Non-Equivalent Donor-Acceptor Type Polymers as Dopant-Free Hole-Transporting Materials for Perovskite Solar Cells.

Electron donor (D)-electron acceptor (A) type conjugated polymers present bright prospects as dopant-free hole-transporting materials (HTMs) for perovskite solar cells (PVSCs). Most of the reported D-A polymeric HTMs contain equivalent amounts of D and A units, while the appropriate excess proportion of D units could optimize the aggregation state of polymer chains and improve the hole transport properties of the polymers. Herein, a non-equivalent D-A copolymerization strategy was utilized to develop three indacenodithiophene-benzotriazole-based polymeric HTMs for PVSCs, named as F-10, F-15, and F-20, and the equivalent D-A polymer F-00 was studied in parallel. Effects of D : A ratio on the hole transport properties of these D-A type polymeric HTMs, including energy level, molecular stacking, hole mobility, and surface morphology, were investigated by theoretical simulation and test analysis. F-15 performed best due to the appropriate D : A ratio, endowing the PVSCs a champion power conversion efficiency of 20.37 % with high stability, which confirms the fine-tuning D : A ratio via non-equivalent D-A copolymerization strategy is very helpful to construct D-A type polymeric HTMs for high-performance PVSCs.

N-Heterocyclic Olefin Type Ionic Liquid with Innate Soft Lewis-Base Character as an Effective Additive for Hybrid Quasi-2D and 3D Perovskite Solar Cells.

In optimizing perovskites with ionic liquid (IL), the comparative study on Lewis acid-base (LAB) and hydrogen-bonding (HB) interactions between IL and perovskite is lacking. Herein, methyl is substituted for hydrogen on 2-position of imidazolium ring of N-heterocyclic carbene (NHC) type IL IdH to weaken HB interactions, and the resulting N-heterocyclic olefin (NHO) type IL IdMe with softer Lewis base character is studied in both hybrid quasi-2D (Q-2D) and 3D perovskites. It is revealed that IdMe participates in constructing high-quality Q-2D perovskite (n = 4) and provides stronger passivation for 3D perovskite compared with IdH. Power conversion efficiency (PCE) of Q-2D PEA2 MA3 Pb4 I13 perovskite solar cells (PVSCs) is boosted to 17.68% from 14.03%. PCE and device stability of 3D PVSCs enhances simultaneously. Both theoretical simulations and experimental results show that LAB interactions between NHO and Pb2+ take the primary optimization effects on perovskite. The success of engineering LAB interactions also offers inspiration to develop novel ILs for high-performance PVSCs.

Light/Force-Sensitive 0D Lead-Free Perovskites: From Highly Efficient Blue Afterglow to White Phosphorescence with Near-Unity Quantum Efficiency.

Herein, new types of zero-dimensional (0D) perovskites (PA6InCl9 and PA4InCl7) with blue room-temperature phosphorescence (RTP) were obtained from InCl3 and aniline hydrochloride. These are highly sensitive to external light and force stimuli. The RTP quantum yield of PA6InCl9 can be enhanced from 25.2 % to 42.8 % upon illumination. Under mechanical force, PA4InCl7 exhibits a phase transform to PA6InCl9, thus boosting ultralong RTP with a lifetime up to 1.2 s. Furthermore, white and orange pure RTP with a quantum yield close to 100 % can be realized when Sb3+ was introduced into PA6InCl9. The white pure phosphorescence with a color-rendering index (CRI) close to 90 consists of blue RTP of PA6InCl9 and orange RTP of Sb3+ . Thus, this work not only overcomes long-standing problems of low quantum yield and short lifetime of blue RTP, but also obtains high-efficiency white RTP. It provides a feasible method to realize near-unity quantum efficiency and has great application potential in the fields of optical devices and smart materials.

Multicolor Output from 2D Hybrid Perovskites with Wide Band Gap: Highly Efficient White Emission, Dual-Color Afterglow, and Switch between Fluorescence and Phosphorescence.

Herein, an organic fluorophore termed NLAC is introduced into 2D hybrid perovskites with wide band gap (>3.54 eV) to give a green emission with quantum yield up to 81%. The highly efficient luminescence is ascribed to avoiding the aggregation of NLAC and formation of an inorganic free exciton which is easy to thermally quench. On this basis, a new strategy to generate efficient white emission with afterglow has been proposed by codoping a short-wavelength fluorophore and long-wavelength phosphor into 2D organic-inorganic hybrid perovskites (OIHPs). As a result, a single-component white-light-emitting material PEPC-3N based on NLAC with CIE of (0.33, 0.36) and quantum yield up to 43% can be obtained. Interestingly, PEPC-3N shows a dual-color organic afterglow and excitation-wavelength-dependent emission, consequently forming a switch between green fluorescence and yellow afterglow. This unique performance indicates PEPC-3N has huge potential in afterglow WLEDs and information storage.

Highly Efficient Organic Afterglow from a 2D Layered Lead-Free Metal Halide in Both Crystals and Thin Films under an Air Atmosphere.

Organic afterglow materials (OAMs) with a lifetime longer than 0.1 s have recently received much attention for their fascinating properties meeting the critical requirements of applications in newly emerged technologies. However, the development of OAMs lags behind for their low luminescence efficiency. Usually, enhancing the phosphorescence efficiency of organic materials causes a short lifetime. Here, we report two kinds of OAMs, two-dimensional (2D) layered organic-inorganic hybrid zinc bromides (PEZB-NTA and PEZB-BPA), obtained in an environmentally friendly ethanol solvent by a low-temperature solution method. They display highly efficient and persistent luminescence in air in both crystals and thin films with phosphorescence quantum yields up to 42% in crystals and 27% in films. For OAMs, the two quantum yields are the highest values ever reported for crystals and films. Due to the excellent crystalline and film-forming ability, PEZB-NTA and PEZB-BPA in ethanol can be used as inks to construct patterns on various rigid and flexible substrates, including paper, iron, plastic, marble, tin foil, and cloth. Consequently, the novel OAMs show great application prospects in the fields of anti-counterfeiting and information storage because of their economic synthesis, solution processing, and easy operation.

Solution-processed, top-emitting, microcavity polymer light-emitting diodes for the pure red, green, blue and near white emission.

Top-emitting microcavity polymer light-emitting diodes (TMPLEDs) are of great significance for active matrix PLED displays with high color purity. However, the complex device structures of highly efficient microcavity organic light-emitting diodes fabricated by the full vapor deposition technology are not suitable for solution-processed PLEDs. Solution-processed TMPLEDs with simple device structures are promising candidates for large-area, mass production display techniques. In this work, three strategies were used to apply microcavity into PLEDs: (1) double Ag electrodes performed as the mirrors of cavity, instead of a multi-layer Bragg reflector, which simplified the device structure and fabrication process; (2) three solution-processed functional layers were specially designed for avoiding the inter-infiltration between the different solutions and to improve the interface contacts; (3) high order microcavities were utilized according to the optical simulation results, in which thick EMLs benefited from thickness control and reproductivity. As a result, the full-color emission including pure red, green, blue was realized, and quasi-white light was also achieved from a single polymer emitting material. The achievement of color purity always requires the sacrifice of part of the current efficiency due to the spectra narrowing, while the higher current efficiency of green TMPLED (10.08 cd A-1) compared to that of non-cavity PLED (~8.60 cd A-1) cast a light on future improvements.

Enhanced Performance and Stability of TiO2 -Nanoparticles-Based Perovskite Solar Cells Employing a Cheap Polymeric Surface Modifier.

Interface engineering of TiO2 nanoparticles (NPs)-based perovskite solar cells (PVSCs) is often necessary to facilitate the extraction and transport of charge carriers. In this work, poly[{9,9-bis[3'-(N,N-dimethyl)propyl]-2,7-fluorene}-alt-2,7-(9,9-dioctylfluorene)] (PFN) and polystyrene (PS) are demonstrated to be effective surface modifiers of the TiO2 NPs electron-transporting layer in n-i-p PVSCs. The low-cost insulating polymer PS performs better than the PFN conjugated polymer owing to its high film quality, low surface energy and insulating characteristics. A peak power conversion efficiency (PCE) of 15.09 % with an open-circuit voltage (VOC ) of 1.05 V and a PCE of 17.13 % with an ultrahigh VOC of 1.18 V is achieved with TiO2 NPs/PS-based PVSCs using poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and spiro-OMeTAD, respectively, as the hole-transporting material.

Optimization of Light Management Layers for Light Harvest of Perovskite Solar Cells.

Recently, with rapid development of perovskite solar cells, the record efficiency has exceeded 24.2%. However, the research of efficiency improvement never stops. This work introduces an effective approach to remarkably reduce the device reflection loss by using light management (LM) cover layer. A specific model combined with ray and wave optics was built to numerically optimize the texture of the LM layers for light harvesting in photovoltaics cells and explore the optical principles in the light trapping. The LM layer texture is made of 2D periodic triangle structures. Both symmetric and asymmetric triangle structures were investigated. The results indicate that asymmetric structures possess the close performance compared with symmetric ones, and notably, on contrary to the symmetric structures, the light trapping abilities are much more insensitive to the bottom thicknesses of asymmetric structures. It will benefit the practical fabrication, since the precise bottom thickness control can be avoided. From the optimization results, 3 optimal structures are found. With the optimal LM layers, a thin active layer (165nm) device is able to produce the short circuit current intensities (Jsc) of around 21mA/cm2, which is approximately equivalent to the Jsc of a thick active layer (800nm) device without LM layers. Meanwhile, about 23% power conversion efficiency (PCE) enhancement is achieved. On the other hand, active layer thickness also makes influence on the light trapping abilities. As the active layer thickness is increased from 165nm to 800nm, the Jsc only improves by about 2.4mA/cm2, while the PCE enhancement is dropped from ~23% to ~11%. In consideration of the compromise between total device energy output and PCE enhancement, as well as material cost reduction, the active layer with around 165nm should be an optimal thickness.

Perylene Diimide-Based Electron-Transporting Material for Perovskite Solar Cells with Undoped Poly(3-hexylthiophene) as Hole-Transporting Material.

Perylene diimide-based small molecules are widely used as intermediates of liquid crystals, owing to their high planarity and electron mobility. In this study, tetrachloroperylene diimide (TCl-PDI) was used as a small-molecule replacement for TiO2 as electron-transporting material (ETM) for planar perovskite solar cells (PVSCs). Among hole-transporting materials (HTMs) for PVSCs, poly(3-hexylthiophene) (P3HT) gives the devices the highest stability and reproducibility. Therefore, PVSCs with the structure of indium tin oxide (ITO)/ETM/perovskite/P3HT/MoO3 /Ag were used to evaluate the performances of new ETMs. A reference device with compact TiO2 and P3HT gave a reasonable power conversion efficiency (PCE) of 12.78 %, whereas the PVSC with TCl-PDI as ETM gave an enhanced PCE of 14.73 %, which is among the highest reported values for PVSCs with undoped P3HT as the HTM. Moreover, TCl-PDI-based devices displayed higher stability than those based on compact TiO2 , owing to the superior perovskite quality.

Randomized controlled clinical trial of polyethylene glycol recombinant human granulocyte colony-stimulating factor in the treatment of neutropenia after chemotherapy for breast cancer.

PURPOSE: To explore the efficacy and safety of daily administration of recombinant human granulocyte colony-stimulating factor (rhG-CSF), and a single subcutaneous injection of polyethylene glycol recombinant human granulocyte colony-stimulating factor (PEG-rhG-CSF, a sustained-duration rhG-CSF) in neutropenia induced after chemotherapy. METHODS: Each patient received two cycles of chemotherapy. In the trial cycle, the patients received a single subcutaneous injection of PEG-rhG-CSF 100 µg/kg 72 h after completion of chemotherapy; and in the control cycle, rhG-CSF 5 µg/kg/day was subcutaneous injected once a day which began 72 h after completion of chemotherapy for continued 14 days or until the absolute neutrophil count (ANC) was ≥ 10.0 × 109/l twice. Therapeutic effect on primary endpoint was the incidence and duration of grade IV ANC neutropenia: comparing the incidence and the mean time of duration of PEG-rhG-CSF with those of rhG-CSF under the circumstance of ANC < 0.5 × 109/l. The immune populations evaluated included, CD3+ T cells, CD4+ T cells, CD8+ T cells, and NK cells. RESULTS: After chemotherapy, comparing to PEG-rhG-CSF, the CD4/CD8 ratio (0.84 ± 0.19 vs.1.06 ± 0.25) and the number of NK cells of rhG-CSF group (12.18 ± 2.13 vs. 15.78 ± 2.57) decreased significantly. The number of NK cells (12.18 ± 2.13 vs. 13.78 ± 2.57) of rhG-CSF group after chemotherapy is significantly less than that before chemotherapy, and the number of CD3+ (54.31 ± 7.51 vs. 57.96 ± 5.55), CD4+ (26.28 ± 6.25 vs. 29.48 ± 6.44), CD8+ (29.97 ± 6.47 vs. 31.68 ± 5.96) is lower than that before chemotherapy in rhG-CSF group, but the difference is not significant. CONCLUSION: The efficacy and side effects of a single subcutaneous injection of PEG-rhG-CSF were similar to that of rhG-CSF multiple administrations. PEG-rhG-CSF may have the effect of promoting immune function repairing.

Highly efficient room-temperature phosphorescence and afterglow luminescence from common organic fluorophores in 2D hybrid perovskites.

Regardless of rapid development of organic room-temperature phosphorescence (RTP) originating from phosphors in crystals, highly efficient and persistent RTP from common fluorophores is very rare. Herein, 1,8-naphthalimide (NI), a common organic fluorophore, is doped into organic cations of 2D layered organic/inorganic hybrid perovskites (OIHPs) to yield thin films and powders with yellow RTP of NI in air. The triplet excitons of NI are mainly derived from Wannier excitons of inorganic perovskite through energy transfer (ET) for films, and from singlet excitons of NI through intersystem crossing (ISC) for powder. Consequently, the quantum yield (Φ P), lifetime (τ) and color of RTP can be tuned by changing the fluorophore and halide in the perovskites, as well as their solid morphology. A white emission, comprising the blue one from the perovskite and yellow RTP (Φ P = 25.6%, τ = 6.3 ms) from NI, is obtained in Br-based OIHPs in powder. Cl-based OIHPs exhibit fluorescence/phosphorescence dual emission in thin films, and yellow afterglow phosphorescence in powders (Φ P = 56.1%, τ = 35 ms). The unique performance of the OIHPs with RTP can make them widely applicable in the field of information technology as security ink, and white and afterglow LEDs as single luminescent materials.

Dual-core star-shaped single white polymers: the effect of host structure on luminescence properties.

The non-emissive benzene ring and green-emissive arylmaleimide are employed as two independent cores to construct dual-core white star-shaped polymers (DC-PFMs). Due to the totally star-shaped structure, DC-PFMs display a higher quantum yield and electroluminescence efficiency for a more efficient energy transfer from the host to the guest than traditional single-core polymers (SC-PFMs).

The efficacy and safety of endostar combined with taxane-based regimens for HER-2-negative metastatic breast cancer patients.

The purpose of the present study was to prospectively evaluate the efficacy and safety of endostar, a recombinant product of endostatin, combined with taxane-based regimens for HER-2 negative metastatic breast cancer (MBC) patients. Women with ages between 18-70 years with histologically confirmed MBC documented as HER-2-negative were included. Endostar was administered at 7.5 mg/m2, d1-14, q21d and was continued until progressive disease, unacceptable toxicity, consent withdrawal, or completion of 24 months of endostar, whichever came first. Taxane-based chemotherapy was continued until progressive disease, unacceptable toxicity, consent withdrawal, or up to 8 cycles. The primary endpoint was overall response rate (ORR). Fifty-seven patients were recruited. The ORRs for the whole population, first-, second-, and third-line therapy or beyond were 68.4%, 79.3%, 54.5%, and 16.7%, respectively. The median PFS was 10.8 (8.0-12.1) months, yet the median OS was still not attained. For the patients receiving first-, second-, and third-line therapy or beyond, median PFS was 11.9, 7.5, and 7.4 months, respectively (P=0.048). No significant difference in median PFS between hormonal receptor-positive and -negative patients was observed. The most common drug-related grade 3-4 hematologic toxicities were neutropenia (80.7%) and leukopenia (77.2%). Six (10.5%) patients experienced febrile neutropenia. The most frequent drug-related grade 3-4 non-hematologic toxicities were liver dysfunction (10.5%) and peripheral neurotoxicity (8.8%). No treatment-related deaths were reported. We conclude that Endostar combined with taxane-based regimens may be effective and safe for the treatment of HER-2-negative MBC. However, further investigations on its long-term efficacy and toxicity are warranted.

Photoreactive and Metal-Platable Copolymer Inks for High-Throughput, Room-Temperature Printing of Flexible Metal Electrodes for Thin-Film Electronics.

Photoreactive and metal-platable copolymer inks are reported for the first time to allow high-throughput printing of high-performance flexible electrodes at room temperature. This new copolymer ink accommodates various types of printing technologies, such as soft lithography molding, screen printing, and inkjet printing. Electronic devices including resistors, sensors, solar cells, and thin-film transistors fabricated with these printed electrodes show excellent electrical performance and mechanical flexibility.

Full-solution processed flexible organic solar cells using low-cost printable copper electrodes.

Full-solution-processed flexible organic solar cells (OSCs) are fabricated using low-cost and high-quality printable Cu electrodes, which achieve a power conversion efficiency as high as 2.77% and show remarkable stability upon 1000 bending cycles. This device performance is thought to be the best among all full-solution-processed OSCs reported in the literature using the same active materials. This printed Cu electrode is promising for application in roll-to-roll fabrication of flexible OSCs.

Design of reflective color filters with high angular tolerance by particle swarm optimization method.

We propose three color filters (red, green, blue) based on a two-dimensional (2D) grating, which maintain the same perceived specular colors for a broad range of incident angles with the average polarization. Particle swarm optimization (PSO) method is employed to design these filters for the first time to our knowledge. Two merit functions involving the reflectance curves and color difference in CIEDE2000 formula are respectively constructed to adjust the structural parameters during the optimization procedure. Three primary color filters located at 637nm, 530nm and 446nm with high saturation are obtained with the peak reflectance of 89%, 83%, 66%. The reflectance curves at different incident angles are coincident and the color difference is less than 8 for the incident angle up to 45°. The electric field distribution of the structure is finally studied to analyze the optical property.

Embedded surface relief gratings by a simple method to improve absorption and electrical properties of polymer solar cells.

We demonstrate a simple rubbing hole injection layer (HIL) to form surface relief gratings (SRGs) on the functional layers of polymer solar cells (PSCs). PSCs studied in this work consist of an ITO/PEDOT:PSS(HIL)/P3HT:PCBM(photoactive layer)/LiF/Al structure. SRGs are successfully formed on HIL in an effective rubbing process, and are over printed on the photoactive layer and cathode consequently. These triplet SRGs change the morphologies of interfaces of PSCs, which can increase optical path lengths, interaction between HIL and P3HT chains, and interface areas between electrode and photoactive layer. Both light trapping and electrical improvement are confirmed by theory and experiments, which lead to overall increase in short-circuit current density, fill factor, and power conversion efficiency (PCE) of PSCs. An average PCE of 3.8% is achieved from PSCs with SRGs without thermal annealing. Different from the directly rubbing the donor polymer film, a suitable degree of orientation of P3HT presents a lower dichroic ratio and higher photovoltaic response in our work.

Large endohedral fullerenes containing two metal ions, Sm2@D2(35)-C88, Sm2@C1(21)-C90, and Sm2@D3(85)-C92, and their relationship to endohedral fullerenes containing two gadolinium ions.

The carbon soot obtained by electric arc vaporization of carbon rods doped with Sm(2)O(3) contains a series of monometallic endohedral fullerenes, Sm@C(2n), along with smaller quantities of the dimetallic endohedrals Sm(2)@C(2n) with n = 44, 45, 46, and the previously described Sm(2)@D(3d)(822)-C(104). The compounds Sm(2)@C(2n) with n = 44, 45, 46 were purified by high pressure liquid chromatography on several different columns. For endohedral fullerenes that contain two metal atoms, there are two structural possibilities: a normal dimetallofullerene, M(2)@C(2n), or a metal carbide, M(2)(µ-C(2))@C(2n-2). For structural analysis, the individual Sm(2)@C(2n) endohedral fullerenes were cocrystallized with Ni(octaethylporphyrin), and the products were examined by single-crystal X-ray diffraction. These data identified the three new endohedrals as normal dimetallofullerenes and not as carbides: Sm(2)@D(2)(35)-C(88), Sm(2)@C(1)(21)-C(90), and Sm(2)@D(3)(85)-C(92). All four of the known Sm(2)@C(2n) endohedral fullerenes have cages that obey the isolated pentagon rule (IPR). As the cage size expands in this series, so do the distances between the variously disordered samarium atoms. Since the UV/vis/NIR spectra of Sm(2)@D(2)(35)-C(88) and Sm(2)@C(1)(21)-C(90) are very similar to those of Gd(2)C(90) and Gd(2)C(92), we conclude that Gd(2)C(90) and Gd(2)C(92) are the carbides Gd(2)(µ-C(2))@D(2)(35)-C(88) and Gd(2)(µ-C(2))@C(1)(21)-C(90), respectively.

Isolation and crystallographic identification of four isomers of Sm@C90.

Four isomers with the composition SmC(90) were obtained from carbon soot produced by electric arc vaporization of carbon rods doped with Sm(2)O(3). These were labeled Sm@C(90)(I), Sm@C(90)(II), Sm@C(90)(III), and Sm@C(90)(IV) in order of their elution times during chromatography on a Buckyprep column with toluene as the eluent. Analysis of the structures by single-crystal X-ray diffraction on cocrystals formed with Ni(octaethylporphyrin) reveals the identities of the individual isomers as follows: I, Sm@C(2)(40)-C(90); II, Sm@C(2)(42)-C(90); III, Sm@C(2v)(46)-C(90) and IV, Sm@C(2)(45)-C(90). This is the most extensive series of isomers of any endohedral fullerene to have their individual structures determined by single-crystal X-ray diffraction. The cage structures of these four isomers can be related pairwise to one another in a formal sense through sequential Stone-Wales transformations.