@article{ArminChenJinetal.2018, author = {Armin, Ardalan and Chen, Zhiming and Jin, Yaocheng and Zhang, Kai and Huang, Fei and Shoaee, Safa}, title = {A Shockley-Type polymer}, series = {Advanced energy materials}, volume = {8}, journal = {Advanced energy materials}, number = {7}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1614-6832}, doi = {10.1002/aenm.201701450}, pages = {9}, year = {2018}, abstract = {Charge extraction rate in solar cells made of blends of electron donating/accepting organic semiconductors is typically slow due to their low charge carrier mobility. This sets a limit on the active layer thickness and has hindered the industrialization of organic solar cells (OSCs). Herein, charge transport and recombination properties of an efficient polymer (NT812):fullerene blend are investigated. This system delivers power conversion efficiency of >9\% even when the junction thickness is as large as 800 nm. Experimental results indicate that this material system exhibits exceptionally low bimolecular recombination constant, 800 times smaller than the diffusion-controlled electron and hole encounter rate. Comparing theoretical results based on a recently introduced modified Shockley model for fill factor, and experiments, clarifies that charge collection is nearly ideal in these solar cells even when the thickness is several hundreds of nanometer. This is the first realization of high-efficiency Shockley-type organic solar cells with junction thicknesses suitable for scaling up.}, language = {en} } @article{YazmaciyanStolterfohtBurnetal.2018, author = {Yazmaciyan, Aren and Stolterfoht, Martin and Burn, Paul L. and Lin, Qianqian and Meredith, Paul and Armin, Ardalan}, title = {Recombination losses above and below the transport percolation threshold in bulk heterojunction organic solar cells}, series = {Advanced energy materials}, volume = {8}, journal = {Advanced energy materials}, number = {18}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1614-6832}, doi = {10.1002/aenm.201703339}, pages = {8}, year = {2018}, abstract = {Achieving the highest power conversion efficiencies in bulk heterojunction organic solar cells requires a morphology that delivers electron and hole percolation pathways for optimized transport, plus sufficient donor:acceptor contact area for near unity charge transfer state formation. This is a significant structural challenge, particularly in semiconducting polymer:fullerene systems. This balancing act in the model high efficiency PTB7:PC70BM blend is studied by tuning the donor:acceptor ratio, with a view to understanding the recombination loss mechanisms above and below the fullerene transport percolation threshold. The internal quantum efficiency is found to be strongly correlated to the slower carrier mobility in agreement with other recent studies. Furthermore, second-order recombination losses dominate the shape of the current density-voltage curve in efficient blend combinations, where the fullerene phase is percolated. However, below the charge transport percolation threshold, there is an electric-field dependence of first-order losses, which includes electric-field-dependent photogeneration. In the intermediate regime, the fill factor appears to be limited by both first- and second-order losses. These findings provide additional basic understanding of the interplay between the bulk heterojunction morphology and the order of recombination in organic solar cells. They also shed light on the limitations of widely used transport models below the percolation threshold.}, language = {en} } @article{AlqahtaniBabicsGorenflotetal.2018, author = {Alqahtani, Obaid and Babics, Maxime and Gorenflot, Julien and Savikhin, Victoria and Ferron, Thomas and Balawi, Ahmed H. and Paulke, Andreas and Kan, Zhipeng and Pope, Michael and Clulow, Andrew J. and Wolf, Jannic and Burn, Paul L. and Gentle, Ian R. and Neher, Dieter and Toney, Michael F. and Laquai, Frederic and Beaujuge, Pierre M. and Collins, Brian A.}, title = {Mixed Domains Enhance Charge Generation and Extraction in Bulk-Heterojunction Solar Cells with Small-Molecule Donors}, series = {Advanced energy materials}, volume = {8}, journal = {Advanced energy materials}, number = {19}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1614-6832}, doi = {10.1002/aenm.201702941}, pages = {16}, year = {2018}, abstract = {The interplay between nanomorphology and efficiency of polymer-fullerene bulk-heterojunction (BHJ) solar cells has been the subject of intense research, but the generality of these concepts for small-molecule (SM) BHJs remains unclear. Here, the relation between performance; charge generation, recombination, and extraction dynamics; and nanomorphology achievable with two SM donors benzo[1,2-b:4,5-b]dithiophene-pyrido[3,4-b]-pyrazine BDT(PPTh2)(2), namely SM1 and SM2, differing by their side-chains, are examined as a function of solution additive composition. The results show that the additive 1,8-diiodooctane acts as a plasticizer in the blends, increases domain size, and promotes ordering/crystallinity. Surprisingly, the system with high domain purity (SM1) exhibits both poor exciton harvesting and severe charge trapping, alleviated only slightly with increased crystallinity. In contrast, the system consisting of mixed domains and lower crystallinity (SM2) shows both excellent exciton harvesting and low charge recombination losses. Importantly, the onset of large, pure crystallites in the latter (SM2) system reduces efficiency, pointing to possible differences in the ideal morphologies for SM-based BHJ solar cells compared with polymer-fullerene devices. In polymer-based systems, tie chains between pure polymer crystals establish a continuous charge transport network, whereas SM-based active layers may in some cases require mixed domains that enable both aggregation and charge percolation to the electrodes.}, language = {en} } @article{LeCorreStolterfohtPerdigonToroetal.2019, author = {Le Corre, Vincent M. and Stolterfoht, Martin and Perdigon Toro, Lorena and Feuerstein, Markus and Wolff, Christian Michael and Gil-Escrig, Lidon and Bolink, Henk J. and Neher, Dieter and Koster, L. Jan Anton}, title = {Charge Transport Layers Limiting the Efficiency of Perovskite Solar Cells: How To Optimize Conductivity, Doping, and Thickness}, series = {ACS Applied Energy Materials}, volume = {2}, journal = {ACS Applied Energy Materials}, number = {9}, publisher = {American Chemical Society}, address = {Washington}, issn = {2574-0962}, doi = {10.1021/acsaem.9b00856}, pages = {6280 -- 6287}, year = {2019}, abstract = {Perovskite solar cells (PSCs) are one of the main research topics of the photovoltaic community; with efficiencies now reaching up to 24\%, PSCs are on the way to catching up with classical inorganic solar cells. However, PSCs have not yet reached their full potential. In fact, their efficiency is still limited by nonradiative recombination, mainly via trap-states and by losses due to the poor transport properties of the commonly used transport layers (TLs). Indeed, state-of-the-art TLs (especially if organic) suffer from rather low mobilities, typically within 10(-5) and 10(-2) cm(-2) V-1 s(-1), when compared to the high mobilities, 1-10 cm(-2) V-1 s(-1), measured for perovskites. This work presents a comprehensive analysis of the effect of the mobility, thickness, and doping density of the transport layers based on combined experimental and modeling results of two sets of devices made of a solution-processed high-performing triple-cation (PCE approximate to 20\%). The results are also cross-checked on vacuum-processed MAPbI(3) devices. From this analysis, general guidelines on how to optimize a TL are introduced and especially a new and simple formula to easily calculate the amount of doping necessary to counterbalance the low mobility of the TLs.}, language = {en} } @phdthesis{LorenteSanchez2017, author = {Lorente S{\´a}nchez, Alejandro Jose}, title = {Synthesis of side-chain polystyrenes for all organic solution processed OLEDs}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-398006}, school = {Universit{\"a}t Potsdam}, pages = {xiv, 131}, year = {2017}, abstract = {In the present work side-chain polystyrenes were synthesized and characterized, in order to be applied in multilayer OLEDs fabricated by solution process techniques. Manufacture of optoelectronic devices by solution process techniques is meant to decrease significantly fabrication cost and allow large scale production of such devices. This dissertation focusses in three series, enveloped in two material classes. The two classes differ to each other in the type of charge transport exhibited, either ambipolar transport or electron transport. All materials were applied in all-organic solution processed green Ir-based devices. In the first part, a series of ambipolar host materials were developed to transport both charge types, holes and electrons, and be applied especially as matrix for green Ir-based emitters. It was possible to increase devices efficacy by modulating the predominant charge transport type. This was achieved by modification of molecules electron transport part with more electron-deficient heterocycles or by extending the delocalization of the LUMO. Efficiencies up to 28.9 cd/A were observed for all-organic solution-process three layer devices. In the second part, suitability of triarylboranes and tetraphenylsilanes as electron transport materials was studied. High triplet energies were obtained, up to 2.95 eV, by rational combination of both molecular structures. Although the combination of both elements had a low effect in materials electron transport properties, high efficiencies around 24 cd/A were obtained for the series in all-organic solution-processed two layer devices. In the last part, benzene and pyridine were chosen as the series electron-transport motif. By controlling the relative pyridine content (RPC) solubility into methanol was induced for polystyrenes with bulky side-chains. Materials with RPC ≥ 0.5 could be deposited orthogonally from solution without harming underlying layers. From the best of our knowledge, this is the first time such materials are applied in this architecture showing moderate efficiencies around 10 cd/A in all-organic solution processed OLEDs. Overall, the outcome of these studies will actively contribute to the current research on materials for all-solution processed OLEDs.}, language = {en} } @article{KroenerKruegerThesen2011, author = {Kr{\"o}ner, Dominik and Kr{\"u}ger, Hartmut and Thesen, Manuel W.}, title = {Electronic structure calculations for Hole-Transporting Triphenylamine Derivatives in Polymer Light-Emitting Diodes}, series = {Macromolecular theory and simulations}, volume = {20}, journal = {Macromolecular theory and simulations}, number = {9}, publisher = {Wiley-Blackwell}, address = {Malden}, issn = {1022-1344}, doi = {10.1002/mats.201100016}, pages = {790 -- 805}, year = {2011}, abstract = {Hole-transporting polymers based on polyethene-triphenylamine derivatives are investigated with respect to their UV/Vis spectra. Two substituents, N-phenyl-1-naphthylamine and carbazole, are examined as their respective polymer light-emitting diodes (PLEDs) show very different luminous efficiencies. In order to identify the origin of these phenomena electronic structure calculations based on TD-DFT were performed using monomer models of the hole-transporting polymers. In experiment these hole-transporting polymers show very specific differences in their absorption and emission (fluorescence and phosphorescence) spectra. The analysis of the simulated absorption and emission spectra, the MOs as well as the ground and excited state geometries give explanations for the different optical performances of the corresponding PLEDs.}, language = {en} } @article{SalertKruegerBagnichetal.2013, author = {Salert, Beatrice Ch. D. and Krueger, Hartmut and Bagnich, Sergey A. and Unger, Thomas and Jaiser, Frank and Al-Sa'di, Mahmoud and Neher, Dieter and Hayer, Anna and Eberle, Thomas}, title = {New polymer matrix system for phosphorescent organic light-emitting diodes and the role of the small molecular co-host}, series = {Journal of polymer science : A, Polymer chemistry}, volume = {51}, journal = {Journal of polymer science : A, Polymer chemistry}, number = {3}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0887-624X}, doi = {10.1002/pola.26409}, pages = {601 -- 613}, year = {2013}, abstract = {A new matrix system for phosphorescent organic light-emitting diodes (OLEDs) based on an electron transporting component attached to an inert polymer backbone, an electronically neutral co-host, and a phosphorescent dye that serves as both emitter and hole conductor are presented. The inert co-host is used either as small molecules or covalently connected to the same chain as the electron-transporting host. The use of a small molecular inert co-host in the active layer is shown to be highly advantageous in comparison to a purely polymeric matrix bearing the same functionalities. Analysis of the dye phosphorescence decay in pure polymer, small molecular co-host film, and their blend lets to conclude that dye molecules distribute mostly in the small molecular co-host phase, where the co-host prevents agglomeration and self-quenching of the phosphorescence as well as energy transfer to the electron transporting units. In addition, the co-host accumulates at the anode interface where it acts as electron blocking layer and improves hole injection. This favorable phase separation between polymeric and small molecular components results in devices with efficiencies of about 47 cd/A at a luminance of 1000 cd/m(2). Investigation of OLED degradation demonstrates the presence of two time regimes: one fast component that leads to a strong decrease at short times followed by a slower decrease at longer times. Unlike the long time degradation, the efficiency loss that occurs at short times is reversible and can be recovered by annealing of the device at 180 degrees C. We also show that the long-time degradation must be related to a change of the optical and electrical bulk properties.}, language = {en} } @article{ProctorKimNeheretal.2013, author = {Proctor, Christopher M. and Kim, Chunki and Neher, Dieter and Thuc-Quyen Nguyen,}, title = {Nongeminate recombination and charge transport limitations in diketopyrrolopyrrole-based solution-processed small molecule solar cells}, series = {Advanced functional materials}, volume = {23}, journal = {Advanced functional materials}, number = {28}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1616-301X}, doi = {10.1002/adfm.201202643}, pages = {3584 -- 3594}, year = {2013}, abstract = {Charge transport and nongeminate recombination are investigated in two solution-processed small molecule bulk heterojunction solar cells consisting of diketopyrrolopyrrole (DPP)-based donor molecules, mono-DPP and bis-DPP, blended with [6,6]-phenyl-C71-butyric acid methyl ester (PCBM). While the bis-DPP system exhibits a high fill factor (62\%) the mono-DPP system suffers from pronounced voltage dependent losses, which limit both the fill factor (46\%) and short circuit current. A method to determine the average charge carrier density, recombination current, and effective carrier lifetime in operating solar cells as a function of applied bias is demonstrated. These results and light intensity measurements of the current-voltage characteristics indicate that the mono-DPP system is severely limited by nongeminate recombination losses. Further analysis reveals that the most significant factor leading to the difference in fill factor is the comparatively poor hole transport properties in the mono-DPP system (2 x 10(-5) cm(2) V-1 s(-1) versus 34 x 10(-5) cm(2) V-1 s(-1)). These results suggest that future design of donor molecules for organic photovoltaics should aim to increase charge carrier mobility thereby enabling faster sweep out of charge carriers before they are lost to nongeminate recombination.}, language = {en} } @phdthesis{Steyrleuthner2014, author = {Steyrleuthner, Robert}, title = {Korrelation von Struktur, optischen Eigenschaften und Ladungstransport in einem konjugierten Naphthalindiimid-Bithiophen Copolymer mit herausragender Elektronenmobilit{\"a}t}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-71413}, school = {Universit{\"a}t Potsdam}, year = {2014}, abstract = {Organische Halbleiter besitzen neue, bemerkenswerte Materialeigenschaften, die sie f{\"u}r die grundlegende Forschung wie auch aktuelle technologische Entwicklung (bsw. org. Leuchtdioden, org. Solarzellen) interessant werden lassen. Aufgrund der starken konformative Freiheit der konjugierten Polymerketten f{\"u}hrt die Vielzahl der m{\"o}glichen Anordnungen und die schwache intermolekulare Wechselwirkung f{\"u}r gew{\"o}hnlich zu geringer struktureller Ordnung im Festk{\"o}rper. Die Morphologie hat gleichzeitig direkten Einfluss auf die elektronische Struktur der organischen Halbleiter, welches sich meistens in einer deutlichen Reduktion der Ladungstr{\"a}gerbeweglichkeit gegen{\"u}ber den anorganischen Verwandten zeigt. So stellt die Beweglichkeit der Ladungen im Halbleiter einen der limitierenden Faktoren f{\"u}r die Leistungsf{\"a}higkeit bzw. den Wirkungsgrad von funktionellen organischen Bauteilen dar. Im Jahr 2009 wurde ein neues auf Naphthalindiimid und Bithiophen basierendes Dornor/Akzeptor Copolymer vorgestellt [P(NDI2OD‑T2)], welches sich durch seine außergew{\"o}hnlich hohe Ladungstr{\"a}germobilit{\"a}t auszeichnet. In dieser Arbeit wird die Ladungstr{\"a}germobilit{\"a}t in P(NDI2OD‑T2) bestimmt, und der Transport durch eine geringe energetischer Unordnung charakterisiert. Obwohl dieses Material zun{\"a}chst als amorph beschrieben wurde zeigt eine detaillierte Analyse der optischen Eigenschaften von P(NDI2OD‑T2), dass bereits in L{\"o}sung geordnete Vorstufen supramolekularer Strukturen (Aggregate) existieren. Quantenchemische Berechnungen belegen die beobachteten spektralen {\"A}nderungen. Mithilfe der NMR-Spektroskopie kann die Bildung der Aggregate unabh{\"a}ngig von optischer Spektroskopie best{\"a}tigt werden. Die Analytische Ultrazentrifugation an P(NDI2OD‑T2) L{\"o}sungen legt nahe, dass sich die Aggregation innerhalb der einzelnen Ketten unter Reduktion des hydrodynamischen Radius vollzieht. Die Ausbildung supramolekularen Strukturen nimmt auch eine signifikante Rolle bei der Filmbildung ein und verhindert gleichzeitig die Herstellung amorpher P(NDI2OD‑T2) Filme. Durch chemische Modifikation der P(NDI2OD‑T2)-Kette und verschiedener Prozessierungs-Methoden wurde eine {\"A}nderung des Kristallinit{\"a}tsgrades und gleichzeitig der Orientierung der kristallinen Dom{\"a}nen erreicht und mittels R{\"o}ntgenbeugung quantifiziert. In hochaufl{\"o}senden Elektronenmikroskopie-Messungen werden die Netzebenen und deren Einbettung in die semikristallinen Strukturen direkt abgebildet. Aus der Kombination der verschiedenen Methoden erschließt sich ein Gesamtbild der Nah- und Fernordnung in P(NDI2OD‑T2). {\"U}ber die Messung der Elektronenmobilit{\"a}t dieser Schichten wird die Anisotropie des Ladungstransports in den kristallographischen Raumrichtungen von P(NDI2OD‑T2) charakterisiert und die Bedeutung der intramolekularen Wechselwirkung f{\"u}r effizienten Ladungstransport herausgearbeitet. Gleichzeitig wird deutlich, wie die Verwendung von gr{\"o}ßeren und planaren funktionellen Gruppen zu h{\"o}heren Ladungstr{\"a}germobilit{\"a}ten f{\"u}hrt, welche im Vergleich zu klassischen semikristallinen Polymeren weniger sensitiv auf die strukturelle Unordnung im Film sind.}, language = {de} } @phdthesis{Schubert2014, author = {Schubert, Marcel}, title = {Elementary processes in layers of electron transporting Donor-acceptor copolymers : investigation of charge transport and application to organic solar cells}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-70791}, school = {Universit{\"a}t Potsdam}, year = {2014}, abstract = {Donor-acceptor (D-A) copolymers have revolutionized the field of organic electronics over the last decade. Comprised of a electron rich and an electron deficient molecular unit, these copolymers facilitate the systematic modification of the material's optoelectronic properties. The ability to tune the optical band gap and to optimize the molecular frontier orbitals as well as the manifold of structural sites that enable chemical modifications has created a tremendous variety of copolymer structures. Today, these materials reach or even exceed the performance of amorphous inorganic semiconductors. Most impressively, the charge carrier mobility of D-A copolymers has been pushed to the technologically important value of 10 cm^{2}V^{-1}s^{-1}. Furthermore, owed to their enormous variability they are the material of choice for the donor component in organic solar cells, which have recently surpassed the efficiency threshold of 10\%. Because of the great number of available D-A copolymers and due to their fast chemical evolution, there is a significant lack of understanding of the fundamental physical properties of these materials. Furthermore, the complex chemical and electronic structure of D-A copolymers in combination with their semi-crystalline morphology impede a straightforward identification of the microscopic origin of their superior performance. In this thesis, two aspects of prototype D-A copolymers were analysed. These are the investigation of electron transport in several copolymers and the application of low band gap copolymers as acceptor component in organic solar cells. In the first part, the investigation of a series of chemically modified fluorene-based copolymers is presented. The charge carrier mobility varies strongly between the different derivatives, although only moderate structural changes on the copolymers structure were made. Furthermore, rather unusual photocurrent transients were observed for one of the copolymers. Numerical simulations of the experimental results reveal that this behavior arises from a severe trapping of electrons in an exponential distribution of trap states. Based on the comparison of simulation and experiment, the general impact of charge carrier trapping on the shape of photo-CELIV and time-of-flight transients is discussed. In addition, the high performance naphthalenediimide (NDI)-based copolymer P(NDI2OD-T2) was characterized. It is shown that the copolymer posses one of the highest electron mobilities reported so far, which makes it attractive to be used as the electron accepting component in organic photovoltaic cells.\par Solar cells were prepared from two NDI-containing copolymers, blended with the hole transporting polymer P3HT. I demonstrate that the use of appropriate, high boiling point solvents can significantly increase the power conversion efficiency of these devices. Spectroscopic studies reveal that the pre-aggregation of the copolymers is suppressed in these solvents, which has a strong impact on the blend morphology. Finally, a systematic study of P3HT:P(NDI2OD-T2) blends is presented, which quantifies the processes that limit the efficiency of devices. The major loss channel for excited states was determined by transient and steady state spectroscopic investigations: the majority of initially generated electron-hole pairs is annihilated by an ultrafast geminate recombination process. Furthermore, exciton self-trapping in P(NDI2OD-T2) domains account for an additional reduction of the efficiency. The correlation of the photocurrent to microscopic morphology parameters was used to disclose the factors that limit the charge generation efficiency. Our results suggest that the orientation of the donor and acceptor crystallites relative to each other represents the main factor that determines the free charge carrier yield in this material system. This provides an explanation for the overall low efficiencies that are generally observed in all-polymer solar cells.}, language = {en} } @phdthesis{Thesen2010, author = {Thesen, Manuel Wolfram}, title = {Synthese und Charakterisierung von phosphoreszenten Terpolymeren und nichtkonjugierten Matrixpolymeren f{\"u}r effiziente polymere Leuchtdioden}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-51709}, school = {Universit{\"a}t Potsdam}, year = {2010}, abstract = {Mit Seitenkettenpolystyrenen wurde ein neues Synthesekonzept f{\"u}r phosphoreszente polymere LED-Materialien aufgestellt und experimentell verifiziert. Zun{\"a}chst erfolgten auf Grundlage strukturell einfacher Verbindungen Untersuchungen zum Einfluss von Spacern zwischen aktiven Seitengruppen und dem Polystyrenr{\"u}ckgrat. Es wurden Synthesemethoden f{\"u}r die Monomere etabliert, durch die aktive Elemente - Elektronen- und Lochleiter - mit und ohne diesen Spacer zug{\"a}nglich sind. Durch Kombination dieser Monomere waren unter Hinzunahme von polymerisierbaren Iridium-Komplexen in unterschiedlicher Emissionswellenl{\"a}nge statistische Terpolymere darstellbar. Es wurde gezeigt, dass die Realisierung bestimmter Verh{\"a}ltnisse zwischen Loch-, Elektronenleiter und Triplettemitter in ausreichender Molmasse m{\"o}glich ist. Die Glasstufen der Polymere zeigten eine deutliche Strukturabh{\"a}ngigkeit. Auf die Lage der Grenzorbitale {\"u}bten die Spacer nahezu keinen Einfluss aus. Die unterschiedlichen Makromolek{\"u}le kamen in polymeren Licht emittierenden Dioden (PLEDs) zum Einsatz, wobei ein deutlicher Einfluss der Spacereinheiten auf die Leistungscharakteristik der PLEDs festzustellen war: Sowohl Effizienz, Leuchtdichte wie auch Stromdichte waren durch den Einsatz der kompakten Makromolek{\"u}le ohne Spacer deutlich h{\"o}her. Diese Beobachtungen begr{\"u}ndeten sich haupts{\"a}chlich in der Verwendung der aliphatischen Spacer, die den Anteil im Polymer erh{\"o}hten, der keine Konjugation und damit elektrisch isolierende Eigenschaften besaß. Diese Schlussfolgerungen waren mit allen drei realisierten Emissionsfarben gr{\"u}n, rot und blau verifizierbar. Die besten Messergebnisse erzielte eine PLED aus einem gr{\"u}n emittierenden und spacerlosen Terpolymer mit einer Stromeffizienz von etwa 28 cd A-1 (bei 6 V) und einer Leuchtdichte von 3200 cd m-2 (bei 8 V). Ausgehend von obigen Ergebnissen konnten neue Matrixmaterialien aus dem Bereich verdampfbarer Molek{\"u}le geringer Molmasse in das Polystyrenseitenkettenkonzept integriert werden. Es wurden Strukturvariationen sowohl von loch- wie auch von elektronenleitenden Verbindungen als Homopolymere dargestellt und als molekular dotierte Systeme in PLEDs untersucht. Sieben verschiedene lochleitende Polymere mit Triarylamin-Grundk{\"o}rper und drei elektronendefizit{\"a}re Polymere auf der Basis von Phenylbenzimidazol konnten erfolgreich in den Polymeransatz integriert werden. Spektroskopische und elektrochemische Untersuchungen zeigten kaum eine Ver{\"a}nderung der Charakteristika zwischen verdampfbaren Molek{\"u}len und den dargestellten Makromolek{\"u}len. Diese ladungstransportierenden Makro-molek{\"u}le wurden als polymere Matrizes molekular dotiert und l{\"o}sungsbasiert zu Einschicht-PLEDs verarbeitet. Als aussichtsreichstes Lochleiterpolymer dieser Reihe, mit einer Strom-effizenz von etwa 33 cd A-1 (bei 8 V) und einer Leuchtdichte von 6700 cd m-2 (bei 10 V), stellte sich ein Triarylaminderivat mit Carbazolsubstituenten heraus. Als geeignetstes Matrixmaterial f{\"u}r die Elektronenleitung wurde ein meta-verkn{\"u}pftes Di-Phenylbenzimidazol ausfindig gemacht, das in der PLED eine Stromeffizienz von etwa 20 cd A-1 (bei 8 V) und eine Leuchtdichte von 7100 cd m-2 (bei 10 V) erzielte. Anschließend wurden die geeignetsten Monomere zu Copolymeren kombiniert: Die lochleitende Einheit bildete ein carbazolylsubstituiertes Triarylamin und die elektronen-leitende Einheit war ein disubstituiertes Phenylbenzimidazol. Dieses Copolymer diente im Folgenden dazu, PLEDs zu realisieren und die Leistungsdaten mit denen eines Homopolymer-blends zu vergleichen, wobei der Blend die bessere Leistungscharakteristik zeigte. Mit dem Homopolymerblend waren Bauteileffizienzen von ann{\"a}hernd 30 cd A-1 (bei 10 V) und Leuchtdichten von 6800 cd m-2 neben einer Verringerung der Einsatzspannung realisierbar. F{\"u}r die abschließende Darstellung bipolarer Blockcopolymere wurde auf die Nitroxid-vermittelte Polymerisation zur{\"u}ckgegriffen. Mit dieser Technik waren kontrollierte radikalische Polymersiationen mit ausgew{\"a}hlten Monomeren in unterschiedlichen Block-l{\"a}ngen durchf{\"u}hrbar. Diese Blockcopolymere kamen als molekular dotierte Matrizes in phosphoreszenten gr{\"u}n emittierenden PLEDs zum Einsatz. Die Bauteile wurden sowohl mit statistischen Copolymeren, wie auch mit Homopolymerblends in gleicher Zusammensetzung aber unterschiedlichem Polymerisationsgrad hinsichtlich der Leistungscharakteristik verglichen. Kernaussage dieser Untersuchungen ist, dass hochmolekulare Systeme eine bessere Leistungscharakteristik aufweisen als niedermolekulare Matrizes. {\"U}ber Rasterkraft-mikroskopie konnte eine Phasenseparation in einem Gr{\"o}ßenbereich von etwa 10 nm f{\"u}r den hochmolekularen Homopolymerblend nachgewiesen werden. F{\"u}r die Blockcopolymere war es nicht m{\"o}glich eine Phasenseparation zu beobachten, was vorwiegend auf deren zu geringe Blockl{\"a}nge zur{\"u}ckgef{\"u}hrt wurde.}, language = {de} }