Transparent electrodes, material systems that transmit light and conduct electricity simultaneously, are essential in several optoelectronic devices, such as solar cells, touch screens, light emitting diodes, smart windows and displays. Typical transparent electrodes applied in solar cells are transparent conductive oxides (TCO). To avoid solar cell efficiency losses, this TCO should guarantee unhindered current flow out of a large device area and efficient light in-coupling (in the UV-Vis-NIR spectral range). This is a challenge, as there is always a trade-off between transparency and conductivity.
Figure 1. Scanning electron micrograph of a In2O3 film used as front contact in solar cells. Bottom: Band structure representation of a typical TCO. Ref.(1).
Another challenge is the fabrication. Sputtering deposition is widely used, but it has the drawback of inducing damage on the substrate or device during film growth. Damage during the electrode deposition in solar cells, will result in low solar power conversion efficiencies. This motivates the search for gentle, soft-landing TCO deposition techniques that will ensure the formation of high-quality films without damaging the devices.
In this context, various BSc and MSc projects are available to explore pulsed-laser deposition (PLD) as an alternative technique for low-damage fabrication of transparent electrodes for solar cells.
Other projects are also possible, such as the development of Earth-abundant electrodes by PLD, or solution process of n- and p-type contacts for solar cells. For more information on the projects contact Monica Morales (firstname.lastname@example.org).
(1) M. Morales-Masis et al. Adv. Electron. Mater. Vol. 3 (2017)