Article
Nanoscience & Nanotechnology
Jihoo Lim, Eunyoung Choi, Moonyong Kim, Minwoo Lee, Daniel Chen, Martin A. Green, Jan Seidel, Changheon Kim, Jongsung Park, Xiaojing Hao, Jae Sung Yun
Summary: This study investigated the direct reaction between Cu and a perovskite under thermal stress as well as the degradation mechanism. The results showed that high temperatures caused Cu to be incorporated into the perovskite lattice near the grain boundaries, resulting in Cu-rich yet organic A-site-poor perovskites and device performance degradation.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Physical
Igal Levine, Amran Al-Ashouri, Artem Musiienko, Hannes Hempel, Artiom Magomedov, Aida Drevilkauskaite, Vytautas Getautis, Dorothee Menzel, Karsten Hinrichs, Thomas Unold, Steve Albrecht, Thomas Dittrich
Summary: Identification of electronic processes at buried interfaces of charge selective contacts is crucial for photovoltaic and photocatalysis research. Transient surface photovoltage and photoluminescence provide complementary information on charge transfer kinetics and trapping/de-trapping mechanisms. Hole transfer rates and interface trap densities can be influenced by the chemical structure of SAMs, and high densities of interface traps can lead to significant losses in solar cells.
Article
Chemistry, Multidisciplinary
Kiyoung Jo, Pawan Kumar, Joseph Orr, Surendra B. Anantharaman, Jinshui Miao, Michael J. Motala, Arkamita Bandyopadhyay, Kim Kisslinger, Christopher Muratore, Vivek B. Shenoy, Eric A. Stach, Nicholas R. Glavin, Deep Jariwala
Summary: This study reports the direct measurement of electrical and optical responses of 2D semiconductor-metal buried interfaces using a metal-assisted transfer technique. Contacting MoS2 with metal induces strain and charge transfer, resulting in improved contact resistance.
Article
Chemistry, Physical
Hwi Je Woo, Seongchan Kim, Young-Jin Choi, Jeong Ho Cho, Seong Heon Kim, Young Jae Song
Summary: The work function of graphene devices on SiO2 substrates is studied using Kelvin probe force microscopy, revealing gate voltage-dependent work-function hysteresis. The inhomogeneous distribution of chemical species at the graphene/SiO2 interface leads to varying degrees of hysteresis across different positions on the graphene.
Article
Nanoscience & Nanotechnology
Woongbin Yim, Van Tu Nguyen, Quynh Thi Phung, Hwan Sik Kim, Yeong Hwan Ahn, Soonil Lee, Ji-Yong Park
Summary: The spatial distribution of photogenerated carriers in atomically thin MoS2 flakes and their correlation with photocurrent generation is investigated using Kelvin probe force microscopy. The study reveals that surface potential changes can image the vertical redistribution of photogenerated carriers, and the trapping of photogenerated holes at the interface between MoS2 and the substrate is the main mechanism for the photoresponse.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Minwoo Lee, Eunyoung Choi, Arman Mahboubi Soufiani, Jihoo Lim, Moonyong Kim, Daniel Chen, Martin Andrew Green, Jan Seidel, Sean Lim, Jincheol Kim, Xinchen Dai, Robert Lee-Chin, Bolin Zheng, Ziv Hameiri, Jongsung Park, Xiaojing Hao, Jae Sung Yun
Summary: This study presents an effective strategy to improve the performance of halide perovskite-based PV devices by using a hole-selective layer formed by PEAI salt, achieving high efficiency and stability under different light conditions.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Nanoscience & Nanotechnology
Ryo Izumi, Masato Miyazaki, Yan Jun Li, Yasuhiro Sugawara
Summary: The recently proposed high-low Kelvin probe force microscopy (KPFM) allows for the evaluation of semiconductor interface states with high spatial resolution using high and low AC bias frequencies. This is important for assessing the energy spectrum of interface state density in semiconductor devices. In this study, a method called high-low Kelvin probe force spectroscopy (high-low KPFS) is proposed, which measures the interface state density inside semiconductors using high and low-frequency AC bias voltages. Preliminary experiments on ion-implanted silicon surfaces confirmed the dependence of electrostatic force on AC bias voltage frequency and obtained the interface state density.
BEILSTEIN JOURNAL OF NANOTECHNOLOGY
(2023)
Article
Chemistry, Physical
Maki Hiraoka, Nobuyuki Ishida, Akio Matsushita, Ryusuke Uchida, Takeyuki Sekimoto, Teruaki Yamamoto, Taisuke Matsui, Yukihiro Kaneko, Kenjiro Miyano, Masatoshi Yanagida, Yasuhiro Shirai
Summary: Kelvin probe force microscopy was used to monitor the potential profile in lead-halide perovskite photovoltaic cells. By studying various devices under different conditions, quantitative profile features were deduced and used to compare against numerical calculations. The technique was applied to devices before and after degradation, allowing the identification of degraded components and inference of performance loss sources.
ACS APPLIED ENERGY MATERIALS
(2022)
Review
Chemistry, Physical
Zhi-Wen Gao, Yong Wang, Wallace C. H. Choy
Summary: This article examines the latest progress in modifying the buried interface of organic-inorganic hybrid perovskite solar cells (PSCs) to enhance their performance and stability. It discusses the use of various materials and techniques and provides valuable insights for achieving higher power conversion efficiency in PSCs and interface adjustment in other layered structure heterojunction devices.
ADVANCED ENERGY MATERIALS
(2022)
Article
Chemistry, Physical
Juan Pei, Xueting Huang, Xue Zhao, Haijun Lv, Shaorui Chen, Shaoyan Zhang, Yingpin Li, Yanzhong Hao
Summary: By employing organic dyes to modulate the interfacial properties, this study improved the compatibility between organic and inorganic materials, enhanced the energy level alignment of the hybrid films, and achieved a notable power conversion efficiency of 2.91%. The intrinsic factors affecting cell performance were investigated through electrochemical impedance and open circuit voltage decay measurements.
SURFACES AND INTERFACES
(2021)
Article
Chemistry, Physical
Yali Chen, Heng Qi, Kun Wang, Ziyong Kang, Guangjiu Pan, Christopher R. Everett, Peter Mueller-Buschbaum, Yu Tong, Hongqiang Wang
Summary: In this study, an ultra-thin ImAcCl layer was used to modify tin perovskite solar cells, resulting in multifunctional improvements and a significant enhancement in power conversion efficiency (PCE). The carboxylate group and hydrogen bond donor in ImAcCl effectively suppressed Sn2+ oxidation and reduced trap density in perovskite films. The modified interface also reduced roughness and promoted the formation of high-quality tin perovskite films with improved crystallinity and compactness. Moreover, the modification of the buried interface facilitated the formation of large bulk-like crystals, enhancing charge carrier transport and suppressing recombination. As a result, the PCE of tin PSCs increased from 10.12% to 12.08%.
Article
Energy & Fuels
C-S Jiang, D. Albin, M. Nardone, K. J. Howard, A. Danielson, A. Munshi, T. Shimpi, C. Xiao, H. R. Moutinho, M. M. Al-Jassim, G. Teeter, W. Sampath
Summary: This paper investigates the stability and electric field distribution of CdTe devices with a structure of TCO/MZO/CdSeTe/CdTe/backcontact. The results show reversible transitions between the light-soak state (LSS) and the dark-soak state (DSS), but irreversible degradation occurs after long-hour light soaking at an elevated temperature. The electric field profiles at different states reveal the presence of a buried homojunction (BHJ) in the LSS and an increased electric field near the MZO/CdSeTe interface at the DgS.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2022)
Article
Chemistry, Multidisciplinary
Devon S. Jakob, Nengxu Li, Huanping Zhou, Xiaoji G. Xu
Summary: This article introduces a novel method to generate Coulombic force in KPFM, increasing the spatial resolution to approximately 25 nm. By integrating PiFM, high spatial resolution chemical distributions and surface potential maps can be obtained concurrently. This is expected to facilitate characterizations of nanoscale electrical properties of photoactive materials, semiconductors, and ferroelectric materials.
Article
Energy & Fuels
Christian Kameni Boumenou, Amala Elizabeth, Finn Babbe, Alice Debot, Harry Moeenig, Alex Redinger
Summary: The study investigated the buried MoSe2/CuInSe2 interface of stoichiometric absorbers in thin film solar cells, revealing differences in local density of states compared to the front-side properties. This sheds new light on the complex interface formation in CuInSe2-based thin film solar cells grown under Cu-rich conditions.
PROGRESS IN PHOTOVOLTAICS
(2021)
Article
Chemistry, Multidisciplinary
Mengkang Xu, Xinpeng Tian, Qian Deng, Qun Li, Shengping Shen
Summary: By introducing nanocracks and applying continuously varying mechanical loading, the evolution of flexoelectricity around the crack tips in SrTiO3, Ba0.67Sr0.33TiO3, and TiO2 samples has been successfully measured. This method provides a reliable way to identify the significance of the flexoelectric effect and may open a new avenue for the study of flexoelectricity involving multiple physics phenomena such as flexoelectronics and the flexo-photovoltaic effect.
Article
Chemistry, Multidisciplinary
Nikita Denisov, Shanshan Qin, Johannes Will, Bojana Nedic Vasiljevic, Natalia V. Skorodumova, Igor A. Pasti, Bidyut Bikash Sarma, Benedict Osuagwu, Tadahiro Yokosawa, Johannes Voss, Janis Wirth, Erdmann Spiecker, Patrik Schmuki
Summary: This paper describes the photoinduced destabilization of Pt single atoms (SAs) on the surface of titanium dioxide (TiO2), a benchmark photocatalyst. The SAs agglomerate into clusters and nanoparticles under illumination in aqueous solutions. The kinetics of this process depend on the presence of sacrificial hole scavengers and the intensity of light used. Despite the aggregation and reduction of the SAs, the overall photocatalytic hydrogen evolution remains largely unaffected.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Markus Freiberger, Martin B. Minameyer, Iris Solymosi, Stefan Fruehwald, Marcel Krug, Youzhi Xu, Andreas Hirsch, Timothy Clark, Dirk M. Guldi, Max von Delius, Konstantin Amsharov, Andreas Goerling, M. Eugenia Perez-Ojeda, Thomas Drewello
Summary: We studied the gas-phase chemistry of [10]cycloparaphenylene ([10]CPP) non-covalent complexes with C-60 and C-70 using atmospheric pressure photoionization and electrospray ionization mass spectrometry. The stability and charge distribution of these complexes were analyzed using energy-resolved collision-induced dissociation (ER-CID). It was found that complexes with a C-70 core exhibited greater stability, and the radical cations were more stable than the radical anions. [2:1] complexes of the ([10]CPP2 superset of C-60/70)(+center dot/-center dot) type were observed as isolated solitary gas-phase species for the first time. The stability of these complexes was reduced compared to the [1:1] complexes.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Organic
Johannes Muller, Janina Buck, Andreas Hirsch
Summary: This paper presents nine pi-expanded mono-substituted 5,8,11,14,17-pentakis-(tert-butyl)-hexa-peri-hexabenzocoronenes (HBC) and explores their synthesis method and the influence of substitution groups on their optoelectronic properties.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Physical
Si-Ming Wu, Imgon Hwang, Benedict Osuagwu, Johannes Will, Zhenni Wu, Bidyut Bikash Sarma, Fu-Fei Pu, Li-Ying Wang, Zdenek Badura, Giorgio Zoppellaro, Erdmann Spiecker, Patrik Schmuki
Summary: Anchoring single platinum atoms on titanium dioxide nanosheets with lattice incorporated fluorine species can achieve uniform dispersion and high efficiency in photocatalytic hydrogen production. The fluorine-stabilized platinum atoms exhibit remarkable photocatalytic activity, with a high production rate and excellent stability in long-term reactions.
Article
Chemistry, Physical
Shanshan Qin, Johannes Will, Hyesung Kim, Nikita Denisov, Simon Carl, Erdmann Spiecker, Patrik Schmuki
Summary: We disperse Pt single atoms on TiO2 thin films and evaluate the photocatalytic H-2 generation. We find that a minuscule loading of Pt single atoms is sufficient to achieve maximized H-2 production rate under common illumination intensities. The overall reaction rate is determined by charge carrier generation, rather than the density of co-catalytic sites.
ACS ENERGY LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Laura von Lueders, Rita Tilmann, Kangho Lee, Cian Bartlam, Tanja Stimpel-Lindner, Tarja K. Nevanen, Kristiina Iljin, Kathrin C. Knirsch, Andreas Hirsch, Georg S. Duesberg
Summary: We present a controllable and specific functionalisation approach for graphene field-effect transistors (GFETs) in order to detect small physiologically active molecules. The key step involves the noncovalent functionalisation of graphene with perylene bisimide (PBI) molecules directly on the growth substrate. This method allows for the homogeneous self-assembly of PBI molecules on graphene, followed by the immobilization of antibodies. The functionalised GFET devices showed excellent performance in terms of atomic force microscopy, Raman spectroscopy, and electrical measurements compared to conventional functionalisation methods. Specific sensing of small molecules such as methamphetamine and cortisol was achieved by monitoring the electrical changes of the functionalised GFET devices. The sensors were able to detect methamphetamine down to a concentration of 300 ng ml(-1).
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Felix Hemauer, Valentin Schwaab, Eva Marie Freiberger, Natalie J. Waleska, Andreas Leng, Cornelius Weiss, Johann Steinhauer, Fabian Duell, Philipp Bachmann, Andreas Hirsch, Hans-Peter Steinrueck, Christian Papp
Summary: This study investigates the surface chemistry of a derivatized norbornadiene/quadricyclane molecule pair and explores their potential as energy storage solutions for renewable energy sources. It demonstrates the success of triggering the release of stored energy on Pt(111) and reveals the decomposition pathways of the two isomers on Ni(111).
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
Jovana Jaksic, Iris Solymosi, Andreas Hirsch, M. Eugenia Perez-Ojeda, Aleksandra Mitrovic, Veselin Maslak
Summary: This study presents the synthesis and characterization of four dumbbell-shaped fullerene molecules connected by isosorbide and isomannide moieties. The electrochemical behavior of these molecules and their ability to form complexes with [10]cycloparaphenylene ([10]CPP) were investigated. The results showed a high electron affinity for the fullerene dumbbells, indicating a strong interaction with carbon nanorings.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Organic
Sven Moersel, Rene Kellner, Andreas Hirsch
Summary: The synthesis of novel fluorinated hexa-peri-hexabenzocoronenes (HBCs) and their thioether-substituted analogs was reported, with the reaction time significantly reduced by using microwave assistance. Increasing fluorination or thioether-substituents led to a decrease in the extinction coefficient of the HBCs. Addition of thioether-moieties caused a shift in absorption and emission bands, while the nature of the thioether did not affect the optoelectronic properties. Oxidation to sulfone and formation of sulfonium salts further modified the electronic environment of the HBC core, resulting in decreased extinction coefficients and broadening of absorption and emission bands.
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Juan S. S. Rocha-Ortiz, Jianchang C. Wu, Jonas Wenzel, Andreas J. J. Bornschlegl, Jose Dario Perea, Salvador Leon, Anastasia Barabash, Anna-Sophie Wollny, Dirk M. M. Guldi, Jiyun Zhang, Alberto Insuasty, Larry Lueer, Alejandro Ortiz, Andreas Hirsch, Christoph J. J. Brabec
Summary: Dumbbell-shaped systems based on PAHs-BODIPY-triarylamine hybrids TM-(01-04) are designed and employed as hole-transporting materials in planar inverted perovskite solar cells, exhibiting remarkable stability and high power conversion efficiency. The conjugated pi-system's covalent attachment and size are found to influence the energy transfer within the systems. Integrating these systems into the solar cells results in outstanding power conversion efficiency, with TM-02-based devices achieving a PCE of 20.26%. The long-term stability of these devices is also measured, with TM-04-based device showing the highest stability of 94%.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Applied
Juan S. Rocha-Ortiz, Joel Jose Montalvo-Acosta, Yakun He, Alberto Insuasty, Andreas Hirsch, Christoph J. Brabec, Alejandro Ortiz
Summary: Eight novel C60-BODIPY-Triarylamine electroactive triads were synthesized and characterized, and the effect of different linkers and functionalization on the electronic properties were studied. The compounds showed strong absorption of visible light and photo-induced electron transfer, confirmed by solvatochromic effects and redox potentials. The study also found that the pyrrolidine derivatives were more stable than isoxazoline analogs and alkoxy units improved thermal endurance.
Article
Chemistry, Multidisciplinary
Markus Freiberger, Iris Solymosi, Eva Marie Freiberger, Andreas Hirsch, M. Eugenia Perez-Ojeda, Thomas Drewello
Summary: In this study, the stability of [n]cycloparaphenylene (nCPP)-based host-guest complexes with Li+@C-60 and C-60 was compared for the first time in both gas and solution phases. Results showed a significant increase in stability for the complexes featuring [9-12]CPP with Li+@C-60, which was also observed in solution. The formation of [10]CPP superset of Li+@C-60 exhibited a two orders of magnitude larger association constant compared to the C-60 analog, along with an increased binding entropy. This research contributes to a better understanding of host-guest complexes between [n]CPPs and endohedral metallofullerenes at a molecular level.
Article
Chemistry, Multidisciplinary
Sebastian W. Krauss, Mirco Eckardt, Johannes Will, Erdmann Spiecker, Renee Siegel, Martin Dulle, Ralf Schweins, Brian Pauw, Juergen Senker, Mirijam Zobel
Summary: The isotopic effect of exchanging H2O with D2O can impact the formation mechanism and colloidal stability of nanoparticles. The equilibrium and dynamics of ligand clusters in solution are changed by the exchange, affecting the size and crystallinity of the nanoparticles. In D2O, the colloidal stability of CdS nanoparticles covered by complexes is significantly reduced.
Article
Chemistry, Multidisciplinary
Wiebke Zika, Andreas Hirsch, Rene Weiss, Simone Pinter, Christoph M. Schuesslbauer, Timothy Clark, Andreas Hirsch, Dirk M. Guldi
Summary: This study investigates the interconversion between QC and NBD and their application in energy storage through photo-assays. An oxidative electron transfer is observed during the QC-to-NBD isomerization using transient absorption spectroscopy. The complementary use of time-resolved and steady-state spectroscopies allows for a complete description of the photoisomerization reaction of NBDs.
Article
Chemistry, Multidisciplinary
Sebastian W. Krauss, Mirco Eckardt, Johannes Will, Erdmann Spiecker, Renee Siegel, Martin Dulle, Ralf Schweins, Brian Pauw, Juergen Senker, Mirijam Zobel
Summary: This study investigates the impact of heavy water (D2O) on CdS nanoparticle formation and colloidal stability. The results suggest that the isotopic effect of D2O influences nanoparticle formation by altering the equilibria and dynamics of ethylenediaminetetraacetate (EDTA) clusters in solution. Despite the stabilizing effect of EDTA in normal water, the colloidal stability of CdS nanoparticles is significantly reduced in heavy water.
