“…It is clear that, given our current state of understanding of THz spectroscopy to these types of systems, future applications of time-resolved terahertz spectroscopy can focus on systems of increasing complexity, such as those encountered in photovoltaic devices where different semiconductor phases are intermixed on nanometer lengths scales (Esenturk et al, 2009). Such complex systems may include, for instance, semiconductor nanostructures (quantum dots or nanorods) embedded in an organic polymer semiconductor phase and quantum dot or dye-sensitized transition metal oxide systems (Tiwana et al, 2009;Nemec, Rochford et al, 2010;Pijpers et al, 2010Pijpers et al, , 2011. The ability to monitor exciton and carrier dynamics on ultrafast time scales, across a wide frequency range, without the necessity to apply contacts to the material makes time-resolved terahertz spectroscopy a rather unique tool for studying carrier dynamics, for instance, allowing us to monitor the conversion of excitons into free charge carriers and vice versa.…”