Ultrafast Snapshots: Understanding the photoinduced charge transfer in donor–(bridge)–acceptor systems

Photoinduced charge transfer (CT) is a fundamental photophysical process that prevails in nature but also plays a pivotal role in various technological fields. This thesis describes spectroscopic studies on photoinduced CT in donor-bridge-acceptor (DBA) systems and their derivatives. Throughout this work, we employ femtosecond transient...

Unfolding the Excited States Dynamics of Tm²⁺-doped Halides: In Prospect of Novel Luminescence Solar Concentrators

Tm²⁺-doped halides exhibit excellent properties for use in Luminescence Solar Concentrator (LSC) applications. Such LSCs consist of a glass waveguide with small Copper-Indium- Selenide (CIS) solar cells attached to its edges. The waveguide contains a luminescent coating based on a Tm²⁺-doped halide, whose 4f125d1 absorption...

Photoluminescence and excited states dynamics of Tm²⁺-doped CsCa(Cl/Br)₃ and CsCa(Br/I)₃ perovskites

In this study, we systematically vary the Cl/Br and Br/I ratios in CsCaX₃:Tm²⁺ (X = Cl, Br, I) and hereby gradually shift the positions of the Tm²⁺ 4f¹²5d¹-levels as relative to the two 4f¹³ levels. At low temperatures up to five distinct Tm²⁺ 4f¹²5d<sup>1...

Experimental and numerical analysis of Tm²⁺ excited-states dynamics and luminescence in CaX₂ (X = Cl, Br, I)

The prospect of using Tm²⁺-doped halides for luminescence solar concentrators (LSCs) requires a thorough understanding of the temperature dependent Tm²⁺ excited states dynamics that determines the internal quantum efficiency (QE) and thereby the efficiency of the LSC. In this study we investigated the dynamics in CaX<sub...

Spectroscopic Evidence for the Contribution of Holes to the Bleach of Cd-Chalcogenide Quantum Dots

In transient absorption (TA) measurements on Cd-chalcogenide quantum dots (QDs), the presence of a band-edge (BE) bleach signal is commonly attributed entirely to conduction-band electrons in the 1S(e) state, neglecting contributions from BE holes. While this has been the accepted view for more than 20 years, and has often been used to...