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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

B—N–Bond–Embedded Triplet Terpolymers with Small Singlet–Triplet Energy Gaps for Suppressing Non–Radiative Recombination and Improving Blend Morphology in Organic Solar Cells

Suppressing the photon energy loss (E loss ), especially the non-radiative loss, is of importance to further improve the device performance of organic solar cells (OSCs). However, typical π-conjugated semiconductors possess a large singlet–triplet energy gap (ΔE ST ), leading to a lower triplet state than charge transfer state and contributing to a non-radiative loss channel of the photocurrent by the triplet state. Herein, a series of triplet polymer donors are developed by introducing a BNIDT block into the PM6 polymer backbone. Further, the high electron affinity of BNIDT and the opposite resonance effect of the B—N bond in BNIDT results in a lowered highest occupied molecular orbital (HOMO) and a largely reduced ΔE ST . Moreover, the morphology of the active blends is also optimized by fine-tuning the BNIDT content. Therefore, non-radiative recombination via the terminal triplet loss channels and morphology traps is effectively suppressed. The PNB-3 (with 3% BNIDT):L8-BO device exhibits both small ΔE ST and optimized morphology, favoring more efficient charge transfer and transport. Finally, the simultaneously enhanced V oc of 0.907 V, J sc of 26.59 mA cm –2 , and FF of 78.86% contribute to a champion PCE of 19.02%. Therefore, introducing B—N bonds into benchmark polymers is a possible avenue toward higher-performance of OSCs.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on B2CN by Materials Project

B2CN is Enargite-like structured and crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. there are two inequivalent B3+ sites. In the first B3+ site, B3+ is bonded to three equivalent C3- and one N3- atom to form corner-sharing BC3N tetrahedra. All B–C bond lengths are 1.66 Å. The B–N bond length is 1.52 Å. In the second B3+ site, B3+ is bonded to one C3- and three equivalent N3- atoms to form corner-sharing BCN3 tetrahedra. The B–C bond length is 1.61 Å. All B–N bond lengths are 1.59 Å. C3- is bonded to four B3+ atoms to form CB4 tetrahedra that share corners with six equivalent CB4 tetrahedra and corners with six equivalent NB4 tetrahedra. N3- is bonded to four B3+ atoms to form NB4 tetrahedra that share corners with six equivalent CB4 tetrahedra and corners with six equivalent NB4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on B2CN by Materials Project

B2CN crystallizes in the orthorhombic Pmma space group. The structure is two-dimensional and consists of one B2CN sheet oriented in the (0, 0, 1) direction. there are two inequivalent B3+ sites. In the first B3+ site, B3+ is bonded to two equivalent C3- and two equivalent N3- atoms to form BC2N2 tetrahedra that share corners with four equivalent BC2N2 tetrahedra and corners with four equivalent CB2C2 tetrahedra. Both B–C bond lengths are 1.67 Å. Both B–N bond lengths are 1.56 Å. In the second B3+ site, B3+ is bonded in a water-like geometry to two equivalent N3- atoms. Both B–N bond lengths are 1.54 Å. C3- is bonded to two equivalent B3+ and two equivalent C3- atoms to form CB2C2 tetrahedra that share corners with four equivalent BC2N2 tetrahedra, corners with four equivalent CB2C2 tetrahedra, and corners with four equivalent NB4 tetrahedra. Both C–C bond lengths are 1.50 Å. N3- is bonded to four B3+ atoms to form NB4 tetrahedra that share corners with four equivalent CB2C2 tetrahedra and corners with four equivalent NB4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BC2N by Materials Project

BC2N crystallizes in the monoclinic C2 space group. The structure is three-dimensional. B3+ is bonded in a 3-coordinate geometry to two C and one N3- atom. There is one shorter (1.59 Å) and one longer (1.82 Å) B–C bond length. The B–N bond length is 1.46 Å. There are two inequivalent C sites. In the first C site, C is bonded in a 2-coordinate geometry to one B3+, one C, and one N3- atom. The C–C bond length is 1.57 Å. The C–N bond length is 1.43 Å. In the second C site, C is bonded in a distorted single-bond geometry to one B3+, two C, and one N3- atom. The C–C bond length is 1.60 Å. The C–N bond length is 1.43 Å. N3- is bonded in a trigonal planar geometry to one B3+ and two C atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgB4(H10N)2 by Materials Project

MgB4(NH10)2 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is zero-dimensional and consists of four MgB4(NH10)2 clusters. Mg2+ is bonded to seven H+0.80+ atoms to form distorted MgH7 pentagonal bipyramids that share a cornercorner with one BH3N tetrahedra and edges with three BH4 tetrahedra. There are a spread of Mg–H bond distances ranging from 1.96–2.15 Å. There are four inequivalent B3- sites. In the first B3- site, B3- is bonded to four H+0.80+ atoms to form BH4 tetrahedra that share an edgeedge with one MgH7 pentagonal bipyramid. There are a spread of B–H bond distances ranging from 1.21–1.24 Å. In the second B3- site, B3- is bonded to four H+0.80+ atoms to form BH4 tetrahedra that share an edgeedge with one MgH7 pentagonal bipyramid. There are a spread of B–H bond distances ranging from 1.21–1.24 Å. In the third B3- site, B3- is bonded to one N3- and three H+0.80+ atoms to form BH3N tetrahedra that share a cornercorner with one MgH7 pentagonal bipyramid. The B–N bond length is 1.59 Å. There is two shorter (1.21 Å) and one longer (1.24 Å) B–H bond length. In the fourth B3- site, B3- is bonded to one N3- and three H+0.80+ atoms to form BH3N tetrahedra that share an edgeedge with one MgH7 pentagonal bipyramid. The B–N bond length is 1.59 Å. There are a spread of B–H bond distances ranging from 1.21–1.24 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a tetrahedral geometry to one B3- and three H+0.80+ atoms. All N–H bond lengths are 1.03 Å. In the second N3- site, N3- is bonded in a tetrahedral geometry to one B3- and three H+0.80+ atoms. There is one shorter (1.02 Å) and two longer (1.03 Å) N–H bond length. There are twenty inequivalent H+0.80+ sites. In the first H+0.80+ site, H+0.80+ is bonded in a single-bond geometry to one N3- atom. In the second H+0.80+ site, H+0.80+ is bonded in a single-bond geometry to one N3- atom. In the third H+0.80+ site, H+0.80+ is bonded in a single-bond geometry to one N3- atom. In the fourth H+0.80+ site, H+0.80+ is bonded in a single-bond geometry to one N3- atom. In the fifth H+0.80+ site, H+0.80+ is bonded in a single-bond geometry to one N3- atom. In the sixth H+0.80+ site, H+0.80+ is bonded in a single-bond geometry to one N3- atom. In the seventh H+0.80+ site, H+0.80+ is bonded in an L-shaped geometry to one Mg2+ and one B3- atom. In the eighth H+0.80+ site, H+0.80+ is bonded in a single-bond geometry to one B3- atom. In the ninth H+0.80+ site, H+0.80+ is bonded in an L-shaped geometry to one Mg2+ and one B3- atom. In the tenth H+0.80+ site, H+0.80+ is bonded in a single-bond geometry to one B3- atom. In the eleventh H+0.80+ site, H+0.80+ is bonded in a single-bond geometry to one B3- atom. In the twelfth H+0.80+ site, H+0.80+ is bonded in an L-shaped geometry to one Mg2+ and one B3- atom. In the thirteenth H+0.80+ site, H+0.80+ is bonded in a single-bond geometry to one B3- atom. In the fourteenth H+0.80+ site, H+0.80+ is bonded in an L-shaped geometry to one Mg2+ and one B3- atom. In the fifteenth H+0.80+ site, H+0.80+ is bonded in a bent 120 degrees geometry to one Mg2+ and one B3- atom. In the sixteenth H+0.80+ site, H+0.80+ is bonded in a single-bond geometry to one B3- atom. In the seventeenth H+0.80+ site, H+0.80+ is bonded in a single-bond geometry to one B3- atom. In the eighteenth H+0.80+ site, H+0.80+ is bonded in a distorted L-shaped geometry to one Mg2+ and one B3- atom. In the nineteenth H+0.80+ site, H+0.80+ is bonded in a single-bond geometry to one B3- atom. In the twentieth H+0.80+ site, H+0.80+ is bonded in a water-like geometry to one Mg2+ and one B3- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MnB4H24(C2N)2 by Materials Project

MnB4H24(C2N)2 crystallizes in the tetragonal I-42d space group. The structure is zero-dimensional and consists of eight MnB4H24(C2N)2 clusters. Mn2+ is bonded in a 8-coordinate geometry to eight H+0.83+ atoms. There are a spread of Mn–H bond distances ranging from 2.00–2.10 Å. There are two inequivalent B sites. In the first B site, B is bonded to one N3- and three H+0.83+ atoms to form BH3N tetrahedra that share a cornercorner with one BH3N tetrahedra and corners with two equivalent CH3N tetrahedra. The B–N bond length is 1.58 Å. There are a spread of B–H bond distances ranging from 1.21–1.25 Å. In the second B site, B is bonded to one N3- and three H+0.83+ atoms to form BH3N tetrahedra that share a cornercorner with one BH3N tetrahedra and corners with two equivalent CH3N tetrahedra. The B–N bond length is 1.58 Å. There are a spread of B–H bond distances ranging from 1.21–1.26 Å. There are two inequivalent C4- sites. In the first C4- site, C4- is bonded to one N3- and three H+0.83+ atoms to form CH3N tetrahedra that share a cornercorner with one CH3N tetrahedra and corners with two equivalent BH3N tetrahedra. The C–N bond length is 1.49 Å. There is one shorter (1.09 Å) and two longer (1.10 Å) C–H bond length. In the second C4- site, C4- is bonded to one N3- and three H+0.83+ atoms to form CH3N tetrahedra that share a cornercorner with one CH3N tetrahedra and corners with two equivalent BH3N tetrahedra. The C–N bond length is 1.49 Å. All C–H bond lengths are 1.10 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a tetrahedral geometry to two equivalent B and two equivalent C4- atoms. In the second N3- site, N3- is bonded in a tetrahedral geometry to two equivalent B and two equivalent C4- atoms. There are twelve inequivalent H+0.83+ sites. In the first H+0.83+ site, H+0.83+ is bonded in a single-bond geometry to one C4- atom. In the second H+0.83+ site, H+0.83+ is bonded in an L-shaped geometry to one Mn2+ and one B atom. In the third H+0.83+ site, H+0.83+ is bonded in a single-bond geometry to one C4- atom. In the fourth H+0.83+ site, H+0.83+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B atom. In the fifth H+0.83+ site, H+0.83+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B atom. In the sixth H+0.83+ site, H+0.83+ is bonded in a single-bond geometry to one C4- atom. In the seventh H+0.83+ site, H+0.83+ is bonded in an L-shaped geometry to one Mn2+ and one B atom. In the eighth H+0.83+ site, H+0.83+ is bonded in a single-bond geometry to one B atom. In the ninth H+0.83+ site, H+0.83+ is bonded in a single-bond geometry to one C4- atom. In the tenth H+0.83+ site, H+0.83+ is bonded in a single-bond geometry to one B atom. In the eleventh H+0.83+ site, H+0.83+ is bonded in a single-bond geometry to one C4- atom. In the twelfth H+0.83+ site, H+0.83+ is bonded in a single-bond geometry to one C4- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on B2CN by Materials Project

B2CN is Enargite-like structured and crystallizes in the tetragonal P-4m2 space group. The structure is three-dimensional. B3+ is bonded to two equivalent C3- and two equivalent N3- atoms to form corner-sharing BC2N2 tetrahedra. Both B–C bond lengths are 1.65 Å. Both B–N bond lengths are 1.56 Å. C3- is bonded to four equivalent B3+ atoms to form CB4 tetrahedra that share corners with four equivalent CB4 tetrahedra and corners with eight equivalent NB4 tetrahedra. N3- is bonded to four equivalent B3+ atoms to form NB4 tetrahedra that share corners with four equivalent NB4 tetrahedra and corners with eight equivalent CB4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(BN)2 by Materials Project

Sr(BN)2 crystallizes in the monoclinic C2/m space group. The structure is two-dimensional and consists of one Sr(BN)2 sheet oriented in the (0, 0, 1) direction. Sr2+ is bonded to six equivalent N1- atoms to form edge-sharing SrN6 octahedra. There are two shorter (2.63 Å) and four longer (2.68 Å) Sr–N bond lengths. B is bonded in a single-bond geometry to one N1- atom. The B–N bond length is 1.28 Å. N1- is bonded in a 4-coordinate geometry to three equivalent Sr2+ and one B atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ga3BN4 by Materials Project

Ga3BN4 is Lavarevi\'{c}ite structured and crystallizes in the cubic P-43m space group. The structure is three-dimensional. Ga3+ is bonded to four equivalent N3- atoms to form GaN4 tetrahedra that share corners with four equivalent BN4 tetrahedra and corners with eight equivalent GaN4 tetrahedra. All Ga–N bond lengths are 1.95 Å. B3+ is bonded to four equivalent N3- atoms to form BN4 tetrahedra that share corners with twelve equivalent GaN4 tetrahedra. All B–N bond lengths are 1.65 Å. N3- is bonded to three equivalent Ga3+ and one B3+ atom to form corner-sharing NGa3B tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Extreme Thermal Stabilization of Carborane–Cyanate Composites via B–N Dative-Bonded Boroxine Barriers

Enhancing the thermal stability of cyanate ester (CE) resins is crucial for high-temperature aerospace applications. This study elucidates the degradation mechanisms of CE composites reinforced with carborane additives, focusing on the formation of boron–nitrogen (B–N) dative bonds and their role in improving thermal resistance. Using thermogravimetric analysis, we examined char formation and evolved gases at multiple degradation stages. Reaction sequences and char products were characterized via Fourier transform infrared spectroscopy (FTIR), solid-state 13C and 11B NMR, and evolved gas analysis using mass spectrometry and FTIR. The solid-state 11B NMR was instrumental in detecting various boron oxidation states and the formation of B–N dative bonds during decomposition. These bonds facilitate cross-linking in the char phase, enhancing material integrity at elevated temperatures. However, in inert environments, the volatility of boron additives like carborane limits their effectiveness. These findings advance the understanding of CE composite degradation mechanisms and offer critical insights for developing high-temperature-resistant materials for aerospace applications.

Fourier transform infrared spectroscopy↗
DOE OSTI2020

Materials Data on AlB3N4 by Materials Project

AlB3N4 is Lavarevi\'{c}ite structured and crystallizes in the cubic P-43m space group. The structure is three-dimensional. Al3+ is bonded to four equivalent N3- atoms to form AlN4 tetrahedra that share corners with twelve equivalent BN4 tetrahedra. All Al–N bond lengths are 1.79 Å. B3+ is bonded to four equivalent N3- atoms to form BN4 tetrahedra that share corners with four equivalent AlN4 tetrahedra and corners with eight equivalent BN4 tetrahedra. All B–N bond lengths are 1.63 Å. N3- is bonded to one Al3+ and three equivalent B3+ atoms to form corner-sharing NAlB3 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GaBN2 by Materials Project

GaBN2 is Enargite-like structured and crystallizes in the tetragonal P-4m2 space group. The structure is three-dimensional. Ga3+ is bonded to four equivalent N3- atoms to form GaN4 tetrahedra that share corners with four equivalent GaN4 tetrahedra and corners with eight equivalent BN4 tetrahedra. All Ga–N bond lengths are 1.91 Å. B3+ is bonded to four equivalent N3- atoms to form BN4 tetrahedra that share corners with four equivalent BN4 tetrahedra and corners with eight equivalent GaN4 tetrahedra. All B–N bond lengths are 1.65 Å. N3- is bonded to two equivalent Ga3+ and two equivalent B3+ atoms to form corner-sharing NGa2B2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GaB3N4 by Materials Project

GaB3N4 is Lavarevi\'{c}ite structured and crystallizes in the cubic P-43m space group. The structure is three-dimensional. Ga3+ is bonded to four equivalent N3- atoms to form GaN4 tetrahedra that share corners with twelve equivalent BN4 tetrahedra. All Ga–N bond lengths are 1.83 Å. B3+ is bonded to four equivalent N3- atoms to form BN4 tetrahedra that share corners with four equivalent GaN4 tetrahedra and corners with eight equivalent BN4 tetrahedra. All B–N bond lengths are 1.63 Å. N3- is bonded to one Ga3+ and three equivalent B3+ atoms to form corner-sharing NGaB3 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Evaluating Use of Boron- and Hafnium-Modified Polysilazanes for Ceramic Matrix Minicomposites

In this study, the potential of polymer-derived Ceramic Matrix Composites (CMCs) is demonstrated by addition of thin ceramic coatings on Carbon Fiber (CF) bundles. Boron- and hafnium- modified polysilazane liquid precursors were synthesized and used to infiltrate the fiber bundles of CF to fabricate lab-scale Si(B)CN/CF and Si(Hf)CN/CF CMC mini-composites, respectively. The precursor-to-ceramic conversion process was achieved at 800°C with crosslinked precursor to ceramic yield of approx. 90% in Ar environment. The Si(B)CN/CF contained Si-N and B-N bonds, while Si-N and Hf-O-Si bonds were observed for Si(Hf)CN/CF sample with uniform and dense surfaces. Room-temperature tensile tests showed that the Si(Hf)CN/CF sample could reach a tensile strength of ~790 MPa and elastic modulus of 66.88 GPa among the composites. Oxidation study of the Si(Hf)CN/CF mini-composites showed higher stability compared to SiCN/CF and Si(B)CN/CF mini-composites up to 1500°C.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Saddle-Shaped Third Component with Out-of-Plane Electrostatic Dipole for Realizing High-Performance Photovoltaic Donor Terpolymers

Terpolymer fabrication is an effective methodology for molecular engineering and generating high-performance organic photovoltaic materials to construct highly efficient polymer solar cells. Modification of the polymer PM6 by incorporating a third component resulting in the formation of a ternary copolymer is reported to outperform PM6 in achieving enhanced device performances. However, one of the major challenges in constructing high-performance terpolymers is to counter the molecular disorder caused by the backbone entropy induced by the third moiety. Here, in this work, double B←N bridged bipyridine (BNBP) is used as the third component, which possesses a strong out-of-plane electrostatic dipole owing to the saddle-shaped B←N fused ring structure. The out-of-plane dipole moment introduced in the modified PM6 terpolymer can be used as a means for tuning and optimizing the nanostructures of the blended films. The prepared PM6-BNBP-4 blend polymer with 4% of the benzodithiophene dione monomers replaced by BNBP results in excellent power conversion efficiency of 19.13%. This work demonstrates that the out-of-plane electrostatic dipole moment in saddle-shaped molecules is valuable for achieving high-performance organic photovoltaic donor materials.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Role of humidity and surface roughness on direct wafer bonding

Bodies made from elastically stiff material usually bind very weakly unless the surfaces are flat and extremely smooth. In direct wafer bonding flat surfaces bind by capillary bridges and by the van der Waals interaction, which act between all solid objects. Here we study the dependency of the work of adhesion on the humidity and surface roughness in hydrophilic direct wafer bonding. We show that the long-wavelength roughness (usually denoted waviness) has a negligible influence on the strength of wafer bonding (the work of adhesion) from the menisci that form from capillary condensation of water vapor.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2026

Evaluation of the interfacial bonding strength between hafnia and silica layers deposited by electron-beam evaporation

Factors contributing to the mechanical strength of multilayer optical coatings involving alternating layers of electron-beam evaporated hafnia and silica is investigated. It is observed that upon rupture resulting from nanosecond laser damage, fragments consisting of layer pairs are produced. These pairs are formed as a result of a strong asymmetry in adhesion strength between interfaces, leading to preferential delamination at interfaces where silica is deposited on hafnia, and not the reverse, despite the fact that both interface types consist of the same pair of materials. The observed disparity in adhesion strength was further studied using nanomechanical scratch tests, revealing loads at which fracture occurs, and fracture morphology, both of which are highly dependent on deposition order. Based on these measurements, along with the morphological analysis of the nanostructure of the coatings, we conclude that the surface microstructure in each coating layer affects its adhesion strength with the succeeding layer. The findings outlined here are particularly relevant to the production of large aperture, high-performance optics designed for use in next-generation lasers.

adhesion strength↗
DOE OSTI2022

Strain dependent electronic and optical responses of penta-BCN monolayer

We report here, structural, dynamic, and mechanical stability in pentagonal boron carbon nitride (p-BCN) monolayer, a new member of direct bandgap two-dimensional (2D) semiconductor. The identified visible range bandgap with excellent mechanical strength allows it to be a promising candidate material in optoelectronics, nanomechanics, and optomechanical sensors. By employing density functional theory (DFT), we reveal a unique geometrical reconstruction with rigidity in B–N and C–N bond lengths with applied strain. These quasi-sp 3 hybridized short and strong covalent bonding and unique geometry support the monolayer to possess extraordinary mechanical response. The desired bandgap is manipulated by loading the biaxial strain. Most importantly, our predictions on p-BCN show excellent optical response such as good static dielectric constant and refractive index, strong optical absorption (up to 1.08 x 10 5 cm -1 in VR and 7.01 x 10 cm -1 in UV) with small energy loss and reflectance both appearing in visible and ultraviolet regions (UV). The desired optical response along with the blue and red shift is demonstrated by tailoring with tensile and compressive strain. The predicted strong optical anisotropy provides it’s application in polarized photodetection.

36 MATERIALS SCIENCE↗