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Lewis base molecules that bind undercoordinated lead atoms at interfaces and grain boundaries (GBs) are known to enhance the durability of metal halide perovskite solar cells (PSCs). Using density functional theory calculations, we found that phosphine-containing molecules have the strongest binding energy among members of a library of Lewis base molecules studied herein. Experimentally, we found that the best inverted PSC treated with 1,3-bis(diphenylphosphino)propane (DPPP), a diphosphine Lewis base that passivates, binds, and bridges interfaces and GBs, retained a power conversion efficiency (PCE) slightly higher than its initial PCE of ~23% after continuous operation under simulated AM1.5 illumination at the maximum power point and at ~40°C for >3500 hours. DPPP-treated devices showed a similar increase in PCE after being kept under open-circuit conditions at 85°C for >1500 hours.

The development of highly stable and efficient wide-bandgap (WBG) perovskite solar cells (PSCs) based on bromine-iodine (Br–I) mixed-halide perovskite (with Br greater than 20%) is critical to create tandem solar cells. However, issues with Br–I phase segregation under solar cell operational conditions (such as light and heat) limit the device voltage and operational stability. This challenge is often exacerbated by the ready defect formation associated with the rapid crystallization of Br-rich perovskite chemistry with antisolvent processes. We combined the rapid Br crystallization with a gentle gas-quench method to prepare highly textured columnar 1.75–electron volt Br–I mixed WBG perovskite films with reduced defect density. With this approach, we obtained 1.75–electron volt WBG PSCs with greater than 20% power conversion efficiency, approximately 1.33-volt open-circuit voltage ( V oc ), and excellent operational stability (less than 5% degradation over 1100 hours of operation under 1.2 sun at 65°C). When further integrated with 1.25–electron volt narrow-bandgap PSC, we obtained a 27.1% efficient, all-perovskite, two-terminal tandem device with a high V oc of 2.2 volts.

Multidimensional perovskite techniques are of intense research interest since they are proved to be advantageous to enhance the perovskite stability. Thereinto, the structure engineering strategy has been widely used to regulate the low dimensional (LD) perovskite structures and obtain expected optoelectronic properties. In this work, we intercalate a thus far unreported metallic coordination compound [Ga-Tpy2]3+ (Tpy: 2,2';6',2″-terpyridine) to the inorganic Pb-I building block as the A-site organic group, and the zero dimensional (0D) [Ga-Tpy2]PbI5 perovskite-like single crystal is obtained. This material displays suitable band edge levels, which enable its potential application as light absorber in solar cells. The DFT calculations manifest delocalized charge distribution on Tpy ligands that can facilitate electron transport, which is attributed to the formation of a double hybrid coordinate bond, i.e., σ bonds and π bonds, between Ga3+ ions and Tpy ligands. These coordinate bonds make metallic complexes promising molecules to regulate structure-associated optoelectronic performances of the LD perovskites.

Owing to the high toxicity of Pb-based hybrid perovskites, a hypotoxic element, e.g., Sn, was employed to partially or completely replace Pb with the aim of gaining environmentally friendly lead-fr...

This paper addresses the issue of minimizing support material in additive manufacturing (AM) during topology optimization (TO) in order to reduce material and post-processing costs. The TO method developed in this paper utilizes the moving morphable components (MMC) approach, where a structure is composed of several building blocks. This work introduces minimum build angle constraints to eliminate overhanging edges, supplementing these with penalty functions to ensure connectivity between building blocks, such that the TO output is printable. The MMC approach uses explicit geometric entities for the morphable components that are controlled by geometric parameters, such as length, thickness, and angle. These parameters are the design variables. Using this approach enables the formulation of geometric manufacturing constraints and the construction of CAD models, which are important advantages of the MMC method. Examples of a short cantilever beam and an MBB beam demonstrate the capabilities of the TO methods.

In this study, for the first time, we in situ introduce a nickel(II)–terpyridine complex [Ni–Tpy2]2+ to replace the A-site ion and grow a series of Ni-based perovskite single crystals, which are proved to have dimension-tunable structures and outstanding optoelectronic performance toward device applications, e.g., solar cells, photodetectors, etc.

Cs xFA1- xPbI3 single crystals are expected to provide more excitement in optoelectronic applications, including photodetector, laser, light-emitting diode, etc. Herein, we aim to gain an in-depth understanding of the growth mechanisms of perovskite single crystal with various morphologies in view of microscopic dynamics by the combination of component, structure, and solvent engineering. A sequence of Cs xFA1- xPbI3 (0 ≤ x ≤ 0.14) perovskite single crystals with a dodecahedron morphology and tunable aspect ratio can be obtained by means of a solution-processed uniform-cooling approach. The optimized Cs0.1FA0.9PbI3 single crystals prepared in γ-butyrolactone mixed with dimethyl sulfoxide are theoretically and experimentally demonstrated to have superior performances, e.g., extremely higher long-term stability, lower trap density, and higher mobility. The broadband absorption, i.e., 300-910 nm, enables its application in near-infrared detection (880 nm), and the corresponding detector demonstrates higher responsivity at different light intensities and a fast photocurrent response (τ1 = 11 μs, τ2 = 10 μs). Equally important, we also explore the application of optimized Cs0.1FA0.9PbI3 single crystals with a tunable aspect ratio in an X-ray detector and the extremely high sensitivity (2772.1 μC Gyair-1 cm-2 under a bias of 150 V) demonstrates their good potential for radiation detection.

Multidimensional perovskite techniques are of intense research interest since they are proved to be advantageous to enhance the perovskite stability. Thereinto, the structure engineering strategy has been widely used to regulate the low dimensional (LD) perovskite structures and obtain expected optoelectronic properties. In this work, we intercalate a thus far unreported metallic coordination compound [Ga-Tpy

Dimensionality engineering has proved to be a reliable strategy for addressing the issue of perovskite stability. In this study, a series of previously unreported low-dimensional organic–inorganic hybrid perovskite single crystals were designed and grown by following a simple hydrothermal approach involving solution processing. The as-prepared terpyridine-derived perovskite single crystals displayed tunable structures and electronic dimensionality, which was closely associated with the crystal growth conditions. The performed DFT calculations suggested that the fluctuating conduction band edge demonstrates obvious charge delocalization associated with the π-conjugation effect, a feature promoting efficient charge transport by means of coupling structural dimensionality and electronic dimensionality. This study has provided new ideas for the design of new materials to be used in fields involving photovoltaic devices.

Despite the rapid development of CsPbI

Lead-free double perovskites have attracted noteworthy attention due to their compositional flexibility and electronic diversity. In this study, we hydrothermally grow a new class of Cs

Incorporating nano fillers such as multi-walled carbon nanotubes (MWCNTs) into polymeric matrix can generate rough surface and transfer stress directly to improve adhesion of metal-polymer interfaces. However, the interfaces became more complicate to optimize the adhesion. In this work, the effects of MWCNTs with different surface chemical groups and different diameter on surface profile, wettability and adhesion were studied. The results showed that the adhesion was related to surface wettability when using pristine MWCNTs and this relationship was extinct after the MWCNTs were functionalized. Out of the intuition, the functionalization was not with perfect universality in improving adhesion. D peaks were expanded with the ID/IG and FWHM of A1 and A4 increased by dual functionalization from 0.33 to 0.62, 92.39 to 105.91 cm−1 and 0.49 to 1.63, 140.47 to 172.24 cm−1, respectively. We found that the adhesion of functionalized MWCNTs depended on multiple factors including surface roughness, wettability, the intrinsic mechanical property of MWCNTs, and stress distribution on MWCNT surface when combined with the surface enhanced Raman spectroscopy (SERS) results. This work will be inspiring for novel technology of metal-polymer interfacial modification.

All-inorganic CsPbIxBr3−x (0 ≤x ≤ 3) perovskites are expected to fundamentally solve the thermal stability issue of perovskite solar cell toward its final commercialization. However, the humidity stability of this class of all-inorganic perovskite is still not intrinsically tackled out. Herein, aminoquinoline is introduced to construct a thus far unreported one-dimensional (1D) perovskite, in which the distorted [PbI6]4- octahedra display a shoulder-by-shoulder arrangement along the [001] direction, and A-site quinoline (Aq) organic groups with π-π conjugate structure orderly distribute among the octahedra space. The structural incorporation of 1D Aq-PbI3(II) perovskite inside 3D CsPbI2Br perovskite is proved to be capable of improving the carrier transport ability, whilst enhancing its hydrophobic performances, which is associated with the unique structure of 1D Aq-PbI3(II) and lattice-matching heterojunction in 1D–3D perovskite. Consequently, the as-fabricated 1D–3D hybrid CsPbI2Br perovskite solar cell allows to increase the device VOC by a factor of 12%, yielding a power conversion efficiency (PCE) as high as 16.1%. Equally importantly, the corresponding 1D–3D perovskite solar cells demonstrate remarkably high stability more than 1300 h in comparison to the control 3D CsPbI2Br perovskite solar cell. This study provides a new strategy for the rational structure design of 1D–3D hybrid perovskite with high PCE and stability.

Cs

A new “bottom up” strategy via incorporating specific fillers into polymeric matrix and forming rough surface as well as exposed fillers without further surface treatment is presented to replace conventional palladium (Pd) activation or molecular grafting in polymer surface metallization hopefully. Transmission electron microscope (TEM), 3D profile, cross-cut testing and surface enhanced Raman spectroscopy (SERS) were conducted to studied the the effects of fillers in generating rough surface and improving adhesion. The results showed that, 1D/ 2D, functionalized fillers generated rougher surface, adhesion improved significantly after functionalization. Before functionalization, the adhesion is influenced by surface roughness and original functional groups of the fillers and after functionalizaton, the adhesion is depended by the mechanical properties and behaviors of the fillers.

Multifunctional lead-free double perovskites demonstrate remarkable potential towards applications in various fields. Herein, an environmentally-friendly, low-cost, high-throughput Cs2NaFeCl6 single crystal with exceedingly high thermal stability is designed and grown. It obtains a cubic lattice system in the temperature range of 80–500 K, accompanied by a completely reversible chromatic variation ranging from yellow to black. Importantly, the intriguing thermochromism is proved to own extremely high reproducibility (over 1000 cycles) without a hysteretic effect, originating from its structural flexibility that including (i) the noteworthy distortion/deformation of [NaCl6]5− and [FeCl6]3− octahedra; (ii) order–disorder arrangement transition of [NaCl6]5− and [FeCl6]3− octahedra as the function of temperature. This study paves the way towards a new class of smart windows and camouflage coatings with an unprecedented colour range based on a Cs2NaFeCl6 perovskite.

Despite the rapid development of CsPbIx Br3-x (0 ≤ x ≤ 3) inorganic perovskite solar cells, associated with their superior thermal stability, their low moisture stability limits their commercial deployment. In this study, 1D-2D-3D multidimensional coupled perovskites are prepared by means of an in situ self-integration approach. This pioneering method allows incorporating thus far unreported 1D-Tpy2 Pb3 I6 and 2D-TpyPb3 I6 (Tpy; terpyridine) perovskites. Heterojunction perovskites demonstrate superior stability against water in comparison with control 3D CsPbI2 Br, which is related to the hydrophobicity of low-dimension (LD) perovskites. Remarkably, the spontaneous involvement of LD perovskites can adjust/reconstruct the interfacial structure. This modification allows releasing the residual strain, establishing effective charge transfer channels that increase the carrier transport ability. Accordingly, 1D-2D-3D hybrid CsPbI2 Br perovskite solar cells demonstrate a stabilized power conversion efficiency as high as 16.1%, which represents a very significant improvement, by a factor of 43%, with respect to control 3D CsPbI2 Br perovskite solar cell. Equally importantly, the multidimensional coupled perovskite solar cells exhibit extraordinary stability, well above 1000 h in ambient atmosphere.

Weak plating performance and poor adhesion between epoxy and silver coatings can restrict the development of miniaturized electronic devices and multi-layer circuits. In this work, we fabricate a novel epoxy-based nanocomposite containing -SH and -NH2 dual functionalized multi-walled carbon nanotubes (d-MWCNTs), with enhanced adhesive properties towards silver particles. The enhanced adhesion mechanisms are also investigated by 3D profiling, scanning electron microscopy, cross-cut test, and Raman spectroscopy. Introducing d-MWCNTs improved the surface roughness of the nanocomposites, but the improvements become unstable when the d-MWCNTs content exceeded 0.6 g/15 g epoxy. In addition, the d-MWCNTs are found to affect the size and shape of the coated silver particles. Besides, we find that neither NH2-dominated nor SH-dominated functionalization improve the adhesion effectively, while a balance proportion of the two (v(-NH2) silane: v(-SH) silane = 4:6) does. These findings may open the door for the simplification and optimization of epoxy-metal plating for multi-layer circuit applications.

The lack of thermal conductance (TC) remains to be a challenge for epoxy resin. Fortunately, the thermal conductance of epoxy resin can be effectively improved by filler incorporation. Recently, compositing epoxy resin with hybrid filler system has been the direction for the development of next-generation thermal conductive functional materials. In this paper, epoxy-based nanocomposites containing nanodiamonds (DNDs)/pristine multi-walled carbon nanotubes (p-MWCNTs) and DNDs/KH550 functionalized MWCNTs (MWCNTs-KH) as the hybrid filler system were prepared respectively, and the thermal conductance of the nanocomposites was compared. The addition of DNDs was found to play a dominating role in the MWCNTs-KH filler systems (0.2 g, from 0.30 W/mK to 0.34 W/mK), but hardly has any effect on the p-MWCNTs filler system (0.2 g, from 0.24 to 0.26 W/mK only). Furthermore, the TC of the DNDs/MWCNTs-KH (2 g) epoxy-based nanocomposite increased to 0.45 W/mK, displaying an enhancement of 114.2 %. A shift of 5 cm-1 recorded by FTIR and the shift of C O revealed by XPS for DNDs/MWCNTs-KH strongly confirmed the existence of hydrogen bonds. Associating with the characterization results of SEM, TEM and dispersion qualitative experiment, the significant improvement in the TC of DNDs/MWCNTs-KH (2 g) epoxy-based nanocomposite was attributed to the hydrogen bond attachment between DNDs and MWCNTs-KH. The mechanism is that the attachment improves the dispersion of the fillers in epoxy, leading to the formation of a more effective thermal conductive network, thus, the enhanced TC. This work may inspire future studies in hybrid filler recognition and self-assemble technology via hydrogen bonds.