Date of Award
6-27-2025
Date Published
August 2025
Degree Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Mechanical and Aerospace Engineering
Advisor(s)
Quinn Qiao
Keywords
Atomic force microscopy, Charge Carrier Dynamics, Optoelectronic Devices, Organic solar cells, Perovskite solar cells, Photovoltaic
Subject Categories
Engineering | Mechanical Engineering
Abstract
In recent years, solution-processable photovoltaic (PV) technologies such as organic solar cells (OSCs), perovskite solar cells (PSCs), and perovskite tandem cells have rapidly advanced, achieving certified power conversion efficiencies (PCEs) of approximately 20%, 27%, and 30.1%, respectively. Despite this progress, challenges remain in fully understanding and controlling performance-limiting factors in the photoactive layers of OSCs and PSCs, including nanoscale surface conductivity, topography, and morphological distortions. This work provides an in-depth exploration of nanoscale imaging and mapping techniques for OSCs and PSCs, highlighting how addressing nanoscale defects can enhance PV device performance. We examine the similarities and differences between these two technologies in key processes such as charge generation, separation, transport, collection, and recombination. Furthermore, we connect these mechanisms to the intrinsic material properties of organic and perovskite semiconductors, elucidating their impact on overall photovoltaic performance. Furthermore, some optoelectronic samples like perovskite nanocrystals (NCs), perovskite-based Light-emitting diodes (LEDs), and some other nanostructure materials have been successfully tested by this technique. To resolve the standard degrading issue in the semiconductor field, the experimental setup has been upgraded with a PID thermal management system and an adjustable pressure gas delivery system to minimize sample degradation caused by moisture and oxygen exposure. An improved fitting algorithm has been applied to measure special samples with short TPV and TPC.
Access
Open Access
Recommended Citation
Zhang, Yuchen, "Nanoscale Mapping of Charge Carrier Dynamics in Photovoltaic or Optoelectronic Devices" (2025). Dissertations - ALL. 2159.
https://surface.syr.edu/etd/2159
