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  • 1.
    Baryshnikov, Gleb V.
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Bohdan Khmelnytsky National University, Ukraine.
    Gawrys, Pawel
    Ivaniuk, Khrystyna
    Witulski, Bernhard
    Whitby, Richard J.
    Al-Muhammad, Ayham
    Minaev, Boris
    Cherpak, Vladyslav
    Stakhira, Pavlo
    Volyniuk, Dmytro
    Wiosna-Salyga, Gabriela
    Luszczynska, Beata
    Lazauskas, Algirdas
    Tamulevicius, Sigitas
    Grazulevicius, Juozas V.
    Nine-ring angular fused biscarbazoloanthracene displaying a solid state based excimer emission suitable for OLED application2016In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 4, no 24, p. 5795-5805Article in journal (Refereed)
    Abstract [en]

    A new biscarbazoloanthracene consisting of nine fused aromatic rings, including two pyrrole units, has been obtained in a straightforward and convergent synthesis. Computational chemistry and conformational analysis revealed that the semiconductor's molecule is not planar, the two carbazole moieties being helical twisted from the plane of the anthracene unit. Photophysical and electrochemical measurements showed that this angular fused heteroacene has a low lying HOMO energy level with a wide band gap despite its extended pi-conjugated molecular framework. Based on its relatively low-lying HOMO level, the semiconductor promises a high environmental stability in comparison to other related linear fused acenes and heteroacenes. The biscarbazoloanthracene has been applied as the light emitting layer in a white light emitting diode (WOLED). It is proposed that the white OLED feature is due to dual light emission properties from the active semiconductor layer being based on both the molecular luminescence of the small molecule and a discrete excimer emission made possible by suitable aggregates in the solid state. Noteworthy, this is the first reported example of such a behavior observed in a small molecule heteroacene rather than an oligomer or a polymer.

  • 2. Chen, S.
    et al.
    Li, W.
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Zhu, W. -H
    Aggregation-controlled photochromism based on a dithienylethene derivative with aggregation-induced emission2017In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 5, no 10, p. 2717-2722Article in journal (Refereed)
    Abstract [en]

    We report novel aggregation-induced emission (AIE) characteristics involving aggregation-controlled photochromism properties of a dithienylethene derivative, BTE-EQ, where two quinolinemalononitrile (EQ) units are covalently attached to a dithienylethene core. The typical AIE effect of BTE-EQ has been found to originate from the AIE character of the EQ units with respect to the reference compound BTE, which does not contain an EQ unit. The photochromism study, together with density functional theory calculations, reveals that the photochromic activity of BTE-EQ can be reversibly switched off and on by controlling the aggregation state during the AIE process, which provides a novel route to controlling the photochromism of diarylethenes.

  • 3. Cheng, Qiaoyun
    et al.
    Chen, Pan
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Ye, Dongdong
    Wang, Junmei
    Song, Guangjie
    Liu, Junjie
    Chen, Zhiquan
    Chen, Lingyun
    Zhou, Qi
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center.
    Chang, Chunyu
    Zhang, Lina
    The conversion of nanocellulose into solvent-free nanoscale liquid crystals by attaching long side-arms for multi-responsive optical materials2020In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 8, no 32, p. 11022-11031Article in journal (Refereed)
    Abstract [en]

    Nanocellulose, with its unique optical and chemical properties, has received increasing attention as feedstock to fabricate sustainable materials. However, achieving a nanocellulose-based solvent-free liquid crystal with good responsiveness still remains a challenge. Herein, for the first time, solvent-free supramolecular liquid crystals were fabricated by attaching long side-arms on the fiber-like nanocellulose derived from tunicate (TCNC) with an average width of 20 nm and 400-3000 nm in length. The side-arms were grafted via surface condensation with a charged organosilane, followed by further functionalization with a counter-ion polyoxyethylene ether. The nanoscale liquid crystals consisted of the stiff TCNC as the core and flexible side-arms as the soft shells, forming the core-shell structure with an average width of 34-36 nm. The resulting solvent-free liquid crystal exhibited transparent and viscous liquid-like fluidity, as well as a bright birefringence between the crossed polarizers at room temperature. In our findings, the stiff core provided crystal-like ordering, whereas the soft shells induced the high mobility of the TCNCs as a result of the increased fractional free volume, as shown by positron annihilation lifetime spectra. The unique flowability enables the possibility of multi-responsiveness to temperature, deformation, and alternating electric fields. In addition, the thermo-responsiveness can be regulated by tailoring the canopy. This work provides a novel strategy for the conversion of solid nanocellulose into a solvent-free nanoscale liquid crystal, which is promising for use as a responsive optical material.

  • 4. Chesnokov, A.
    et al.
    Gryaznov, D.
    Skorodumova, Natalia
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering. Department of Physics and Astronomy, Uppsala University, Box 516, 751 20 Uppsala, Sweden.
    Kotomin, E. A.
    Zitolo, A.
    Zubkins, M.
    Kuzmin, A.
    Anspoks, A.
    Purans, J.
    The local atomic structure and thermoelectric properties of Ir-doped ZnO: hybrid DFT calculations and XAS experiments2021In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 9, no 14, p. 4948-4960Article in journal (Refereed)
    Abstract [en]

    We combined the hybrid density functional theory (DFT) calculations and X-ray absorption spectroscopy (XAS) experiments in the study of the local atomic structure around Ir ions in ZnO thin films with different iridium content. This was then used in the first principles analysis of the thermoelectric properties of material. The emphasis has been put on the conditions for a positive Seebeck coefficient and p-type electrical conductivity as the functions of the Fermi level. We studied both computationally and experimentally several possible IrOxpolyhedra (complexes) with a different number of surrounding oxygens and Ir oxidation states, including those with the formation of peroxide ions (O22−). In particular, octahedral coordination of iridium ions was identified by reverse Monte Carlo (RMC) simulations of the Ir L3-edge EXAFS spectra of ZnO:Ir thin films as the predominant complex, which is supported by the calculated lowest interstitial oxygen incorporation energies. All the calculated IrOx(x= 4, 5, 6) complexes, regardless of Ir the oxidation state, demonstrate potential for p-type conduction if the Fermi level (μF) falls in the range of 0-0.8 eV from the valence band maximum (VBM) and the Ir concentration is high enough (12.5% in the present DFT calculations). Even though the corresponding calculated Seebeck coefficient (S) around 80-89 μV K−1slightly exceeds the experimental values, we emphasise the presence of an important plateau in the dependence ofSonμFin this range for two complexes with the formation of peroxide ions (O22−). We predicted also that peroxide ions O22−are characterized by the calculated phonon frequencies of 810-942 cm−1in agreement with our previous Raman experimental results. In this light, we discuss the high sensitivity of calculatedS(μF) dependences to the atomic and electronic structure. 

  • 5. Colusso, E.
    et al.
    De Ferrari, Fabio
    Minzioni, P.
    Martucci, A.
    Wang, Y.
    Omenetto, F. G.
    Engineering optical defects in biopolymer photonic lattices2018In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 6, no 5, p. 966-971Article in journal (Refereed)
  • 6. Giri, Anupam
    et al.
    Goswami, N.
    Pal, M.
    Zar Myint, M. T.
    Al-Harthi, S.
    Singha, A.
    Ghosh, B.
    Dutta, Joydeep
    Deparment in Nanotechnology, Water Research Center, Sultan Qaboos University, Al-Khoudh, Oman.
    Pal, S. K.
    Rational surface modification of Mn3O4 nanoparticles to induce multiple photoluminescence and room temperature ferromagnetism2013In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 1, no 9, p. 1885-1895Article in journal (Refereed)
    Abstract [en]

    Surface modification can have a significant influence on the materials behavior at the nanoscale and can lead to nanostructures with novel properties. Here, we demonstrate the surface modification induced multiple photoluminescence and room temperature ferromagnetic activation of Mn3O4 nanoparticles (NPs). Employing a systematic variation of the ligands, their functional groups and the structural position of the functional groups, we have identified the necessary and sufficient structural requirements of the surface co-ordinating ligands, in order to induce unprecedented optical/magnetic responses from the NPs. Using a multitude of spectroscopic techniques, we have investigated the mechanism behind the emergence of the multiple photoluminescence (PL), and it is revealed that the presence of a α-hydroxy carboxylate moiety in the ligands is necessary to activate the Jahn-Teller (J-T) splitting of Mn3+ ions on the NP surface and the corresponding d-d transitions along with the ligand-to-metal charge transfer transitions (LMCT, associated with Mn2+/3+-ligand interactions) is the key factor. However, the presence of a carboxylate group on the surface coordinating ligands is sufficient to activate the room temperature ferromagnetism of the NPs. Moreover, it has been observed that the ligands that induced the smallest crystal field splitting energy (CFSE) resulted in the strongest ferromagnetic activation of the NPs. Finally, the functionalized material has been identified as an efficient catalyst for the photo-degradation of a model cationic organic dye. Apart from the fundamental scientific interest, these results represent a promising route for the rational design of Mn 3O4 NPs adaptable to diverse applications.

  • 7. Grybauskaite-Kaminskiene, Gintare
    et al.
    Ivaniuk, Khrystyna
    Bagdziunas, Gintautas
    Turyk, Pavlo
    Stakhira, Pavlo
    Baryshnikov, Gleb V.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Bohdan Khmelnytsky National University, Ukraine.
    Volyniuk, Dmytro
    Cherpak, Vladyslav
    Minaev, Boris F.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Bohdan Khmelnytsky National University, Ukraine.
    Hotra, Zenon
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Siberian Federal University, Russian Federation.
    Grazulevicius, Juozas Vidas
    Contribution of TADF and exciplex emission for efficient "warm-white" OLEDs2018In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 6, no 6, p. 1543-1550Article in journal (Refereed)
    Abstract [en]

    The bicarbazole derivative 4,4'-(9H, 9'H-[3,3'-bicarbazole]-9,9'-diyl) bis(3-(trifluoromethyl) benzonitrile), denoted as pCNBCzoCF(3), was synthesized and tested for white OLED applications. pCNBCzoCF3 demonstrated an extremely small value of the singlet-triplet energy gap that caused intensive thermally activated delayed fluorescence (TADF). In addition, this compound is able to form exciplex-type excited states at the interface with star-shaped 4,40,400-tris[phenyl(m-tolyl) amino] triphenylamine (m-MTDATA). Combining the TADF emission of pCNBCzoCF3 with the exciplex emission from the pCNBCzoCF(3) m-MTDATA interface, we fabricated a number of highly efficient "warm-white'' OLEDs, the electroluminescence of which was close to candle emission. The best device demonstrated a very high brightness of 40 900 Cd m(-2) (at 15 V), current efficiency of 53.8 Cd A(-1) and power efficiency of 19.3 lm W-1, while the external quantum efficiency reached 18.8%. The fabricated devices demonstrated high emission characteristics even for the standard test at 1000 Cd m(-2) (current efficiency of 46.2 Cd A(-1), power efficiency of 10.6 lm W-1, EQE of 17.0%).

  • 8.
    Han, Siyuan
    et al.
    Dalian Univ Technol DUT, State Key Lab Fine Chem, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Energy Sci & Technol,Inst Artificial Photosy, Dalian 116024, Peoples R China..
    Jiang, Xiaoqing
    Dalian Univ Technol DUT, State Key Lab Fine Chem, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Energy Sci & Technol,Inst Artificial Photosy, Dalian 116024, Peoples R China..
    Yu, Ze
    Dalian Univ Technol DUT, State Key Lab Fine Chem, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Energy Sci & Technol,Inst Artificial Photosy, Dalian 116024, Peoples R China..
    Wan, Xiaojing
    Dalian Univ Technol DUT, State Key Lab Fine Chem, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Energy Sci & Technol,Inst Artificial Photosy, Dalian 116024, Peoples R China..
    Zang, Jiadong
    Dalian Univ Technol DUT, State Key Lab Fine Chem, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Energy Sci & Technol,Inst Artificial Photosy, Dalian 116024, Peoples R China..
    Zhang, Caiyun
    Dalian Univ Technol DUT, State Key Lab Fine Chem, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Energy Sci & Technol,Inst Artificial Photosy, Dalian 116024, Peoples R China..
    Rui, Hailong
    Dalian Univ Technol DUT, State Key Lab Fine Chem, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Energy Sci & Technol,Inst Artificial Photosy, Dalian 116024, Peoples R China..
    Yang, Xichuan
    Dalian Univ Technol DUT, State Key Lab Fine Chem, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Energy Sci & Technol,Inst Artificial Photosy, Dalian 116024, Peoples R China..
    Hagfeldt, Anders
    Ecole Polytech Fed Lausanne, Lab Photomol Sci, CH-1015 Lausanne, Switzerland..
    Sun, Licheng
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Organic chemistry. Dalian Univ Technol DUT, State Key Lab Fine Chem, DUT KTH Joint Educ & Res Ctr Mol Devices, Inst Energy Sci & Technol, Inst Artificial Photosy, Dalian 116024, Peoples R China..
    Side-chain engineering of PEDOT derivatives as dopant-free hole-transporting materials for efficient and stable n-i-p structured perovskite solar cells2020In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 8, no 27, p. 9236-9242Article in journal (Refereed)
    Abstract [en]

    Low-cost poly(3,4-ethylenedioxythiophene) (PEDOT) and its derivatives have been widely used as hole-transporting materials (HTMs) in p-i-n perovskite solar cells (PSCs). However, reports on the use of PEDOT-based HTMs in regular PSCs have been rather limited up till now due to the low solubility of PEDOT in organic solvents. In this work, we report three PEDOT derivatives, namely, PEDOT-C6 (P6), PEDOT-C10 (P10), and PEDOT-C14 (P14), with a simple synthetic process by tailoring the length of the alkyl side-chains, and apply them as dopant-free HTMs in mesoscopic n-i-p structured PSCs. It is revealed that the alkyl side-chain length has a significant impact on the film morphology, hole transport capability, and thus the overall solar cell performance. The devices with P10 afford a champion PCE of 16.2% at one sun illumination (100 mW cm(-2), AM 1.5G), which is significantly higher compared to those based on P6 (12.1%) and P14 (14.8%) under identical conditions. This has been the highest PCE reported so far for dopant-free PEDOT-based HTMs in conventional PSCs. The greatly enhanced photovoltaic performance observed for the P10-based devices is mainly attributed to the superior film formation property and hole transport capability of P10. Furthermore, the devices utilizing P10 also show excellent ambient stability, retaining 75% of their initial performance at a relative humidity (RH) of 80% after 120 h due to the high moisture resistivity of the HTM. The present work provides a new avenue for further developing low-cost, efficient, and stable HTMs in PSCs in the future.

  • 9. Huang, Wei
    et al.
    Wang, Huan
    Sun, Lu
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Li, Bo
    Su, Jianhua
    Tian, He
    Propeller-like D-pi-A architectures: bright solid emitters with AIEE activity and large two-photon absorption2014In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 2, no 33, p. 6843-6849Article in journal (Refereed)
    Abstract [en]

    Two novel molecules TABzPA and TATpPA with D-pi-A structure and large pi-conjugation have been synthesized via Wittig reaction. Unlike common molecules, which exhibit the aggregation-caused quenching (ACQ) phenomenon, TABzPA and TATpPA exhibit aggregation-induced emission enhancement (AIEE) activity: weak luminescence in common solvents but strong emission when aggregated as nanoparticles and solid powders. Due to their intramolecular charge transfer (ICT) attribution and AIEE features, TABzPA and TATpPA display bathochromic effects. Combining ICT and AIEE features, these molecules are intensely yellow solid emitters with high quantum efficiencies of about 23.2% and 24.1%. Moreover, TABzPA and TATpPA have excellent two-photon absorption (2PA) properties owing to good planarity and large pi-conjugation. The values of 2PA cross sections at 800 nm are 7590 GM and 7648 GM. The excellent optical properties of TABzPA and TATpPA pave the way for future potential applications in biophotonics and optoelectronics.

  • 10. Ivaniuk, K. B.
    et al.
    Baryshnikov, Glib V.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Bohdan Khmelnytsky National University of Cherkasy, Ukraine.
    Stakhira, P. Y.
    Pedersen, S. K.
    Pittelkow, M.
    Lazauskas, A.
    Volyniuk, D.
    Grazulevicius, J. V.
    Minaev, Boris F.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Khmelnytsky National University of Cherkasy, Ukraine.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology. Siberian Federal University, Russia.
    New WOLEDs based on pi-extended azatrioxa[8]circulenes2017In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 5, no 17, p. 4123-4128Article in journal (Refereed)
    Abstract [en]

    New stable WOLEDs based on pi-extended azatrioxa[8]circulenes have been fabricated. Combining the own blue emission of the azatrioxa[8] circulenes with the yellow-green emission of the "m-MTDATA:azatrioxa[8]circulene'' exciplex a broad visible region, from 400 to 700 nm, is covered. The so constructed WOLEDs exhibit a luminance exceeding 23 700 cd m(-2) and an external quantum efficiency reaching 3%.

  • 11. Karaush-Karmazin, Nataliya N.
    et al.
    Baryshnikov, Gleb V.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Kuklin, Artem, V
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Saykova, Diana, I
    Ågren, Hans
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Minaev, Boris F.
    Impact of molecular and packing structure on the charge-transport properties of hetero[8]circulenes2021In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 9, no 4, p. 1451-1466Article in journal (Refereed)
    Abstract [en]

    In organic photovoltaic cells, absorption of light leads to the formation of excitons, which then diffuse to the donor/acceptor interface to generate photocurrent. The distance from which excitons can reach the interface is constrained by the exciton diffusion length, which has been difficult to quantitatively model or predict due to structural and energetic disorder. Modern non-fullerene acceptors have been shown to possess exceptionally large diffusion lengths, along with well-defined molecular and packing structures, suggesting that a predictive framework for materials design and computational screening may be possible. In this work, we demonstrate that the large diffusion coefficient recently observed in an archetypical non-fullerene acceptor, IDIC, can be accurately quantified using density functional theory, and that the low energetic disorder means that the crystal structure provides a meaningful starting point to understand exciton motion in thin films. Accounting for the short- and long-range excitonic interactions, as well as spatiotemporal disorder, we demonstrate that both Monte-Carlo techniques and a simple sum-over-rates method can accurately predict experimental values for exciton diffusivity and diffusion length. The simplicity and accuracy of this approach are directly linked to the structural order of these materials, and an electronic coupling profile that is unusually resilient to thermal distortions - highlighting the potential of the sum-over-rates method for computational materials screening. Moreover, we show that these factors, combined with the low reorganisation energy and significant long-range electronic coupling, lead to diffusion rates that approach the upper limit of incoherent energy transfer and long diffusion lengths that relieve constraints on organic solar cell device architectures.

  • 12. Li, Wenlong
    et al.
    Cai, Yunsong
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Tian, He
    Zhu, Wei-Hong
    Sterically hindered diarylethenes with a benzobis(thiadiazole) bridge: photochemical and kinetic studies2015In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 3, no 33, p. 8665-8674Article in journal (Refereed)
    Abstract [en]

    Four rationally designed diarylethenes (DAEs) 1-4 with a benzobis(thiadiazole) bridge are specifically designed for gaining insights into steric effects on photochromic performances. It is shown that, upon increasing steric hindrance, the exchanging rate between two main conformers in the ring-open form gradually slows down, offering the opportunity for isolating photoactive anti-parallel conformers. Impressively, the separated anti-parallel conformer shows high cyclization quantum yields over the unresolved common DAEs. The typical donor-pi-acceptor (D-pi-A) feature in ring-open DAEs 1-4 endows their prominent fluorescence, which can be conveniently modulated by photocyclization. In the ring-closed form, the excess steric hindrance is found to seriously disrupt the thermal bistability, and particularly 3c fades quickly with a half-life of several hours at ambient temperature. In contrast, both 1c and 2c exhibit excellent stability, which originates from the stabilization effects of intramolecular hydrogen bonds. This work demonstrates the steric effects on the photochemical and kinetic behaviors of DAEs, providing a unique approach to develop photochromic DAEs with high photosensitivity.

  • 13. Majumdar, Arnab
    et al.
    Adeleke, Adebayo A.
    Chakraborty, Sudip
    Ahuja, Rajeev
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Properties.
    Emerging piezochromism in lead free alkaline earth chalcogenide perovskite AZrS(3) (A = Mg, Ca, Sr and Ba) under pressure2020In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 8, no 46, p. 16392-16403Article in journal (Refereed)
    Abstract [en]

    Hydrostatic pressure is an effective tool that can give rise to novel crystal structures and physical properties. It has proven to be an alternative to chemical pressure. Therefore new functional materials with intriguing properties can be designed by exerting external pressure. Metal chalcogenide perovskites are a class of perovskites that have several advantages, namely high stability against moisture and light induced degradation along with nontoxic elemental composition. In this letter, we have used first principles methods to study the structural, electronic and optical properties of AZrS(3) where A = Mg, Ca, Sr and Ba upon compression. Upon being compressed, the direct band gaps decrease to desired values which can enable this class of zirconium based chalcogenide perovskites to be used in tandem solar cells. The mobility of the charge carriers increases with pressure as the effective masses decrease. Piezochromism is seen to exist upon compression which can be verified from the modifications in the optical absorption spectra. This work elucidates the effects of pressure on the sensitive tuning of properties of zirconium based chalcogenide perovskites, which can have significant photovoltaic applications.

  • 14. Mao, L.
    et al.
    Dun, S.
    Ren, H.
    Jiang, J.
    Guo, X.
    Huang, F.
    Heng, P.
    Wang, L.
    Zhang, J.
    Ågren, Hans
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology. Institute of Upconversion Nanoscale Materials, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475004, China.
    Introducing chenodeoxycholic acid coadsorbent and strong electron-withdrawing group in indoline dyes to design high-performance solar cells: A remarkable theoretical improvement2021In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 9, no 17, p. 5800-5807Article in journal (Refereed)
    Abstract [en]

    The addition of coadsorbents and the introduction of electron-withdrawing groups in dye sensitizers are considered feasible strategies for improving the power conversion efficiency (PCE) of dye-sensitized solar cells (DSSCs). However, facile and precise predictions of the influence of these two strategies on their photovoltaic properties, including PCE, are challenging. In this contribution, we studied a known D-A-π-A indoline dye WS-2 adsorbed on a TiO2 anode represented by a supercell model. The PCE of this dye was evaluated to be between 9.69% and 13.70%, depending on the supercell representation, compared with an experimental value of 8.55%. The PCE could be increased to 16.39% on a moderate supercell by adding chenodeoxycholic acid (CDCA) as a coadsorbent. Such an enhancement could be ascribed to the intermolecular interaction between WS-2 and CDCA, suppressing excessively high dye coverage and thereby resulting in a remarkable increase in the open-circuit voltage. Based on WS-2, a new molecule WS-2a was rationally designed by substituting the benzothiadiazole moiety of WS-2 with a stronger electron-withdrawing thienyl-diketopyrrolopyrrole group. Consequently, the maximum absorption band showed a large red-shift from 522 to 638 nm, broadening the spectral response into the near-infrared region. A higher PCE of 16.62% was obtained for WS-2a. Moreover, the coadsorption of WS-2a and CDCA onto the TiO2 supercell achieved the best photovoltaic efficiency with a value as high as 24.15%. Therefore, the present study quantitatively reveals the impact of the coadsorbent and electron-withdrawing groups on the optoelectronic properties of dyes, which opens a new avenue to design high-efficiency D-A-π-A-structured organic sensitizers for promising DSSC applications. A discussion on the qualification of these results is given.

  • 15.
    Migas, Dmitry B.
    et al.
    Belarusian State Univ Informat & Radioelect, P Browki 6, Minsk 220013, BELARUS.;Natl Res Nucl Univ, MEPhI Moscow Engn Phys Inst, Kashirskoe Shosse 31, Moscow 115409, Russia..
    Turchenko, Vitaliy A.
    Joint Inst Nucl Res, 6 Joliot Curie Str, Dubna 141980, Russia..
    Rutkauskas, A. V.
    Joint Inst Nucl Res, 6 Joliot Curie Str, Dubna 141980, Russia..
    Trukhanov, Sergey V.
    NAS Belarus, SSPA Sci Pract Mat Res Ctr, Minsk 220072, BELARUS.;NUST MISiS, Smart Sensors Lab, Moscow 119049, Russia..
    Zubar, Tatiana I.
    NAS Belarus, SSPA Sci Pract Mat Res Ctr, Minsk 220072, BELARUS..
    Tishkevich, Daria I.
    NAS Belarus, SSPA Sci Pract Mat Res Ctr, Minsk 220072, BELARUS..
    Trukhanov, Alex V.
    NAS Belarus, SSPA Sci Pract Mat Res Ctr, Minsk 220072, BELARUS.;NUST MISiS, Smart Sensors Lab, Moscow 119049, Russia.;LN Gumilyov Eurasian Natl Univ, Astana 010000, Kazakhstan..
    Skorodumova, Natalia
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Structures. Luleå Univ Technol, Luleå, Sweden.
    Temperature induced structural and polarization features in BaFe12O192023In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 11, no 36, p. 12406-12414Article in journal (Refereed)
    Abstract [en]

    We report the observation of a peculiar polarization behavior of BaFe12O19 in electric field where the linear polarization is detected at temperatures below 150 K whereas at higher temperatures a hysteresis-like polarization response is observed. At the same time, the performed neutron diffraction analysis shows no variations in crystal or magnetic structures with temperature. Based on the results of ab initio calculations we suggest the mechanism able to explain the experimentally observed behavior. We show that specific Fe atoms do not occupy the positions formally assigned to them by the conventional centrosymmetric P6(3)/mmc (#194) space group (z = 0.25; 0.75) as these positions correspond to local energy maxima. Instead, these Fe atoms are shifted along the z-axis to positions z = 0.259 (0.241) and z = 0.759 (0.741), which correspond to local energy minima. To an inversion center move between these minima Fe atoms need to overcome an energy barrier. This barrier is rather insignificant for smaller volumes but it becomes larger for expanded volumes due to coupling between the displacements of these Fe atoms. Additionally, our analysis suggests that the non-centrosymmetric and polar P6(3)mc (#186) space group could be appropriate for the description of the BaFe12O19 structure.

  • 16. Monni, N.
    et al.
    Angotzi, M. S.
    Oggianu, M.
    Sahadevan, Suchithra Ashoka
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Applied Physical Chemistry.
    Mercuri, M. L.
    Redox-active benzoquinones as challenging ": non-innocent " linkers to construct 2D frameworks and nanostructures with tunable physical properties2022In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 10, no 5, p. 1548-1572Article in journal (Refereed)
    Abstract [en]

    Exploiting redox activity in supramolecular frameworks such as coordination polymers, metal-organic frameworks and related nanostructures is of paramount importance both at the molecular level and for their technological applications, since the modulation of their redox states is an emerging strategy to enhance their physical properties. In the plethora of organic linkers, quinone derivatives are excellent redox-active ligands, widely used for various applications such as electrode materials, flow batteries, pseudocapacitors, etc. Benzoquinones undergo a one-electron reversible reduction to form a semiquinone radical species that can be further reduced to form hydroquinone. Remarkably, the quinoid ring can be functionalized with various functional groups making these systems excellent linkers to construct supramolecular frameworks as well as challenging platforms to tune the redox potential and therefore the stability of radical anions and electrochemical performances of the obtained materials. The recent advances on benzoquinone-based 2D CPs/MOFs and related nanostructures are reported, highlighting the extreme versatility of this class of redox-active linkers in tailoring the physical properties of the obtained materials. The current/future potential of these materials in electrochemical and technologically relevant applications will also be envisioned.

  • 17.
    Ouyang, Liangqi
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Buchmann, Sebastian
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Benselfelt, Tobias
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Centres, Wallenberg Wood Science Center. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Coating Technology.
    Musumeci, Chiara
    Laboratory of Organic Electronics, ITN, Linköping University, Campus Norrköping, SE 60221, Sweden.
    Wang, Zhen
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Khaliliazar, Shirin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Tian, Weiqian
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Li, Hailong
    Fysikum, Stockhohlm University, Roslagstullsbacken 21, Stockholm, Sweden.
    Herland, Anna
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Hamedi, Mahiar
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Fibre Technology.
    Rapid prototyping of heterostructured organic microelectronics using wax printing, filtration, and transfer2021In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 9, no 41, p. 14596-14605Article in journal (Refereed)
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  • 18. Shen, S.
    et al.
    Baryshnikov, Glib
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Yue, B.
    Wu, B.
    Li, X.
    Zhang, M.
    Ågren, H.
    Zhu, L.
    Manipulating crystals through photoexcitation-induced molecular realignment2021In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 9, no 35, p. 11707-11714Article in journal (Refereed)
    Abstract [en]

    Numerous efforts have been invested in improving the uniform rearrangement in photoinduced crystal engineering due to the fact that molecular ordering is hardly addressedviaa traditional photochemical process as a whole. Herein, we present a nonequilibrium strategy, photoexcitation-induced molecular realignment, to manipulate crystal growth and transformation. This strategy allows a dynamic change of molecular conformation upon continuous photoirradiation, wherein the molecular structure remains intact. Consequently, crystal photomanipulation from solution growth to single crystals, polycrystals, and finally to doped films is achieved, accompanied by the phototuning of a series of crystal optical behaviors (e.g.absorption, refraction, fluorescence, and room-temperature phosphorescence). The developed materials are stable because of the molecular conformation kinetically trapped within the minimum energy on the basis of a steady-state design conception. This strategy, relying on the materialization of photoexcitation, provides a paradigm for controlling molecular ordering by light. 

  • 19. Silvearv, Fredrik
    et al.
    Larsson, Peter
    Jones, Sarah. L. T.
    Ahuja, Rajeev
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics. Uppsala University, Sweden .
    Larsson, J. Andreas
    Establishing the most favorable metal-carbon bond strength for carbon nanotube catalysts2015In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 3, no 14, p. 3422-3427Article in journal (Refereed)
    Abstract [en]

    We have studied a wide range of transition metals to find potential carbon nanotube (CNT) catalysts for chemical vapor deposition (CVD) production. The adhesion strengths between a CNT and a metal cluster were calculated using first principle density functional theory (DFT) for all 1st, 2nd and 3rd row transition metals. We have developed the criterion that the metal-carbon adhesion strength per bond must fulfill a Goldilocks principle for catalyzing CNT growth and used it to identify, besides the well known catalysts Fe, Co and Ni, a number of other potential catalysts, namely Y, Zr, Rh, Pd, La, Ce and Pt. Our results are consistent with previous experiments performed either in a carbon arc discharge environment or by a CVD-process with regard to CNT catalyst activity.

  • 20. Song, X.
    et al.
    Zhang, W.
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Jiang, H.
    Shen, C.
    Zhu, W. -H
    Influence of ethynyl position on benzothiadiazole based D-A-π-A dye-sensitized solar cells: Spectral response and photovoltage performance2016In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 4, no 39, p. 9203-9211Article in journal (Refereed)
    Abstract [en]

    The ethynyl group has been widely employed in dye-sensitized solar cells (DSSCs) as an efficient π-spacer to prolong conjugation and promote electronic coupling at the interface of TiO2 films. However, systematic studies of the ethynyl position on metal-free organic sensitizers remain relatively rare. Herein we report indoline-based organic dyes bearing an ethynyl group at different positions of D-A-π-A organic dyes. Based on the reference dye D1, we inserted an ethynyl unit in either the left or right side of benzothiadiazole to construct two novel dyes D2 and D3. It was found that inserting an ethynyl unit to the side of the anchoring group obtained a higher molar extinction coefficient with a red shift in the absorption band. Interestingly, D2 and D3 displayed a better photovoltaic performance with respect to D1. In particular, D3 exhibits an over 90 mV enhanced open-circuit voltage (VOC) than D2 owing to a longer electron lifetime and slower charge recombination. With this incredible increase of VOC, D3 bestows a high efficiency of 7.13% with respect to D1 and D2. Coadsorption strategies are exploited for further improving the cell behaviour. As a result, cosensitization with a long-wavelength-responsive dye WS-2 was demonstrated to efficiently compensate the light-harvesting, achieving an excellent efficiency of 9.83% in the iodine electrolyte. This work has paved a useful and practical way for molecular engineering in D-A-π-A metal-free organic dyes.

  • 21. Wang, Shangshang
    et al.
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Zhao, Wandong
    Chen, Xuanying
    Zhang, Junji
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Zou, Qi
    Zhu, Liangliang
    Chen, Wenbo
    Cu2+-Selectivity gated photochromism in Schiff-modified diarylethenes with a star-shaped structure2017In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 5, no 2, p. 282-289Article in journal (Refereed)
    Abstract [en]

    A great deal of effort has been devoted to developing gated photochromic systems due to their advantages in the smart materials and opto-electronic fields, whereas the gating function through certain ions has rarely been addressed. Since the photochromic materials gated by ions can be readily further processed into a multi-functional molecular switch and probe, we herein designed and conveniently synthesized a star-shaped Schiff-based diarylethene derivative showing typical photochromic properties in solution. This compound possesses two response channels (colorimetric and fluorogenic) to Cu2+ ions with photoswitching characteristics, making it a viable photochromic probe. It is noteworthy that its photochromic reactivity can be locked when Cu2+ ions are introduced into the solution. Moreover, the photoinactive and photoactive states can be interchanged reversibly by binding Cu2+ ions and unbinding Cu2+ ions using EDTA, which shows promise for application in multi-controlled molecular switches and smart materials. The mechanism of the photochromic properties locked by Cu2+ ions is reasonably proposed by theoretical simulations. These results could be valuable for the further development of molecular switching systems with multiple stimuli responses.

  • 22.
    Yang, Xiaoyong
    et al.
    Southwest Univ Sci & Technol, Natl Collaborat Innovat Ctr Nucl Waste & Environm, Mianyang 621010, Sichuan, Peoples R China.;Uppsala Univ, Dept Phys & Astron, Condensed Matter Theory Grp, Mat Them Div, Box 516, S-75120 Uppsala, Sweden..
    Singh, Deobrat
    Uppsala Univ, Dept Phys & Astron, Condensed Matter Theory Grp, Mat Them Div, Box 516, S-75120 Uppsala, Sweden..
    Xu, Zhitong
    Southwest Univ Sci & Technol, Natl Collaborat Innovat Ctr Nucl Waste & Environm, Mianyang 621010, Sichuan, Peoples R China..
    Wang, Ziwei
    Southwest Univ Sci & Technol, Natl Collaborat Innovat Ctr Nucl Waste & Environm, Mianyang 621010, Sichuan, Peoples R China..
    Ahuja, Rajeev
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Applied Material Physics. Uppsala Univ, Dept Phys & Astron, Condensed Matter Theory Grp, Mat Them Div, Box 516, S-75120 Uppsala, Sweden..
    An emerging Janus MoSeTe material for potential applications in optoelectronic devices2019In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 7, no 39, p. 12312-12320Article in journal (Refereed)
    Abstract [en]

    Motivated by the extraordinary physical and chemical properties of Janus transition-metal dichalcogenides (TMDs) due to the change of the crystal field originating from their asymmetry structures, the electronic and optical properties of the MoSeTe monolayer in 2H and 1T phases are systematically studied by first-principles calculations, and a detailed comparison with the parental MoSe2 and MoTe2 monolayer is made. It is found that 2H-MoSeTe exhibits a direct bandgap of 1.859 eV and an indirect band gap of 0.391 eV in the 1T phase, resulting in a different way to interact with sunlight. Besides, the obtained results show that the SOC has little effects on the band gaps. The calculated optical properties show a significant red shift from the MoSe2 to MoSeTe to MoTe2 monolayer. However, a blue shift is observed from the in-plane to out-of-plane direction. Moreover, both electron-electron and electron-hole correlation effects are considered for obtaining the optical spectra of systems by G(0)W(0) and G(0)W(0) + BSE approaches. Besides, the absorption coefficient value reaches up to 1 x 10(6) cm(-1) in both phases, implying the high efficiency in the utilization of solar energy for the MoSeTe monolayer. Additionally, the 1T-MoSeTe monolayer is a good hot mirror material in that its maximum reflectivity could reach up to 51% in the infrared region. Additionally, the average optical absorbance of the Janus MoSeTe monolayer in the visible light region is calculated to be about 2% and the corresponding average transmittance is around 80%. More importantly, the difference in the optical response for the two side surfaces is considered in our work due to the intrinsic asymmetric structure of Janus MoSeTe. These results not only predict the great potential application of Janus MoSeTe in optoelectronics-electronic devices, but may enable the discovery of new optical science and the realization of various light emissions, detection, modulation and manipulation functions of specific frequencies.

  • 23.
    Zalesny, Robert
    et al.
    Wroclaw Univ Sci & Technol, Fac Chem, Dept Phys & Quantum Chem, Wybrzeze Wyspianskiego 27, PL-50370 Wroclaw, Poland..
    Alam, Md Mehboob
    Indian Inst Technol Bhilai, Dept Chem, Raipur 492015, Chhattisgarh, India..
    Day, Paul N.
    Air Force Res Lab, Dayton, OH 45433 USA..
    Nguyen, Kiet A.
    Air Force Res Lab, Dayton, OH 45433 USA..
    Pachter, Ruth
    Air Force Res Lab, Dayton, OH 45433 USA..
    Lim, Chang-Keun
    Univ Buffalo State Univ New York, Inst Lasers Photon & Biophoton, Dept Chem, Buffalo, NY 14260 USA.;Nazarbayev Univ, Dept Chem & Mat Engn, Sch Engn & Digital Sci, Nur Sultan City 010000, Kazakhstan..
    Prasad, Paras N.
    Univ Buffalo State Univ New York, Inst Lasers Photon & Biophoton, Dept Chem, Buffalo, NY 14260 USA..
    Ågren, Hans
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Theoretical Chemistry and Biology.
    Computational design of two-photon active organic molecules for infrared responsive materials2020In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 8, no 29, p. 9867-9873Article in journal (Refereed)
    Abstract [en]

    In this study we report theoretical studies of the linear and nonlinear optical properties of a series of pi-conjugated organic cations and their neutral precursors which show pi-stacking to exhibit aggregation-enhanced optical properties. These organic cations show promise as photoactive layers in hybrid quasi-2D perovskites for applications in optoelectronics, particularly in the short wavelength infrared region. We analyze the one- and two-photon (2P) absorption (2PA) transition strengths of several excited states in the considered systems at the coupled-cluster level theory employing the CC2 model. Furthermore, a microscopic insight into their 2P activity has been obtained using the generalized few-state model (GFSM). Based on our GFSM results, we pinpoint the origin of the desired nonlinear optical properties and provide a design strategy for efficient IR photoactive organic materials with potential application in organic-inorganic hybrid quasi-2D perovskites.

1 - 23 of 23
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