Hsin-Che Lu

Planar Heterojunction Perovskite Solar Cells Incorporating Metal–Organic Framework Nanocrystals

Zr-based porphyrin metal-organic framework (MOF-525) nanocrystals with a crystal size of about 140 nm are synthesized and incorporated into perovskite solar cells. The morphology and crystallinity of the perovskite thin film are enhanced since the micropores of MOF-525 allow the crystallization of perovskite to occur inside; this observation results in a higher cell efficiency of the obtained MOF/perovskite solar cell.

Thermally Cured Dual Functional Viologen-Based All-in-One Electrochromic Devices with Panchromatic Modulation

Vinyl benzyl viologen (VBV) was synthesized and utilized to obtain all-in-one thermally cured electrochromic devices (ECDs). The vinyl moiety of VBV monomer could react with methyl methacrylate (MMA) to yield bulky VBV/poly(methyl methacrylate) (PMMA) chains and even cross-linked network without the assistance of additional cross-linker. Both the bulky VBV/PMMA chains and the resulting polymer network can hinder the aggregation of the viologens and reduce the possibility of dimerization, rendering enhanced cycling stability. Large transmittance changes (ΔT) over 60% at both 570 and 615 nm were achieved when the VBV-based ECD was switched from 0 V to a low potential bias of 0.5 V. Ultimately, the dual functional of VBV molecules, serving simultaneously as a promising electrochromic material and a cross-linker, is fully utilized in the proposed electrochromic system, making its fabrication process much easier. Negligible decays in ΔT at both wavelengths were observed for the cured ECD after being subjected to 1000 repetitive cycles, while 17.1% and 22.0% decays were noticed at 570 and 615 nm, respectively, for the noncured ECD. In addition, the low voltage-driven feature of the VBV-based ECD enables it to be incorporated with phenyl viologen (PV), further expanding the absorption range of the ECD. Panchromatic characteristic of the proposed PV/VBV-based ECD was demonstrated while exhibiting ΔT over 60% at both wavelengths. Only 5.3% and 6.9% decays, corresponding at 570 and 615 nm, respectively, were observed in the PV/VBV-based ECD after 10 000 continuous cycles at bleaching/coloring voltages of 0/0.5 V with an interval of 10 s for both bleaching and coloring processes.

Inkjet-printed porphyrinic metal–organic framework thin films for electrocatalysis

In this study, a simple and effective direct inkjet printing method was developed to prepare porphyrinic metal–organic framework (MOF) thin films for electrocatalysis. First, crystals of a zirconium-based porphyrinic MOF (MOF-525) with crystal sizes ranging from 100 to 700 nm were synthesized by adjusting the content of benzoic acid in a solvothermal synthetic process. The synthesized crystals showed a similar surface area of 2500 m2 g−1 with a unique pore size of 1.85 nm. However, some structural defects were found in the smallest crystals of 100 nm due to the fast crystallization process. After being suspended in dimethylformamide, the MOF crystal suspensions were inkjet printed to fabricate uniform MOF-525 thin film patterns. With the help of great precision in liquid deposition, the thicknesses of the printed MOF-525 thin films can be accurately controlled by the number of printed layers. With smaller crystal sizes, the printed MOF thin films showed more compact stacking and better contact with the substrate. The printed MOF thin films were applied for electrocatalytic nitrite oxidation. The effects of both film thickness and crystal size on the printed film morphology and electrocatalytic activity were investigated in detail. The printed MOF nitrite sensor showed a great detection limit of 0.72 μM and a high sensitivity of 40.6 μA mM−1 cm−2. In summary, this study demonstrated the feasibility of the proposed printing process for electrochemically addressable MOF thin films and can be further applied for many other electrochemical applications.