Photo-induced charge separation and charge transport are fundamental processes in many energy conversion techniques, where light is converted into chemical energy (PEC), into electrical energy (solar cells) or in the opposite sense if electrical energy is converted into light (LEDs). In all cited examples, charge carriers have either to be transported towards an interface where they can undergo radiative recombination, trigger a chemical reaction, or they have to be evacuated from the interface as free charge carriers to be able to perform work in an external electrical circuit. In this work the charge generation dynamics and transport is studied using THz time domain spectroscopy and complimentary techniques on systems finding application in dye sensitized solar cells and PEC cells for water splitting. The functioning of a dye sensitized solar cell is based on the kinetic competition between several reactions, i.e. electron injection, dye-regeneration, electron back- reaction and charge extraction. Accordingly the rates of all of these reactions have to be optimized in order to optimize the cell performance. This requires a good understanding of the underlying mechanism of these processes. In photochemical cells, the encountered processes are in a way similar. After initial excitation, the generated charges have to be separated and have to reach either the interface to the electrolyte or the external circuit before being annihilated by recombining. Knowing the diffusion length and carrier lifetime in a specific material might therefore be helpful to optimize the film morphology, i. e. the aspect ratio. Chapter 1 gives an overview over the functioning of DSCs and PEC cells and summarizes some theoretical aspects of the processes encountered in these devices. Chapter 2 is devoted to the description of the experimental tools used and built in this work. In chapter 3, charge transport in a liquid molecular hole conductor, 10- methylphenoxazine, is investigated. The transport is rationalized using a model taking into account ionic diffusion and intermolecular hole transfer, i. e. hopping. It is found that the conduction occurs principally by hopping, as the HTM cation seems to be mainly present in an ion-paired form with the anion from the doping agent. Hopping of charge requires molecular vibration to bring acceptor and donor molecule in electronic resonance. Two vibrational modes of the HTM cation and neutral molecules that might be coupled to charge transport are observed. In chapter 4, electron injection from a dye into the conduction band of TiO2 films is investigated by monitoring the appearance of the free electron. This signal is compared to the signal arising from direct UV excitation of the TiO2. In addition to previous studies done in the group, the effect of dye aggregation leading to decelerated electron injection is investigated. Comparing the THz signal amplitude to the injected charge carrier concentration, the THz mobility in TiO2 films was found to be 0.1-0.15 cm2V-1s-1 and constant over the investigated charge carrier concentrations. Furthermore the influence of sintering temperature of the TiO2 film has been addressed in a preliminary study. In chapter 5, the influence of liquid electrolytes, of a solid state hole conducting material and of the commonly used additives Li+ and tBP on the charge generation dynamics have been investigated. While in this work the presence of an electrolyte/HTM has not shown any influence on the electron injection dynamics, the generation of the free electron seems to be strongly dependent on the molecular surrounding. This discrepancy is discussed in terms of a coulombic bound electron- hole pair as an intermediate state in the electron injection dynamics. Chapter 6 contains a study on the charge carrier dynamics in cuprous oxide, being used as material for photoelectrochemical water splitting. The wavelength and fluence dependence on the charge carrier lifetime, mobility and diffusion length was studied. The strong dependence of the charge carrier lifetime is discussed in terms of trapping mediated recombination.