Optochemical Self-Organisation of Functional Microstructures

Abstract

Our group previously reported an optochemical organization route to 3-D optical and microstructural lattices that combines the spontaneity of self-organisation to the precision and directionality of lithography. This method exploits the inherent instability of a broad, uniform beam of white light propagating in a photopolymer and its consequent division into identical filaments of light. By imposing spatially controlled noise on the light beam, the self-organizing filaments can be coaxed into 2-D and 3-D lattices. Unlike any other known self-organised or lithographically constructed structure, these lattices comprise functional, multimode and multi-wavelength cylindrical waveguides.The objective of the work presented here is to apply multidirectional waveguide lattices (MWGLs) as wide-angled, light-capturing coatings that increase the intensity of light that is incident on optical devices including photovoltaic (PV) cells. Our approach is strongly motivated by the fact that even small increments of energy conversion efficiency (<1%) of PV modules are critical in the field. Furthermore, wide-angled, light-capture could eliminate (expensive) mechanised rotation of solar panels to track the Sun’s diurnal trajectory. We employ optochemical organization to prepare elastomer films comprising up to 5 intersecting arrays of waveguide lattices, which are oriented over a large range of angles with respect to the surface normal. When integrated into solar cell devices for example, the MWGLs could capture light seamlessly over a large range of angles and deliver intensity to the photovoltaic module and in this way, could increase conversion efficiencies.