Luminescent Waveguide Encoded Lattices (LWELs) for Indoor Photovoltaics

The Internet of Things (IoT) underpins our future smart world where various electronic devices could be integrated with, and controlled by, wireless communication. Many of these devices will be standalone or portable, creating an urgent demand for off-grid power sources. Photovoltaic (PV) cells have significant potential for the purpose of recycling indoor artificial light to power the wireless electronics that form the basis of the IoT. However, there are currently two obstacles facing the use of conventional crystalline Silicon solar cells in this application: (i) they are optimised to work with sunlight, whose spectral output is very different to artificial indoor lighting and (ii) they perform poorly in diffuse, low intensity light that is typical of indoor lighting.

Here we present a new concept for indoor-light harvesting based on luminescent waveguide encoded lattices (LWELS). These are intricate photonic devices containing embedded lumophores within a planar polymer film that contains multiple waveguide channels. The LWEL is placed on the surface of a finished solar cell, where its roles to (i) convert incident light into energies that a better matched to the solar cell, (ii) provide a wide field of view to capture as much light as possible and (iii) work efficiently in diffuse light. The aim of this project is to understand the fundamental structure-property function relationships that underpin the design of an efficient LWEL. This includes designing and making LWELs with different waveguide patterns, modelling and measuring the light transport pathways within the device and testing the performance under indoor lighting when integrated with solar cells. Our ultimate goal through understanding these relationships is to demonstrate a functional LWEL prototype that enhances the performance of silicon solar cells under diffuse artificial lighting. Our hope is that this will unleash the potential of silicon solar cells for indoor photovoltaics and unlock exciting new research and commercial opportunities for applications in the IoT.