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Origami-based membrane structures have shown great potential to revolutionize the construction of deployable and lightweight space structures in the future. However, the efficient unfolding mechanism puts forward major challenges to the practical realization of space-deployable structures. Here, a smart grid-reinforced membrane origami (SGRMO) is presented. The unfolding action hinges upon the application of forces facilitated by shape memory polymer composites (SMPCs). Subsequent locking action ensues through the restoration of the initial rigidity, accomplished via cooling mechanisms. This novel structure achieves the required lightweight and functionality by employing the grid design concept and effectively reduces the decline in unfolding extent caused by irreversible plastic deformation at the crease. Its recovery properties, including unfolding angle, distance, and surface precision, are experimentally and analytically investigated under different conditions. The results indicate that the structure can be reliably unfolded into the predefined shapes. In the case of Miura-SGRMO, the optimal surface precision is attained when the angle-ψ registers at 30°. The results of this study are expected to serve as the design of ultra-large flexible solar arrays and deployable antenna structures. [ABSTRACT FROM AUTHOR]

To get insights into the relationship between molecular structure and performance in photovoltaic cells, two small molecules of T(3TDRCN)2 and Pr(3TDRCN)2 were synthesized with an A‐π‐D‐π‐A type backbone structure. The T(3TDRCN)2 and Pr(3TDRCN)2 were using n‐octyl side chains substituted trithiophene (3T) as the π‐linker and 2‐(1,1‐dicyanomethylene)‐rhodanine (DRCN) as terminal acceptor (A) group, while varied the central donor (D) unit from thiophene (T) to 2,7‐pyrene (Pr). Both SMs were applied as donor materials along with fullerene acceptor (PC71BM) for solution‐processed bulk‐heterojunction solar cells. The impacts of central donor units on their optical absorption, electrochemical property, hole mobility, and solar cell performance were primarily studied. The T(3TDRCN)2:PC71BM based devices yielded a power conversion efficiency (PCE) of 2.60 % with an open circuit voltage (Voc) of 0.89 V. Interestingly, the Pr(3TDRCN)2 based solar cell exhibited an higher PCE of 4.47 % with an improved Voc of 0.95 V. Our work indicates that using large π‐conjugated aromatic donor with weak‐electron donating property as central unit can improve Voc, as well as high photovoltaic efficiency of the A‐π‐D‐π‐A type SMs in organic solar cells. [ABSTRACT FROM AUTHOR]

Increasing molecular π‐conjugation length generally improves the light‐harvesting ability and enhancing π‐π stacking interactions could improve the charge‐carrier transport ability in small molecules (SMs). Both are beneficial for increasing power conversion efficiencies (PCEs) in organic solar cells. In this work, two linear (A−D)2Ar‐type SMs of (DTBT‐TPA)2An and (DPP‐TPA)2An were designed and synthesized, in which 4,7‐di(thiophen‐2‐yl)benzothiadiazole (DTBT) and diketopyrrolopyrrole (DPP) were selected as electron acceptors (A), triphenylamine (TPA) was used as electron donor (D) and 9,10‐anthracene (An) was used as π‐bridge (Ar group), respectively. For comparison, two D−A‐type SMs of DTBT‐TPA and DPP‐TPA were also prepared without anthracene unit. By systematically comparing their optical and electronic properties, it was found that (A−D)2Ar‐type SMs show stronger photo response with higher absorption coefficients than the D−A‐type counterparts. And introducing anthracene unit could slightly lower their HOMOs of the resulting (A−D)2Ar‐type SMs. In bulk heterojunction solar cells, PCEs of 1.72% and 1.36% were achieved in (DTBT‐TPA)2An and (DPP‐TPA)2An based devices without any solvent additive, which are about 1.5 and 1.9 times the corresponding values of the DTBT‐TPA and DPP‐TPA based devices, respectively. Two (D−A)2Ar‐type small molecules (SMs) of (DTBT‐TPA)2An and (DPP‐TPA)2An with anthracene unit were synthesized. Both SMs exhibited higher light‐harvesting ability and lower HOMOs than the corresponding D−A‐type SMs of DTBT‐TPA and DPP‐TPA, which resulted in much better photovoltaic performance. The highest power conversion efficiency (PCE) of 1.72% with a Jsc of 6.17 mA/cm2 was achieved in (DTBT‐TPA)2An based organic solar cell. [ABSTRACT FROM AUTHOR]

Small molecules of ThQuTh, CzQuTh, CzQuCz and TPAQuCz were designed and synthesized, based on quinoxaline acceptor, and electron donating groups, i.e. alkyl-thioephene, carbazole and triphenylamine on both side chains and molecular backbones. Their thermal, optical and electrochemical properties were systematically compared and studied. The absorption spectra of the small molecules were strongly affected by the donor units attached to quinoxaline. Strong electron donating groups, such as carbazole on the molecular backbone would lower optical band gap, resulting in a wide absorption and the strong donor on the side chain would enhance the absorption intensity in short wavelength region. The highest occupied molecular orbital (HOMO) energy levels of the four molecules were up-shifted with increasing the electron donating properties of donor units. The bulk-heterojunction organic solar cells with a device structure of ITO/PEDOT:PSS/SMs:PC61BM/LiF/Al were fabricated, in which the small molecules functioned as donors while PC61BM as acceptor. Because the electron-donating ability of carbazole (Cz), triphenylamine (TPA) is higher than that of thiophene (Th), CzQuTh, CzQuCz and TPAQuCz show higher power conversion efficiency (PCE) than that of ThQuTh. Furthermore, being the strongest in absorption intensity and widest in absorption spectrum, TPAQuCz has the highest power conversion efficiency. Further improvement of the device efficiency by optimizing the device structure is currently under investigation [ABSTRACT FROM AUTHOR]

Novel multi-walled carbon nanotubes (MWCNTs) and copper phthalocyanine (CuPc) modified conductive silver-plated fiber (MCA-fiber) was successfully prepared via chemical liquid deposition method with polyester as soft template. The structures and morphologies were characterized by X-ray photoelectron spectroscopy and field emission scanning electron microscopy. The binding energy of oxygen and carbon are 543, 296 eV respectively and the SEM images show CuPc and MWCNTs are deposited on the surface of silvered fiber continuously. The MCA-fiber is about 75 μm in diameter. The effect of process conditions on the properties of MCA-fiber was investigated. With the increasing of the concentration of AgNO, the coating amount and electrical conductivity first increase and then decrease. The decrease of MWCNTs can bring down the electrical conductivity, but can improve the coating amount of materials on the surface of fibers. There is a sharp decrease from 7.20 × 10 to 1.33 × 10 s/cm when the MWCNT-doping content is 20 %. When the doping ratio of MWCNTs and CuPc is 2:8, the coating amount rises to 19.2 %. The mechanism study on the photovoltaic properties of MCA-fiber verifies that it can be used in fiber-shaped solar cells. [ABSTRACT FROM AUTHOR]

A new photoanode by employing Ni 2+ doping of CdS used to fabricate PbS and Ni 2+ doped CdS cosensitized quantum dot-sensitized solar cell (QDSSCs). Under AM 1.5 G (100 mW/cm 2 ) illumination, the cell device exhibit a power conversion efficiency (η) of 3.60 %, which is higher than the value of 2.65 % obtained with CdS without dopant. The improved photoelectric performance is due to the impurities from Ni 2+ doping of CdS, which have an impact on the electronic and photophysical properties, and the dopant creates electronic states in the midgap region of CdS thus altering the charge separation and recombination dynamics. Furthermore, the cell device based on the Ni 2+ doped CdS photoanode shows superior stability in the sulfide/polysulfide electrolyte, resulting in a highly reproducible performance, which is a serious challenge for the Ni 2+ doped solar cell. This finding can provide an effective method for the fabrication of new photoanode, which can pave the way to further improve the power conversion efficiency of the future QDSSCs. [ABSTRACT FROM AUTHOR]

Highlights: [•] The synthetic of ZnS/CdS QDs/AHC-ZnO photoanode with a simple method. [•] The power conversion efficiency of the ZnS/CdS QDs/AHC-ZnO is 1.81%. [•] The effects of photovoltaic performances caused by CdS and ZnS amounts were studied. [•] ZnS passivation layer enhanced electron lifetime significantly. [Copyright &y& Elsevier]

Two novel D(A-Ar) 2 type small molecules (SMs) of 3T(DPP-BTI) 2 and 4T(DPP-BTI) 2 were synthesized and characterized, which contain diketopyrrolopyrrole (DPP) arms, 6-dodecyl-6 H -benzo[4,5]thieno[2,3- b ]indole (BTI) terminals, and oligomerthiophene donor unit (3T=trithiophene, 4T=tetrathiophene). The relation-ship between structure and property was investigated. Compared with their corresponding parent A-D-A type SMs, both D(A-Ar) 2 type SMs exhibited a significantly increasing circuit current density ( J sc ) by 1.39∼1.59 times and hole mobility (μ h ) by one order of magnitude, as well as a comparable power conversion efficiency (PCE) in their OPV and hole-only devices. The better photovoltaic properties with PCE of 3.02% and J sc of 10.41 mA cm −2 were obtained in the 3T(DPP-BTI) 2 based OPV cells. It indicates that appending the BTI terminal unit into A-D-A-type SMs is beneficial to increasing the J sc and μ h values of its resulting D(A-Ar) 2 type SMs in their corresponding devices. [ABSTRACT FROM AUTHOR]

The emergence of non-fullerene acceptors (NFAs) has revived organic solar cells (OSCs) and promoted its industrialization significantly. Nowadays there are two main kinds of fused-ring electron acceptors: ITIC series and Y-series NFAs. Herein, two hybrid NFAs TIT-H and TIT-EH integrated ITIC series and Y-series NFAs have been developed, which based on thieno[2′,3′:4,5]thieno[3,2- b ]indole-thiophene with one spiro group. TIT-H and TIT-EH both exhibited excellent thermal stability, low optical bandgaps of ∼1.5 eV, planar molecular geometries, and suitable energy levels. As a result, OSCs based on PM6:TIT-EH afforded a decent PCE of 13.32 %, with an V OC of 0.856 V, a J SC of 23.50 mA/cm2 and a FF of 65.91 %, which was due to the suitable intermolecular interactions of TIT-EH, balanced charge carrier mobilities and face-on orientation in blend films. As comparison, PM6:TIT-H cell exhibited lower PCE of 12.26 %. These results demonstrated that hybrid NFAs are promising for OSC applications. [Display omitted] • Two hybrid nonfullerene acceptors TIT-H and TIT-EH based on thieno[2′,3′:4,5]thieno[3,2- b ]indole were synthesized. • These NFAs exhibited low optical bandgaps of ∼1.5 eV, planar molecular geometries, and suitable energy levels. • OSCs based on PM6:TIT-H or PM6:TIT-EH achieved decent PCEs of 12.26 % or 13.32 %, respectively. [ABSTRACT FROM AUTHOR]

Two novel polymer donors PBF-STTz and PBSiCl-STTz based on benzo [1,2- b :4,5- b ']dithiophene (BDT) and thiazolo[5,4- d ]thiazole (TTz) with alkythiol side chain and different heteroatoms (F, Cl, Si) modification were designed and synthesized. Both polymers show the similar and strong absorption within the range of 300 nm–650 nm. By incorporation the Cl atoms, Si alkyl chains and thioalkyl chains, the deeper HOMO level of PBSiCl-STTz was obtained to −5.59 eV. The PBSiCl-STTz:Y6-based device achieved an optimized power conversion efficiency (PCE) of 7.61%. While the device based on PBF-STTz:Y6 shows better PCE of 11.01% because of its better blend film morphology. In addition, in order to enhance the photovoltaic performance of device based on PBF-STTz, we fabricated devices using L8-BO as the acceptor and PBF-STTz as the donor. Due to better suppression of charge recombination probability, higher and more balanced hole and electron mobilities, as well as further improved blend film morphology, the PBF-STTz:L8-BO-based device achieved higher PCE of 11.52% with a boosted V oc and FF of 0.909 V and 66.25%, respectively. These results not only advance our understanding of the structure-performance relationships of BDT-TTz based donor polymers, but also provide a new avenue to design high-performance donor materials. [Display omitted] [ABSTRACT FROM AUTHOR]

Highlights: [•] Two novel D–A–Ar-type small molecules were obtained as photovoltaic materials. [•] The photophysical and photovoltaic properties were investigated. [•] Both molecules showed better photovoltaic property than the D–A-type counterpart. [•] The improved photovoltaic property for the D–A–Ar-type molecules was explained. [Copyright &y& Elsevier]

Graphical abstract: A new donor–acceptor–donor ternary copolymer PTh-BDT-2DTDPP pending additional diketopyrrolopyrrole unit in the side of a donor unit has been synthesized and characterized. The bulk heterojunction polymer solar cells with an active layer of PTh-BDT-2DThDPP and PC61BM showed a high power conversion efficiency of 4.36%. Display Omitted Highlights: [•] The D–A–D ternary copolymer with diketopyrrolopyrrole side chain was synthesized. [•] This ternary copolymer exhibited a broad absorption spectrum from 300nm to 850nm. [•] This ternary copolymer showed a decreased HOMO energy level of −5.31eV. [•] The made bulk heterojunction solar cells displayed improved photovoltaic properties. [•] The maximum power conversion efficiency of 4.36% was observed in these solar cells. [ABSTRACT FROM AUTHOR]