Local and Global Electronic Effects in Single and Double Boron-Doped Carbon Nanotubes

The foreign atom doping influences the properties of carbon materials, and it is a possible way of designing materials of desired characteristics. Density functional calculations have been carried out on various isomers of boron-doped (4,0) and (9,0) carbon nanotubes as templates to investigate the doping effect on the structure and electronic properties on such systems. The results indicate that these boron-doped carbon nanotubes show local structural changes, mostly due to the elongation of bonds. The insertion of heteroatoms perturbs the π-conjugation system, which, in effect, destabilizes the material through higher energy cost of formation. The position of the foreign atom controls the new organization of electron density and leads to one of two possible distributions, viz., global (where electron density is distributed over the molecular surface) or local (localized distribution of electron density). This feature, in turn, can influence the bonding of the reactants while interacting with the surface. The charge distribution at a particular boron-doped site always possesses the local characteristics with a positively charged boron atom surrounded by negatively charged carbons. Such a character is also a measure of the driving force for influencing the substitution reaction in the vicinity of boron through an ionic mechanism

Interface Passivation of Inverted Perovskite Solar Cells by Dye Molecules

The interface between [6,6]-phenyl C61-butyric acid methyl ester (PC61BM) and the electrode has a critical effect on the performance of inverted perovskite solar cells (PSCs). Three organic cationic cyanine dye molecules with different highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) states are designed to passivate the PC61BM and Ag electrode interface to improve PSCs performance. The effects of energy-level alignment and the interfacial charge transfer resistance on the device performance are compared and studied. The dye interface passivation layer significantly reduces charge recombination. Moreover, the ClO4– anions associated with the dye molecules improve the charge extraction and charge transport in the devices. Reduced interface charge recombination and improved charge transport are confirmed by photoluminescence (PL), time-resolved photoluminescence (TRPL), electrochemical impedance spectra (EIS), and charge-only device performance studies. The PSCs with one of the dyes as an interface passivation layer show an optimized power conversion efficiency (PCE) of 19.14% with an open-circuit voltage (Voc) of 1.09 V, a short-circuit current density (Jsc) of 22.87 mA/cm2, and a fill factor (FF) of 76.81%. The devices maintain over 90% of the initial PCE for 120 h of storage under an ambient environment (25 °C and 30 ± 5% relative humidity (RH). The use of small dye molecules as an interface passivation layer to reduce charge recombination in PSCs represents a paradigm for improving the performance and stability of PSCs

Heteroacene-Based Polymer with Fast-Switching Visible–Near Infrared Electrochromic Behavior

The electrochromic properties and application of electronically conducting polymers (ECPs) (PTRPZ-EDOT) consisting of a 3,4-ethylenedioxythiophene (EDOT) and the heteroacene-based molecular scaffold, 6H-pyrrolo­[3,2-b:4,5-b′] bis [1,4] benzothiazine (TRPZ), are reported. Known for its high electron mobility and conducting properties, the novel TRPZ scaffold was synthesized to possess two EDOT molecules termini affording TRPZ-EDOT. Electropolymerization of TRPZ-EDOT resulted in remarkable spectroscopic and conductive properties suitable for electrochromic device fabrication. Using atomic force microscopy (AFM), the average surface roughness and surface topography of PTRPZ-EDOT polymer thin films were determined. Spectroelectrochemical data showed that the polymer achieved switching times of 4.07 (coloration) and 0.47 s (bleaching) at 539 nm. The PTRPZ-EDOT film exhibits an optical contrast of 36–44% at 539 nm between its neutral and colored states, respectively. The NIR region from 1000 to 1700 nm shows the appearance of charge carrier bands with a 0–1 V potential range. An electrochromic device was successfully fabricated from PTRPZ-EDOT, showcasing the potential and applicability of the polymer material for advanced technologies such as smart windows, flexible electrochromic screens, and energy storage devices

Heteroacene-Based Polymer with Fast-Switching Visible–Near Infrared Electrochromic Behavior

The electrochromic properties and application of electronically conducting polymers (ECPs) (PTRPZ-EDOT) consisting of a 3,4-ethylenedioxythiophene (EDOT) and the heteroacene-based molecular scaffold, 6H-pyrrolo­[3,2-b:4,5-b′] bis [1,4] benzothiazine (TRPZ), are reported. Known for its high electron mobility and conducting properties, the novel TRPZ scaffold was synthesized to possess two EDOT molecules termini affording TRPZ-EDOT. Electropolymerization of TRPZ-EDOT resulted in remarkable spectroscopic and conductive properties suitable for electrochromic device fabrication. Using atomic force microscopy (AFM), the average surface roughness and surface topography of PTRPZ-EDOT polymer thin films were determined. Spectroelectrochemical data showed that the polymer achieved switching times of 4.07 (coloration) and 0.47 s (bleaching) at 539 nm. The PTRPZ-EDOT film exhibits an optical contrast of 36–44% at 539 nm between its neutral and colored states, respectively. The NIR region from 1000 to 1700 nm shows the appearance of charge carrier bands with a 0–1 V potential range. An electrochromic device was successfully fabricated from PTRPZ-EDOT, showcasing the potential and applicability of the polymer material for advanced technologies such as smart windows, flexible electrochromic screens, and energy storage devices

Efficient and Stable Self-Passivation Perovskite Solar Cells Prepared in Ambient Air Based on an Antisolvent-Free Method

Solution processable perovskite solar cells (PSCs) are one of the most promising candidates for commercialization. However, the perovskite film preparation method is limited by the mandatory antisolvent process under an inert gas atmosphere which significantly influenced its mass production. In this study, we developed a perovskite film preparation without the requirement of antisolvent dripping in air. We employed various solvents to prepare perovskite films and studied their influence on perovskite nucleation and morphology for the respective solvents. Among them, the perovskite prepared using dimethylacetamide (DMAc), which has low solubility and high interaction with PbI2, demonstrated a highly crystalline perovskite black phase without antisolvent dripping. Furthermore, we found that the perovskite concentration played an important role in the perovskite film quality, where the high concentration DMAc-based perovskite produced a smooth and dense perovskite film by the antisolvent-free method in air. PSCs fabricated using this technique delivered a champion power conversion efficiency (PCE) of 20.1%. At the same time, the best device prepared by the blade-coated method also got 18% PCE. Moreover, the unencapsulated devices exhibited excellent stability, which retained more than 90% of their initial efficiency after 47 days in air. This work provides a facile and cost-effective method toward a controllable fabrication of high-performance antisolvent-free MAPbI3-based solar cells

Efficient and Stable Self-Passivation Perovskite Solar Cells Prepared in Ambient Air Based on an Antisolvent-Free Method

Solution processable perovskite solar cells (PSCs) are one of the most promising candidates for commercialization. However, the perovskite film preparation method is limited by the mandatory antisolvent process under an inert gas atmosphere which significantly influenced its mass production. In this study, we developed a perovskite film preparation without the requirement of antisolvent dripping in air. We employed various solvents to prepare perovskite films and studied their influence on perovskite nucleation and morphology for the respective solvents. Among them, the perovskite prepared using dimethylacetamide (DMAc), which has low solubility and high interaction with PbI2, demonstrated a highly crystalline perovskite black phase without antisolvent dripping. Furthermore, we found that the perovskite concentration played an important role in the perovskite film quality, where the high concentration DMAc-based perovskite produced a smooth and dense perovskite film by the antisolvent-free method in air. PSCs fabricated using this technique delivered a champion power conversion efficiency (PCE) of 20.1%. At the same time, the best device prepared by the blade-coated method also got 18% PCE. Moreover, the unencapsulated devices exhibited excellent stability, which retained more than 90% of their initial efficiency after 47 days in air. This work provides a facile and cost-effective method toward a controllable fabrication of high-performance antisolvent-free MAPbI3-based solar cells

DataSheet1_Heteroacene-Based Amphiphile as a Molecular Scaffold for Bioimaging Probes.PDF

The challenges faced with current fluorescence imaging agents have motivated us to study two nanostructures based on a hydrophobic dye, 6H-pyrrolo[3,2-b:4,5-b’]bis [1,4]benzothiazine (TRPZ). TRPZ is a heteroacene with a rigid, pi-conjugated structure, multiple reactive sites, and unique spectroscopic properties. Here we coupled TRPZ to a tert-butyl carbamate (BOC) protected 2,2-bis(hydroxymethyl)propanoic acid (bisMPA) dendron via azide-alkyne Huisgen cycloaddition. Deprotection of the protected amine groups on the dendron afforded a cationic terminated amphiphile, TRPZ-bisMPA. TRPZ-bisMPA was nanoprecipitated into water to obtain nanoparticles (NPs) with a hydrodynamic radius that was <150 nm. For comparison, TRPZ-PG was encapsulated in pluronic-F127 (Mw = 12 kD), a polymer surfactant to afford NPs almost twice as large as those formed by TRPZ-bisMPA. Size and stability studies confirm the suitability of the TRPZ-bisMPA NPs for biomedical applications. The photophysical properties of the TRPZ-bisMPA NPs show a quantum yield of 49%, a Stokes shift of 201 nm (0.72 eV) and a lifetime of 6.3 ns in water. Further evidence was provided by cell viability and cellular uptake studies confirming the low cytotoxicity of TRPZ-bisMPA NPs and their potential in bioimaging.</p

Efficient and Stable Self-Passivation Perovskite Solar Cells Prepared in Ambient Air Based on an Antisolvent-Free Method

Solution processable perovskite solar cells (PSCs) are one of the most promising candidates for commercialization. However, the perovskite film preparation method is limited by the mandatory antisolvent process under an inert gas atmosphere which significantly influenced its mass production. In this study, we developed a perovskite film preparation without the requirement of antisolvent dripping in air. We employed various solvents to prepare perovskite films and studied their influence on perovskite nucleation and morphology for the respective solvents. Among them, the perovskite prepared using dimethylacetamide (DMAc), which has low solubility and high interaction with PbI2, demonstrated a highly crystalline perovskite black phase without antisolvent dripping. Furthermore, we found that the perovskite concentration played an important role in the perovskite film quality, where the high concentration DMAc-based perovskite produced a smooth and dense perovskite film by the antisolvent-free method in air. PSCs fabricated using this technique delivered a champion power conversion efficiency (PCE) of 20.1%. At the same time, the best device prepared by the blade-coated method also got 18% PCE. Moreover, the unencapsulated devices exhibited excellent stability, which retained more than 90% of their initial efficiency after 47 days in air. This work provides a facile and cost-effective method toward a controllable fabrication of high-performance antisolvent-free MAPbI3-based solar cells

Efficient and Stable Self-Passivation Perovskite Solar Cells Prepared in Ambient Air Based on an Antisolvent-Free Method

Solution processable perovskite solar cells (PSCs) are one of the most promising candidates for commercialization. However, the perovskite film preparation method is limited by the mandatory antisolvent process under an inert gas atmosphere which significantly influenced its mass production. In this study, we developed a perovskite film preparation without the requirement of antisolvent dripping in air. We employed various solvents to prepare perovskite films and studied their influence on perovskite nucleation and morphology for the respective solvents. Among them, the perovskite prepared using dimethylacetamide (DMAc), which has low solubility and high interaction with PbI2, demonstrated a highly crystalline perovskite black phase without antisolvent dripping. Furthermore, we found that the perovskite concentration played an important role in the perovskite film quality, where the high concentration DMAc-based perovskite produced a smooth and dense perovskite film by the antisolvent-free method in air. PSCs fabricated using this technique delivered a champion power conversion efficiency (PCE) of 20.1%. At the same time, the best device prepared by the blade-coated method also got 18% PCE. Moreover, the unencapsulated devices exhibited excellent stability, which retained more than 90% of their initial efficiency after 47 days in air. This work provides a facile and cost-effective method toward a controllable fabrication of high-performance antisolvent-free MAPbI3-based solar cells

Efficient and Stable Self-Passivation Perovskite Solar Cells Prepared in Ambient Air Based on an Antisolvent-Free Method

Solution processable perovskite solar cells (PSCs) are one of the most promising candidates for commercialization. However, the perovskite film preparation method is limited by the mandatory antisolvent process under an inert gas atmosphere which significantly influenced its mass production. In this study, we developed a perovskite film preparation without the requirement of antisolvent dripping in air. We employed various solvents to prepare perovskite films and studied their influence on perovskite nucleation and morphology for the respective solvents. Among them, the perovskite prepared using dimethylacetamide (DMAc), which has low solubility and high interaction with PbI2, demonstrated a highly crystalline perovskite black phase without antisolvent dripping. Furthermore, we found that the perovskite concentration played an important role in the perovskite film quality, where the high concentration DMAc-based perovskite produced a smooth and dense perovskite film by the antisolvent-free method in air. PSCs fabricated using this technique delivered a champion power conversion efficiency (PCE) of 20.1%. At the same time, the best device prepared by the blade-coated method also got 18% PCE. Moreover, the unencapsulated devices exhibited excellent stability, which retained more than 90% of their initial efficiency after 47 days in air. This work provides a facile and cost-effective method toward a controllable fabrication of high-performance antisolvent-free MAPbI3-based solar cells