More Like this

1. Anthradithiophene (ADT)‐Based Polymerized Non‐Fullerene Acceptors for All‐Polymer Solar Cells

   https://doi.org/10.1002/chem.202300653  

   Forti, Giacomo ; Pankow, Robert M. ; Qin, Fei ; Cho, Yongjoon ; Kerwin, Brendan ; Duplessis, Isaiah ; Nitti, Andrea ; Jeong, Seonghun ; Yang, Changduk ; Facchetti, Antonio ; et al ( July 2023 , Chemistry – A European Journal)

   Realizing efficient all‐polymer solar cell (APSC) acceptors typically involves increased building block synthetic complexity, hence potentially unscalable syntheses and/or prohibitive costs. Here we report the synthesis, characterization, and implementation in APSCs of three new polymer acceptorsP1–P3using a scalable donor fragment, bis(2‐octyldodecyl)anthra[1,2‐b : 5,6‐b’]dithiophene‐4,10‐dicarboxylate (ADT) co‐polymerized with the high‐efficiency acceptor units, NDI, Y6, and IDIC. All three copolymers have comparable photophysics to known polymers; however, APSCs fabricated by blendingP1,P2andP3with donor polymersPM5andPM6exhibit modest power conversion efficiencies (PCEs), with the championP2‐basedAPSCachieving PCE=5.64 %. Detailed morphological and microstructural analysis by AFM and GIWAXS reveal a non‐optimal APSC active layer morphology, which suppresses charge transport. Despite the modest efficiencies, these APSCs demonstrate the feasibility of usingADTas a scalable and inexpensive electron rich/donor building block for APSCs.

    

   more » « less
2. Global planning of accelerated degradation tests based on exponential dispersion degradation models

   https://doi.org/10.1002/nav.21923  

   Lee, I‐Chen ; Tseng, Sheng‐Tsaing ; Hong, Yili ( July 2020 , Naval Research Logistics (NRL))

   The accelerated degradation test (ADT) is an efficient tool for assessing the lifetime information of highly reliable products. However, conducting an ADT is very expensive. Therefore, how to conduct a cost‐constrained ADT plan is a great challenging issue for reliability analysts. By taking the experimental cost into consideration, this paper proposes a semi‐analytical procedure to determine the total sample size, testing stress levels, the measurement frequencies, and the number of measurements (within a degradation path) globally under a class of exponential dispersion degradation models. The proposed method is also extended to determine the global planning of a three‐level compromise plan. The advantage of the proposed method not only provides better design insights for conducting an ADT plan, but also provides an efficient algorithm to obtain a cost‐constrained ADT plan, compared with conventional optimal plans by grid search algorithms.

    

   more » « less
3. Topotactic BI 3 -assisted borodization: synthesis and electrocatalysis applications of transition metal borides

   https://doi.org/10.1039/D2TA04266E  

   Woo, Katherine E. ; Kong, Seongyoung ; Chen, Wei ; Chang, Tsz Hin ; Viswanathan, Gayatri ; Díez, Aida M. ; Sousa, Viviana ; Kolen'ko, Yury V. ; Lebedev, Oleg I. ; Costa Figueiredo, Marta ; et al ( October 2022 , Journal of Materials Chemistry A)

   A facile and universal route for synthesizing transition metal borides has been developed by reaction of boron triiodide (BI 3 ) with elemental transition metals. This method employs relatively low synthesis temperatures to afford single-phase samples of various binary and ternary metal borides, such as Fe 2 B, Co 2 B, Ni 3 B, TiB 2 , VB 2 , CrB 2 , and Ni 2 CoB. This synthesis protocol can be utilized for the topotactic transformation of metal shapes into their respective borides, as exemplified by transformation of Ni foam to Ni 3 B foam. In situ powder X-ray diffraction studies of the Ni–BI 3 system showed that the crystalline nickel borides, Ni 4 B 3 and Ni 2 B, start to form at temperatures as low as 700 K and 877 K, respectively, which is significantly lower than the typical synthesis temperatures required to produce these borides. Ni 3 B synthesized by this method was tested as a supporting material for oxygen evolution reaction (OER) in acidic media. Composite electrocatalysts of IrO 2 /Ni 3 B with only 50% of IrO 2 exhibit current densities and stability similar to pure IrO 2 at mass loadings lower than 0.5 mg cm −2 , indicating Ni 3 B could be a promising supporting material for acidic OER. 

   more » « less
4. Twisted Crystalline Organic Semiconductor Photodetectors

   https://doi.org/10.1002/adfm.202212531  

   Jeong, Sehee ; Barbosa, Natercia ; Tiwari, Akash ; Holland, Emma K. ; Huang, Ling‐Yi ; Bhat, Vinayak ; Yang, Yongfan ; Zhang, Yuze ; Whittaker, St. John ; Kim, Min‐Woo ; et al ( March 2023 , Advanced Functional Materials)

   Optoelectronic properties of anisotropic crystals vary with direction requiring that the orientation of molecular organic semiconductor crystals is controlled in optoelectronic device active layers to achieve optimal performance. Here, a generalizable strategy to introduce periodic variations in the out‐of‐plane orientations of 5,11‐bis(triisopropylsilylethynyl)anthradithiophene (TIPS ADT) crystals is presented. TIPS ADT crystallized from the melt in the presence of 16 wt.% polyethylene (PE) forms banded spherulites of crystalline fibrils that twist in concert about the radial growth direction. These spherulites exhibit band‐dependent light absorption, photoluminescence, and Raman scattering depending on the local orientation of crystals. Mueller matrix imaging reveals strong circular extinction (CE), with TIPS ADT banded spherulites exhibiting domains of positive or negative CE signal depending on the crystal twisting sense. Furthermore, orientation‐dependent enhancement in charge injection and extraction in films of twisted TIPS ADT crystals compared to films of straight crystals is visualized in local conductive atomic force microscopy maps. This enhancement leads to 3.3‐ and 6.2‐times larger photocurrents and external quantum efficiencies, respectively, in photodetectors comprising twisted crystals than those comprising straight crystals.

    

   more » « less
5. Regulating the electronic structures of mixed B-site pyrochlore to enhance the turnover frequency in water oxidation

   https://doi.org/10.1186/s40580-022-00311-z  

   Zhang, Cheng ; Wang, Fangfang ; Xiong, Beichen ; Yang, Hong ( May 2022 , Nano Convergence)

   This paper describes the development of mixed B-site pyrochlore Y₂MnRuO₇electrocatalyst for oxygen evolution reaction (OER) in acidic media, a challenge for the development of low-temperature electrolyzer for green hydrogen production. Recently, several theories have been developed to understand the reaction mechanism for OER, though there is an  uncertainty in most of the cases, due to the complex surface structures. Several key factors such as lattice oxygen, defect, electronic structure, oxidation state, hydroxyl group and conductivity were identified and shown to be important to the OER activity. The contribution of each factor to the performance however is often not well understood, limiting their impact in guiding the design of OER electrocatalysts. In this work, we showed mixed B-site pyrochlore Y₂MnRuO₇catalyst exhibits 14 times higher turnover frequency (TOF) than RuO₂while maintaining a low overpotential of ~ 300 mV for the entire testing period of 24 h in acidic electrolyte. X-ray photoelectron spectroscopy (XPS) analysis reveals that this B-site mixed pyrochlore Y₂MnRuO₇has a higher oxidation state of Ru than those of Y₂Ru₂O₇, which could be crucial for improving OER performance as the broadened and lowered Ru 4d band resulted from the B-site substitution by Mn is beneficial to the OER kinetics.

    

   more » « less