Photoinduced charge separation and recombination under distance, orientation, and spin controlled conditions

Abstract

Abstract. Great efforts have been made to mimic the efficient photoinduced charge separation and concomitant energy storage of natural photosynthetic systems via artificial (supra)molecular constructs as well as to design molecules with potential use for application in molecular electronic circuits. Close packing of such molecules introduces the problem of short-circuiting and cross talk between the separate molecular components. In the present paper the limits will be investigated to which such short-circuiting can be prevented by the use of saturated hydrocarbon (alkane) type insulating structures. Furthermore, as will be shown, several typically molecular scale operating principles such as orbital symmetry and spin multiplicity control can allow the realisation of systems in which fast and efficient charge separation is combined with very slow charge recombination even when the distance between the D(onor) and A(cceptor) moieties is very small.

Long‐lived Charge‐Transfer States in 9‐Aryl‐Acridinium Ions; A Critical Reinvestigation

“…The most successful of such systems seem to be those in which "spin control" is applied by populating a chargetransfer state which is of different spin multiplicity (e.g. a triplet) than the ground state (usually a singlet) whereby charge recombination becomes a spin forbidden process [9][10][11][12].…”

Functional Nanohybrid Materials from Photosynthetic Reaction Center Proteins

“…Light-matter interactions are fundamental importance both from the point of view of basic science and practical applications (e.g., in optoelectronic systems designed for energy conversion, imaging devices, optical switches, and sensor technologies) [2][3][4][5][6]. There are various principles for light energy conversion both in living systems and in artificial molecular devices [7][8][9][10][11][12]. Light energy can be converted, for example, into (a) heat (photothermal processes; most typical example is the greenhouse effect or phenomenon used in solar panels which heat water); (b) the energy of charge pairs (photoelectric processes in energy-converting proteins or in CCD-imaging detectors, photocells); and (c) utilization of the free energy of chemical reactions (photography and photosensibilization reactions).…”