Dry and Binder-Free Deposition of Single-Walled Carbon Nanotubes on Fabrics for Thermal Regulation and Electromagnetic Interference Shielding

Conductive textiles with good flexibility and durability are highly demanded for wearable electronics. However, the common approaches of making conductive textiles require multi-step solvent processes, which is tedious and environment unfriendly. Herein, the high-quality single-walled carbon nanotubes (SWCNTs), synthesized by the floating catalyst chemical vapor deposition method, were directed and dry coated on the melt-blown fabrics (MBFs) recycled from the waste masks with binder-free chemical. The obtained MBF/SWCNT composites displayed excellent conductivity and flexibility and thus can be further used as wearable and heatable textiles. The sheet resistance of MBF/SWCNT composites can be further reduced by gold chloride (AuCl3) doping from 57 to 26 Ω/sq. The electrical–thermal measurement showed that the pristine MBF/SWCNT composites can reach the surface temperature of ∼48 °C at a low voltage (5 V), whereas it increased to ∼110 °C after AuCl3 doping at the same voltage. In addition, the AuCl3-doped MBF/SWCNT film with a thickness of ∼150 μm displays a high electromagnetic interference shielding efficiency of 27.1 dB at the X-band. Also, the MBF/SWCNT composites displayed good stability after long-term heating, bending, and washing. Our multi-functional MBF/SWCNT textiles not only demonstrated the reusability of waste masks but also showed great potential applications in electromagnetic interference and heat management, such as thermotherapy pads and fast water evaporators

Defect Passivation by Natural Piperine Molecule Enabling for Stable Perovskite Solar Cells with Efficiencies over 23%

Effective modulation of defects and carrier transport behaviors at the surfaces and grain boundaries of solution-processed perovskites has proven to be a vital strategy for suppressing charge recombination, allowing for efficient and stable perovskite solar cells (PSCs). Herein, a natural molecule (E,E)-1-[5-(1,3-benzodioxol-5-yl)-1-oxo-2,4-pentadienyl]-piperidine (BOPP) with a carbonyl group and π-conjugated structure is incorporated into perovskites using a one step antisolvent procedure. The as-prepared perovskites improved crystallization and decreased defect density, which is ascribed to the passivation effect of BOPP due to the carbonyl group forming coordination bonds with undercoordinated Pb2+ ions via Lewis acid–base interactions. Incorporating BOPP into the perovskite layer results in a better arrangement of energy levels between the perovskite and Spiro-OMeTAD interface, contributing to more efficient carrier injection and transport. The results show that the BOPP-passivated device achieves a champion power conversion efficiency (PCE) of 23.37% with a steady-state power output of 22.95%, compared with a PCE of 21.49% for the pristine device. At the same time, the unencapsulated devices maintained around 95% of their original PCEs after aging under relative humidities of 15%–30% over 3000 h. Moreover, this work gives a viable avenue to fabricate high-quality perovskite layers for optoelectronic applications using natural compound additives

Identifying the Molecular Structures of Intermediates for Optimizing the Fabrication of High-Quality Perovskite Films

During the past two years, the introduction of DMSO has revolutionized the fabrication of high-quality pervoskite MAPbI₃ (MA = CH₃NH₃) films for solar cell applications. In the developed DMSO process, the formation of (MA)₂Pb₃I₈·2DMSO (shorted as Pb₃I₈) has well recognized as a critical factor to prepare high-quality pervoskite films and thus accomplish excellent performances in perovskite solar cells. However, Pb₃I₈ is an I-deficient intermediate and must further react with methylammonium iodide (MAI) to be fully converted into MAPbI₃. By capturing and solving the molecular structures of several intermediates involved in the fabrication of perovskite films, we report in this work that the importance of DMSO is <b>NOT</b> due to the formation of Pb₃I₈. The use of different PbI₂-DMSO ratios leads to two different structures of PbI₂-DMSO precursors (PbI₂·DMSO and PbI₂·2DMSO), thus dramatically influencing the quality of fabricated perovskite films. However, such an influence can be minimized when the PbI₂-DMSO precursor films are thermally treated to create mesoporous PbI₂ films before reacting with MAI. Such a development makes the fabrication of high-quality pervoskite films highly reproducible without the need to precisely control the PbI₂:DMSO ratio. Moreover, the formation of ionic compound (MA)₄PbI₆ is observed when excess MAI is used in the preparation of perovskite film. This I-rich phase heavily induces the hysteresis in PSCs, but is readily removed by isopropanol treatment. On the basis of all these findings, we develop a new effective protocol to fabricate high-performance PSCs. In the new protocol, high-quality perovskite films are prepared by simply treating the mesoporous PbI₂ films (made from PbI₂-DMSO precursors) with an isopropanol solution of MAI, followed by isopropanol washing. The best efficiency of fabricated MAPbI₃ PSCs is up to 19.0%. As compared to the previously reported DMSO method, the devices fabricated by the method reported in this work display narrow efficiency distributions in both forward and reverse scans. And the efficiency difference between forward and reverse scans is much smaller

Identifying the Molecular Structures of Intermediates for Optimizing the Fabrication of High-Quality Perovskite Films

During the past two years, the introduction of DMSO has revolutionized the fabrication of high-quality pervoskite MAPbI3 (MA = CH3NH3) films for solar cell applications. In the developed DMSO process, the formation of (MA)2Pb3I8·2DMSO (shorted as Pb3I8) has well recognized as a critical factor to prepare high-quality pervoskite films and thus accomplish excellent performances in perovskite solar cells. However, Pb3I8 is an I-deficient intermediate and must further react with methylammonium iodide (MAI) to be fully converted into MAPbI3. By capturing and solving the molecular structures of several intermediates involved in the fabrication of perovskite films, we report in this work that the importance of DMSO is NOT due to the formation of Pb3I8. The use of different PbI2-DMSO ratios leads to two different structures of PbI2-DMSO precursors (PbI2·DMSO and PbI2·2DMSO), thus dramatically influencing the quality of fabricated perovskite films. However, such an influence can be minimized when the PbI2-DMSO precursor films are thermally treated to create mesoporous PbI2 films before reacting with MAI. Such a development makes the fabrication of high-quality pervoskite films highly reproducible without the need to precisely control the PbI2:DMSO ratio. Moreover, the formation of ionic compound (MA)4PbI6 is observed when excess MAI is used in the preparation of perovskite film. This I-rich phase heavily induces the hysteresis in PSCs, but is readily removed by isopropanol treatment. On the basis of all these findings, we develop a new effective protocol to fabricate high-performance PSCs. In the new protocol, high-quality perovskite films are prepared by simply treating the mesoporous PbI2 films (made from PbI2-DMSO precursors) with an isopropanol solution of MAI, followed by isopropanol washing. The best efficiency of fabricated MAPbI3 PSCs is up to 19.0%. As compared to the previously reported DMSO method, the devices fabricated by the method reported in this work display narrow efficiency distributions in both forward and reverse scans. And the efficiency difference between forward and reverse scans is much smaller

Methylamine-Dimer-Induced Phase Transition toward MAPbI₃ Films and High-Efficiency Perovskite Solar Modules

Perovskite films prepared with CH3NH2 molecules under ambient conditions have led to rapid fabrication of perovskite solar cells (PSCs), but there remains a lack of mechanistic studies and inconsistencies with operability in their production. Here the crystal structure of CH3NH2–CH3NH3PbI3 was analyzed to involve hydrogen bonds (CH3NH2···CH3NH3+) and has guided the facile, reproducible preparation of high-quality perovskite films under ambient conditions. Hydrogen bonds within CH3NH2···CH3NH3+ dimers were found in the CH3NH2–CH3NH3PbI3 intermediates, accompanied by 1D-PbI3– chains (δ-phase). The weakly hydrogen-bonded CH3NH2 molecules were easily released from the CH3NH2–CH3NH3PbI3 intermediates, contributing to rapid, spontaneous phase transition from 1D-PbI3– (δ-phase) to 3D-PbI3– (α-phase). Further introduction of CH3NH3Cl into the CH3NH2–CH3NH3PbI3 intermediates led to interruption of 1D-PbI3– transition into 0D-Pb2I9‑xClx5–(0 x 3–. On the basis of the above understanding, CH3NH2 solution in ethanol and CH3NH3Cl were used for precursors and a best efficiency of 20.3% in PSCs was achieved. Large-scale modules (12 cm2 aperture area) fabricated by a dip-coating technology exhibited an efficiency up to 16.0% and outstanding stability over 10 000 s under continuous output. The developed preparation method of perovskite precursors and insightful research into the methylamine-dimer-induced phase transition mechanism have enabled the production of high-quality perovskite films with robust operability, showing great potential for large-scale commercialization

Methylamine-Dimer-Induced Phase Transition toward MAPbI₃ Films and High-Efficiency Perovskite Solar Modules

Perovskite films prepared with CH3NH2 molecules under ambient conditions have led to rapid fabrication of perovskite solar cells (PSCs), but there remains a lack of mechanistic studies and inconsistencies with operability in their production. Here the crystal structure of CH3NH2–CH3NH3PbI3 was analyzed to involve hydrogen bonds (CH3NH2···CH3NH3+) and has guided the facile, reproducible preparation of high-quality perovskite films under ambient conditions. Hydrogen bonds within CH3NH2···CH3NH3+ dimers were found in the CH3NH2–CH3NH3PbI3 intermediates, accompanied by 1D-PbI3– chains (δ-phase). The weakly hydrogen-bonded CH3NH2 molecules were easily released from the CH3NH2–CH3NH3PbI3 intermediates, contributing to rapid, spontaneous phase transition from 1D-PbI3– (δ-phase) to 3D-PbI3– (α-phase). Further introduction of CH3NH3Cl into the CH3NH2–CH3NH3PbI3 intermediates led to interruption of 1D-PbI3– transition into 0D-Pb2I9‑xClx5–(0 x 3–. On the basis of the above understanding, CH3NH2 solution in ethanol and CH3NH3Cl were used for precursors and a best efficiency of 20.3% in PSCs was achieved. Large-scale modules (12 cm2 aperture area) fabricated by a dip-coating technology exhibited an efficiency up to 16.0% and outstanding stability over 10 000 s under continuous output. The developed preparation method of perovskite precursors and insightful research into the methylamine-dimer-induced phase transition mechanism have enabled the production of high-quality perovskite films with robust operability, showing great potential for large-scale commercialization

Identifying the Molecular Structures of Intermediates for Optimizing the Fabrication of High-Quality Perovskite Films

During the past two years, the introduction of DMSO has revolutionized the fabrication of high-quality pervoskite MAPbI₃ (MA = CH₃NH₃) films for solar cell applications. In the developed DMSO process, the formation of (MA)₂Pb₃I₈·2DMSO (shorted as Pb₃I₈) has well recognized as a critical factor to prepare high-quality pervoskite films and thus accomplish excellent performances in perovskite solar cells. However, Pb₃I₈ is an I-deficient intermediate and must further react with methylammonium iodide (MAI) to be fully converted into MAPbI₃. By capturing and solving the molecular structures of several intermediates involved in the fabrication of perovskite films, we report in this work that the importance of DMSO is <b>NOT</b> due to the formation of Pb₃I₈. The use of different PbI₂-DMSO ratios leads to two different structures of PbI₂-DMSO precursors (PbI₂·DMSO and PbI₂·2DMSO), thus dramatically influencing the quality of fabricated perovskite films. However, such an influence can be minimized when the PbI₂-DMSO precursor films are thermally treated to create mesoporous PbI₂ films before reacting with MAI. Such a development makes the fabrication of high-quality pervoskite films highly reproducible without the need to precisely control the PbI₂:DMSO ratio. Moreover, the formation of ionic compound (MA)₄PbI₆ is observed when excess MAI is used in the preparation of perovskite film. This I-rich phase heavily induces the hysteresis in PSCs, but is readily removed by isopropanol treatment. On the basis of all these findings, we develop a new effective protocol to fabricate high-performance PSCs. In the new protocol, high-quality perovskite films are prepared by simply treating the mesoporous PbI₂ films (made from PbI₂-DMSO precursors) with an isopropanol solution of MAI, followed by isopropanol washing. The best efficiency of fabricated MAPbI₃ PSCs is up to 19.0%. As compared to the previously reported DMSO method, the devices fabricated by the method reported in this work display narrow efficiency distributions in both forward and reverse scans. And the efficiency difference between forward and reverse scans is much smaller

Additional file 1: of Light-Trapping Engineering for the Enhancements of Broadband and Spectra-Selective Photodetection by Self-Assembled Dielectric Microcavity Arrays

Figure S1. Fabrication of ZnO MCAs on Si PIN substrate. Figure S2. Detailed morphology of ZnO MCA arrays on PIN substrate. Figure S3. Large-scale ZnO MCA arrays on PIN silicon substrate. Figure S4. Near-field distribution patterns of ZnO MCA with shell thickness of 40 nm. Figure S5. Simulation method and setup for the absorption profile. Figure S6. Comparison of the absorption profile and near-field distribution for the MCAs on silicon substrates under on/off-resonance wavelengths. Figure S7. Near-field distribution patterns of ZnO MCA with shell thickness of 60 nm. Figure S8. Response stability of MCA-decorated PIN PD. (DOCX 3687 kb