The discovery of conducting and semiconducting polymers has opened the possibility to produce integrated circuits entirely of plastic with standard continuous printing techniques. Nowadays several of this polymers are commercial available, however the performances of this materials are strongly affected by their supramolecular order achieved after deposition. In this research, the influence of some standard printing techniques on the electrical performances of conjugated polymers is evidenced in order to realise logic devices with these materials.

Im Rahmen dieser Arbeit wurden die Wechselwirkung von Indium (In) und Magnesium (Mg) als Topelektroden auf zwei Perylen-Derivativen, 3,4,9,10-Perylentetracarbonsäure Dianhydrid (PTCDA) und Dimethyl-3,4,9,10- Perylentetracarbonsäure Diimid (DiMe-PTCDI) untersucht. Die Metal/organische Schichten wurden auf S-passivierten GaAs(100):2x1-Substraten hergestellt und unter Ultrahochvakuum (UHV)-Bedingungens aufgedampft. Als Hauptcharakterisierungsmethode wird die Raman-Spektroskopie eingesetzt, die eine nicht-destruktive Methode ist,und auch in situ Untersuchungen des Wachstumsprozesses ermöglicht. Die experimentell Ergebnisse haben gezeigt, dass alle aufgedampft Metallen auf die organische Schichten von PTCDA und DiMe-PTCDI eine Verstärkung des aktive Raman Signals von interne Schwingungsmoden fördern, begleitet durch die Aktivierung von normalerweise Infrarotaktivemoden. Diesem Phänomen als Oberflächenverstärkte Raman-Spektroskopie (SERS) genannt ist. Das Mg Wachstum auf beiden Molekularstrukturen wurde durch die viel niedrigere Diffusion des Metalls in die organischen Molekülen im Vergleich zum Indium, es war durch die Bewahrung des von externe molekulare Schwingungsmoden nach das Metallswachstum, und in ersten Mal in einem Ramanexperiment beobachtet. Die PTCDA/Mg Strukturen formen sich durch zwei Stufen des Metallwachstum, die erste gehört zu einer neuen molekularen Struktur für eine Mg Schicht dünner als 2.8 nm, wo das PTCDA Molekühl des Sauerstoff-Atoms von die dianhydride Gruppe verliert. Die zweite gehört zu das SERS Spektrum von die vorherige Struktur. Im Fall von Mg/DiMe-PTCDI Heterostrukturen, den Molekühl wird gut bewahrt, wo die Raman Verschiebung an der diimide Gruppe wird nicht modifiziert. Auch von dieser Struktur eine interessante Eigenschaft wurde durch die Kopplung zwischen diskret Moleküleigenschwingungen am 221 cm^-1, 1291 cm^-1 und 1606 cm^-1 des organischen Materials und den elektronischen Kontinuum-Zuständen des Mg-Metallkontakts. Ihre entsprechenden Energieliniengestalten werden gut durch die Breit-Wigner-Fano-Funktion beschrieben. Die Untersuchungen auf dem vorherigen Heterostrukturen half, die Kanalbildung von Pentacen-basierten organische Feldeffekt-Transistoren (OFETs) experimentell zu analysieren, und in ersten Mal in einem Ramanexperiment durchgeführt. Der organische Kanal war gebildet durch die organische Molekularstrahldeposition (OMBD) unter UHV-Bedingungens der Pentacen Moleküle, und es war mit eine Evaporationsrate von ca. 0.65 Å/min aufgedampft. Nach jede Aufdampfung von ca. 0.1 nm des organische Moleküle, den Strom und den Ramansignal in den Kanal wurden in situ gemessen. Die minimale nominelle Dicke des organischen Materials erforderlich für den effizienten Ladungstransport durch den OFET Kanal wurde um ungefähr 1.5 nm nomineller Einschluss oder 1.1 Monolagen (ML) zu sein. Eigenschaften der ersten Monolagen werden gut im Vergleich mit dickeren Schichten definiert, wo die 1.1 ML eine gestrecktes Natur wegen seines direkten Kontakts mit dem Gate-Isolator präsentieren. Es wurde gefunden, dass der leitende organische Kanal bzw. -organische erhöhende Schicht (OBL)- eine Druckdeformierung hat. Dieses Phänomen durch die rote Verschiebung der Ramanbanden beobachtet war. Das Ausgangskennlinienfeld des OFETs wurden nach die letzte aufgedampft organische Schicht gemessen. Es wurde gefunden, dass der Drain-Strom einem Relaxationsprozesse mit zwei Zeitkonstanten hat, wo eine in der Ordnung von 10¹ min ist und die zweite unter 10² min. Ein ähnliches Experiment mit der Beleuchtung des Kanals mit einer 676.4 nm Laserquelle, es erhöht der Drain- Strom und lässt ummodifiziert die Zeitkonstanten. In der Ergänzung, die OFET-Strukturen waren ex situ durch Landungstransientspektroskopie (QTS) unstersucht. Die QTS Spektren zeigten positive und negative Banden zum Gesamtsignal der relaxierte Ladung in Bezug auf die einzigartige Biaspulsepolarität. Wir haben dieses Phänomen als ,,anomales Verhalten des QTS-Signals“ genannt, und in ersten Mal in einem QTS-Experiment beobachtet. Bei Wiederholung der QTS-Messung innerhalb ca. 100 min, die QTS-Spektre eine langsame Relaxationsprozesse von Störstellen am 5 μs in bereich ca. 63 min < 10^2 min hat. Die Einfangsquerschnitten sind Zeitabhängig, es bedeutet, dass die Störstellendichte nicht Konstant im Lauf der Betriebs des OFET bleibt. Dafür des Drain-Strom verändert sich und die Beweglichkeit unabhängige des elektrisches Feld ist. Experimentell Untersuchungen auf dem OFETs mit der Kombination der Ramanspektroskopie und elektrischen Felder zeigten eine Erhöhung des Ramanseinfangsquerschnitt in endliche Bereich als die chemische SERS-Verstärkung von In bzw. Mg auf die Perylen-Derivativen PTCDA und DiMe-PTCDI. Nach den Ausschaltung des elektrisches Felds den Ramansignal des Pentacen-basierten OFET eine Relaxationsprozesse mit Zeitkonstant von ca. 94 min hat. Deshalb ist die Summe von Störstellensdichte wegen dieser am organische/anorganische Grenze plus dieser dass die elektrisches Felds am die organische Halbleiter induziert.

Photo-induced charge transfer which occurs between molecules or different parts of a large molecule is the pivotal process related to performances of organic electronics. In particular, injection of charge carriers into conjugated polymers and dissociation of photo-generated excitons at the heterojunction between a donor and acceptor system are of great importance in determining the luminescence efficiency of organic light emitting diodes (OLEDs) and solar energy conversion efficiency of organic solar cells, respectively. However, the complex nature of organic semiconductors as well as complicated primary processes involved in the functioning of these devices have prevented us from understanding unique characteristics of these processes and thereby engineering better materials for higher performances. In this dissertation, two different types of photo-induced (or -related) charge transfer processes occurring in organic semiconductors were investigated by using single molecule spectroscopy (SMS) techniques to unravel the complexities of these processes. The carefully designed functioning capacitor-like model devices similar to OLEDs and photovoltaic cells were fabricated where isolated single nanoparticles were introduced as an active medium to mitigate the complexities of these materials. We observed that injection of positively charged carriers (holes) into poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) single nanoparticles from the carbazole hole transport layer does not occur in the absence of light. We denoted the observed hole injection in aid of light as the light-induced hole transfer mechanism (LIHT). It was revealed that the charging dynamics are highly consistent with a cooperative charging effect. In addition, the LIHT was proposed as the possible source for the formation of deep trapped hole in organic devices. Local exciton dissociation yields across a nanostructured domain between poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) single nanoparticles and either poly(9,9- dioctylfluorene - co - bis-N,N- (4 -butylphenyl)-bis-N,N-phenyl-1,4-phenylene diamine) (PFB) or poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine) (TFB) film in model photovoltaic devices was also investigated. A wide distribution of exciton dissociation yields was observed from each nanodomain due to the device geometry. The observed hysteresis in fluorescence voltage curve was ascribed to accumulated charges following charge separations. The dynamics of charge separation under the applied electric field was described in more detail. / text

Maleimide based highly luminescent material Cbz-MI with donor acceptor donor (D-A-D) backbone has been synthesized and characterized. An organic light emitting diode fabricated using this material as emitting layer exhibited EQE of 2.5% in the yellow region of visible spectrum. Due to the small energy gap of materials emitting in this region of spectrum, EQE of OLED is usually limited by various non-radiative decays and high EQE of OLED using this material proves that most of the nonradiative decay pathways have been avoided by the careful design of molecule and device structure. Although Cbz-MI did not show TADF properties, but if tailored with right electron donor along with maleimide as an acceptor, such derivatives may exhibit TADF properties

The work carried out in this thesis systematically investigates the correlation between microstructures and electronic properties of organic semiconductors. The major directions that were pursued in this thesis are: (i) studies on structure-property relationship by rational design and synthesis of monodisperse oligomers with varying chain-lengths (ii) role of electronic properties and aggregation (microstructures) in governing singlet fission (SF). In the first part of the thesis, the optical, structural and charge transport properties of Diketopyrrolopyrrole (DPP)-based oligomers, as a function of the chain length, has been discussed. The energy bands became wider with an increase in chain length and a gain in backbone electron affinity was observed, with an offset in microstructural order. With an increase in chain length, the tendency to form intramolecular aggregates increased as compared to intermolecular aggregates due to the onset of backbone conformational defects and chain folding. An insight into the solid-state packing and microstructural order has been obtained by steady-state and transient spectroscopy, grazing incidence small angle x-ray scattering (GISAXS), atomic force microscopy (AFM) and transmission electron microscopy (TEM) studies. The charge-carrier mobilities varied in accordance with the degree of microstructural order as: dimer > trimer > pentamer. A library of DPP-DPP based trimers was also generated by modifying the donor chromophore (phenyl, thiophene and selenophene) in the oligomer backbone. Highest n-channel mobility of ~0.2 cm2V-1s-1 was obtained which validated that: (a) the effect of solid-state packing predominates the effect of backbone electronic structure on charge carrier mobility. Although oligomers possess lesser backbone defects than polymers in general, their charge carrier mobilities were not comparable to that of 2DPP-OD-TEG polymer, which forms highly oriented and isotropic edge-on crystallites/microstructures in the thin film, shows high n-channel mobility of 3 cm2V-1s-1 and band-like transport ;(b) although delocalized electronic states are achieved at greater chain lengths, the degree of solid-state microstructural order drastically reduces which leads to lower charge carrier mobilities; (c) conformational collapse resulted in lower electron mobilities and an increase in ambipolarity. The later part of the thesis debates on the relative contribution of electronic structure and aggregation (microstructures) in governing singlet fission (SF). Motivated by the recent SF model in carotenoid aggregates, a DPP-DPP based oligomer was synthesized by incorporating a vinylene bridge to imbue “polyene” character in the chromophore. Transient Spectroscopy (TA) measurements were carried out to monitor the formation of triplet states in the oligomer and to probe the occurrence of singlet fission. Although the oligomer exhibits “polyene” character like a typical “carotenoid aggregate”, it did not show singlet fission because of the additional stabilization of the singlet (S1) state which reduces the ∆EST. This study rationalized the importance of judicious control of band structures as well as microstructures to observe the SF phenomenon in this category of chromophores. The novel synthetic protocol provides the scope to tailor DPP-DPP based materials with desired effective conjugation lengths and side chains and can foreshow great prospects for future generation of organic electronics.

Le but de cette thèse était d’élaborer et d’étudier des films minces hybrides orientés et nanostructurés composés d’un polymère semi-conducteur, le poly(3-hexylthiophène) regiorégulier (P3HT) et de nanocristaux semiconducteurs de CdSe (sphères, bâtonnets). Pour cela, deux méthodes ont été mises en œuvre: la croissance épitaxiale directionnelle et le brossage mécanique. Les films de P3HT purs épitaxiés et brossés se différencient en termes de nanomorphologie, d’ordre cristallin et de structure. Les premiers présentent une morphologie lamellaire et une structure de fibre où les chaînes conjuguées sont alignées suivant l’axe de fibre. Les films brossés ne présentent pas de structure lamellaire et les domaines cristallins sont orientés préférentiellement «flat-on». Ces différences se reflètent dans les propriétés optiques des films épitaxiés et brossés. Le degré d’orientation des films brossés dépend fortement du poids moléculaire et une forte anisotropie du transport de charges a été observée. Les films hybrides épitaxiés sont nanostructurés avec localisation des nanocristaux dans les zones amorphes du P3HT. Par ailleurs, l’analyse par tomographie électronique de ces films montre une structure en bicouche avec une couche hybride surmontée d’une couche de P3HT pur. Les films hybrides brossés montrent clairement un alignement des nanobâtonnets de CdSe et des chaînes du P3HT parallèlement à l’axe du brossage. Les degrés d’orientation du P3HT et des nanobâtonnets sont corrélés et dépendent de la proportion en nanoparticules indiquant que c’est la matrice polymère qui induit l’orientation des nanobâtonnets. / The aim of this thesis was to elaborate and characterize hybrid oriented and nanostructured thin films composed of a semiconducting polymer, regioregular poly(3-hexylthiophène) (P3HT) and semiconducting CdSe nanocrystals (spheres, rods). Two orientation methods were used: directional epitaxial crystallization and mechanical rubbing. Epitaxied and rubbedfilms of pure P3HT show strong differences in terms of nanomorphology, crystalline order and structure. Epitaxied films possess a lamellar morphology, a 3D crystalline order and fiber symmetry where the P3HT backbones (cP3HT) are aligned along the fiber axis. Rubbed films do not show a lamellar morphology and have a 2D crystalline order with crystalline domains preferentially oriented “flat-on” relative to the substrate. These differences are reflected in the optical properties of the films. The orientation degree achieved in rubbed films strongly depends on the molecular weight of the polymer. There is also a strong anisotropy of the charge transport properties. Regarding hybrid epitaxied layers, we observed a nanostructuration with a localization of the CdSe nanocrystals into the amorphous zones of the P3HT. Moreover, electron tomography analysis shows that such films have a bilayer structure with a hybrid layer covered by pure P3HT. In rubbed hybrid films prepared with nanorods, the long axis of the nanorods as well as the P3HT backbone are oriented parallel tothe rubbing direction. The degree of in-plane orientation of the rods and of the P3HT matrix match closely and depend on the proportion of CdSe nanrods in the films. These results suggest that the P3HT matrix enforces the orientation of the rods.

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-01-09T14:16:49Z No. of bitstreams: 1 rodrigocouradias.pdf: 2508131 bytes, checksum: a85f5360d98ae17dab9812e3e61a46cd (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-01-23T11:19:39Z (GMT) No. of bitstreams: 1 rodrigocouradias.pdf: 2508131 bytes, checksum: a85f5360d98ae17dab9812e3e61a46cd (MD5) / Made available in DSpace on 2018-01-23T11:19:39Z (GMT). No. of bitstreams: 1 rodrigocouradias.pdf: 2508131 bytes, checksum: a85f5360d98ae17dab9812e3e61a46cd (MD5) Previous issue date: 2017-11-24 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Um tipo de dispositivo que tem atraído atenção nos últimos anos no campo da Eletrônica Orgânica é as Células Eletroquímicas Emissoras de Luz, mais conhecidas como LECs (ou LEECs), do inglês Light Emitting Electrochemical Cells. Esses dispositivos eletrônicos têm baixa voltagem de operação, fabricação simples e barata, alto desempenho, ligeira independência dos materiais usados como eletrodo ou da espessura de suas camadas emissoras, além de terem a possibilidade de serem fabricados sobre substratos flexíveis. Por essas razões, as LECs têm sido usadas como possíveis substitutas para os já conhecidos OLEDs (Diodos Orgânicos Emissores de Luz), e o estudo de suas propriedades ópticas e elétricas e de seu princípio de funcionamento têm sido foco de trabalho de muitos cientistas. Dentre os modelos conhecidos que propõem descrever o funcionamento das LECs podemos citar três: a Teoria da Difusão, a Teoria da Dopagem Eletroquímica e a Teoria Mista. No primeiro a injeção de portadores na camada ativa seria facilitada pelos compostos iônicos presentes na blenda que a compõe, com posterior movimentação de cargas por difusão e recombinação no centro da camada. No segundo modelo ocorre a formação de três regiões dentro da blenda polimérica: uma região dopada do tipo p, uma região dopada do tipo n e uma camada isolante onde ocorre a recombinação de cargas para emissão de luz. A teoria mista assume que ambas são possíveis dependendo das condições em que se encontra o dispositivo. A fim de compreender como esses processos ocorrem e interferem no desempenho desses dispositivos propusemos diversas experiências alterando parâmetros importantes na sua fabricação. É proposto um modelo para a influência do tipo de cátion e ânion usado no sal presente na camada ativa e para descrever a influência da concentração desse sal na blenda polimérica que a compõe. Com base nas teorias descritas é colocada em evidência a influência da concentração de polímero transportador de íons na camada emissora e da espessura desta camada. Ao fim de todo o estudo obtivemos um dispositivo otimizado que é comparado com um dispositivo feito com um material novo sintetizado por colaboradores do departamento de Química da UFJF a fim de gerar expectativas para futuros trabalhos. / One type of device that has attracted attention in recent years in the field of Organic Electronics are the Light Emitting Electrochemical Cells, better known as LECs (or LEECs) These electronic devices have low operating voltage, simple and inexpensive manufacture, high-performance, light independence of the material used as electrode or the thickness of its emissive layer, besides having the possibility to be manufactured on flexible substrates. For these reasons the LECs have been used as possible substitutes for known OLEDs (Organic Light Emitting Diodes), and the study of their optical and electrical properties, and its operating principle have been working focus of many scientists. Among the known models proposed to describe the operation of LECs we can name three: the Theory of Diffusion, the Theory of Electrochemical Doping, and the Mixed Theory. In the first, injection of carriers in the active layer would be facilitated by the ionic compounds present in the blend that makes up, with subsequent movement of charges by diffusion and recombination in the center of the layer. In the second model happens the formation of three layers within the polymer blend: A p-type doped region, a n-type doped region and an insulating layer where recombination occurs for emitting light. Mixed theory assumes that both are possible depending on the conditions in which the device is. In order to understand how these processes occur and interfere with the performance of these devices we have proposed several experiments changing important parameters in its manufacture. A model is proposed for the influence of the type of cation and anion used in the salt present in the active layer, and to describe the influence of the concentration of this salt in the polymer blend that makes up. Based on the theories described it is put in evidence the influence of the concentration of the ion carrier polymer in the emitter layer and the thickness of this layer. After all the study we obtained an optimized device that is compared with a device made with a new material synthesized by employees from the Chemistry Department of UFJF to generate expectations for future work.

The present thesis deals with a theoretical study of electronic structures in -conjugated molecular materials with focus on their application in organic elec-tronics. We also discuss a modified and efficient symmetrized DMRG algorithm for studying excited states in these systems. In recent times, organic conjugated systems have emerged as potential candidates in a wide range of fascinating fields by virtue of their tunable electronic properties, easy processability and low cost. Tunability in the electronic and optical properties primarily are centered on the or-dering and nature of the low-lying excited states. Probing these important excited states also demands development of efficient and adaptable techniques. Chapter 1 provides a basic overview of conjugated organic polymers which have been utilized over decades in diverse fields as in organic light emitting diodes (OLED), organic solar cells (OSC) and non-linear optical (NLO) devices. These systems also contribute significantly to theoretical understanding as they pro vide important insights of one and quasi-one dimensional systems. In this chapter, we have given basic description of the electronic processes in OLED and OSC along with a brief theoretical description of -conjugated organic systems. Chapter 2 gives an account of the numerical techniques which are necessary for the study of low-dimensional strongly correlated systems like -conjugated sys-tems. For this purpose, effective low-energy model Hamiltonians viz. Huckel,¨ Hubbard and Pariser-Parr-Pople Hamiltonians are discussed. Exact diagonalization technique within the diagrammatic valence bond (DVB) basis and density matrix renormalization group (DMRG) technique are discussed in details. We have also given brief accounts of the methods employed to study real-time dynamics. A short description of different computational techniques for the study of NLO properties in -conjugated systems is also provided. Engineering the position of the lowest triplet state (T1) relative to the first excited singlet state (S1) is of great importance in improving the efficiencies of organic light emitting diodes and organic photovoltaic cells. In chapter 3, we have carried out model exact calculations of substituted polyene chains to understand the fac-tors that affect the energy gap between S1 and T1. The factors studied are backbone dimerization, different donor-acceptor substitutions and twisted backbone geome-try. The largest system studied is an eighteen carbon polyene which spans a Hilbert space of about 991 million in the triplet subspace. We show that for reverse inter-system crossing (RISC) process, the best choice involves substituting all carbon sites on one half of the polyene with donors and the other half with acceptors. Singlet fission (SF) is a potential pathway for significant enhancement of efficiency in OSC. In chapter 4, we study singlet fission in a pair of polyene molecules in two different stacking arrangements employing exact many-body wave packet dy-namics. In the non-interacting model, SF is absent. The individual molecules are treated within Hubbard and Pariser-Parr-Pople (PPP) models and the interac-tion between them involves transfer terms, intersite electron repulsions and site-charge—bond-charge repulsion terms. Initial wave packet is construc ted from ex-cited singlet state of one molecule and ground state of the other. Time develop-ment of this wave packet under the influence of intermolecular interactions is fol-lowed within the Schrodinger¨ picture by an efficient predictor-corrector scheme. In unsubstituted Hubbard and PPP chains, 21A state leads to significant SF yield while the 11B state gives negligible fission yield. On substitution by donor-acceptor groups of moderate strength, the lowest excited state will have sufficient 2 1A char-acter and hence gives significant SF yield. Because of rapid internal c onversion, the nature of the lowest excited singlet will determine the SF contribution to OSC effi - ciency. Furthermore, we find the fission yield depends considerably on th e stacking arrangement of the polyene molecules. In chapter 5, we have given an account of a new modified algorithm for symmetry adaptation within symmetrized density matrix renormalization group (SDMRG) technique. SDMRG technique has been an efficient method for studying low-lying eigenstates in one and quasi-one dimensional electronic systems. However, SDMRG method until now, had bottlenecks involving construction of linearly in-dependent symmetry adapted basis states as the symmetry matrices in the DMRG basis were not sparse. Our modified algorithm overcomes this bottleneck. T he new method incorporates end-to-end interchange symmetry (C2), electron-hole symmetry (J) and parity or spin-flip symmetry (P) in these calculations. The one-to-one correspondence between direct-product basis states in the DMRG Hilbert space for these symmetry operations renders the symmetry matrices in the new ba-sis with maximum sparseness, just one non-zero matrix element per row. Using methods similar to those employed in exact diagonalization technique for Pariser-Parr-Pople (PPP) models, developed in the eighties, it is possible to construct or-thogonal SDMRG basis states while bypassing the slow step of Gram-Schmidt orthonormalization procedure. The method together with the PPP model which incorporates long-range electronic correlations is employed to study the correlated excited states of 1,12-benzoperylene. In chapter 6, we have studied the correlated excited states of coronene and ova-lene within Pariser-Parr-Pople (PPP) model employing symmetry adapted density matrix renormalization group technique. These polynuclear aromatic hydrocar-bons can be considered as graphene nanoflakes and study of their ele ctronic struc-tures will shed light on the electron correlation effects in these finite-size gr aphene analogues. The electron correlation effect usually diminishes on going from one-dimensional to higher-dimensional systems, yet, it is significant within these fin ite-size graphene derivatives where it depends on the molecular topology. We have characterized these low-lying energy states by calculating bond orders, spin den-sities in the lowest triplet state and two-photon absorption cross-sections for low-lying two-photon states. vi

Thesis describes recent advances in the synthesis of donor-acceptor conjugated copolymers and their efficient doping via molecular p-dopants.

This thesis outlines investigations of metal oxide/organic interfaces in photo-voltaic devices. It focuses on device instabilities originating from the metal oxide layer surface sensitivity and it presents suggested mechanisms behind these in- stabilities. A simple sol-gel solution deposition technique for the fabrication of stable and highly performing transparent conducting mixed metal oxides (ZnMO) is presented. It is demonstrated that the use of amorphous, mixed metal oxides allows improving the performance and stability of interfacial charge extraction layers for organic solar cells. Two novel ternary metal oxides, zinc-strontrium- oxide (ZnSrO) and zinc-barium-oxide (ZnBaO), were fabricated and their use as electron extraction layers in inverted organic photovoltaics is investigated. We show that using these ternary oxides can lead to superior devices by: prevent- ing a dipole forming between the oxide and the active organic layer in a model ZnMO/P3HT:PCBM OPV as well as lead to improved surface coverage by a self assembled monolayer and promote a significantly improved charge separation efficiency in a ZnMO/P3HT hybrid device. Additionally a spectroscopic technique allowing a versatility of characterisa- tion for long-term stability investigations of organic solar cells is reported. A device instability under broadband light exposure in vacuum conditions for an inverted ZnSrO/PTB7:PC71BM OPV is observed. Direct spectroscopic evidence and electrical characterisation indicate the formation of the PC71BM radical an- ion associated with a loss in device performance. A charge transfer mechanism between a heavily doped oxide layer and the organic layers is suggested and dis- cussed.