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C60 is a nanomaterial produced from the pyrolysis of hydrocarbons that needs to be extracted and purified to obtain the desired properties. Previous studies reported purification as the environmental hotspot of the C60 production process. However, no study has evaluated existing C60 purification methods and proposed alternatives based on environmental, cost, and chemical hazards. Here we used life cycle assessment (LCA) and evaluated the most common existing C60 purification methods (chromatography-crystallization, crystallization, & complexation) and identified selective complexation with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as the greenest existing C60 purification technique that has less environmental (70% from chromatography-crystallization & 50% from crystallization), cost (70% from chromatography-crystallization & 80% from crystallization), and chemical (30% from chromatography-crystallization & crystallization) hazards. The solvent (1,2,4-trymethylbenzene (TMB)) was identified as the environmental hotspot contributing to more than 95% of the cumulative energy demand (CED) of the complexation process. We employed green chemistry principles and an iterative approach to assess the performance of potential replacements (linseed oil, olive oil, toluene, & xylene) for TMB. Although we evaluated solvents that are expected to be greener than petroleum-based solvents, we determined toluene as the greenest alternative. Compared to the baseline complexation method, using toluene reduced the environmental impact by 59%, cost by 85%, and chemical hazards by 42%. Identifying toluene as the alternative green solvent for C60 purification can reduce the carbon footprint of C60-containing products used for various emerging applications, such as solar cells, hydrogen storage, biofuels, etc., which aligns with current decarbonization strategies. [ABSTRACT FROM AUTHOR]

Lanthanide incorporated perovskite is one of the most promising systems for efficient energy conversion or light-emitting materials in terms of upconversion (UC). Investigation of the photophysical mechanism of UC in the lanthanide-doped system is here continued. However, research on the 4I13/2 energy state in Er3+ is rare and more is still needed. In our work, BaTiO3:Er3+ (E-BT) was irradiated by a 1532 nm laser which is a resonance to the energy between 4I13/2 and the ground 4I15/2 state in Er3+. Bright 1532 nm-pumped UC was generated, and the UC color changed from red to yellow under increasing laser power. In addition, pump-power-dependent UC contained interesting clues about the photophysical pathway of UC. By analyzing photon numbers for each UC (green: 2H11/2/4S3/2 → 4I15/2, red: 4F9/2 → 4I15/2, infrared: 4I9/2 → 4I15/2), we found that changes in photon number with pump-power increase contain three different phases (P). P1 is a red UC phase with a small cross-relaxation between Er3+ ions. However, in P2, there is a rapid decrease in the photon number with green UC generation, which is due to the enhancement of 4I13/2-populating cross-relaxation. Finally, in P3, a saturated 4I13/2 state causes little increase of photon number (compared with P2), with different mechanistic cross-relaxation enhancement. With these three different phases under 1532 nm pumping, photophysical mechanisms in E-BT are interpreted. [ABSTRACT FROM AUTHOR]

Upconversion nanoparticles (UCNPs) have attracted enormous interest over the past few years because of their unique optical properties and potential for use in various applications such as bioimaging probes, biosensors, and light-harvesting materials for photovoltaics. The improvement of imaging resolution is one of the most important goals for UCNPs used in biological applications. Super-resolution imaging techniques that overcome the fundamental diffraction limit of light rely on the photochemistry of organic dyes or fluorescent proteins. Here we report our progress toward super-resolution microscopy with UCNPs. We found that the red emission (655 nm) of core/shell UCNPs with the structure NaYF4:Yb3+,Er3+/NaYF4 could be modulated by emission depletion (ED) of the intermediate state that interacts resonantly with an infrared beam (1540 nm). In contrast, the green emission bands (525 and 545 nm) of the UCNPs were less affected by irradiation with the infrared beam. The origin of such distinct behaviors between the green and red emissions was attributed to their different photophysical pathways. [ABSTRACT FROM AUTHOR]

Lanthanide incorporated perovskite is one of the most promising systems for efficient energy conversion or light-emitting materials in terms of upconversion (UC). Investigation of the photophysical mechanism of UC in the lanthanide-doped system is here continued. However, research on the 4I13/2 energy state in Er3+ is rare and more is still needed. In our work, BaTiO3:Er3+ (E-BT) was irradiated by a 1532 nm laser which is a resonance to the energy between 4I13/2 and the ground 4I15/2 state in Er3+. Bright 1532 nm-pumped UC was generated, and the UC color changed from red to yellow under increasing laser power. In addition, pump-power-dependent UC contained interesting clues about the photophysical pathway of UC. By analyzing photon numbers for each UC (green: 2H11/2/4S3/2 → 4I15/2, red: 4F9/2 → 4I15/2, infrared: 4I9/2 → 4I15/2), we found that changes in photon number with pump-power increase contain three different phases (P). P1 is a red UC phase with a small cross-relaxation between Er3+ ions. However, in P2, there is a rapid decrease in the photon number with green UC generation, which is due to the enhancement of 4I13/2-populating cross-relaxation. Finally, in P3, a saturated 4I13/2 state causes little increase of photon number (compared with P2), with different mechanistic cross-relaxation enhancement. With these three different phases under 1532 nm pumping, photophysical mechanisms in E-BT are interpreted.

Upconversion nanoparticles (UCNPs) have attracted enormous interest over the past few years because of their unique optical properties and potential for use in various applications such as bioimaging probes, biosensors, and light-harvesting materials for photovoltaics. The improvement of imaging resolution is one of the most important goals for UCNPs used in biological applications. Super-resolution imaging techniques that overcome the fundamental diffraction limit of light rely on the photochemistry of organic dyes or fluorescent proteins. Here we report our progress toward super-resolution microscopy with UCNPs. We found that the red emission (655 nm) of core/shell UCNPs with the structure NaYF 4 :Yb 3+ ,Er 3+ /NaYF 4 could be modulated by emission depletion (ED) of the intermediate state that interacts resonantly with an infrared beam (1540 nm). In contrast, the green emission bands (525 and 545 nm) of the UCNPs were less affected by irradiation with the infrared beam. The origin of such distinct behaviors between the green and red emissions was attributed to their different photophysical pathways.