c mice tumor-bearing xenografts. This is the first established H-aggregation of charge-transfer complexes in a noncovalent system, which not only provides a new strategy to develop ultra-efficient NIR-II PT materials but also paves the way for constructing functional materials with aggregates of charge-transfer complexes. Download figure Download PowerPoint Introduction Due to their unique physicochemical properties, functional photothermal (PT) materials such as organic materials capable of PT conversion by near-infrared (NIR) light, in particular, that within the second NIR region (NIR-II; 1000–1700 nm), have attracted significant interest in the areas of energy, medical imaging, and PT therapy (PTT).1–6 However, inherently low PT conversion efficiency (PCE) and photobleaching properties limit their development.7–11 Fortunately, the photophysical process of organic molecules can be adjusted by changing the spatial arrangement of their microstructures.12–16 It has been confirmed that the construction of a function-oriented stacking mode (i.e., J- and H-aggregation) aids in regulating their optical properties because J- (head-to-tail stacking) and H-aggregation (head-to-head stacking) could trigger bathochromic and hypsochromic absorption shift of π-conjugated molecules, respectively.17–20 Aggregation constructions are frequently applied to fabricate PT materials,21,22 especially H-aggregation, reported as an effective strategy to improve light stability, reduce photobleaching rate, and promote non-radiation relaxation pathways to quench fluorescence and reactive oxygen species (ROS).23,24 However, since building blocks of H-aggregation are limited by single-molecule chromophore with wide band gap and inherent spectral hypsochromic characteristics, the development of efficient PT materials based on H-aggregation, especially in the NIR-II region, remains a challenge. Organic charge-transfer complex (CTC), an assembly composed of charge-donor and -acceptor through noncovalent charge-transfer interaction, has attracted widespread attention in the field of functional materials.25,26 To date, organic CTC mainly exists in the form of molecular cocrystals, reported to possess a variety of unique functions, including anisotropic conductivity, luminescent materials, ambipolar transportation, ferroelectricity, nonlinear optics, and so on.27–31 On the other hand, some researchers have devoted time to study supramolecular assembly based on charge-transfer interaction between donors and acceptors and have achieved efficient and controllable assembly.32–35 Since Hu et al. proposed the first PT conversion cocrystal,36 CTC has been regarded as a promising PT material due to their effective charge-transfer mechanism between the donor and the acceptor that narrows the band gap, with the production of a spectral redshift, thereby increasing the absorption in the NIR region.37–39 However, most CTC-based PT materials that currently exist only work in the first NIR region (NIR-I; 700–1000 nm). Since the electron-donating properties of aromatic amine structure, 3,3′,5,5′-Tetramethylbenzidine (TMB) can easily undergo charge transfer with its dication (TMB++) and form CTCs (TMB–TMB++ complexes or TTC) with strong absorption in the NIR-II region (1000–1200 nm).40 There has been widespread attention in PT detection and NIR-II PTT due to the significant increase of penetration depth in tissue and maximum permissible exposure (MPE) to a laser.41,42 However, the inherent thermal instability of TTC seriously prevents it from becoming a highly efficient PT material. Intermolecular hydrogen-bonding (IHB) interactions are vital in supramolecular assembly and can induce or assist the directional arrangement of molecules. For instance, IHB interactions not only induce the formation of strong supramolecular H-aggregation to turn on the luminescence of the green fluorescent protein luminophore43 but also utilize the difference in the aggregation mode of small molecules in the assembly process to achieve supramolecular chirality inversion.44 Herein, a novel strategy was proposed, whereby intermolecular hydrogen-bonding interactions were utilized to induce H-aggregation of CTCs, which realized ultra-efficient NIR-II PT conversion, for the first time, to the best of our knowledge. Intermolecular hydrogen-bonding interactions between the amino groups of TTC and the peripheral hydroxyl groups of LAG induced the face-to-face stacking of TTC to form H-aggregation (H-TTC/LAG) during the co-assembly process, especially when the agarose hydrogel dehydrated into an anhydrous film. Interestingly, the H-aggregation greatly promoted non-radiative relaxation to improve PT stability of TTC significantly; it also widened the NIR-II absorption (>1400 nm) by further narrowing the band gap of TTC. Consequently, the surface temperature of H-TTC/LAG quickly increased by 140 °C in 15 s under the NIR-II laser (1064 nm, 1.0 W cm−2) irradiation. Such H-TTC/LAG has good biocompatibility and is used for PTT, demonstrating superior tumor growth inhibition efficiency. This work provides an effective method to fabricate high-efficiency NIR-II PT materials and paves the way for constructing functional materials with aggregation of CTC. Experimental Methods Materials and instruments Details of materials and equipment are shown in the Supporting Information. BALB/c mice were purchased from the Hunan SLRC Laboratory Animal Co., Ltd. (Changsha, Hunan, China) and were used under protocols approved by the Institutional Animal Care and Use Committee of Hunan University. Synthesis of [email protected] nanoparticles [email protected] ([email protected]) nanoparticles were synthesized through a chemical vapor deposition method, as reported previously.45 First, 1 g-fumed silicon was dissolved in 200 mL methanol and sonicated for 1.5 h. Then 70 mg Co(NO3)2 and 50 mg H2PtCl6 were added and continued to sonicate for 0.5 h. Afterward, methanol was removed, and the powder was dried at 45 °C and ground. Next, 0.5 g of the fumed powder was put into a tube furnace with a flow of 150 cm3 min−1 methane for 5 min at 1000 °C. After growth, the sample was etched by hydrogen fluoride (HF) in ethanol to dissolve the silicon. The products were washed with deionized water and ethanol until neutral, then poly(ethylene glycol) (PEG) was added and crushed using ultrasonication for 1 h. Oxidase-like properties of [email protected] nanoparticles TMB was used as a safe oxidase substrate to study the oxidase-like property of [email protected] [email protected] (10 μg mL−1) was added to 25 mM phosphate-buffered solution (PBS; pH 5) containing 0.2 mM TMB, then changes in UV–vis absorption spectra were measured under aerobic and deoxygenated conditions. The catalytic activity of [email protected] depended on pH, temperature, and concentration. We varied the [email protected] concentration from 0 to 10 μg mL−1, the pH from 2 to 12, and the temperature from 10 to 80 °C. We found that the catalytic ability of [email protected] positively correlated with its concentration. The optimal pH and temperature for catalysis were approximately pH 3–4 and 10 °C, respectively. Given the effect of pH on the stability of its activity, [email protected] was first incubated in PBS with different pH (pH 2–12) for 2 h at a fixed temperature of 25 °C. Then the [email protected] was collected by centrifugation (10,000 rpm, 20 min), and their catalytic activities were measured in pH 5 PBS. Similarly, [email protected] was incubated at fixed pH (pH 4) at varying temperatures (30 to 105 °C), then their catalytic activities were measured, as described above. Reversible conversion between TMB and TTC An initial amount of TMB (20 μM) solution before oxidation was obtained by UV–vis spectra measurement at 285 nm. Then blue TTC solutions (0.5–100 μM) were prepared through the catalytic oxidation of TMB using horseradish peroxidase (HRP)-H2O2 and measurement of the absorption maxima at 285 and 652 nm.46 Finally, the color of the blue TTC solutions was faded after heating, measured by UV–vis absorption spectrometry. In a 25 mM pH 5 PBS reaction system, 10 μg mL−1 [email protected] nanoparticles were added to catalyze the oxidation of 0.2 mM TMB, and the absorption was measured at 652 nm after 1 h. Subsequently, the blue TTC solutions were placed in a 60 °C water bath for 15 min, and the absorption was measured at 652 nm. The discolored solutions were left at room temperature for 3 h to repeat the absorption measurements. The process of heating in a 60 °C water bath and recoloring at room temperature was repeated twice. The native enzyme HRP was compared with the [email protected] nanozyme; the blue TTC solutions prepared by HRP-H2O2 were put into a 60 °C water bath for 15 min, then the absorption at 652 nm was measured as above. Preparation of H-TTC/LAG The H-aggregation of TMB–TMB++ complexes in LAG (H-TTC/LAG) was fabricated by preparing H-TTC agarose hydrogel and then dried naturally to form a film. In particular, the blue TTC composite solution for sol was prepared in a beaker containing 25 mM pH 5 PBS, 10 μg mL−1 [email protected], and 0.2 mM TMB (10 mM in ethanol). Meanwhile, a desirable amount of agarose powder (0.2, 0.5, 0.7, 1.0, 2.0, and 3.0 wt % relative to the composite solution) was added into the blue TTC composite solution. Then the beaker was sealed with parafilm to reduce water loss during a 30 s microwave heating process. Next, the hot sol was poured quickly into a polyethylene lid and re-catalyzed completely for 24 h at 16 °C, followed by drying for another 24 h in a ventilated environment to form a fully dried film. For control experiments, the LAG, TMB in LAG (T/LAG), and [email protected] in LAG (CP/LAG) were synthesized using the same procedures but without adding TMB and [email protected], [email protected], TMB, respectively. Other routine experimental steps are shown in Supporting Information. Results and Discussion Design and construction of H-TTC/LAG TMB was selected as the raw material for the preparation of CTCs because the strong CT interaction between TMB and its two-electron oxidation product TMB++ could achieve NIR-II absorption (Figure 1a). To further adjust the photophysical process and improve the thermal stability of TTC, H-aggregation was introduced: A polyhydroxy compound LAG was selected to induce TTC to form H-aggregation through intermolecular hydrogen-bonding interactions between the amino groups of TTC and the hydroxyl groups of LAG. We prepared H-aggregates of TTC via a hydrogen-bonding-induced co-assembly strategy (Figure 1b). However, the agarose could only dissolve above 90 °C, which made it challenging to mix TTC with the agarose thoroughly, owing to the thermal instability of TTC. Interestingly, we found that the thermal decomposition product of TTC was still the parent TMB ( Supporting Information Figure S1), which could be re-oxidized to form TTC after cooling. To realize re-oxidation of TMB, [email protected] nanoparticles with robust oxidase-like properties were synthesized through the chemical vapor deposition method ( Supporting Information Figure S2).41 In the presence of oxygen, and under acidic conditions, the [email protected] nanoparticles could catalyze the oxidation of TMB to form TTC even after [email protected] nanoparticles had been treated in extensive pH (pH 2–12) and temperature (30–105 °C) environments for 2 h ( Supporting Information Figure S3). Therefore, temperature-controlled reversible conversion between TMB and TTC could be achieved through integrating robust oxidase-like property and stable structure of [email protected] nanoparticles. However, the natural enzyme HRP/H2O2 system failed to re-oxidize TMB because of the inactivation of HRP caused by high temperatures and depletion of H2O2 ( Supporting Information Figure S4). Figure 1 | Preparation and assembly mechanism of H-TTC/LAG. (a) Route for oxidation of TMB and thermally induced decomposition of TTC. (b) Schematic of the assembly process of H-aggregates of TTC induced by intermolecular hydrogen-bonding interactions. Download figure Download PowerPoint Physicochemical and PT properties of H-TTC/LAG TTC exhibited strong interaction with peripheral LAG, especially when the agarose hydrogel dehydrated into an anhydrous purple H-TTC agarose film (H-TTC/LAG; Supporting Information Figure S5). Figure 2a and Supporting Information Figure S6 show the differences in UV–vis–NIR absorption spectra and color of TTC in solution, agarose hydrogel, and film, respectively. Compared with non-aggregated TTC (N-TTC) in solution, the interactions between TTC and LAG resulted in a blueshift of an initial high-energy absorption peak (369 nm) and the secondary high-energy absorption peak (652 nm) with a blueshift of 5 and 20 nm in the agarose hydrogel, and 13 and 98 nm in the agarose film, showing a characteristic H-aggregation.16 The Raman spectra (Figure 2b) demonstrated almost no essential difference in their principal components. The Raman peaks at 1192, 1339, 1408, and 1610 cm−1 could be assigned to ring C–H in-plane bending, inter-ring C–C stretching, ring C–N stretching, and benzene ring C=C stretching of TTC, respectively. Electron paramagnetic resonance (EPR) measurements ( Supporting Information Figure S7) displayed a strong signal in H-TTC/LAG (the corresponding g factor was 2.0040) and a weak signal in N-TTC (the corresponding g factor was 2.0042), demonstrating the existence of unpaired electrons in TTC, either as monomers or aggregates, consistent with CT interaction in the ground state. Theoretical calculation of binding energy (Figure 2c) demonstrated that intermolecular hydrogen-bonding interactions were formed between the amino groups of TTC and the hydroxyl groups of LAG to obtain a stable complex with stabilization energy of −20.4 kcal mol−1 for H-TTC/LAG. After an introduction of excess water, the stabilization energy of this complex was −4.2 kcal mol−1. We presumed that water might destroy the original hydrogen bonding, making the system unstable. On the other hand, Fourier transform infrared (FT-IR) spectroscopy was employed to corroborate the intermolecular hydrogen-bonding interaction between TTC and LAG at the molecular scale. When compared with the LAG, T/LAG, and CP/LAG with the C–O stretching band (vC–O of COH) at 1038 cm−1, the C–O stretching band of H-TTC/LAG was redshifted to 1048 cm−1 ( Supporting Information Figure S8), a slight increase that was most likely due to the enhanced electron-withdrawing effect of the C–O stretching band when the hydroxyl groups formed hydrogen bonding with the amino groups. Meanwhile, compared with the LAG, T/LAG, and CP/LAG, H-TTC/LAG showed an enhanced broad absorption peak in the range of 3200–3500 cm−1, which may be ascribed to an increased hydrogen bonding between the hydroxyl groups and the amino groups in the system. Thus, various molecules with different amounts of hydroxyl groups were chosen to verify further that the intermolecular hydrogen-bonding interactions were the main cause of the H-aggregation. As shown in Supporting Information Figure S9, three kinds of films prepared with agarose, sodium alginate, and gelatin as substrate molecules were different in color: purple, dark-blue, and pale-blue, respectively. The UV–vis absorption peak at 652 nm of TTC gelatin film without hydroxyl groups had no blueshift, but the TTC sodium alginate film with small amounts of hydroxyl groups had a blueshift of ∼53 nm. This indicated that intermolecular hydrogen-bonding interactions might be the primary cause of the H-aggregation. On the other hand, the mass fraction of agarose hydrogel was proportional to the amount of intermolecular hydrogen bonding in this system. The higher mass fraction of agarose hydrogel resulted in a significant blueshift in the position of the maximum absorption peak (Figure 2d). This also demonstrated the necessity of hydrogen-bonding interactions in H-aggregation. After drying the agarose hydrogels with different mass fractions into films, TTC was unevenly distributed in the low mass fraction agarose film, and even blue TTC microcrystals in LAG (M-TTC/LAG) were precipitated out of local oversaturation ( Supporting Information Figure S10). While a higher mass fraction of agarose not only made TTC uniformly dispersed, it also induced TTC to form a good H-aggregation. Figure 2 | The physicochemical and PT properties of H-TTC/LAG. (a) UV–vis absorption spectra and (b) Raman spectra of TTC in solution (S), agarose hydrogel (H), and agarose film (F), respectively. Inset: Corresponding photographs of S, H, and F. (c) Schematic of the simulation calculation of the interaction mechanism between the TTC and agarose. (d) Blueshift value of UV–vis absorption peak of TTC hydrogels prepared with different agarose concentrations, compared with N-TTC. (e) High transparency, high flexibility, easy tailorability, and high mechanical performance of the H-TTC/LAG. (f) IR camera images of the H-TTC/LAG at the laser power density of 1.0 W cm−2 per 3 s. (g) PT heating curves of H-TTC/LAG, CP/LAG, T/LAG, and LAG at the laser power density of 0.5 W cm−2. (h) Temperature changes of H-TTC/LAG during the five on/off laser cycles at the power density of 0.5 W cm−2. (i) Temperature changes of H-TTC/LAG at different depths under 1064 nm laser irradiation (1.0 W cm−2). Error bars indicated the s.d., n = 3. Download figure Download PowerPoint The influence of temperature (16, 30, 45, and 60 °C) and relative humidity (RH; 30% and 90%) on the H-aggregation during the preparation process were investigated. These results suggested that high-quality H-TTC/LAG required low temperature and low RH during the drying process ( Supporting Information Figure S11). The temperature cause N-TTC to In high RH the drying time which was to the of TTC to form As shown in Figure H-TTC/LAG the of high transparency, good flexibility, easy tailorability, and strong mechanical properties that could a of We further the physicochemical properties of H-TTC/LAG with LAG, T/LAG, and CP/LAG as control groups. images ( Supporting Information Figure showed that H-aggregation of TTC and [email protected] nanoparticles had almost no effect on the structure of agarose films, that the were uniformly distributed with the of LAG, no were UV–vis–NIR absorption spectra ( Supporting Information Figure showed that only H-TTC/LAG and CP/LAG NIR-II to the increased of hydrogen bonding in the films, H-TTC/LAG and 0.5 had maximum other groups 0.2 for for demonstrated through ( Supporting Information Figure The measurement of ( Supporting Information Figure showed that H-TTC/LAG and other groups for for for had good performance for To the PT conversion performance of H-TTC/LAG, thermal images of H-TTC/LAG were NIR irradiation (1064 nm, 1.0 W cm−2). As in Figure the surface temperature of H-TTC/LAG quickly above °C from °C in 15 with a in temperature laser To verify that such PT effect from H-aggregation of TTC, we the temperature of T/LAG, CP/LAG, and H-TTC/LAG in and their solutions under 1064 nm laser W cm−2) irradiation. As shown in Figure and Supporting Information Figure in the surface temperature of H-TTC/LAG quickly by 60 °C within 20 s and the temperature of CP/LAG by 10 °C due to the presence of [email protected] nanoparticles. There was almost no temperature in LAG and under the laser irradiation. In the N-TTC and only increased by 10 °C, the 60 °C obtained with H-TTC/LAG in the same amount of time (20 Subsequently, we the influence of laser power on the PT effect of H-TTC/LAG and the laser power density from to W cm−2. As the results in Supporting Information Figure the heating of H-TTC/LAG correlated positively with the laser power the maximum temperature was as high as °C, it stable within 2 min without thermal To the best of our such PT conversion and thermal stability of TTC had been To the PT conversion was due to the function-oriented stacking mode we compared the PT conversion of H-TTC/LAG and Supporting Information Figure showed that the surface temperature of H-TTC/LAG increased by °C, increased by only °C under the same irradiation (1064 nm, 0.5 W cm−2). This confirmed that H-aggregation a critical role in the efficient PT The PT stability of H-TTC/LAG was measured through five cycles of heating and The results in Figure exhibited its good PT To the penetration performance of the NIR-II PT with different were used as tissue in PT The results (Figure indicated that the PT effect of H-TTC/LAG was The maximum temperature changes under 1064 nm laser irradiation (1.0 W cm−2) in 2 min was and °C when the tissue depth was and 10 respectively. In we the ability of PT conversion of the H-aggregation of TTC and the same H-TTC/LAG for within a The results ( Supporting Information Figure suggested that H-TTC/LAG had an stable PT results demonstrated that the H-TTC/LAG had an ultra-efficient and robust PT conversion in the NIR-II PT mechanism of H-TTC/LAG We then the molecular of H-TTC/LAG with the chemical The energy and suggested that the molecular of H-TTC/LAG was which was to the The molecular of H-TTC/LAG eV) was to the The band gap of H-TTC/LAG (0.96 eV) was that of N-TTC Supporting Information Figure