Hexaxial external fixator versus intramedullary nail in treating segmental tibial fractures: a retrospective study.

BACKGROUND: It's difficult to treat segmental tibial fractures (STFs), which are intricate injuries associated with significant soft tissue damage. The aim of this study was to compare the clinical effect of hexaxial external fixator (HEF) and intramedullary nail (IMN) in treatment of STFs. METHODS: A total of 42 patients with STFs were finally recruited between January 2018 and June 2022. There were 25 males and 17 females with age range of 20 to 60 years. All fractures were classified as type 42C2 using the Arbeitsgemeinschaftfür Osteosythese/Orthopaedic Trauma Association (AO/OTA) classification. 22 patients were treated with HEF and 20 patients were treated with IMN. The condition of vascular and neural injuries, time of full weight bearing, bone union time and infection rate were documented and analyzed between the two groups. The mechanical medial proximal tibial angle (mMPTA), mechanical posterior proximal tibial angle (mPPTA), mechanical lateral distal tibial angle (mLDTA), mechanical anterior distal tibial angle (mADTA), hospital for special surgery (HSS) knee joint score, American Orthopaedic Foot and Ankle Society (AOFAS) ankle joint score, range of motion (ROM) of flexion of keen joint and ROM of plantar flexion and dorsal flexion of ankle joint were compared between the two groups at the last clinical visit. RESULTS: There were no vascular and neural injuries or other severe complications in both groups. All 22 patients in HEF group underwent closed reduction but 3 patients in IMN group were treated by open reduction. The time of full weight bearing was (11.3 ± 3.2) days in HEF group and (67.8 ± 5.8) days in IMN group(P < 0.05), with bone union time for (6.9 ± 0.8) months and (7.7 ± 1.4) months, respectively(P < 0.05). There was no deep infection in both groups. In the HEF group and IMN group, mMPTA was (86.9 ± 1.5)° and (89.7 ± 1.8)°(P < 0.05), mPPTA was (80.8 ± 1.9)° and (78.6 ± 2.0)°(P < 0.05), mLDTA was (88.5 ± 1.7)° and (90.3 ± 1.7)°(P < 0.05), while mADTA was (80.8 ± 1.5)° and (78.4 ± 1.3)°(P < 0.05). No significant differences were found between the two groups at the last clinical visit concerning HSS knee joint score and AOFAS ankle joint score, ROM of flexion of keen joint and ROM of plantar flexion of ankle joint (P > 0.05). The ROM of dorsal flexion of ankle joint in IMN group was (30.4 ± 3.5)°, better than (21.6 ± 2.8)° in HEF group (P < 0.05). CONCLUSION: In terms of final clinical outcomes, the use of either HEF or IMN for STFs can achieve good therapeutic effects. While HEF is superior to IMN in terms of completely closed reduction, early full weight bearing, early bone union and alignment. Nevertheless, HEF has a greater impact on the ROM of dorsal flexion of the ankle joint, and much more care and adjustment are needed for the patients than IMN.

Spectra stable deep-blue light-emitting diodes based on cryolite-like cerium(III) halides with nanosecond d-f emission.

Next-generation wide color gamut displays require the development of efficient and toxic-free light-emitting materials meeting the crucial Rec. 2020 standard. With the rapid progress of green and red perovskite light-emitting diodes (PeLEDs), blue PeLEDs remain a central challenge because of the undesirable color coordinates and poor spectra stability. Here, we report Cs3CeBrxI6-x (x = 0 to 6) with the cryolite-like structure and stable and tunable color coordinates from (0.17, 0.02) to (0.15, 0.04). Further encouraged by the short exciton lifetime (26.1 ns) and high photoluminescence quantum yield (~76%), we construct Cs3CeBrxI6-x-based rare-earth LEDs via thermal evaporation. A seed layer strategy is conducted to improve the device's performance. The optimal Cs3CeI6 device achieves a maximum external quantum efficiency of 3.5% and a luminance of 470 cd m-2 with stable deep-blue color coordinates of (0.15, 0.04). Our work opens another avenue to achieving efficient and spectrally stable deep-blue LEDs.

B-Site Columnar-Ordered Halide Double Perovskites: Theoretical Design and Experimental Verification.

Halide double perovskites A2B(I)B(III)X6, in which monovalent B(I) and trivalent B(III) cations are arranged in the B-sites of the perovskite structure with a rock-salt ordering, have attracted substantial interest in the field of optoelectronics. However, the rock-salt ordering generally leads to low electronic dimensionality, with relatively large bandgaps and large carrier effective masses. In this work, we demonstrate, by density functional theory (DFT) calculations, that the electronic dimensionality and thus the electronic properties of halide double perovskites can be effectively modulated by manipulating the arrangement of the B-site cations. Through symmetry analysis and DFT calculations, we propose a family of halide double perovskites A2B(I)B(II)X5 where the B-site cations adopt a columnar-ordered arrangement. Among the considered compounds, Cs2AgPdCl5, Cs2AgPdBr5, and Cs2AgPtCl5 were successfully synthesized as the first examples of the B-site columnar-ordered halide double perovskites. These compounds exhibit small bandgaps of 1.33-1.77 eV that are suitable for visible light absorption, small carrier effective masses along the octahedra chains, and good thermal and air stability. Our work provides a prototype double perovskite structure to incorporate cations in +1 and +2 oxidation states, which may significantly expand the large family of the halide double perovskites and offer a platform to explore prospective optoelectronic semiconductors.

Lead-Free Perovskite Variant Solid Solutions Cs2 Sn1- x Tex Cl6 : Bright Luminescence and High Anti-Water Stability.

Underwater lighting is important for the exploration of the underwater world in different areas. It is of great significance for developing underwater emitters with high penetrability, high luminous efficiency, good anti-water stability, and environmental friendliness. Stable lead-free perovskite luminescent materials, represented by vacancy-ordered double perovskites, are worthy of research because they can almost meet the above requirements. Here, lead-free perovskite variant solid solutions with the formula of Cs2 Sn1- x Tex Cl6 are reported. Upon the exchange of Sn/Te ions, strong Jahn-Teller distortion of octahedra occurs in the lattice structure. The combination of Te luminescent center and Jahn-Teller-like self-trapped excitons gives this material yellow-green luminescence with a wavelength of 580 nm and a high photoluminescence quantum yield of 95.4%. Moreover, these solid solutions can withstand the extreme conditions of immersion in water probably due to the formation of amorphous alteration phase. Such good anti-water stability is also supported by the molecule dynamics simulation result that no reaction occurs on the water/Cs2 SnCl6 interface. The high luminous, suitable wavelength, and good anti-water stability enable the solid solutions suitable for the application for underwater lighting.

Efficiency above 12% for 1 cm2 Flexible Organic Solar Cells with Ag/Cu Grid Transparent Conducting Electrode.

With the rapid progress of organic solar cells (OSCs), improvement in the efficiency of large-area flexible OSCs (>1 cm2) is crucial for real applications. However, the development of the large-area flexible OSCs severely lags behind the growth of the small-area OSCs, with the electrical loss due to the large sheet resistance of the electrode being a main reason. Herein, a high conductive and high transparent Ag/Cu composite grid with sheet resistance <1 Ω sq-1 and an average visible light transparency of 84% is produced as the transparent conducting electrode of flexible OSCs. Based on this Ag/Cu composite grid electrode, a high efficiency of 12.26% for 1 cm2 flexible OSCs is achieved. The performances of large-area flexible OSCs also reach 7.79% (4 cm2) and 7.35% (9 cm2), respectively, which are much higher than those of the control devices with conventional flexible indium tin oxide electrodes. Surface planarization using highly conductive PEDOT:PSS and modification of the ZnO buffer layer by zirconium acetylacetonate (ZrAcac) are two necessary steps to achieve high performance. The flexible OSCs employing Ag/Cu grid have excellent mechanical bending resistance, maintaining high performance after bending at a radius of 2 mm.

Synthesis of N,S-Doped Carbon Quantum Dots for Use in Organic Solar Cells as the ZnO Modifier To Eliminate the Light-Soaking Effect.

Zinc oxide (ZnO) is one of the most extensively used electron-transporting layers (ETLs) in organic solar cells. However, owing to numerous surface defects and mismatched energy bands with the photoactive layer, light-soaking process is usually required to achieve a high device performance for the ZnO-based cells. Herein, we reported the synthesis of N,S-doped carbon quantum dots (N,S-CQDs) by a simple hydrothermal treatment using ascorbic acid and ammonium persulfate as reagents. As characterized by high-resolution transmission electron microscopy and X-ray diffraction, the synthesized CQDs were found to be 2-7 nm in dimensions, having a graphite-structured core and amorphous carbon on the shell. Fourier transform infrared and X-ray photoelectron spectroscopy analyses confirmed that these CQDs are highly nitrogen- and sulfur-doped, which leads to efficient (with a quantum yield of 33%) downconversion and excitation-dependent photoluminescence character. Application of these N,S-CQDs as surface modifier for ZnO layer in inverted organic solar cells was investigated. Results indicate that the cells with N,S-CQDs-decorated ZnO ETL showed higher power conversion efficiency without S-shaped kink in the current density-voltage curves. The performance improvement and the elimination of light-soaking effect for ZnO:N,S-CQDs cells are attributed to the ZnO surface defect passivation by N,S-CQDs, as confirmed by fluorescence spectroscopy and scanning Kelvin probe microscopy. The cells with N,S-CQDs-modified ZnO ETL showed a high power conversion efficiency of 9.31%, which is higher than the reference ZnO cells. The current work provides a feasible way to achieve shell element-doped CQDs for specific application in organic electronic devices.

Silane-Capped ZnO Nanoparticles for Use as the Electron Transport Layer in Inverted Organic Solar Cells.

Zinc oxide (ZnO) nanoparticles are widely used as electron- transport layer (ETL) materials in organic solar cells and are considered to be the candidate with the most potential for ETLs in roll-to-roll (R2R)-printed photovoltaics. However, the tendency of the nanoparticles to aggregate reduces the stability of the metal oxide inks and creates many surface defects, which is a major barrier to its printing application. With the aim of improving the stability of metal oxide nanoparticle dispersions and suppressing the formation of surface defects, we prepared 3-aminopropyltrimethoxysilane (APTMS)-capped ZnO (ZnO@APTMS) nanoparticles through surface ligand exchange. The ZnO@APTMS nanoparticles exhibited excellent dispersibility in ethanol, an environmentally friendly solvent, and remained stable in air for at least one year without any aggregation. The capping of the ZnO nanoparticles with APTMS also reduced the number of surface-adsorbed oxygen defects, improved the charge transfer efficiency, and suppressed the light-soaking effect. The thickness of the ZnO@APTMS ETL could reach 100 nm without an obvious decrease in the performance. Large-area APTMS-modified ZnO films were successfully fabricated through roll-to-roll microgravure printing and exhibited good performance in flexible organic solar cells. This work demonstrated the distinct advantages of this ZnO@APTMS ETL as a potential buffer layer for printed organic electronics.

Fully Coated Semitransparent Organic Solar Cells with a Doctor-Blade-Coated Composite Anode Buffer Layer of Phosphomolybdic Acid and PEDOT:PSS and a Spray-Coated Silver Nanowire Top Electrode.

In the aim to realize high performance semitransparent fully coated organic solar cells, printable electrode buffer layers and top electrodes are two important key technologies. An ideal ink for the preparation of the electrode buffer layer for printed top electrodes should have good wettability and negligible solvent corrosion to the underlying layer. This work reports a novel organic-inorganic composite of phosphomolybdic acid (PMA) and PEDOT:PSS that features excellent wettability with the active layer and printed top Ag nanowires and high resistibility to solvent corrosion. This composite buffer layer can be easily deposited on a polymer surface to form a smooth, homogeneous film via spin-coating or doctor-blade coating. Through the use of this composite anode buffer layer, fully coated semitransparent devices with doctor-blade-coated functional layers and spray-coated Ag nanowire top electrodes showed the highest power conversion efficiency (PCE) of 5.01% with an excellent average visible-light transmittance (AVT) of 50.3%, demonstrating superior overall characteristics with a comparable performance to and a much higher AVT than cells based on a thermally evaporated MoO3/Ag/MoO3 thin film electrode (with a PCE of 5.77% and AVT of 19.5%). The current work reports the fabrication of fully coated inverted organic solar cells by combining doctor-blade coating and spray coating and, more importantly, demonstrates that a nanocomposite of a polyoxometalate and conjugated polymer could be an excellent anode buffer layer for the fully coated polymer solar cells with favorable interfacial contact, hole extraction efficiency, and high comparability with full printing.