Commercially available jeffamine additives for p-i-n perovskite solar cells.

Commercially available Jeffamines (polyetheramine) with average molecular weights of 2000 and 3000 g mol-1; one (M2005), two (D2000), and three (T3000) primary amino groups end-capping on the polyether backbone; and propylene oxide (PO) and ethylene oxide (EO) functionality were explored as additives for application in MAPbI3 perovskite solar cells (PSCs). The results indicated that the embedding of Jeffamine additives effectively passivates the defects in the grain boundaries of perovskite through the coordination bonding between the nitrogen atom and the uncoordinated lead ion of perovskite. We fabricated p-i-n PSC devices with the structure of glass/indium tin oxide (ITO)/NiOx/CH3NH3PbI3 (with and without Jeffamine)/PC61BM/BCP/Ag. We observed the interaction between the Jeffamine and perovskites. This interaction led to increased lifetimes of the carriers of perovskite, which enabled the construction of high-performance p-i-n PSCs. For the Jeffamine-D2000-derived device, we observed an increase in the power conversion efficiency from 14.5% to 16.8% relative to the control device. Furthermore, the mechanical properties of the perovskite films were studied. The interaction between the additive and perovskite reinforced the flexibility of the thin film, which may pave the way for stretchable optoelectronics.

The Twisted Benzo[ghi]-Perylenetriimide Dimer as a 3D Electron Acceptor for Fullerene-Free Organic Photovoltaics.

A series of twisted N,N-linked benzo[ghi]-perylenetriimide dimers (t-BPTI) with various lengths of the α-branched alkyl side chain at the six-membered imide ring position was designed, synthesized, and characterized. These compounds showed the low-lying LUMO energy level of -3.78 eV, which was similar to that of PC61 BM (-3.71 eV), but with intensive optical absorption in the range 350-500 nm. The twisted molecular geometry with two nearly perpendicular BPTI planes achieved a favorable nanoscale phase separation by relieving the self-aggregation of rigid BPTI units in blend films. The acceptor t-BPTI-3 unit with the longest alkyl side chains has been demonstrated to be an efficient electron acceptor in solution-processed bulk heterojunction organic photovoltaics (OPV), giving a power conversion efficiency of 3.68 % when using conjugated polymer PTB7-Th as the donor and without additional treatments.

Structure-Property Relationship Study of Donor and Acceptor 2,6-Disubstituted BODIPY Derivatives for High Performance Dye-Sensitized Solar Cells.

Seven donor and acceptor 2,6-disubstituted 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) dyes have been synthesized and characterized. Including MPBTCA, which is a known compound, the seven BODIPY dyes have been characterized by varied physical methods, such as UV/Visible absorption spectroscopy, low energy photo-electron spectroscopy (AC-2), and HOMO-LUMO DFT/TDDFT calculation. All seven BODIPY dyes have absorption λmax around 535-545 nm, which is significantly longer than 499 nm of 4,4-difluoro-1,3,5,7,8-pentamethyl-4-bora-3a,4a-diaza-s-indacene (PM 546). Having structural variation on donor group, acceptor group, donor π-spacer, acceptor π-spacer, and the substituent on boron, some BODIPY dyes exhibit small extinction coefficients or spectral integrals in solution (MPCtBTCA, MPBT-pyO, MPBTT-pyO, MTBTCA), broadening absorption spectral profile (MTBTCA), weak intramolecular charge transfer characteristics (MPBT-pyO, MPBTT-pyO, MTBTCA), too low LUMO energy level (PPBTCA), or insufficient dye-uptake by TiO2 FTO (MPBT-pyO, MPBTT-pyO, MTBTCA). Two of the seven BODIPY dyes, MPBTCA and MPBTTCA, do not show the adverse properties like other BODIPY dyes. With our improved TiO2 FTO (fluorine doped tin oxide) dyeing method, namely a solution dropping method, high performance dye-sensitized solar cells (DSCs) have been realized by MPBTCA and MPBTTCA photosensitizers. Power conversion efficiencies of 6.3 and 6.4 % have been achieved by MPBTCA and MPBTTCA DSCs, respectively. To the best of our knowledge, MPBTCA and MPBTTCA are the most efficient dyes for the donor and acceptor 2,6-disubstituted BODIPY DSCs so far.

Environment-noise-free optical heterodyne retardation measurement using a double-pass acousto-optic frequency shifter.

We demonstrate an environment-noise-free optical heterodyne interferometer (OHI) based on a double-pass acousto-optic frequency shifter (AOFS) for phase retardation measurements. The OHI generates intermediate-frequency (IF) heterodyne beat signals for each orthogonal linear polarization mode of a birefringence sample. The phase differences of the IF signals are compared by using a wide-bandwidth lock-in amplifier. This scheme provides 20 dB rejection of common-mode environmental disturbances. Measurements of the half-wave voltage of an electro-optics modulator and the electro-optic coefficient of an LiNbO3 plate are demonstrated as application examples.

Biowaste Eggshell Membranes for Bio-triboelectric Nanogenerators and Smart Sensors.

In this study, we used a simple and cost-effective method to fabricate triboelectric nanogenerators (TENGs) based on biowaste eggshell membranes (EMs). We prepared stretchable electrodes with various types of EMs (hen, duck, goose, and ostrich) and employed them as positive friction materials for bio-TENGs. A comparison of the electrical properties of the hen, duck, goose, and ostrich EMs revealed that the output voltage of the ostrich EM could reach up to 300 V, due to its abundant functional groups, natural fiber structure, high surface roughness, high surface charge, and high dielectric constant. The output power of the resulting device reached 0.18 mW, sufficient to power 250 red light-emitting diodes simultaneously, as well as a digital watch. This device also displayed good durability when subjected to 9000 cycles at 30 N at a frequency of 3 Hz. Furthermore, we designed an ostrich EM-TENG as a smart sensor for the detection of body motion, including leg movement and the pressing of different numbers of fingers.

Spiro-Twisted Benzoxazine Derivatives Bearing Nitrile Group for All-Solid-State Polymer Electrolytes in Lithium Batteries.

In this study, two nitrile-functionalized spiro-twisted benzoxazine monomers, namely 2,2'-((6,6,6',6'-tetramethyl-6,6',7,7'-tetrahydro-2H,2'H-8,8'-spirobi[indeno[5,6-e][1,3]oxazin]-3,3'(4H,4'H)-diyl)bis(4,1-phenylene))diacetonitrile (TSBZBC) and 4,4'-(6,6,6',6'-tetramethyl-6,6',7,7'-tetrahydro-2H,2'H-8,8'-spirobi[indeno[5,6-e][1,3]oxazin]-3,3'(4H,4'H)-diyl)dibenzonitrile (TSBZBN) were successfully developed as cross-linkable precursors. In addition, the incorporation of the nitrile group by covalent bonding onto the crosslinked spiro-twisted molecular chains improve the miscibility of SPE membranes with lithium salts while maintaining good mechanical properties. Owing to the presence of a high fractional free volume of spiro-twisted matrix, the -CN groups would have more space for rotation and vibration to assist lithium migration, especially for the benzyl cyanide-containing SPE. When combined with poly (ethylene oxide) (PEO) electrolytes, a new type of CN-containing semi-interpenetrating polymer networks for solid polymer electrolytes (SPEs) were prepared. The PEO-TSBZBC and PEO-TSBZBN composite SPEs (with 20 wt% crosslinked structure in the polymer) are denoted as the BC20 and BN20, respectively. The BC20 sample exhibited an ionic conductivity (σ) of 3.23 × 10-4 S cm-1 at 80 °C and a Li+ ion transference number of 0.187. The LiFePO4 (LFP)|BC20|Li sample exhibited a satisfactory charge-discharge capacity of 163.6 mAh g-1 at 0.1 C (with approximately 100% coulombic efficiency). Furthermore, the Li|BC20|Li cell was more stable during the Li plating/stripping process than the Li|BN20|Li and Li|PEO|Li samples. The Li|BC20|Li symmetric cell could be cycled continuously for more than 2700 h without short-circuiting. In addition, the specific capacity of the LFP|BC20|Li cell retained 87% of the original value after 50 cycles.

Intelligent and thermo-responsive Au-pluronic® F127 nanocapsules for Raman-enhancing detection of biomolecules.

Thermo-responsive Raman-enhanced nanocapsules were successfully fabricated by Pluronic® F127 (F127) decorated with gold nanoparticles (AuNPs) for surface-enhanced Raman scattering (SERS) detection of biomolecules. F127 nanocapsules changes from hydrophilicity (swelling) to hydrophobicity (de-swelling) when the temperature increases from 15 °C to 37 °C, owing to the lower critical solution temperature (LCST) of F127 is about 26.5 °C. The size of nanocapsules would be enormous shrinking from 160 nm to 20 nm, resulting in a significant decrease in the distance between AuNPs to enhance hot spot effect, which increases the sensitivity of SERS detection. Based on the thermo-sensitive behavior, the ratio of AuNPs and F127 would be manipulated to find the optimal SERS enhancement effect. SERS nanocapsules can rapidly detect biomolecules (adenine and R6G) with limit of detection (LOD) lower than 10-6 M. In addition, the relatively difficult to detect clinical samples, carboxyl-terminal parathyroid hormone fragments (C-PTH), can also be measured by the thermo-responsive SERS nanocapsules developed in this work. It is expected the biomolecules can be adsorbed at low temperature (15 °C), as well as collected and concentrated at high temperature (37 °C) for SERS detection, to increase the sensitivity and stability of SERS detection.

Reduced graphene oxide nanosheets decorated with core-shell of Fe3O4-Au nanoparticles for rapid SERS detection and hyperthermia treatment of bacteria.

In this study, the core-shell of Fe3O4-Au nanoparticles (NPs) were prepared by seeding AuNPs onto Fe3O4 NPs modified with poly-ethylenimine (PEI). Later, Fe3O4-Au NPs were attached to cationic poly(dimethyldiallylammonium chloride) (PDDA)-modified graphene oxide (GO) nanosheets through in situ self-assembly behaviors, termed as Fe3O4-Au@RGO nanocomposites, for surface-enhanced Raman scattering (SERS) detection and hyperthermia treatment of bacteria. The resulting Fe3O4-Au@RGO nanocomposites were evaluated systematically by transmission electron microscope, zeta potential, X-ray diffraction, X-ray photoelectron spectroscopy, and vibrating sample magnetometer. It revealed that the core-shell structured Fe3O4-Au NPs were dispersed homogeneously on the surface of the GO nanosheets. Furthermore, the rapid SERS detection for small biomolecules and bacteria was conducted by Raman spectroscopy. The results showed that the greatest SERS intensity was fne tuned at the weight ratio of Fe3O4-Au/RGO nanosheets was 20/1, displaying the optimal interparticle gap of AuNPs to induce the huge hot-spots effect. The magnetic inductive heating capability of Fe3O4-Au@RGO nanocomposites was produced under high frequency magnetic field exposure and can kill high than 90% of the bacteria at 10 min. Hence, the newly developed Fe3O4-Au@RGO nanocomposites were demonstrated to be viable for SERS detection of biomolecules and microbes and potential applications for magnetically capturing and hyperthermia treatment of bacteria.

Immobilization of Air-Stable Copper Nanoparticles on Graphene Oxide Flexible Hybrid Films for Smart Clothes.

Through the use of organic/inorganic hybrid dispersants-which are composed of polymeric dispersant and two-dimension nanomaterial graphene oxide (GO)-copper nanoparticles (CuNPs) were found to exhibit nano stability, air-stable characteristics, as well as long-term conductive stability. The polymeric dispersant consists of branched poly(oxyethylene)-segmented esters of trimellitic anhydride adduct (polyethylene glycol-trimethylolpropane-trimellitic anhydride, designated as PTT). PTT acts as a stabilizer for CuNPs, which are synthesized via in situ polymerization and redox reaction of the precursor Cu(CH3COO)2 within an aqueous system, and use graphene oxide to avoid the reduction reaction of CuNPs. The results show that after 30 days of storage the CuNPs/PTT/GO composite film maintains a highly conductive network (9.06 × 10-1 Ω/sq). These results indicate that organic/inorganic PTT/GO hybrid dispersants can effectively maintain the conductivity stability of CuNPs and address the problem of CuNP oxidation. Finally, the new CuNPs/PTT/GO composite film was applied to the electrocardiogram (ECG) smart clothes. This way, a stable and antioxidant-sensing electrode can be produced, which is expected to serve as a long-term ECG monitoring device.

Chromatic Fulleropyrrolidine as Long-Lived Metal-Free Catalyst for CO2 Photoreduction Reaction.

Conversion of CO2 into carbonaceous fuels with the aid of solar energy has been an important research subject for decades. Owing to their excellent electron-accepting capacities, fullerene derivatives have been extensively used as n-type semiconductors. This work reports that the fulleropyrrolidine functionalized with 4,7-di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole, abbreviated as DTBT-C60 , could efficiently catalyze the photoreduction of CO2 to CO. The novel C60 -chromophore dyad structure facilitated better usage of solar light and effective dissociation of excitons. Consequently, the DTBT-C60 exhibited a promising CO yield of 144 µmol gcat -1 under AM1.5G solar illumination for 24 h. Moreover, the isotope experiments demonstrated that water molecules could function as an electron source to reactivate DTBT-C60 . Impressively, DTBT-C60 exhibited an extremely durable catalytic activity for more than one week, facilitating the practical application of photochemical CO2 reaction.

Naphthalene Diimide-Based Donor-Acceptor-Donor Small Molecules as Metal-Free Organocatalysts for Photocatalytic CO2 Reaction.

The application of organic small molecules as metal-free photocatalysts for light-driven photoreduction of carbon dioxide (CO2) has seldom been explored. This work developed four naphthalene diimide (NDI)-derived donor-acceptor-donor small molecules with different numbers of thiophene units, namely, NDI-2T, NDI-TT, NDI-4T, and NDI-6T, as metal-free photocatalysts to catalyze the reduction of CO2 under irradiation with an air mass 1.5G solar simulator at one-sun intensity. The structure-property relationship was investigated by exploring the effects of the electron-donating ability of the donor units on the optical properties, redox potential, electron-hole distribution, and exciton lifetime. NDI-6T exhibited the most red-shifted absorption, longest exciton lifetime, and strongest electron-hole separation. However, the large upshift in oxidation potential because of the elevated electron-donating ability of the hexathiophene unit significantly reduced the driving force for catalyst regeneration, leading to poor catalytic performance. Alternatively, NDI-4T possessed proper redox potentials, reduced charge-transfer resistance, and excellent photocurrent intensity; therefore, it effectively converted CO2 to a single product of CO in the presence of water as an electron donor without a sacrificial reagent or cocatalyst with a product yield of 168.6 µmol gcat-1 24 h-1, which was considerably higher than those of NDI-TT (111.9 µmol gcat-1 24 h-1), NDI-2T (88.4 µmol gcat-1 24 h-1), and NDI-6T (40.5 µmol gcat-1 24 h-1). This study provides a practical guideline for the molecular design of conjugated organic molecules as promising photocatalysts for CO2 photoreduction.

Single-layered graphene oxide nanosheet/polyaniline hybrids fabricated through direct molecular exfoliation.

In this study, we used direct molecular exfoliation for the rapid, facile, large-scale fabrication of single-layered graphene oxide nanosheets (GOSs). Using macromolecular polyaniline (PANI) as a layered space enlarger, we readily and rapidly synthesized individual GOSs at room temperature through the in situ polymerization of aniline on the 2D GOS platform. The chemically modified GOS platelets formed unique 2D-layered GOS/PANI hybrids, with the PANI nanorods embedded between the GO interlayers and extended over the GO surface. X-ray diffraction revealed that intergallery expansion occurred in the GO basal spacing after the PANI nanorods had anchored and grown onto the surface of the GO layer. Transparent folding GOSs were, therefore, observed in transmission electron microscopy images. GOS/PANI nanohybrids possessing high conductivities and large work functions have the potential for application as electrode materials in optoelectronic devices. Our dispersion/exfoliation methodology is a facile means of preparing individual GOS platelets with high throughput, potentially expanding the applicability of nanographene oxide materials.

Epoxy-Based Interlocking Membranes for All Solid-State Lithium Ion Batteries: The Effects of Amine Curing Agents on Electrochemical Properties.

In this study, a series of crosslinked membranes were prepared as solid polymer electrolytes (SPEs) for all-solid-state lithium ion batteries (ASSLIBs). An epoxy-containing copolymer (glycidyl methacrylate-co-poly(ethylene glycol) methyl ether methacrylate, PGA) and two amine curing agents, linear Jeffamine ED2003 and hyperbranched polyethyleneimine (PEI), were utilized to prepare SPEs with various crosslinking degrees. The PGA/polyethylene oxide (PEO) blends were cured by ED2003 and PEI to obtain slightly and heavily crosslinked structures, respectively. For further optimizing the interfacial and the electrochemical properties, an interlocking bilayer membrane based on overlapping and subsequent curing of PGA/PEO/ED2003 and PEO/PEI layers was developed. The presence of this amino/epoxy network can inhibit PEO crystallinity and maintain the dimensional stability of membranes. For the slightly crosslinked PGA/PEO/ED2003 membrane, an ionic conductivity of 5.61 × 10-4 S cm-1 and a lithium ion transference number (tLi+) of 0.43 were obtained, along with a specific capacity of 156 mAh g-1 (0.05 C) acquired from an assembled half-cell battery. However, the capacity retention retained only 54% after 100 cycles (0.2 C, 80 °C), possibly because the PEO-based electrolyte was inclined to recrystallize after long term thermal treatment. On the other hand, the highly crosslinked PGA/PEO/PEI membrane exhibited a similar ionic conductivity of 3.44 × 10-4 S cm-1 and a tLi+ of 0.52. Yet, poor interfacial adhesion between the membrane and the cathode brought about a low specific capacity of 48 mAh g-1. For the reinforced interlocking bilayer membrane, an ionic conductivity of 3.24 × 10-4 S cm-1 and a tLi+ of 0.42 could be achieved. Moreover, the capacity retention reached as high as 80% after 100 cycles (0.2 C, 80 °C). This is because the presence of the epoxy-based interlocking bilayer structure can block the pathway of lithium dendrite puncture effectively. We demonstrate that the unique interlocking bilayer structure is capable of offering a new approach to fabricate a robust SPE for ASSLIBs.

Sustainable Synthesis of Cyclic Carbonates from Terminal Epoxides by a Highly Efficient CaI2/1,3-Bis[tris(hydroxymethyl)-methylamino]-propane Catalyst.

The nonstopping increment of atmospheric carbon dioxide (CO2) concentration keeps harming the environment and human life. The traditional concept of carbon capture and storage (CCS) is no longer sufficient and has already been corrected to carbon capture, utilization, and storage (CCUS). CCUS involves significant CO2 utilization, such as cyclic carbonate formation, for its cost effectiveness, less toxicity, and abundant C1 synthon in organic synthesis. However, the high thermodynamic and kinetic stability of CO2 limits its applications. Herein, we report a mild, efficient, and practical catalyst based on abundant, nontoxic CaI2 in conjunction with biocompatible ligand 1,3-bis[tris(hydroxymethyl)-methylamino]-propane (BTP) for CO2 fixation under atmospheric pressure with terminal epoxides to give the cyclic carbonates. The Job plot detected the 1:1 Ca2+/BTP binding stoichiometry. Furthermore, formation of a single crystal of the 1:1 Ca2+/BTP complex was confirmed by single-crystal X-ray crystallography. The bis(cyclic carbonate) products exhibit potentials for components in the non-isocyanate polyurethanes (NIPUs) process. Notably, this protocol shows attractive recyclability and reusability.

Improved Blend Film Morphology and Free Carrier Generation Provide a High-Performance Ternary Polymer Solar Cell.

Non-fullerene organic photovoltaics (OPVs) have displayed the highest power conversion efficiencies (PCEs) among OPVs. Herein, we describe a two-donor (PM6, TPD-3F)/one-acceptor (Y6) ternary blend having an optimized blend morphology that leads to improved OPV performance. Because TPD-3F has a HOMO energy level deeper than that of PM6, the value of VOC of the corresponding ternary device increased. Good miscibility between PM6 and TPD-3F, in conjunction with device optimization through the use of 1-chloronaphthalene as an additive, provided an optimized ternary blend morphology for efficient exciton dissociation and carrier transport and, therefore, larger PCE. Compared with the preoptimized PM6:Y6 binary device, the ternary device functioned with improvements in its short-circuit current density, value of VOC, and fill factor. As a result, the device PCE improved from 15.5 ± 0.19 to 16.6 ± 0.25% under AM 1.5G (100 mW cm-2) irradiation. The champion cell exhibited a PCE of 17.0%-a value that is one of the highest for a ternary OPV. Furthermore, such devices exhibited outstanding shelf lifetimes, with long-term stability in air (25 °C, 40% humidity) without encapsulation; the performance remained high (at 15.4%) after storage for 820 h.

High-Performance Semitransparent Organic Photovoltaics Featuring a Surface Phase-Matched Transmission-Enhancing Ag/ITO Electrode.

In this study, we designed a surface phase-matched transmission enhancement top electrode-Ag/indium tin oxide (ITO) structure for highly efficient and aesthetic semitransparent organic photovoltaics (ST-OPVs). The purposed highly transparent back electrodes (Ag/ITO) could selectively decrease visible reflection and increase transparency accordingly. By altering the thicknesses of the Ag and ITO layers, we could control the transmittance curve and increase the transparency of the ST-OPV devices. Devices based on PTB7-Th:IEICO-4F and PM6:Y6:PC71BM displayed outstanding performance (8.1 and 10.2%, respectively) with high photopic-weighted visible light transmittance (36.2 and 28.6%, respectively). The outstanding visible and near-infrared light harvesting of PM6:Y6:PC71BM further allowed a new application: double-sided energy harvesting from solar and indoor illumination. The simple optical design of a top electrode displaying high transparency/conductivity has a wide range of potential applications in, for example, greenhouse photovoltaics, tandem cells, and portable devices.

Design of Thienothiophene-Based Copolymers with Various Side Chain-End Groups for Efficient Polymer Solar Cells.

Three two-dimensional donor-acceptor conjugated copolymers consisting of a benzo[1,2-b:4,5-b']dithiophene derivative and thieno[3,2-b]thiophene with a conjugated side chain were designed and synthesized for use in bulk heterojunction (BHJ) or nonfullerene polymer solar cells (PSCs). Through attaching various acceptor end groups to the conjugated side chain on the thieno[3,2-b]thiophene moiety, the electronic, photophysical, and morphological properties of these copolymers were significantly affected. It was found that the intermolecular charge transfer interactions were enhanced with the increase in the acceptor strength on the thieno[3,2-b]thiophene moiety. Moreover, a better microphase separation was obtained in the copolymer: PC71BM or ITIC blend films when a strong acceptor end group on the thieno[3,2-b]thiophene moiety was used. As a result, BHJ PSCs based on copolymer:PC71BM blend films as active layers exhibited power conversion efficiencies from 2.82% to 4.41%, while those of nonfullerene copolymer:ITIC-based inverted PSCs ranged from 6.09% to 7.25%. These results indicate the side-chain engineering on the end groups of thieno[3,2-b]thiophene unit through a vinyl bridge linkage is an effective way to adjust the photophysical properties of polymers and morphology of blend films, and also have a significant influence on devices performance.

Evaluation of Carbon Dioxide-Based Urethane Acrylate Composites for Sealers of Root Canal Obturation.

A new root canal sealer was developed based on urethane acrylates using polycarbonate polyol (PCPO), a macrodiol prepared in the consumption of carbon dioxide as feedstock. The superior mechanical properties and biostability nature of PCPO-based urethane acrylates were then co-crosslinked with a difunctional monomer of tripropylene glycol diarylate (TPGDA) as sealers for resin matrix. Moreover, nanoscale silicate platelets (NSPs) immobilized with silver nanoparticles (AgNPs) and/or zinc oxide nanoparticles (ZnONPs) were introduced to enhance the antibacterial effect for the sealers. The biocompatibility and the antibacterial effect were investigated by Alamar blue assay and LDH assay. In addition, the antibacterial efficiency was performed by using Enterococcus faecalis (E. faecalis) as microbial response evaluation. These results demonstrate that the PCPO-based urethane acrylates with 50 ppm of both AgNP and ZnONP immobilized on silicate platelets, i.e., Ag/ZnO@NSP, exhibited great potential as an antibacterial composite for the sealer of root canal obturation.

A Near-Infrared Absorption Small Molecule Acceptor for High-Performance Semitransparent and Colorful Binary and Ternary Organic Photovoltaics.

An acceptor-donor-acceptor (A-D-A)-type non-fullerene acceptor (NFA), PTTtID-Cl, featuring thieno[3,2-b]thieno[2''',3''':4'',5'']-pyrrolo[2'',3'':4',5']thieno[2',3':4,5]thieno-[2,3-d]pyrrole (DTPTt) as the electron-rich core and 2-(5,6-dichloro-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (ID-Cl) as the peripheral electron-deficient terminal group was synthesized and characterized. PTTtID-Cl exhibited strong absorption in the range of 700-850 nm in CHCl3 and redshifted absorption centered at 881 nm in a thin film. The near infrared (NIR)-absorption of PTTtID-Cl was combined with a low-bandgap polymer donor (PTB7-Th) to achieve binary and semitransparent organic photovoltaics (OPVs) with a power conversion efficiency (PCE) of 8.9 % and 7.7 % (with an average visible transmittance (AVT) of 16.7 %), respectively. A ternary device with a ratio of PM7/PTTtID-Cl/IT-4F=1:0.15:0.85 (w/w) achieved a short-circuit current density of 19.46 mA cm-2 , an open-circuit voltage of 0.87 V, and a fill factor of 71.2 %, giving a PCE of 12.0 %. In addition, by employing the Ag/ITO/Ag microcavity structure, semitransparent colorful binary organic photovoltaics (OPVs) with superior transparency of 27.9 % at 427 nm and 22.7 % at 536 nm for blue and green devices, respectively, were prepared. The semitransparent colorful devices based on the optimized ternary blend gave PCEs of 8.7 %, 8.4 %, and 9.1 % for blue, green, and red devices, respectively. These results indicate the promising potential of PTTtID-Cl as a NIR-absorption NFA for applications in semitransparent colorful binary and ternary OPVs.

Preparation and supramolecular self-assembly of amphiphilic dendron-POSS nanohybrids.

Organic/inorganic urea/malonamide dendron-POSS nanohybrids with different generations of dendrons and peripheral groups were prepared. Chemical structures of the nanohybrids were characterized with FTIR, 1H NMR, molecular mass spectrometry, and elemental analysis. The nanohybrids exhibited better solubility in organic solvents as compared to their corresponding dendrons. Self-assembled layered dendron/POSS structures were observed for the nanohybrids with the low generation dendrons, as evidenced by TEM analysis. The nanohybrids also exhibited amphiphilic property because of the hydrophilicity of urea/malonamide dendrons. Moreover, the morphologies of the nanohybrids could be tailored via using various casting solvents.