A5007611079- Organic Electronics and Photovoltaics
- Conducting polymers and applications
- Molecular Junctions and Nanostructures
- Perovskite Materials and Applications
- Organic Light-Emitting Diodes Research
- Thin-Film Transistor Technologies
- Silicon and Solar Cell Technologies
- Fullerene Chemistry and Applications
- Nanowire Synthesis and Applications
- Quantum Dots Synthesis And Properties
- X-ray Diffraction in Crystallography
- Semiconductor materials and interfaces
- Crystallization and Solubility Studies
- Photochemistry and Electron Transfer Studies
- Chalcogenide Semiconductor Thin Films
- solar cell performance optimization
- Luminescence and Fluorescent Materials
- Liquid Crystal Research Advancements
- Organic and Molecular Conductors Research
- Photovoltaic System Optimization Techniques
- Photovoltaic Systems and Sustainability
- Graphene research and applications
- Phase-change materials and chalcogenides
- Semiconductor materials and devices
- Force Microscopy Techniques and Applications
University of Oxford
2015-2024
Diamond Light Source
2017-2022
University of Arizona
2022
University of Florence
2022
Oxfam
2020-2021
Technische Universität Dresden
2008-2018
Science Oxford
2014-2018
Kurt J. Lesker (United Kingdom)
2017
Institut für angewandte Photonik
2015
Massachusetts Institute of Technology
2015
Abstract The understanding and applications of organic semiconductors have shown remarkable progress in recent years. This material class has been developed from being a lab curiosity to the basis first successful products as small LED (OLED) displays; other areas application such OLED lighting photovoltaics are on verge broad commercialization. Organic superior inorganic ones for low‐cost large‐area optoelectronics due their flexibility, easy deposition, variety, making tailor‐made...
Thorough measurements of the optical constants CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub>are used to determine limiting parasitic losses in solar cells revealing up 100% IQE and excellent performance at oblique incidence.
Abstract Organic solar cells have the potential to become cheapest form of electricity, beating even silicon photovoltaics. This article summarizes state art in field, highlighting research challenges, mainly need for an efficiency increase as well improvement long‐term stability. It discusses possible current and future applications, such building integrated photovoltaics or portable electronics. Finally, environmental footprint this renewable energy technology is evaluated, be generation...
In this paper we focus on the current status of organic solar cells based small molecules. Since their discovery, much progress has been made, and main steps are highlighted that led to state-of-the-art devices. However, still need be improved further, strategies for improving power conversion efficiency, namely raising open circuit voltage V(oc) increasing short density J(sc), discussed. theory, efficiencies around 15% should possible with a single heterojunction; higher efficiencies,...
Abstract The effect of injection and extraction barriers on flat heterojunction (FHJ) bulk (BHJ) organic solar cells is analyzed. are realized by a combination p‐type materials with HOMOs varying between –5.0 –5.6 eV as hole‐transport layer (HTL) donor in vacuum‐evaporated multilayer p‐i‐metal small‐molecule cells. HTL/donor interface can be seen model for the influence contacts general. Using drift‐diffusion simulations we well able to reproduce explain experimental I– V curves...
A general strategy for the in-plane structuring of organic–inorganic perovskite films is presented. The method used to fabricate an industrially relevant distributed feedback (DFB) cavity, which a critical step toward all-electrially pumped injection laser diodes. This approach opens prospects materials much improved optical control in LEDs, solar cells, and also applications as devices. As service our authors readers, this journal provides supporting information supplied by authors. Such...
The novel methyl-substituted dicyanovinyl-capped quinquethiophenes 1-3 led to highly efficient organic solar cells with power conversion efficiencies of 4.8-6.9%. X-ray analysis single crystals and evaporated neat blend films gave insights into the packing morphological behavior compounds that rationalized their improved photovoltaic performance.
Abstract Efficient synthesis of a series terminally dicyanovinyl (DCV)‐substituted oligothiophenes, DCV n T 1–6, without solubilizing side chains synthesized via novel convergent approach and their application as electron donors in vacuum‐processed m‐i‐p‐type planar p‐i‐n‐type bulk heterojunction organic solar cells is described. Purification the products gradient sublimation yields thermally highly stable semiconducting materials single crystalline quality which allows for X‐ray structure...
Abstract In this paper, two vacuum processed single heterojunction organic solar cells with complementary absorption are described and the construction optimization of tandem based on combination these heterojunctions demonstrated. The red‐absorbing consists C 60 a fluorinated zinc phthalocyanine derivative (F4‐ZnPc) that leads to 0.1–0.15 V higher open circuit voltage oc than commonly used ZnPc. second incorporates dicyanovinyl‐capped sexithiophene (DCV6T) mainly absorbs in green. both into...
The charge carrier lifetime in small molecule: C60 photovoltaic devices is increased by reducing the physical interface area availabe for recombination. For donor contents below 10%, gain open-circuit voltage (Voc) depends logarithmically on while energy of interfacial charge-transfer state ECT remains invariant.
We show that S-kinks in the current voltage characteristics, which decrease fill factor significantly, can be caused by a strong imbalance of charge carrier mobilities (hole mobility donor and electron acceptor) planar/flat heterojunction organic solar cells. Electrical simulations according to drift-diffusion model predict occurrence an S-kink for mismatch larger than 100. By combining low-mobility material, (1,2,3,4,9,10,11,12-octaphenyl-diindeno[1,2,3-cd:1′,2′,3′-lm]perylene), with...
We investigate the role charge carrier mobility plays for loss mechanisms in organic bulk heterojunction solar cells. For this purpose, we perform drift-diffusion calculations several recombination models and properties of contacts. show that case selective contacts, higher mobilities increase device efficiency, independent injection barrier heights, energy level bending at amount background dark carriers device. Nonselective contacts provide a source photocarrier ``wrong'' electrode. This...
We study the mechanism of molecular doping organic small molecule N,N,N${}^{\ensuremath{'}}$,N${}^{\ensuremath{'}}$-tetrakis(4-methoxyphenyl)-benzidine (MeO-TPD) doped with fluorinated fullerene ${\mathrm{C}}_{60}{\mathrm{F}}_{36}$ or acceptor 2,2${}^{\ensuremath{'}}$-(perfluoronaphthalene-2,6-diylidene)dimalononitrile (F6-TCNNQ). Varying concentration, photoemission spectroscopy measurements show a comparable Fermi level shift for both dopants. The efficiency, defined as ratio free charge...
Abstract A series of novel aza‐diisoindolmethine dyes 9 with six different aryl and heteroaryl groups at the indole moiety have been synthesized by addition Grignard compounds to phthalodinitrile subsequent reaction formamide. plausible mechanism, through a Leuckart–Wallach‐type reduction has confirmed means DFT calculations related transition intermediate states. The corresponding boron difluoride complexes ( 10) were prepared in step spectroscopic electrochemical properties 10 investigated...
2-(2-Methoxyphenyl)-1,3-dimethyl-1H-benzoimidazol-3-ium iodide (o-MeO-DMBI-I) was synthesized and employed as a strong n-type dopant for fullerene C(60), well-known n-channel semiconductor. The coevaporated thin films showed maximum conductivity of 5.5 S/cm at doping concentration 8.0 wt% (14 mol%), which is the highest value reported to date molecular conductors. o-MeO-DMBI-I can be stored handled in air extended periods without degradation thus promising various organic electronic devices.
X-ray investigations on single crystals of a series terminally dicyanovinyl-substituted quaterthiophenes and co-evaporated blend layers with C60 give insight into molecular packing behavior morphology, which are crucial parameters in the field organic electronics. Structural characteristics various levels length scales correlated photovoltaic performance bulk heterojunction small-molecule solar cells.
Organic–inorganic perovskites are highly promising solar cell materials with laboratory-based power conversion efficiencies already matching those of established thin film technologies. Their exceptional photovoltaic performance is in part attributed to the presence efficient radiative recombination pathways, thereby opening up possibility light-emitting devices. Here, we demonstrate optically pumped amplified spontaneous emission (ASE) at 780 nm from a 50 nm-thick CH3NH3PbI3 perovskite that...