Grazing incidence X‐ray scattering (GIXS) provides unique insights into the morphology of active materials and thin film layers used in organic photovoltaic devices. With grazing incidence wide angle ...X‐ray scattering (GIWAXS) the molecular arrangement of the material is probed. GIWAXS is sensitive to the crystalline parts and allows for the determination of the crystal structure and the orientation of the crystalline regions with respect to the electrodes. With grazing incidence small angle X‐ray scattering (GISAXS) the nano‐scale structure inside the films is probed. As GISAXS is sensitive to length scales from nanometers to several hundred nanometers, all relevant length scales of organic solar cells are detectable. After an introduction to GISAXS and GIWAXS, selected examples for application of both techniques to active layer materials are reviewed. The particular focus is on conjugated polymers, such as poly(3‐hexylthiophene) (P3HT).
The possibilities and limitations
of the advanced scattering techniques grazing incidence small angle X‐ray scattering (GISAXS) and grazing incidence wide angle X‐ray scattering (GIWAXS) are reviewed. Basics of both scattering techniques are explained and selected examples from application of GISAXS and for the use of GIWAXS in the analysis OPV device relevant structures are presented.
Organic electrochemical transistors (OECTs) are highly attractive for applications ranging from circuit elements and neuromorphic devices to transducers for biological sensing, and the archetypal ...channel material is poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate), PEDOT:PSS. The operation of OECTs involves the doping and dedoping of a conjugated polymer due to ion intercalation under the application of a gate voltage. However, the challenge is the trade‐off in morphology for mixed conduction since good electronic charge transport requires a high degree of ordering among PEDOT chains, while efficient ion uptake and volumetric doping necessitates open and loose packing of the polymer chains. Ionic‐liquid‐doped PEDOT:PSS that overcomes this limitation is demonstrated. Ionic‐liquid‐doped OECTs show high transconductance, fast transient response, and high device stability over 3600 switching cycles. The OECTs are further capable of having good ion sensitivity and robust toward physical deformation. These findings pave the way for higher performance bioelectronics and flexible/wearable electronics.
Ionic‐liquid doping in poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) allows good electronic and ionic transport. The ionic liquid induces more closely packed order of PEDOT units and forms fibrillar morphology to enhance its carrier mobility and volumetric capacitance simultaneously. Consequently, ionic‐liquid‐doped organic electrochemical transistors (OECTs) show high transconductance, fast transient response, and high device stability over 3600 switching cycles.
Organic solar cells (OSCs) have made rapid progress in terms of their development as a sustainable energy source. However, record‐breaking devices have not shown compatibility with large‐scale ...production via solution processing in particular due to the use of halogenated environment‐threatening solvents. Here, slot‐die fabrication with processing involving hydrocarbon‐based solvents is used to realize highly efficient and environmentally friendly OSCs. Highly compatible slot‐die coating with roll‐to‐roll processing using halogenated (chlorobenzene (CB)) and hydrocarbon solvents (1,2,4‐trimethylbenzene (TMB) and ortho‐xylene (o‐XY)) is used to fabricate photoactive films. Controlled solution and substrate temperatures enable similar aggregation states in the solution and similar kinetics processes during film formation. The optimized blend film nanostructures for different solvents in the highly efficient PM6:Y6 blend is adopted to show a similar morphology, which results in device efficiencies of 15.2%, 15.4%, and 15.6% for CB, TMB, and o‐XY solvents. This approach is successfully extended to other donor–acceptor combinations to demonstrate the excellent universality of this method. The results combine a method to optimize the aggregation state and film formation kinetics with the fabrication of OSCs with environmentally friendly solvents by slot‐die coating, which is a critical finding for the future development of OSCs in terms of their scalable production and high‐performance.
Highly efficient temperature‐dependent‐aggregation polymer‐based organic solar cells are fabricated by hot slot‐die coating with hydrocarbon solvents. Power conversion efficiencies of 15.2%, 15.4%, and 15.6% are obtained when chlorobenzene, 1,2,4‐trimethylbenzene (TMB), and ortho‐xylene are used, respectively.
Si has been regarded as one of the most promising next generation lithium-ion battery (LIB) anodes due to its exceptional capacity and proper working voltage. However, the dramatic volume change ...during lithiation/delithiation processes has caused severe detrimental consequences, leading to very poor cyclic stability. It has been one of the critical problems hampering the practical applications of the silicon based LIB anode. Extensive research has been carried out to resolve the problem since early 1990s. For the first time, the studies on the Si anode in the time frame more than two decades are summarized and discussed in this review with a novel chronicle perspective. Through this article, the evolution of the concept, fundamental scientific and technology development of the silicon LIB anode are clearly presented. It provides unique eyesight into this rapid developing field and will shed light on the future trend of the Si LIB anode research.
The research on the Si-based lithium-ion battery anode has been systematically reviewed in a chronicle perspective from early 1990s to 2016, where the evolution trends of the structure feature and modification strategy of Si have been elaborated. Display omitted
•The emergence and preliminary stage of the Si LIB anode research until 2000 is addressed.•The Rise of the Si-based anode studies between 2001 and 2005 is recorded.•The rapid development of Si-based anodes from 2006 to 2010 is reviewed.•The explosive progress of the Si-based anodes research from 2011 to 2015 is systematically interpreted.•The evolution trend of the research on the Si LIB anode over more than two decades is summarized and discussed.
Titanium dioxide of bronze phase (TiO2(B)) has attracted considerable attention as a promising alternative lithium/sodium‐ion battery anode due to its excellent operation safety, good reversible ...capacity, and environmental friendliness. However, several intrinsic critical drawbacks, including moderate electrochemical kinetics and unsatisfactory long cyclic stability, significantly limit its practical applications. It is crucial to develop reliable strategies to resolve these issues to advance the TiO2(B) based materials into practical applications in lithium/sodium‐ion batteries. In this review, both the theoretical and experimental investigations on the TiO2(B) based materials over the last few decades are chronically elaborated. Insights on the general and detailed evolution trends of the research on TiO2(B) anodes are provided. The review also points to future directions for the TiO2(B) anode research to advance the practical application of TiO2(B) anodes.
A comprehensive chronicle review of the TiO2(B) lithium/sodium‐ion battery anodes over the last few decades is performed. With the unique perspective, the evolution trends of the related studies are revealed, which are instructive and inspiring for the development of high‐performance rechargeable batteries.
Volatile solids with symmetric π‐backbone are intensively implemented on manipulating the nanomorphology for improving the operability and stability of organic solar cells. However, due to the ...isotropic stacking, the announced solids with symmetric geometry cannot modify the microscopic phase separation and component distribution collaboratively, which will constrain the promotion of exciton splitting and charge collection efficiency. Inspired by the superiorities of asymmetric configuration, a novel process‐aid solid (PAS) engineering is proposed. By coupling with BTP core unit in Y‐series molecule, an asymmetric, volatile 1,3‐dibromo‐5‐chlorobenzene solid can induce the anisotropic dipole direction, elevated dipole moment, and interlaminar interaction spontaneously. Due to the synergetic effects on the favorable phase separation and desired component distribution, the PAS‐treated devices feature the evident improvement of exciton splitting, charge transport, and collection, accompanied by the suppressed trap‐assisted recombination. Consequently, an impressive fill factor of 80.2% with maximum power conversion efficiency (PCE) of 18.5% in the PAS‐treated device is achieved. More strikingly, the PAS‐treated devices demonstrate a promising thickness‐tolerance character, where a record PCE of 17.0% is yielded in PAS devices with a 300 nm thickness photoactive layer, which represents the highest PCE for thick‐film organic solar cells.
A low‐cost, high volatile, and asymmetric halogen benzene derivate, 1,3‐dibromo‐5‐chlorobenzene, is applied as process‐aid solid to manipulate the blend nanomorphology and enhance the crystallinity in Y‐series small molecule‐based photoactive layer system. A champion power conversion efficiency of 17.0% is yielded, which is one of the highest performances for thick‐film organic solar cells.
The colloidal synthesis and assembly of semiconductor nanowires continues to attract a great deal of interest. Herein, we describe the single‐step ligand‐mediated synthesis of single‐crystalline ...CsPbBr3 perovskite nanowires (NWs) directly from the precursor powders. Studies of the reaction process and the morphological evolution revealed that the initially formed CsPbBr3 nanocubes are transformed into NWs through an oriented‐attachment mechanism. The optical properties of the NWs can be tuned across the entire visible range by varying the halide (Cl, Br, and I) composition through subsequent halide ion exchange. Single‐particle studies showed that these NWs exhibit strongly polarized emission with a polarization anisotropy of 0.36. More importantly, the NWs can self‐assemble in a quasi‐oriented fashion at an air/liquid interface. This process should also be easily applicable to perovskite nanocrystals of different morphologies for their integration into nanoscale optoelectronic devices.
Cubes, wires, and assemblies: Single‐crystalline perovskite nanowires were prepared directly from precursor powders in a single‐step ligand‐assisted process by ultrasonication. The nanowires likely resulted from the oriented attachment of nanocubes. Quasi‐oriented self‐assemblies of the perovskite nanowires were fabricated at air/liquid interfaces.
The complex nano-morphology of modern soft-matter materials is successfully probed with advanced grazing-incidence techniques. Based on grazing-incidence small- and wide-angle X-ray and neutron ...scattering (GISAXS, GIWAXS, GISANS and GIWANS), new possibilities arise which are discussed with selected examples. Due to instrumental progress, highly interesting possibilities for local structure analysis in this material class arise from the use of micro- and nanometer-sized X-ray beams in micro- or nanofocused GISAXS and GIWAXS experiments. The feasibility of very short data acquisition times down to milliseconds creates exciting possibilities for in situ and in operando GISAXS and GIWAXS studies. Tuning the energy of GISAXS and GIWAXS in the soft X-ray regime and in time-of flight GISANS allows the tailoring of contrast conditions and thereby the probing of more complex morphologies. In addition, recent progress in software packages, useful for data analysis for advanced grazing-incidence techniques, is discussed.
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