Organic electronics offers a promising route toward lightweight, flexible, and sustainable devices, driven by the inherent advantages of π-conjugated molecular systems. Their compatibility with solution-based and low-temperature processing allows for a wide range of form factors and substrate integrations. Crucially, the precise structural control achieved through these solution-based methods enabled detailed investigations of organic materials at unprecedented resolution. This thesis reveals how morphological precision—beyond facilitating high-performance device fabrication—can also unlock new dimensions of organic material behavior, revealing fundamental insights into structure–property relationship. The results presented in this work offer a comprehensive investigation into the fabrication and microspectroscopic evaluation of next-generation organic electronic circuitry at the device-level, employing solution-processing techniques to develop and study a range of carbon-rich materials, including dielectric polymers, small-molecule semiconductors, crystalline charge-transfer complexes, and printable polymer hybrid electrodes. Among the foundational components of many organic electronic devices, the dielectric layer plays a significant role in charge modulation and electrical insulation. Its structure, thickness, and morphological uniformity are crucial for achieving low-voltage operation and long-term stability, particularly under ambient processing conditions. Although traditionally developed for amphiphilic materials, Langmuir-Blodgett (LB) technique was extended in this work to fabrication of polymethyl methacrylate (PMMA) ultrathin, defect-minimized layers down to 1 nm in the monolayer regime. The method also enabled the formation of multilayer stacks (~ 35 nm) suited for low-voltage organic field-effect transistors (OFET) applications. It was found that avoiding sequential film re-immersion into the aqueous subphase and employing instead a single-step high-compression process for multilayer fabrication effectively minimizes water-induced morphological defects arising from water incorporation and swelling. Devices incorporating such ultrathin high-quality dielectrics exhibited low leakage currents and stable ambient operation, validating the use of dielectric films fabricated via LB assembly. Beyond insulation, the PMMA dielectric surface acts as an interface that influences the orientation of deposited molecules, which, in turn, governs overall charge transport within the film. In this context, an all-organic interface between the C13-BTBT semiconductor, a long-alkylated benzothienobenzothiophene derivative, and PMMA was studied on a monolayer level. It was shown that the charge-transporting BTBT cores adopt an upright orientation being in contact with the dielectric, while flexible alkyl chains extend outward. This highly advantageous alignment, confirmed through Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy, molecular dynamics simulations and nanoscale force-distance spectroscopy, promotes stronger π-orbital overlap and enhances charge carrier mobility. These findings highlight the importance of interface engineering not only for electronic compatibility, but also for achieving conformational control - a subtle yet powerful lever for performance optimization in organic electronics. The theme of nanoarchitectural control through solution processing extends further into the area of organic photovoltaics. Ultrathin p-n heterojunctions were fabricated via LB deposition of PM6 and N2200 polymers. Solvent spreading parameters were finely tuned to yield mono- and multilayers with high structural quality and precise thickness control. Though morphologically uniform and homogeneous, the layers displayed distinct, yet occasional organizational features: PM6 formed isotropic films with tangled coiled structures, while N2200 showed anisotropic domains with directional π-stacking and extended branch-like polymer chains. Simplified device testing, with no emphasis on optimized performance showed a nine-fold increase in short-circuit current upon the addition of a single bilayer, remaining within a total active layer thickness of <20 nm. Notably, this performance enhancement was attributed not to structural quality or phase separation, as absorbance measurements confirmed a linear relationship between optical density and film thickness, thereby decoupling the effects of thickness and light absorption from those related to film structural quality. The thesis further explores the charge-transport dynamics in a distinct class of organic semiconductors, namely charge-transfer complexes (CTCs) - a type of materials with enhanced intrinsic electronic properties in comparison to the precursor components, driven by donor-acceptor interactions. Contrary to the prevailing assumption that molecular di-oxygen degrades electron transport in n-type organic semiconductors, it was found that oxygen can enhance the charge-transfer activity in phenazine-TCNQ complexes. Microspectroscopic and electrical analyses revealed that O2 passivates electron traps through non-covalent interaction, leading to a threefold increase in photoluminescence quantum yield and improved conductivity. These effects were reversible and observed across multiple CTC systems, suggesting oxygen as an externally tunable parameter for performance modulation in n-type advanced semiconductor systems. To better understand the structure-property relationships in CTCs, the thesis investigates benzoghiperylene-TCNQ (BP-TCNQ) crystalline complexes. By utilizing polymorphic BP crystals as both structural and functional templates, we developed a solution-based, template-assisted method to fabricate spatially organized CTC architectures with TCNQ. These needle-like CTC arrays exhibit mechanical flexibility, strain resistance, and tunable dimensions from ~ 0.5 mm down to nanometers - key features for next-generation soft organic electronics. The self-assembly occurs anisotropically at the BP surface, preserving the template and enabling repeated formation of free-standing, highly conductive crystalline networks. Microspectroscopic analysis revealed that specific unoccupied π* orbitals of TCNQ within the CTC vary reversibly with temperature, while core charge-transfer states remain stable, underscoring thermal robustness. Efficient charge-transfer quenches BP fluorescence and induces a new emission at 980 nm, with UV exposure prompting both localized and delocalized changes in electronic structure. These results reveal how crystal engineering, combined with spectroscopic insights, enables programmable optoelectronic responses, offering a scalable platform for adaptive and high-performance organic devices. Additional studies further revealed how ground-state electronic structure of BP-TCNQ-based CTC governs photoinduced excited-state charge-transfer dynamics. Upon direct photoexcitation into the CT band, a substantial polarization with 1.66 ps stabilization time, leads to the rapid exciplex formation (BP2+...TCNQ2-) with a 12 ps lifetime. This process involves an increased HOMO-LUMO gap in the photoexcited state (1.6 eV vs. 1.27 eV) and is driven by TCNQ's reduction behavior and BP's efficient HOMO depopulation. Finally, to complete the aspects of device architecture, this thesis explores polymer-based hybrid electrodes using microcontact printing of aqueous high-conductivity grade PEDOT:PSS ink blended with multi-walled carbon nanotubes (MWCNTs). Using a patterned PDMS elastomer stamp with modified surface free energy via oxygen plasma treatment, precise and reproducible electrode patterning in micrometer range was achieved. These electrodes were integrated into OFETs based on the C8-BTBT-C8 semiconductor and exhibited competitive performance compared to conventional gold contacts, due to lowered contact resistance and improved energy level alignment at the all-organic interface. The addition of MWCNTs, in turn, increased electrical conductivity through the formation of a dense nanotube network. This fully solution-processable fabrication strategy, compatible with roll-to-roll manufacturing, offers a sustainable, metal-free alternative for high-performance organic electronics. The last part of this thesis reviews the studies with focus on organic photovoltaics optimization strategies and on improving the photocatalytic hydrogen evolution. Doped polymer nanoparticles were tailored as selective hole transport layers, achieving high-efficiency, stable, and scalable non-fullerene solar cells by finely tuning dopant concentration and interfacial energetics. Extending this concept, mesoscopic nanoparticle networks were sequentially doped to form highly conductive, durable charge extraction layers, enabling record efficiencies and exceptional mechanical robustness in both rigid and flexible devices. Complementarily, a PM6-based amphiphilic block copolymer was synthesized to create stable, ligand-free nanoparticle dispersions in green solvents such as methanol, preserving the optoelectronic properties of PM6 while improving processability and environmental compatibility. Expanding beyond photovoltaics, the final study demonstrates how integrating redox-active phenazine chromophores into a polycitric acid-based carbon nanodot matrix enhances photocatalytic hydrogen generation. This hybrid nanostructure stabilizes reactive intermediates and suppresses deactivation pathways, achieving superior catalytic efficiency and durability. Overall, these works advance the understanding of nanoscale doping, interface control, and sustainable material design for next-generation organic and hybrid energy conversion technologies. Collectively, this work demonstrates how advanced solution-processing methods, combined with microspectroscopic insights, can be used to design, fabricate, and optimize high-performance organic electronic devices. From controlling molecular orientat
Kirill Gubanov (Thu,) studied this question.