1
|
Kastner J, Tomarchio F, Decorde N, Kehrer M, Hesser G, Fuchsbauer A. Integration of Inkjet Printed Graphene as a Hole Transport Layer in Organic Solar Cells. MICROMACHINES 2023; 14:1858. [PMID: 37893294 PMCID: PMC10608915 DOI: 10.3390/mi14101858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 09/25/2023] [Accepted: 09/26/2023] [Indexed: 10/29/2023]
Abstract
This work demonstrates the green production of a graphene ink for inkjet printing and its use as a hole transport layer (HTL) in an organic solar cell. Graphene as an HTL improves the selective hole extraction at the anode and prevents charge recombination at the electronic interface and metal diffusion into the photoactive layer. Graphite was exfoliated in water, concentrated by iterative centrifugation, and characterized by Raman. The concentrated graphene ink was incorporated into inverted organic solar cells by inkjet printing on the active polymer in an ambient atmosphere. Argon plasma was used to enhance wetting of the polymer with the graphene ink during printing. The argon plasma treatment of the active polymer P3HT:PCBM was investigated by XPS, AFM and contact angle measurements. Efficiency and lifetime studies undertaken show that the device with graphene as HTL is fully functional and has good potential for an inkjet printable and flexible alternative to PEDOT:PSS.
Collapse
Affiliation(s)
- Julia Kastner
- Functional Surfaces and Nanostructures, Profactor GmbH, 4407 Steyr-Gleink, Austria
| | - Flavia Tomarchio
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, UK
| | - Nicolas Decorde
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, UK
| | - Matthias Kehrer
- Center of Surface- and Nanoanalytics, Johannes Kepler University, 4040 Linz, Austria (G.H.)
| | - Günter Hesser
- Center of Surface- and Nanoanalytics, Johannes Kepler University, 4040 Linz, Austria (G.H.)
| | - Anita Fuchsbauer
- Functional Surfaces and Nanostructures, Profactor GmbH, 4407 Steyr-Gleink, Austria
| |
Collapse
|
2
|
Liu A, Wang S, Song H, Liu Y, Gedda L, Edwards K, Hammarström L, Tian H. Excited-state and charge-carrier dynamics in binary conjugated polymer dots towards efficient photocatalytic hydrogen evolution. Phys Chem Chem Phys 2023; 25:2935-2945. [PMID: 36606387 DOI: 10.1039/d2cp04204e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Aqueous dispersed conjugated polymer dots (Pdots) have shown promising application in photocatalytic hydrogen evolution. To efficiently extract photogenerated charges from type-II heterojunction Pdots for hydrogen evolution, the mechanistic study of photophysical processes is essential for Pdot optimization. Within this work, we use a PFODTBT donor (D) polymer and an ITIC small molecule acceptor (A) as a donor/acceptor (D/A) model system to study their excited states and charge/energy transfer dynamics via steady-state and time-resolved photoluminescence spectroscopy, respectively. Charge-carrier generation and the recombination dynamics of binary Pdots with different D/A ratios were followed using femtosecond transient absorption spectroscopy. A significant spectral relaxation of photoluminescence was observed for individual D Pdots, implying an energetic disorder by nature. However, this was not seen for charge carriers in binary Pdots, probably due to the ultrafast charge generation process at an early time (<200 fs). The results showed slower charge recombination upon increasing the ratio of ITIC in binary Pdots, which further resulted in an enhanced photocatalytic hydrogen evolution, twice that as compared to individual D Pdots. Although binary Pdots prepared via the nanoprecipitation method exhibit a large interfacial area that allows high charge generation efficiencies, it also provides a high possibility for charge recombination and limits the further utilization of free charges. Therefore, for the future design of type-II heterojunction Pdots, suppressing the charge carrier recombination via increasing the crystallinity and proper phase segregation is necessary for enhanced photocatalytic hydrogen evolution.
Collapse
Affiliation(s)
- Aijie Liu
- Department of Chemistry-Ångström Lab., Box 523, SE 751 20, Uppsala University, Sweden.
| | - Sicong Wang
- Department of Chemistry-Ångström Lab., Box 523, SE 751 20, Uppsala University, Sweden.
| | - Hongwei Song
- Department of Chemistry-Ångström Lab., Box 523, SE 751 20, Uppsala University, Sweden.
| | - Yawen Liu
- Department of Chemistry-Ångström Lab., Box 523, SE 751 20, Uppsala University, Sweden.
| | - Lars Gedda
- Department of Chemistry-Ångström Lab., Box 523, SE 751 20, Uppsala University, Sweden.
| | - Katarina Edwards
- Department of Chemistry-Ångström Lab., Box 523, SE 751 20, Uppsala University, Sweden.
| | - Leif Hammarström
- Department of Chemistry-Ångström Lab., Box 523, SE 751 20, Uppsala University, Sweden.
| | - Haining Tian
- Department of Chemistry-Ångström Lab., Box 523, SE 751 20, Uppsala University, Sweden.
| |
Collapse
|
3
|
Zeiske S, Sandberg OJ, Kurpiers J, Shoaee S, Meredith P, Armin A. Probing Charge Generation Efficiency in Thin-Film Solar Cells by Integral-Mode Transient Charge Extraction. ACS PHOTONICS 2022; 9:1188-1195. [PMID: 35571262 PMCID: PMC9097587 DOI: 10.1021/acsphotonics.1c01532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Indexed: 06/15/2023]
Abstract
The photogeneration of free charges in light-harvesting devices is a multistep process, which can be challenging to probe due to the complexity of contributing energetic states and the competitive character of different driving mechanisms. In this contribution, we advance a technique, integral-mode transient charge extraction (ITCE), to probe these processes in thin-film solar cells. ITCE combines capacitance measurements with the integral-mode time-of-flight method in the low intensity regime of sandwich-type thin-film devices and allows for the sensitive determination of photogenerated charge-carrier densities. We verify the theoretical framework of our method by drift-diffusion simulations and demonstrate the applicability of ITCE to organic and perovskite semiconductor-based thin-film solar cells. Furthermore, we examine the field dependence of charge generation efficiency and find our ITCE results to be in excellent agreement with those obtained via time-delayed collection field measurements conducted on the same devices.
Collapse
Affiliation(s)
- Stefan Zeiske
- Sustainable
Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, Wales, United Kingdom
| | - Oskar J. Sandberg
- Sustainable
Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, Wales, United Kingdom
| | - Jona Kurpiers
- Disordered Semiconductor Optoelectronics,
Institute
of Physics and Astronomy, University Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
| | - Safa Shoaee
- Disordered Semiconductor Optoelectronics,
Institute
of Physics and Astronomy, University Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Potsdam-Golm, Germany
| | - Paul Meredith
- Sustainable
Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, Wales, United Kingdom
| | - Ardalan Armin
- Sustainable
Advanced Materials (Sêr-SAM), Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP, Wales, United Kingdom
| |
Collapse
|
4
|
Schwaiger DM, Lohstroh W, Müller-Buschbaum P. The Influence of the Blend Ratio, Solvent Additive, and Post-production Treatment on the Polymer Dynamics in PTB7:PCBM Blend Films. Macromolecules 2021. [DOI: 10.1021/acs.macromol.1c00313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dominik M. Schwaiger
- Physik-Department, Technische Universität München, Lehrstuhl für Funktionelle Materialien James-Franck-Straße 1, 85748 Garching, Germany
| | - Wiebke Lohstroh
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstraße 1, 85748 Garching, Germany
| | - Peter Müller-Buschbaum
- Physik-Department, Technische Universität München, Lehrstuhl für Funktionelle Materialien James-Franck-Straße 1, 85748 Garching, Germany
- Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstraße 1, 85748 Garching, Germany
| |
Collapse
|
5
|
Cha H, Li J, Li Y, Kim SO, Kim YH, Kwon SK. Effects of Bulk Heterojunction Morphology Control via Thermal Annealing on the Fill Factor of Anthracene-based Polymer Solar Cells. Macromol Res 2020. [DOI: 10.1007/s13233-020-8107-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
6
|
Role of Molecular Orbital Energy Levels in OLED Performance. Sci Rep 2020; 10:9915. [PMID: 32555238 PMCID: PMC7303122 DOI: 10.1038/s41598-020-66946-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 05/27/2020] [Indexed: 11/08/2022] Open
Abstract
Abundant molecules enable countless combinations of device architecture that might achieve the desirable high efficiency from organic light-emitting diodes (OLEDs). Due to the relatively high cost of OLED materials and facilities, simulation approaches have become a must in further advancing the field faster and saver. We have demonstrated here the use of state-of-art simulation approaches to investigate the effect of molecular orbital energy levels on the recombination of excitons in OLED devices. The devices studied are composed of 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) as hole transporting material (HTM), 4,4'-Bis(9-carbazolyl)-1,1'-biphenyl (CBP) as host, 2,2',2"-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) or bathophenanthroline (Bphen) as electron transporting materials. The outcomes reveal that exciton recombination highly sensitive to the energy-level alignment, injection barriers, and charge mobilities. A low energy-barrier (<0.4 eV) between the layers is the key to yield high recombination. The lowest unoccupied molecular orbital (LUMO) levels of the organic layers have played a more pivotal role in governing the recombination dynamics than the highest occupied molecular orbital (HOMO) level do. Furthermore, the Bphen based device shows high exciton recombination across the emissive layer, which is >106 times greater than that in the TPBi based device. The high carrier mobility of Bphen whose electron mobility is 5.2 × 10-4 cm2 V-1 s-1 may lead to low charge accumulation and hence high exciton dynamics. The current study has successfully projected an in-depth analysis on the suitable energy-level alignments, which would further help to streamline future endeavours in developing efficient organic compounds and designing devices with superior performance.
Collapse
|
7
|
Niklas J, Zheng T, Neshchadin A, Mardis KL, Yu L, Poluektov OG. Polaron and Exciton Delocalization in Oligomers of High-Performance Polymer PTB7. J Am Chem Soc 2020; 142:1359-1366. [PMID: 31860294 DOI: 10.1021/jacs.9b10859] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A key characteristic of organic photovoltaic cells is the efficient charge separation in the active layer. Sufficient delocalization of the positive polaron in organic photovoltaics is considered essential for the effective separation of the opposite charges and the suppression of recombination. We use light-induced EPR and ENDOR spectroscopy combined with DFT calculations to determine the electronic structure of the positive polaron in PTB7-type oligomers. Utilizing the superior spectral resolution of high-frequency (130 GHz) D-band EPR, the principal components of the g tensors were determined. Pulsed ENDOR spectroscopy at X-band allowed the measurement of 1H hyperfine coupling constants. A comparison of g tensors and 1H hyperfine coupling constants of the PTB7-type oligomers with the high-performance PTB7 polymer revealed a delocalization of the positive polaron in the polymer over about four monomeric units, corresponding to about 45 Å in length. Our current study thus not only determines the polaron delocalization length in PTB7 but also validates the approach combining EPR/ENDOR spectroscopy with DFT-calculated magnetic resonance parameters. This is of importance in those cases where oligomers of defined length are not easily obtained. In addition, the delocalization of the neutral triplet exciton was also determined in the oligomers and compared with polymer PTB7. The analysis revealed that the neutral triplet exciton is substantially more delocalized than the positive polaron, exceeding 10 monomeric units.
Collapse
Affiliation(s)
- Jens Niklas
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Lemont , Illinois 60439 , United States
| | - Tianyue Zheng
- Department of Chemistry and James Franck Institute , University of Chicago , Chicago , Illinois 60637 , United States
| | - Andriy Neshchadin
- Department of Chemistry and James Franck Institute , University of Chicago , Chicago , Illinois 60637 , United States
| | - Kristy L Mardis
- Department of Chemistry, Physics, and Engineering Studies , Chicago State University , Chicago , Illinois 60628 , United States
| | - Luping Yu
- Department of Chemistry and James Franck Institute , University of Chicago , Chicago , Illinois 60637 , United States
| | - Oleg G Poluektov
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Lemont , Illinois 60439 , United States
| |
Collapse
|
8
|
Athanasopoulos S, Tscheuschner S, Bässler H, Köhler A. Efficient Charge Separation of Cold Charge-Transfer States in Organic Solar Cells Through Incoherent Hopping. J Phys Chem Lett 2017; 8:2093-2098. [PMID: 28436660 DOI: 10.1021/acs.jpclett.7b00595] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
We demonstrate that efficient and nearly field-independent charge separation of electron-hole pairs in organic planar heterojunction solar cells can be described by an incoherent hopping mechanism. Using kinetic Monte Carlo simulations that include the effect of on-chain delocalization as well as entropic contributions, we simulate the dissociation of the charge-transfer state in polymer-fullerene bilayer solar cells. The model further explains experimental results of almost field independent charge separation in bilayers of molecular systems with fullerenes and provides important guidelines at the molecular level for maximizing the efficiencies of organic solar cells. Thus, utilizing coherent phenomena is not necessarily required for highly efficient charge separation in organic solar cells.
Collapse
Affiliation(s)
- Stavros Athanasopoulos
- Departamento de Física, Universidad Carlos III de Madrid , Avenida Universidad 30, Leganés 28911, Madrid, Spain
| | | | | | | |
Collapse
|