Larry Luer is interested in the quantification of elementary charge and energy transfer processes in organic conjugated materials. Goal is to improve the efficiency and stability of organic optoelectronic devices such as lasers, solar cells, and natural photosynthesis. In such devices, typical time scales of elementary processes range from femtoseconds to milliseconds; the method of choice is therefore transient absorption spectroscopy, in combination with electrical methods. We analyse the TA spectra by a combination of global and target analysis, which we recently combined with quantum chemical methods to allow direct fitting of a Hamiltonian (and thus structural insight) to transient spectroscopic data. Currently, we are looking for specific optical probes for organic/organic and organic/inorganic interfaces, to resolve open questions in interface design for organic optoelectronic devices.