Charge Transport in Functional Devices : Physics-Grounded Simulation to Physics-Inspired Design

Understanding and controlling charge transport is central to advancing functional semiconductor devices, yet conventional approaches often treat transport phenomena as inherent material properties rather than tunable design variables.This thesis establishes a methodology that progresses from physics-grounded simulation and modeling toward mechanistic insight to physics-inspired structural innovation, using charge transport as both the analytical lens and the design principle.This thesis investigates how a detailed understanding of carrier-transport mechanisms can guide the design of high-performance optoelectronic and sensing devices.Through device simulation and theoretical modeling of perovskite light-emitting diodes and gas sensors, complemented by experimental studies reported in the associated publications, this thesis shows that systematic analysis of transport processes can reveal design principles that transcend specific device architectures.The first part develops physics-grounded understanding through device simulation and modeling.By investigating charge injection dynamics, interfacial carrier accumulation, and non-radiative recombination processes in perovskite LEDs, the work establishes simulation-backed relationships between device architecture, transport properties, and performance limits.Particular emphasis is placed on understanding how energy level alignment, film morphology, and ionic effects modulate carrier transport pathways.An ion-electron coupled transport model under steady-state conditions is developed, showing how ionic redistribution alters internal electric-field distributions and radiative recombination profiles, thereby extending standard drift-diffusion descriptions used for perovskite devices.The second part demonstrates physics-inspired innovation by applying transport insights to motivate and evaluate novel device architectures.Moving beyond incremental optimization, this work introduces the concept of functional decoupling: spatially separating sensing and transport functions in gas sensors to overcome the trade-off between sensitivity and response speed.Transport-based modeling rationalizes the architectural choices and predicts the conditions for ultrafast response, consistent with experimental demonstrations in the companion work, exemplifying how mechanistic understanding can inspire architectural innovations that challenge conventional device paradigms.This thesis makes three principal contributions.First, it uses charge-transport simulations to systematically analyze the impact of carrier transport in perovskite optoelectronic devices across operating regimes.Second, it develops and applies a steadyiii state ion-electron coupled description based on drift-diffusion-type modeling, clarifying how ionic redistribution reshapes internal electric fields and recombination profiles and how these effects should be reflected in device modeling and optimization.Third, it demonstrates a generalizable workflow for translating transport-based understanding into simulation-guided device concepts and architectural choices, including designs that decouple sensing and transport functions to overcome speed-sensitivity trade-offs.The work bridges device physics, materials engineering, and innovative design, offering specific insights for perovskite optoelectronics and gas sensors, and broader methodological lessons for the development of functional devices.By demonstrating how simulation-driven understanding can evolve into design principles for novel architectures, this thesis contributes to device engineering methodology by transforming physics from a tool for analysis into a source of innovation.