Science News: 2021 Nat. Energy (IF 60.858), SAM applied to C-PSC back electrode. A solution for traditional metal back electrode degradation?

　　Perovskite solar cells (PSCs) have so far been certified with a high power conversion efficiency of 25.5%, but the issue of their stability remains a major obstacle for the large-scale application of PSCs. In addition, Ag or Au back electrodes widely used in traditional perovskites are the main source of deterioration of battery performance. Studies have confirmed that carbon-based replacement of metal back electrodes is a good strategy. Carbon-based perovskite solar cells (C-PSCs) are stable and cost-effective photovoltaic materials. However, the power conversion efficiency (PCE) of C-PSCs is relatively low due to the severe energy loss associated with the electrodes.

　　The journal Nature Energy (IF 60.858) published the research results of Michael Grätzel et al. at EPFL in December 2021. In this study, the research team applied single-atom materials (SAMs) to the back electrodes of carbon-based perovskite solar cells (C-PSCs). The Ti₁-rGO consisted of a single titanium (Ti) adatom immobilized on reduced graphene oxide (rGO). With a well-defined Ti₁O₄-OH configuration, the adatom was capable of tuning the electronic properties of rGO.

　　Through theoretical calculations combined with an advanced modular cell architecture, the research team finally achieved a carbon-based perovskite solar cell (C-PSC) with a steady-state PCE of up to 20.6%. This value is currently the highest among low-cost carbon electrode perovskite solar cells. In addition, the unencapsulated device retained 98% and 95% of its initial value for 1,300 hours at 25°C and 60°C under 1 standard sunlight exposure through a sun simulator, respectively.