A perspective on using experiment and theory to identify design principles in dye-sensitized solar cells

Dye-sensitized solar cells (DSCs) have been the subject of wide-ranging studies for many years because of their potential for large-scale manufacturing using roll-to-roll processing allied to their use of earth abundant raw materials. Two main challenges exist for DSC devices to achieve this goal; uplifting device efficiency from the 12 to 14% currently achieved for laboratory-scale ‘hero’ cells and replacement of the widely-used liquid electrolytes which can limit device lifetimes. To increase device efficiency requires optimized dye injection and regeneration, most likely from multiple dyes while replacement of liquid electrolytes requires solid charge transporters (most likely hole transport materials – HTMs). While theoretical and experimental work have both been widely applied to different aspects of DSC research, these approaches are most effective when working in tandem. In this context, this perspective paper considers the key parameters which influence electron transfer processes in DSC devices using one or more dye molecules and how modelling and experimental approaches can work together to optimize electron injection and dye regeneration. This paper provides a perspective that theory and experiment are best used in tandem to study DSC device

Charge transfer mechanics in transparent dye-sensitised solar cells under low concentration

In dye-sensitized solar cells (DSSCs), the incoming sunlight can influence many of the key electron transfer processes occurring at the TiO2/dye/electrolyte interface. So, the intensity of incident light is crucial in determining the overall efficiency of the devices. Here, transparent DSSC exhibiting an average light transmittance of 53% and high energy conversion efficiency (5.93%) is fabricated. A low solar concentrator with 3X optical concentration is coupled with the device to improve the photovoltaic performance without affecting its transparency. The internal resistances of the fabricated transparent DSSCs with and without the low solar concentrator are analysed using impedance spectroscopy. The results indicate that the charge transfer resistance at the TiO2/dye/electrolyte interface of concentrator coupled devices are lower than the bare devices. Moreover, the device active area is scaled up and charge transport properties are compared with a low concentrator coupled device. The overall results show that the concentrator coupled device performs better than the scaled-up device