Carbon Nanotubes in Carbon Electrode Based Perovskite Solar Cells

Perovskite photovoltaics have emerged as a cost-effective, fast developing technology with interesting light harvesting properties allowing for impressive breakthroughs in the field photovoltaic solar energy conversion. Charge selective layers are crucial to achieving optimal performances in this kind of solar cells. This conference paper presents preliminary results exploring the potential of carbon nanotubes in improving the performance of perovskite solar cells. The optimization of the dispersion of commercially available carbon nanotubes is first examined, where acid functionalized carbon nanotubes in chlorobenzene are found to allow for a visibly better dispersion. Considering their renown charge transport properties, the potential of introducing carbon nanotubes in conventional perovskite solar cells (PSCs) is then studied. This demonstrated a visible increase in performance, highlighted by an improved fill factor and photovoltage. Though as conventional PSCs are prone to metal oxidation induced losses, carbon electrodes are introduced as an alternative. This work thus puts the perovskite/carbon interface under the spotlight as it is identified as a major loss channel in carbon electrode PSCs due to the absence of compatible hole selective layers. Accordingly, carbon nanotubes are introduced at this interface, leading to an enhanced device performance with a recorded fill factors approaching 70%.