Article
Multidisciplinary Sciences
Zhen Li, Bo Li, Xin Wu, Stephanie A. Sheppard, Shoufeng Zhang, Danpeng Gao, Nicholas J. Long, Zonglong Zhu
Summary: Functionalizing the interfaces of multication and halide perovskite solar cells with an organometallic compound, ferrocenyl-bis-thiophene-2-carboxylate (FcTc(2)), enhances their efficiency and stability. The resulting devices exhibit high performance and stability, as demonstrated by tests and continuous operation.
Article
Nanoscience & Nanotechnology
Abigail R. Meyer, Rohan P. Chaukulkar, Noemi Leick, William Nemeth, David L. Young, Paul Stradins, Sumit Agarwal
Summary: In this study, the atomistic-level mechanism for the chemical passivation of the monocrystalline Si surface with thermally annealed Al2O3 was investigated using in situ infrared spectroscopy and photoconductance decay measurements. The results showed that surface Si-H bonds are preserved after the ALD of Al2O3 on H-terminated Si, and restructuring occurs at the c-Si/Al2O3 interface during annealing to form interfacial SiOx. Isotope labeling was used to differentiate interfacial SiD bonds on the c-Si surface from H incorporated in Al2O3, and no net migration of atomic H or D from Al2O3 to the c-Si/Al2O3 interface was observed within the sensitivity of the infrared setup. Passivation studies were also conducted on c-Si/SiO2/Al2O3 stacks, revealing that an O-2-containing atmosphere led to the best surface chemical passivation.
ACS APPLIED NANO MATERIALS
(2021)
Article
Chemistry, Physical
Jiwei Liang, Xuzhi Hu, Chen Wang, Chao Liang, Cong Chen, Meng Xiao, Jiashuai Li, Chen Tao, Guichuan Xing, Rui Yu, Weijun Ke, Guojia Fang
Summary: This study reveals the origins and influences of metallic lead (Pb-0) in metal-halide perovskites, and provides a strategy for avoiding the formation of detrimental Pb-0 byproducts. This has significant implications for enhancing the performance of devices such as perovskite solar cells.
Article
Multidisciplinary Sciences
Waseem Raja, Erkan Aydin, Thomas G. Allen, Stefaan De Wolf
Summary: Ultrathin solar cells offer cost advantages due to reduced material consumption and shorter deposition times, but may require efficient light-trapping structures to overcome reduced light absorption. Novel 3-D modeling can aid in analyzing new optical and electrical designs for ultrathin solar cells, resulting in improved power conversion efficiencies.
ADVANCED THEORY AND SIMULATIONS
(2021)
Article
Engineering, Electrical & Electronic
Jiatao Yu, Wenhui Li, Kunming Zhang, Xiuxun Han
Summary: By treating the CsPbI2Br layer with NPTMS, the surface states are passivated and nonradiative recombination is inhibited, resulting in an increase in the power conversion efficiency of the CsPbI2Br perovskite solar cell.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Chemistry, Multidisciplinary
Panus Sundarapura, Xiao-Mei Zhang, Ryoji Yogai, Kazuki Murakami, Alain Fave, Manabu Ihara
Summary: The process of forming SiO2 on the surface of PS was studied to achieve optimal passivation for high-efficiency Si solar cells while maintaining the nanostructure. The results showed that the surface of PS solar cells could be successfully passivated through electrochemical anodization.
Article
Multidisciplinary Sciences
Christopher Woepke, Clemens Goehler, Maria Saladina, Xiaoyan Du, Li Nian, Christopher Greve, Chenhui Zhu, Kaila M. Yallum, Yvonne J. Hofstetter, David Becker-Koch, Ning Li, Thomas Heumueller, Ilya Milekhin, Dietrich R. T. Zahn, Christoph J. Brabec, Natalie Banerji, Yana Vaynzof, Eva M. Herzig, Roderick C. MacKenzie, Carsten Deibel
Summary: The stability of organic solar cells is crucial for their commercialization. This study investigates the thermal degradation of inverted photovoltaic devices based on the PM6:Y6 non-fullerene system and identifies trap-induced transport resistance as the primary cause of the drop in fill factor. By suppressing trap formation, device lifetimes could be significantly increased, offering a promising future for organic solar cells.
NATURE COMMUNICATIONS
(2022)
Article
Engineering, Electrical & Electronic
Namitha Dsouza, Ashish K. Singh, Rajesh Maurya, Rajesh Kanakala, Ramakrishna Madaka, Narendra Bandaru, Md. Seraj Uddin, Jatindra K. Rath
Summary: c-Si based carrier selective contact solar cells achieve high efficiency through silicon surface passivation. Atomic layer deposition (ALD) is used to deposit ultrathin Al2O3 passivation layers, known for their conformance and homogeneity. In this study, thermal ALD is used to deposit Al2O3 films on n-type CZ Si wafers, and post-deposition annealing in forming gas environments improves the passivation quality. The results demonstrate that the passivation obtained here is of device quality for CZ Si wafers and facilitates the development of high-efficiency Si heterojunction (SHJ) solar cells.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2023)
Article
Multidisciplinary Sciences
Qi Cao, Yongjiang Li, Hong Zhang, Jiabao Yang, Jian Han, Ting Xu, Shuangjie Wang, Zishuai Wang, Bingyu Gao, Junsong Zhao, Xiaoqiang Li, Xiaoyan Ma, Shaik Mohammed Zakeeruddin, Wei E. Sha, Xuanhua Li, Michael Graetzel
Summary: This study introduces a star-shaped polymer to enhance charge transport and inhibit ion migration in perovskite solar cells, leading to improved efficiency and stability. Modified devices demonstrate significant performance enhancements and excellent long-term operational stability.
Article
Energy & Fuels
Jose M. V. Cunha, Kevin Oliveira, Jackson Lontchi, Tomas S. Lopes, Marco A. Curado, Joao R. S. Barbosa, Carlos Vinhais, Wei-Chao Chen, Jerome Borme, Helder Fonseca, Joao Gaspar, Denis Flandre, Marika Edoff, Ana G. Silva, Jennifer P. Teixeira, Paulo A. Fernandes, Pedro M. P. Salome
Summary: Through the use of industrial techniques, it has been demonstrated that a passivation layer with nanocontacts based on silicon oxide can significantly improve the optoelectronical performance of ultrathin CIGS solar cells. The passivation layer shows positive passivation properties for two different CIGS growth conditions, leading to a 2.6% improvement in light to power conversion efficiency compared to nonpassivated devices. However, there is a trade-off between passivation effect and charge extraction, as demonstrated by the balance between open-circuit voltage and short-circuit current density compared with fill factor.
Review
Chemistry, Physical
Miguel Albaladejo-Siguan, Elizabeth C. Baird, David Becker-Koch, Yanxiu Li, Andrey L. Rogach, Yana Vaynzof
Summary: Colloidal quantum dot solar cells (QDSCs) show great potential in energy conversion efficiency, but their stability under sunlight exposure needs improvement. This review focuses on the degradation mechanisms and stability improvement strategies of three classes of QDs, proposing a methodology for characterizing QDSCs' stability.
ADVANCED ENERGY MATERIALS
(2021)
Article
Optics
Guang Yang, Zhenyi Ni, Zhengshan J. Yu, Bryon W. Larson, Zhenhua Yu, Bo Chen, Abdulwahab Alasfour, Xun Xiao, Joseph M. Luther, Zachary C. Holman, Jinsong Huang
Summary: By employing tribromide ions to reduce charge recombination, efficient wide-bandgap mixed-halide perovskite-silicon tandem solar cells with an efficiency of up to 28.6% are reported, while also enhancing device stability.
Article
Chemistry, Physical
Sudeshna Ghosh, Debasmita Pariari, Tejmani Behera, Pablo P. Boix, Narasimha Ganesh, Susmita Basak, Arya Vidhan, Nisha Sarda, Ivan Mora-Sero, Arindam Chowdhury, Kavassery Sureswaran Narayan, D. D. Sarma, Shaibal K. Sarkar
Summary: In this study, the nonradiative recombination losses in conventional (n-i-p) solar cells using hybrid halide perovskite materials were investigated. It was found that the deposition of organic cations on the perovskite led to buried defect states, which negatively impacted the operational stability of the devices. A passivation technique using atomic layer deposition of Al2O3 was proposed, which significantly improved the device performance, increased the open-circuit voltage, and enhanced the photoluminescence and electroluminescence quantum efficiency.
ACS ENERGY LETTERS
(2023)
Article
Energy & Fuels
Roel J. Theeuwes, Jimmy Melskens, Wolfhard Beyer, Uwe Breuer, Lachlan E. Black, Wilhelmus J. H. Berghuis, Bart Macco, Wilhelmus M. M. Kessels
Summary: Passivation of semiconductor surfaces is crucial for enhancing device performance. Thin-film stacks of phosphorus oxide (POx) and aluminum oxide (Al2O3) have shown excellent passivation on various semiconductor surfaces. The POx/Al2O3 stacks possess unique properties and stability, making them promising for high-aspect-ratio structures.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2022)
Article
Energy & Fuels
He Wei, Yuheng Zeng, Jingming Zheng, Zhenhai Yang, Mingdun Liao, Shihua Huang, Baojie Yan, Jichun Ye
Summary: In this study, a systematic investigation combining experiments and simulations was conducted to clarify the passivation mechanism of the c-Si/SiOx/poly-Si contact. The results showed that optimizing SiOx quality, tailoring the in-diffusion profile, and performing hydrogenation can lead to the best passivation. It was also found that high-level passivation can be achieved even without impurity doping if the SiOx quality is good enough. Additionally, the presence of pinholes negatively affects the passivation performance, especially in cases with good surface passivation, shallow in-diffusion, and low doping concentration of poly-Si.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2023)
Article
Chemistry, Multidisciplinary
Haojie Zhang, Dirk J. Hagen, Xiaopeng Li, Andreas Graff, Frank Heyroth, Bodo Fuhrmann, Ilya Kostanovskiy, Stefan L. Schweizer, Francesco Caddeo, A. Wouter Maijenburg, Stuart Parkin, Ralf B. Wehrspohn
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2020)
Article
Thermodynamics
Felix Marske, Titus Lindenberg, Juliana Martins de Souza e Silva, Ralf B. Wehrspohn, A. Wouter Maijenburg, Thomas Hahn, Dirk Enke
Summary: Monolithic shape-stabilized phase change materials (ss-PCMs) are a promising material for storing solar energy, waste heat, and off-peak electricity in energy-saving buildings, battery heating systems, and water heating systems. Experimental studies have shown that ss-PCMs containing 5-20 wt% BN with a particle size of 25 μm have significantly higher thermal conductivity compared to smaller BN particles, potentially due to stronger exfoliation and orderly arrangement within the silica structure.
APPLIED THERMAL ENGINEERING
(2021)
Article
Optics
Prerak Dhawan, Maria Gaudig, Alexander Sprafke, Ralf B. Wehrspohn, Carsten Rockstuhl
Summary: The study explores a transformation optics approach to map nanopatterned textures onto a planar equivalent, improving the electrical properties of light-absorbing layers and paving the way for implementing light-trapping structures into planar solar cells.
Article
Materials Science, Multidisciplinary
Peter M. Piechulla, Bodo Fuhrmann, Evgeniia Slivina, Carsten Rockstuhl, Ralf B. Wehrspohn, Alexander N. Sprafke
Summary: This study demonstrates that hyperuniform disorder in arrays of high refractive index nanodisks allows both structure and form factor to impact light scattering patterns, offering novel ways to tailor light scattering effects. The scattering response from nearly hyperuniform interfaces can be utilized in a wide range of applications, representing a new class of advanced optical materials.
ADVANCED OPTICAL MATERIALS
(2021)
Article
Chemistry, Physical
Fernando Vazquez Luna, Michael Gerstenberger, Guido Dittrich, Juliana Martins de Souza e Silva, Patrick Huber, Ralf Wehrspohn, Martin Steinhart
Summary: This study used phase-contrast X-ray computed tomography to image frozen transient imbibition states in arrays of straight cylindrical pores with a diameter of 400 nm, and described a semi-automatic algorithm for identifying brightness profiles along all pores. Deviations from the expected relationship between average imbibition front position and imbibition time were found, highlighting the need to resolve ambiguities related to the exponent of the imbibition time in order to determine the pre-exponential factor in the power law governing the relationship between imbibition front position and imbibition time.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Nanoscience & Nanotechnology
Peter M. Piechulla, Evgeniia Slivina, Derk Batzner, Ivan Fernandez-Corbaton, Prerak Dhawan, Ralf B. Wehrspohn, Alexander N. Sprafke, Carsten Rockstuhl
Summary: In this study, a tailored disordered arrangement of high-index dielectric submicron-sized titanium dioxide (TiO2) disks is used as an antireflective Huygens' metasurface for standard silicon solar cells, resulting in a significant improvement in short-circuit current. The fabrication of the disordered array using a scalable bottom-up technique allows for wide broadband reduction of reflectance compared to a reference cell with an optimized flat antireflective layer. The theoretical model based on Born's first approximation links the current increase to the structure factor of the disk array, providing insights into the optical performance of the metasurface within the framework of helicity preservation.
Article
Multidisciplinary Sciences
Felix Marske, Titus Lindenberg, Juliana Martins de Souza Silva, Ralf B. Wehrspohn, A. Wouter Maijenburg, Thomas Hahn, Dirk Enke
Summary: Shape-stabilized phase change materials (ss-PCMs) based on silica and butyl stearate were thermally enhanced by adding different hexagonal boron nitride particles (BN) during in situ sol-gel synthesis. The experimental data analyzed the influence of different BN particles on the hydrolysis degree of the silica network and the chemical nature of porogens used in ss-PCM synthesis. The spectra and data presented can serve as a reference for researchers and engineers in synthesizing ss-PCMs or as a reference for pure BN, SDS, stabilized silica sol, and PVA.
Article
Chemistry, Physical
Fernando Vazquez Luna, Anjani K. Maurya, Juliana Martins de Souza e Silva, Guido Dittrich, Theresa Paul, Dirk Enke, Patrick Huber, Ralf Wehrspohn, Martin Steinhart
Summary: In this study, we comparatively analyzed the imbibition of polystyrene into two different pore models using X-ray computed tomography and EDX spectroscopy. The results showed that the movement of the imbibition front was influenced by the tortuosity of the porous matrix, with slower movement in larger pore models and faster movement in smaller pore models with more nodes. This research has important implications for applications such as printing and adhesive bonding, as well as for the optimization of production and properties of engineering materials.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Materials Science, Multidisciplinary
Maria Gaudig, Wolfram Muenchgesang, Juliana Martins de Souza e Silva, Fabian Pascher, Thorsten Hickmann, Ralf B. Wehrspohn
Summary: Titanium polymer composites were evaluated as a replacement for milled Titanium bipolar plates in acid water electrolysis. Highly filled polymer composites with 80 wt.-% Titanium powder met the criteria for electric conductivity and mechanical stability set by the US Department of Energy. Coating the composites with a 0.5 mu m thin layer of Titanium improved their electrochemical corrosion behavior, and the coated Titanium composite bipolar plate was successfully integrated in a PEM fuel cell. Though the polarization curves showed good electrolysis performances for short time, further improvements on the coating and surface roughness are needed for long-time stability.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2023)
Article
Optics
Prerak Dhawan, Linus Schulte, Peter Piechulla, Yannick Augenstein, Maria Gaudig, Alexander Sprafke, Ralf B. Wehrspohn, Carsten Rockstuhl
Summary: High-index nanodisk metasurfaces with correlated disorder show promise as an anti-reflective metasurface for optoelectronic devices. However, their computational analysis is challenging due to the need for large simulation domains, which is costly. To address this challenge, we investigate the collective coordinate method (CCM) to identify smaller and optimal super-cells for computational analysis. Our results demonstrate that CCM offers a robust solution to accurately simulate large-scale systems with hyperuniform disorder.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA B-OPTICAL PHYSICS
(2023)
Article
Chemistry, Physical
Donghwan Ji, Pilseon Im, Sunmi Shin, Jaeyun Kim
Summary: Synthetic tough hydrogels have attracted attention for their ability to imitate the mechanical properties of natural hydrogels, but comparing their properties in different reports is challenging due to variations in testing specimen shapes and sizes. This study investigates how the geometry of a tough double-network hydrogel specimen affects its tensile mechanical values, specifically comparing the elastic modulus using various specimen shapes and sizes. The results highlight the importance of considering specimen dimensions in the measurement of tough hydrogel properties.
Article
Chemistry, Multidisciplinary
Peter M. M. Piechulla, Ralf B. B. Wehrspohn, Alexander N. N. Sprafke
Summary: This work evaluates 2D patterns formed by the sedimentation of charged particles from a colloidal dispersion. It demonstrates that monodisperse colloids can exhibit random sequential adsorption-like, fluid, and crystalline phases, with the fluid phase effectively suppressing density fluctuations. Bidisperse colloids, on the other hand, tend to segregate at high density, reducing the system's ability to suppress density fluctuations. It also suggests that tuning the size distribution to the eutectic point can increase the degree of hyperuniformity.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Richard Schalinski, Stefan L. Schweizer, Ralf B. Wehrspohn
Summary: Silicon-air batteries are promising next-generation batteries made from non-critical raw materials. However, current silicon-air batteries with alkaline electrolytes often experience premature termination of the discharge process. In this study, we investigated the relationship between dissolved silicon in the electrolyte and the duration of discharge until passivation. It was found that the concentration of silicates in the electrolyte, rather than the air or Si-electrode, was the determining factor. Maintaining a low silicate concentration in the electrolyte is crucial for sustained discharge and full consumption of the silicon electrode in alkaline silicon-air batteries.
Article
Materials Science, Multidisciplinary
Peter M. M. Piechulla, Yidenekachew J. J. Donie, Ralf B. B. Wehrspohn, Uli Lemmer, Guillaume Gomard, Alexander N. N. Sprafke
Summary: In this study, an efficient light extraction method from waveguide modes in OLEDs is achieved by integrating a disordered array of TiO2 nanodisk scatterers into the OLED substrate. The nanodisks are fabricated using a colloidal lithography technique and a high refractive index TiO2 material. A polymer planarization layer is spin-coated onto the substrate to ensure reproducible optoelectronic properties of the OLED, and the nanodisks near the thin film stack allow efficient out-of-plane scattering of waveguide modes. The device shows a 44.2% increase in external quantum efficiency compared to a device without scattering structure. Further improvements to the scattering structure are being numerically evaluated.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Cristine S. de Oliveira, Richard Kohns, Felix Meyerhoefer, Simon Carstens, Dirk Enke, Ralf B. Wehrspohn, Juliana Martins de Souza e Silva
Summary: Glass foams with a complex multimodal pore structure were successfully synthesized and characterized in this study for the first time, using a combination of techniques including N-2 sorption, Hg intrusion, scanning electron microscopy, and high-resolution X-ray computed tomography. The results revealed the effectiveness of a multi-technique approach in characterizing pores and developing novel porous materials with features in the nanometric range.
MATERIALS CHEMISTRY FRONTIERS
(2021)
