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1.
A novel multi-functional thiophene-based organic cation as passivation, crystalline orientation, and organic spacer agent for low-dimensional 3D/1D perovskite solar cells
Ali Semerci, Ali Buyruk, Saim Emin, Rik Hooijer, Daniela Kovacheva, Peter Mayer, Manuel A. Reus, Dominic Blätte, Marcella Günther, Nicolai F. Hartmann, 2023, original scientific article

Abstract: Recently, the mixed-dimensional (3D/2D or 3D/1D) perovskite solar cellsusing small organic spacers have attracted interest due to their outstandinglong-term stability. Here, a new type of thiophene-based organic cation2-(thiophene-2yl-)pyridine-1-ium iodide (ThPyI), which is used to fabricatemixed-dimensional 3D/1D perovskite solar cells, is presented. TheThPyI-based 1D perovskitoid is applied as a passivator on top of a 3D methylammonium lead iodide (MAPI) to fabricate surface-passivated 3D/1Dperovskite films or added alone into the 3D perovskite precursor to generatebulk-passivated 3D MAPI. The 1D perovskitoid acts as a passivating agent atthe grain boundaries of surface-passivated 3D/1D, which improves the powerconversion efficiency (PCE) of the solar cells. Grazing incidence wide-angleX-ray scattering (GIWAXS) studies confirm that ThPyI triggers the preferentialorientation of the bulk MAPI slabs, which is essential to enhance chargetransport. Champion bulk-passivated 3D and surface-passivated 3D/1Ddevices yield 14.10% and 19.60% PCE, respectively. The bulk-passivated 3Doffers favorable stability, with 84% PCE retained after 2000 h withoutencapsulation. This study brings a new perspective to the design of organicspacers having a different binding motif and a passivation strategy to mitigatethe impact of defects in hybrid 3D/1D perovskite solar cells.A. Semerci, A. Buyruk, R. Hooijer, P. Mayer, D. Blätte, M. Günther, T. Bein,T. AmeriDepartment of Chemistry and Center for NanoScience (CeNS)Ludwig-Maximilians-Universität MünchenButenandtstrasse 5–13 (E), 81377 Munich, GermanyE-mail:tayebeh.ameri@ed.ac.ukS.EminMaterialsResearchLaboratoryUniversityofNovaGoricaVipavska13c,Ajdovšˇcina5270,SloveniaThe ORCID identification number(s) for the author(s) of this articlecan be found under https://doi.org/10.1002/adom.202300267© 2023 The Authors. Advanced Optical Materials published byWiley-VCH GmbH. This is an open access article under the terms of theCreative Commons Attribution-NonCommercial License, which permitsuse, distribution and reproduction in any medium, provided the originalwork is properly cited and is not used for commercial purposes.DOI: 10.1002/adom.2023002671. IntroductionDuring the last decade, 3D organic–inorganic halide perovskites (OIHPs) haveemerged as promising absorber materialsfor photovoltaic applications due to theirsuperior properties such as high absorp-tion coefficient, long diffusion length ofthe charge carriers, fast charge transport,and tunable bandgap. The 3D OIHPs havedemonstrated rapid increase in powerconversion efficiency (PCE) from 3.8% to25.2%.[1–9]On the other hand, their mod-erate intrinsic stability against moistureand heat still has been a concern with aview on possible commercialization.[10–14]Instability of the 3D methyl ammoniumlead iodide (MAPI) perovskite is assumedto be due to its crystalline structure. Ionicmigration is now well recognized to affectthe photovoltaic properties of perovskitesolar cells. Especially, the ionic migrationcauses the generation and displacement ofvacancies in perovskite materials. OIHPsare mixed ionic–electronic conductors withiodide ions as the majority of ionic carriers.D. KovachevaInstitute of General and Inorganic ChemistryBulgarian Academy of SciencesSofia 1113, BulgariaM. A. Reus, P. Müller-BuschbaumTUM School of Natural SciencesDepartment of PhysicsChair for Functional MaterialsTechnical University of MunichJames-Franck-Str. 1, 85748 Garching, GermanyN. F. HartmannAttocube systems AGNanoscale AnalyticsneaspecEglfinger Weg 2, 85540 Haar, GermanyS. Lotfi, J. P. HofmannSurface Science LaboratoryDepartment of Materials and Earth SciencesTechnical University of DarmstadtOtto-Berndt-Str. 3, 64287 Darmstadt, GermanyAdv. Optical Mater.2023,11, 23002672300267 (1 of 13)© 2023 The Authors. Advanced Optical Materials published by Wiley-VCH GmbH
Keywords: perovskites, solar cells, passivation
Published in RUNG: 04.12.2023; Views: 845; Downloads: 3
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2.
The challenge with high permittivity acceptors in organic solar cells : a case study with Y-series derivatives
Peter Fürk, Suman Mallick, Thomas Rath, Matiss Reinfelds, Mingjian Wu, Erdmann Spiecker, Nikola Simic, Georg Haberfehlner, Gerald Kothleitner, Barbara Ressel, 2023, original scientific article

Abstract: Y-series acceptors have brought a paradigm shift in terms of power conversion efficiencies of organic solar cells in the last few years. Despite their high performance, these acceptors still exhibit substantial energy loss, stemming from their low-permittivity nature. To tackle the energy loss situation, we prepared modified Y-series acceptors with improved permittivities via an alternative synthetic route.
Keywords: solar cells, Y-series acceptors, morphology, efficiency measurements
Published in RUNG: 29.06.2023; Views: 1481; Downloads: 10
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Coevaporation of doped inorganic carrier-selective layers for high-performance inverted planar perovskite solar cells
Jiexuan Jiang, Andraž Mavrič, Nadiia Pastukhova, Matjaž Valant, Qiugui Zeng, Zeyu Fan, Beibei Zhang, Yanbo Li, 2022, original scientific article

Abstract: Inorganic carrier selective layers (CSLs), whose conductivity can be effectively tuned by doping, offer low-cost and stable alternatives for their organic counterparts in perovskite solar cells (PSCs). Herein, we employ a dual-source electron-beam co-evaporation method for the controlled deposition of copper-doped nickel oxide (Cu:NiO) and tungsten-doped niobium oxide (W:Nb2O5) as hole and electron transport layers, respectively. The mechanisms for the improved conductivity using dopants are investigated. Owing to the improved conductivity and optimized band alignment of the doped CSLs, the all-inorganic-CSLs-based PSCs achieves a maximum power conversion efficiency (PCE) of 20.47%. Furthermore, a thin titanium buffer layer is inserted between the W:Nb2O5 and the silver electrode to prevent the halide ingression and improve band alignment. This leads to a further improvement of PCE to 21.32% and a long-term stability (1200 h) after encapsulation. Finally, the large-scale applicability of the doped CSLs by co-evaporation is demonstrated for the device with 1 cm2 area showing a PCE of over 19%. Our results demonstrate the potential application of the co-evaporated CSLs with controlled doping in PSCs for commercialization.
Keywords: carrier selective layers, Cu-doped nickel oxide, electron-beam evaporation, perovskite solar cells, W-doped niobium oxide
Published in RUNG: 17.03.2022; Views: 2187; Downloads: 121
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5.
A pyrrolopyridazinedione-based copolymer for fullerene-free organic solar cells
Astrid-Caroline Knall, Samuel Rabensteiner, Sebastian F. Hoefler, Matiss Reinfelds, Mathias Hobisch, Heike M. A. Ehmann, Nadiia Pastukhova, Egon Pavlica, Gvido Bratina, Illie Hanzu, Shuguang Wen, Renqiang Yang, Gregor Trimmel, Thomas Rath, 2021, original scientific article

Abstract: The recent success of non-fullerene acceptors in organic photovoltaics also entails a change in the requirements to the polymer donor in terms of optical and morphological properties leading to a demand for novel conjugated polymers. Herein, we report on the synthesis of a 1,4-bis-(thiophene-2-yl)-pyrrolopyridazinedione based copolymer with 2-ethylhexyl substituents on the pyrrolopyridazinedione moiety. A 2D conjugated benzodithiophene (BDT) was chosen as comonomer. The resulting copolymer T-EHPPD-T-EHBDT showed a molecular weight of 10.2 kDa, an optical band gap of 1.79 eV, a hole mobility of 1.8 × 10−4 cm2 V−1 s−1 and a preferred face-on orientation with regard to the substrate. The comparably wide band gap as well as the determined energy levels (HOMO: −5.47 eV, LUMO: −3.68 eV) match well with the narrow band gap non-fullerene acceptor ITIC-F, which was used as the acceptor phase in the bulk heterojunction absorber layers in the investigated solar cells. The solar cells, prepared in inverted architecture, revealed power conversion efficiencies up to 7.4% using a donor:acceptor ratio of 1 : 1 in the absorber layer.
Keywords: non-fullerene solar cells, charge transport, charge mobility, power conversion efficiency
Published in RUNG: 27.01.2021; Views: 2885; Downloads: 0
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6.
Interface phenomena between CdTe and ZnTe: Cu back contact
Alessio Bosio, Roberta Ciprian, Alessio Lamperti, I Rago, Barbara Ressel, Greta Rosa, Matija Stupar, E Weschke, 2018, original scientific article

Abstract: Thin film technology has reached a maturity to achieve conversion efficiencies of the order of 22%. Among thin films, CdTe-based photovoltaic modules represent 80% of the total production. Nonetheless, some issues concerning back-contact are still open. In industrial process a chemical etching is required in order to make the CdTe film surface rich in Te. The Te-excess is fundamental in order to form a stable telluride compound with copper and to obtain an ohmic, low-resistance back-contact. Moreover, the Te-excess hinders the fast diffusion of copper in CdTe and its achievement of the junction region, preventing the destruction of the device. In this paper we study a ZnTe:Cu buffer layer deposited onto a CdTe film, characterized by a naturally Te-rich surface obtained with a particular chlorine heat treatment without any chemical etching. Copper diffusion and the CdTe/ZnTe:Cu interface were studied by x-ray
Keywords: solar cells, CdTe, ZnTe:Cu back contact
Published in RUNG: 29.11.2018; Views: 4077; Downloads: 0
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7.
Fabrication and characterization of ZnO and GaN devices for electronic and photonic applications
Fei Tong, 2014, doctoral dissertation

Abstract: The research work presented in this book is based on two direct and wide band gap semiconductors: ZnO and GaN. On the first part of the book, the synthesis of ZnO nanorod array via the low temperature solution growth method was discussed. Due to the high surface-to-volume ratio of ZnO nanorod, to alleviate the some of the drawbacks such as carrier mobility and thickness dilemma of organic solar cells, ZnO nanorod array were integrated into organic solar cells. Power conversion efficiency (η) of 1.8% is achieved in our ZnO nanorods integrated bulk heterojunction organic solar cells on flexible In2O3-PET substrates. On the second part of the book, the fabrication and characterization of Aluminum gallium nitride/gallium nitride high electron mobility transistors (AlGaN/GaN HEMTs) were discussed. Device testing and characterization under both room temperature and high temperature up to 300 °C were performed. The results show that the device can operate even at 300 °C with minimal degradation.
Keywords: ZnO nanorod array, organic-inorganic solar cells, AlGaN/GaN HEMTs.
Published in RUNG: 25.01.2017; Views: 4434; Downloads: 0
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