Article
Physics, Applied
Lei Liu, Xingyue Zhangyang, Zhisheng Lv, Feifei Lu, Jian Tian
Summary: This study proposes a new design for vacuum photoelectron emitting devices to address the issue of secondary absorption, utilizing a theoretical model of field-assisted negative electron affinity Alx1Ga1-x1N/Alx2Ga1-x2N heterojunction nanocone array photocathode. By applying electric fields, the electron collection ratio and efficiency of the nanocone photocathode are significantly improved. This work could serve as a theoretical guideline for the design and manufacture of high-performance solar-blind ultraviolet detectors.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Physical
Zhenhuang Su, Wei Hui, Yanan Dong, Chenyue Wang, Jinping Hu, Kongchao Shen, Wen Wen, Yimin Xiong, Liang Cao, Yonghua Chen, Xingyu Gao
Summary: The study found that although the interfacial energetics of X55 and X60 molecules deposited on CH3NH3PbI3 perovskite are favorable for hole transfer/injection, the PSCs using these molecules as HTLs perform poorly due to their low HTL conductivity/mobility. After LiTFSI/tBP doping, although the interfacial energetics may improve slightly or even become more favorable, the hole mobility in both films only shows slight improvement, resulting in PSCs with low power conversion efficiency. However, subsequent air exposure triggering a doping effect leads to a significant increase in hole mobility, dramatically improving the PSC performance with champion PCEs.
ACS APPLIED ENERGY MATERIALS
(2021)
Article
Chemistry, Physical
Wenjing Yu, Xiaoran Sun, Mu Xiao, Tian Hou, Xu Liu, Bolin Zheng, Hua Yu, Meng Zhang, Yuelong Huang, Xiaojing Hao
Summary: Lead halide perovskite solar cells have rapidly developed in the past decade, with interface engineering playing a crucial role in optimizing device performance and long-term stability through defect passivation, inhibiting ion migration, optimizing energy band alignment, and morphological control.
Article
Chemistry, Physical
Dorothee Menzel, Amran Al-Ashouri, Alvaro Tejada, Igal Levine, Jorge Andres Guerra, Bernd Rech, Steve Albrecht, Lars Korte
Summary: Through ultra-sensitive near-UV photoelectron spectroscopy, the energy level alignment and defect formation at the perovskite/C-60 interface are investigated. It is found that the fullerene C-60 as the electron transport layer limits the open circuit voltage in metal halide perovskite solar cells. The voltage enhancement with the incorporation of a LiF interlayer at the interface can be attributed to a dipole effect and the presence of fixed charges.
ADVANCED ENERGY MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Hong Zou, Yuwei Duan, Shaomin Yang, Dongfang Xu, Lu Yang, Jian Cui, Hui Zhou, Meizi Wu, Jungang Wang, Xuruo Lei, Na Zhang, Zhike Liu
Summary: This study introduces a new approach to improve the performance of CsPbI3 perovskite solar cells by depositing a new zwitterion ion at the interface between the electron transporting layer and perovskite layer. The zwitterion ions can effectively passivate defects and improve the band alignment, resulting in a significant increase in power conversion efficiency.
Article
Chemistry, Physical
Manoj K. Jamarkattel, Adam B. Phillips, Indra Subedi, Abasi Abudulimu, Ebin Bastola, Deng-Bing Li, Xavier Mathew, Yanfa Yan, Randy J. Ellingson, Nikolas J. Podraza, Michael J. Heben
Summary: The study demonstrates that CdTe-based solar cells can achieve higher efficiencies by using (InxGa1-x)(2)O-3 emitters, with the potential for further improvement through optimizing the transmission and reducing recombination.
ACS APPLIED ENERGY MATERIALS
(2022)
Article
Chemistry, Physical
Mengmeng Chen, Muhammad Akmal Kamarudin, Ajay K. Baranwal, Gaurav Kapil, Teresa S. Ripolles, Kohei Nishimura, Daisuke Hirotani, Shahrir Razey Sahamir, Zheng Zhang, Chao Ding, Yoshitaka Sanehira, Juan Bisquert, Qing Shen, Shuzi Hayase
Summary: This study explores the fabrication of wide band gap ASnI(2)Br perovskite solar cells and demonstrates the potential of tin-halide perovskite solar cells in the fabrication of lead-free all-perovskite tandem solar cells.
ACS APPLIED ENERGY MATERIALS
(2021)
Article
Chemistry, Physical
Hui Li, Zhongxiao Wang, Lian Wang, Bohong Chang, Zhen Liu, Lu Pan, Yutong Wu, Longwei Yin
Summary: This study developed a comprehensive dual-passivation strategy to repair defects in the grain boundaries and surfaces of CsPbI2Br perovskite solar cells. The improved CsPbI2Br films showed reduced lattice strains and enlarged grains after the dual-passivation. The strategy significantly improved the photovoltaic performance by suppressing charge recombination and enhancing hole transport ability.
Article
Chemistry, Physical
Changjo Kim, Irem Kozakci, Junho Kim, Sang Yeon Lee, Jung-Yong Lee
Summary: In this study, a design strategy to improve the performance of silver bismuth disulfide (AgBiS2) nanocrystal/organic hybrid solar cells is proposed by optimizing the energy level structure and charge extraction. By selecting an appropriate hole-transporting layer material and surface treatment method, the power conversion efficiency of the solar cell is increased from 3.3% to 7.1%.
ADVANCED ENERGY MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Hao Chen, Zijian Peng, Kaimin Xu, Qi Wei, Danni Yu, Congcong Han, Hansheng Li, Zhijun Ning
Summary: Research explores a high-efficiency and stable room-temperatureprocessed HTL for Sn-Pb solar cells, which outperforms high-temperature-annealed films, improves the efficiency of solar cells, and maintains 96% of the original efficiency after 50 days.
SCIENCE CHINA-MATERIALS
(2021)
Article
Materials Science, Ceramics
Luanhong Sun, Wei Wang, Lingyun Hao, Adil Raza, Yijie Zhao, Zhengxia Tang, Guowei Zhi, Hanyu Yao
Summary: This study introduces a TiN diffusion barrier as a means to improve the efficiency and flexibility of flexible CZTSSe solar cells. The TiN barrier layer alleviates residual stress, reduces the porosity of CZTSSe, and inhibits carrier recombination paths. By optimizing the TiN layer thickness, the power conversion efficiency of CZTSSe solar cells is significantly enhanced, making it a promising method for large-scale production of flexible electronic devices.
CERAMICS INTERNATIONAL
(2022)
Article
Engineering, Environmental
Mengmeng Chen, Gaurav Kapil, Liang Wang, Shahrir Razey K. Sahamir, Ajay Baranwal, Kohei Nishimura, Yoshitaka Sanehira, Zheng Zhang, Muhammad Akmal Kamarudin, Qing Shen, Shuzi Hayase
Summary: This study successfully improved the efficiency and stability of inverted tin-based perovskite solar cells by using a bilayer structure of PEDOT-PSS and 2PACz monolayer.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Chemistry, Physical
Muhammad Fahim, Irum Firdous, Weihai Zhang, Walid A. Daoud
Summary: The research converts the surface of zinc oxide to ZnS, forming a bifunctional interfacial layer. This new design improves the power conversion efficiency of flexible perovskite solar cells and enhances the stability of the devices. By modulating the energy band structure, efficient control of electron transport is achieved.
Article
Energy & Fuels
Taro Kuwano, Ryoji Katsube, Kenji Kazumi, Yoshitaro Nose
Summary: The study revealed that the formation of Cu3P at the interface between Cu and ZnSnP2 helps to enhance the current density in ZnSnP2 solar cells, prevents roll-over of J-V curves, and achieves the highest efficiency of 3.87%. It is concluded that Cu3P is a promising back buffer material for ZnSnP2 solar cells due to its alignment with ZnSnP2 in terms of band and lattice structures.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2021)
Article
Physics, Applied
I Shlyakhov, S. Achra, N. Bosman, I Asselberghs, C. Huyghebaert, I Radu, J. Chai, M. Yang, S. J. Wang, A. Bol, K. Iakoubovskii, M. Houssa, A. Stesmans, V. V. Afanas'ev
Summary: Understanding the energy alignment of electronic bands in metal/MoS2/insulator stacks is crucial for the design of MoS2-based electronic devices. Internal photoemission spectroscopy (IPE) has been applied to analyze the barrier heights, allowing for a simple explanation of electron injection at the interface between aluminum and 1ML MoS2 based on relative energy positions.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Chemistry, Physical
Mao-Hua Zhang, Niloofar Hadaeghi, Sonja Egert, Hui Ding, Hongbin Zhang, Pedro B. Groszewicz, Gerd Buntkowsky, Andreas Klein, Jurij Koruza
Summary: In this study, a general approach was demonstrated to promote the reversibility of the unique electric-field-induced phase transition in antiferroelectric materials by modifying the material's local structure. A new composition based on NaNbO3, (1- x)NaNbO3-xSrSnO(3), was designed using first-principles calculations and experimental characterization. The results showed that the addition of SrSnO3 can enhance the stability of the antiferroelectric order and increase the energy storage density of the modified compositions.
CHEMISTRY OF MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Katharina N. S. Schuldt, Hui Ding, Jean-Christophe Jaud, Jurij Koruza, Andreas Klein
Summary: The study on Schottky barrier formation between polycrystalline acceptor-doped BaTiO3 and high work function RuO2 using photoelectron spectroscopy revealed that the barrier height for electrons is approximately 1.4 eV, independent of doping level and oxygen vacancy concentration of the substrates. The high permittivity of BaTiO3 results in wider space-charge regions, making SCRs more important for electronic and ionic conductivities in BaTiO3 compared to materials with lower permittivity. A Ba-rich phase at the surface of reduced acceptor-doped BaTiO3 is also identified, explained by the formation of Ti vacancies in the 2D electron gas region at the surface.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2021)
Article
Chemistry, Physical
Philipp Wendel, Dominik Dietz, Jonas Deuermeier, Andreas Klein
Summary: ZnO/RuO2 Schottky diodes prepared by magnetron sputtering exhibit reversible hysteresis behavior in their current-voltage characteristics, with the Schottky barrier height varying between 0.9 and 1.3 eV during voltage cycling. This variation is attributed to trapping and de-trapping of electrons in oxygen vacancies.
Article
Chemistry, Physical
Raphael Poulain, Jochen Rohrer, Yannick Hermans, Christian Dietz, Joachim Brotz, Joris Proost, Marian Chatenet, Andreas Klein
Summary: The interaction between water and oriented NiO films was studied using a combination of photoelectron spectroscopy, in situ sample preparation, and electrochemical measurements. The exposure to room temperature water induced a more positive surface charge on the (110)- and (111)-oriented films compared to NiO(100), which was attributed to dissociative adsorption of water and removal of oxygen. This explains the role of water as an electron donor on oxide surfaces.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Hans F. Wardenga, Katharina N. S. Schuldt, Stephan Waldow, Roger A. De Souza, Andreas Klein
Summary: The study investigated the influence of different doping methods, concentrations, and surface orientations on the surface Fermi level positions, ionisation potentials, and work functions of CeO2. It was found that the ionisation potentials are significantly affected by doping and oxygen activity, while the work functions are largely unaffected. In terms of oxygen surface exchange coefficients, similar magnitudes were observed under different conditions.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Elaheh Ghorbani, Lorenzo Villa, Paul Erhart, Andreas Klein, Karsten Albe
Summary: This study presents a systematic assessment of the behavior of self-trapped electrons in PbTiO3, a prototypical ferroelectric material with various technological applications. The study aimed to identify the parameters used in density functional theory (DFT) that accurately predict the properties of self-trapped electrons. It was found that the choice of pseudopotential and lattice parameters significantly influenced the magnitude of the trapping energy. A comparison of two different functionals showed the DFT-PU result to be close to the HSE06 result. The study also provided configuration coordinate diagrams for the polaron-associated absorption and luminescence peaks in PbTiO3.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Nicole Bein, Brigita Kmet, Tadej Rojac, Andreja Bencan Golob, Barbara Malic, Julian Moxter, Thorsten Schneider, Lovro Fulanovic, Maryam Azadeh, Till Froemling, Sonja Egert, Hongguang Wang, Peter van Aken, Jutta Schwarzkopf, Andreas Klein
Summary: The valence band maximum energy of NaNbO3 is determined and found comparable to SrTiO3 and BaTiO3, while the conduction band minimum is yet to be determined. In addition, Sr- and Ca-doped NaNbO3 ceramics exhibit low electrical conductivity.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Julia E. Medvedeva, Bishal Bhattarai, Ivan A. Zhuravlev, Federico Motti, Piero Torelli, Anita Guarino, Andreas Klein, Emiliano Di Gennaro, Fabio Miletto Granozio
Summary: Understanding the short-range structure of amorphous materials is crucial for predicting their macroscopic properties. This study investigates the contradictory experimental findings regarding the oxygen environment of titanium in amorphous strontium titanate and reveals that the discrepancy is caused by differences in the material's density. The study also analyzes the density-dependent structural characteristics and electronic properties of amorphous strontium titanate, providing insights into the structure-property relationship.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Chemistry, Physical
Issei Suzuki, Binxiang Huang, Sakiko Kawanishi, Takahisa Omata, Andreas Klein
Summary: This study demonstrates that the Fermi energy of SnS at the interface can be shifted through the entire band gap, indicating the absence of Fermi-level pinning. The mechanisms behind the existence or lack of Fermi-level pinning at SnS interfaces were discussed, and suggestions were offered to achieve higher photovoltages by avoiding Fermi-level pinning in SnS solar cells.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Physics, Applied
Yunwei Sheng, Mathieu Mirjolet, Mario Villa, Jaume Gazquez, Jose Santiso, Andreas Klein, Jordi Fraxedas, Josep Fontcuberta
Summary: Epitaxial LaFeO3-based photocells with different thicknesses were grown on LSAT single-crystal substrates, using LSMO and Pt/BLSO electrodes, to determine their photoresponse. The short-circuit photocurrent initially increases and then decreases with LFO thickness, and is larger or smaller with Pt or BLSO electrodes. The open-circuit voltage shows the opposite trend, being smaller or larger with Pt and BLSO, respectively, consistent with the electronic band alignments and rectifying character of the dark current-voltage data. The complex microstructure and grain boundaries of the films play a significant role in the observed responsivity, which is larger than in similar LFO-based structures.
PHYSICAL REVIEW APPLIED
(2023)
Article
Chemistry, Physical
Shanmugapriya Periyannan, Laura Manceriu, Andreas Klein, Wolfram Jaegermann, Catherine Henrist, Rudi Cloots
Summary: In this study, a surface cleaning procedure involving vacuum annealing under oxygen was employed to clean the ZNR scaffold film's surface before NiO deposition for heterostructure formation. The properties of the scaffold were studied and correlated to the NiO/ZNR interface and photo-response properties. The optimized NiO/ZNR showed improved photo-response and photodegradation efficiency compared to the ZNR scaffold.
Article
Chemistry, Multidisciplinary
Binxiang Huang, Paul Erhart, Tongqing Yang, Andreas Klein
Summary: Interface stability is crucial for the reliable performance of electronic and electrochemical devices. In this study, an operando analysis approach using photoelectron spectroscopy in a solid oxide electrochemical cell was introduced to investigate interfaces. The experiment provided chemical and electronic information, revealing the importance of both chemical and electrostatic boundary conditions for interface stability. The approach was demonstrated using (anti-)ferroelectric (Pb,La)(Zr,Sn,Ti)O-3 dielectrics.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Nanoscience & Nanotechnology
Issei Suzuki, Zexin Lin, Taichi Nogami, Sakiko Kawanishi, Binxiang Huang, Andreas Klein, Takahisa Omata
Summary: Recently, it has been reported that there is a large band bending at the interface between n-type single crystalline SnS and MoO3, which has a high work function. In this study, we applied this interface to solar cells for the first time and evaluated its photovoltaic properties. The highest achieved open-circuit voltage (V-OC) was 437 mV, which is lower than the expected value but the highest recorded for SnS solar cells. The highest power conversion efficiency (PCE) was 4.4%. Based on device parameter analysis, we propose methods for improving the device performance, including V-OC, short-circuit current, and PCE. The study also estimated the carrier-collection length of n-type SnS single crystals to be around 200 nm using external quantum efficiency measurements. This study demonstrates that the V-OC of SnS solar cells can be improved by fabricating a junction with MoO3 thin films.
Article
Materials Science, Ceramics
Andreas Klein, Karsten Albe, Nicole Bein, Oliver Clemens, Kim Alexander Creutz, Paul Erhart, Markus Frericks, Elaheh Ghorbani, Jan Philipp Hofmann, Binxiang Huang, Bernhard Kaiser, Ute Kolb, Jurij Koruza, Christian Kuebel, Katharina N. S. Lohaus, Juergen Roedel, Jochen Rohrer, Wolfgang Rheinheimer, Roger A. Souza, Verena Streibel, Anke Weidenkaff, Marc Widenmeyer, Bai-Xiang Xu, Hongbin Zhang
Summary: Chemical substitution is a primary strategy for tailoring material properties, with isovalent and heterovalent substitution being the two types. By controlling the different compensation mechanisms, it is possible to predict and adjust material properties. The Fermi energy can be used as a common descriptor for these mechanisms.
JOURNAL OF ELECTROCERAMICS
(2023)
Article
Engineering, Electrical & Electronic
Raphael Poulain, Gunnar Lumbeeck, Jonas Hunka, Joris Proost, Henri Savolainen, Hosni Idrissi, Dominique Schryvers, Nicolas Gauquelin, Andreas Klein
Summary: Although there are contradictory results on the properties of nickel oxide (NiO) in the literature, this comprehensive study provides valuable insights into the conductivity, surface properties, and charge defects compensation mechanism of NiO materials. The experiments reveal that the surface and bulk properties of NiO are strongly influenced by the deposition temperature, leading to variations in the Fermi level pinning, work function, and grain boundaries. This study contributes to a better understanding of the electrical conductivity and charge compensation mechanism of NiO thin films.
ACS APPLIED ELECTRONIC MATERIALS
(2022)