Light management films for enhanced harvesting in printable photovoltaics

Abstract

Printed organic photovoltaics promise lightweight and flexible light harvesting devices for conformable integration into buildings, portable electronics or vehicles. Besides the challenges in material synthesis and engineering of the printing processes, the optical design of these thin film layer devices is inevitable to achieve high power conversion efficiencies. In this respect, light management, which denotes the control of light in-coupling and light absorption in the device by photonic micro- and nanostructures, plays an increasingly important role. In this thesis, dielectric diffractive nanostructures are introduced as such light management solution, which stands out due to its device-independent fabrication. The optical properties of the periodic structures and the angle dependent absorption in the OPV devices are carefully analyzed and their enhancement potential is demonstrated experimentally on single-junction and tandem devices. To demonstrate the applicability of this class of light management solutions, advanced nanostructures are fabricated, on the one hand, as self-standing foils to reveal their potential for mass production and, on the other hand, as buried structures, which provide protection against abrasion. An optical model is developed in this thesis, which enables the optimization of the geometrical parameters of the nanostructure, with respect to the yearly harvested energy in different application-relevant device orientations (facade, consumer electronics, shading, automotive).