Development of the ultrafast spectroscopy microscope for next-generation optoelectronic materials

Abstract

The development of high-efficiency solar cells is receiving much attention as a means to solve the current global warming problem. Currently, a number of materials and solar cells based on the materials are being actively discussed, and show remarkable results. Understanding the dynamics of the internal energy dynamics for a more efficient system is essential, however, has shown great limitations in providing direct clues of the dynamics due to insufficient spatial, temporal and energy resolutions. Since an all-optical analysis system directly shows the operation of a real solar cell, an all-optical system with high spatial, temporal and energetic resolution can reveal the energy conversion dynamics of a material. Therefore, to achieve this, this thesis describes the properties of two new materials developed for high-efficiency solar cell systems and three systems designed to study their properties. The first is the observation of ion transport, photo-decomposition process, and quantum efficiency change according to strain according to the nanostructure of MAPI perovskite, which is currently in the limelight, using integrated-optical confocal microscopy. Secondly, hyperspectral image processing combined with micro transient absorption and cryogenic station successfully correlates the singlet decay exhibited in a specific organic material (diF-TES-ADT in this study) with the crystallinity of the organic material and demonstrates different carrier dynamics corresponding to the inhomogeneous crystallinity. This thesis discusses not only the physical properties of the listed materials but also the experimental methods for analyzing the physical properties of these materials. Therefore, it is expected that the cornerstone can be laid for application to other solar cell systems using the developed techniques throughout this thesis.

Date of Award	1 Aug 2023
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Wendy Flavell (Supervisor) & Patrick Parkinson (Supervisor)