Sodium doping of solution‐processed amine‐thiol based CIGS solar cells by thermal evaporation of NaCl

Poor crystallinity, high degree of porosity and rough surfaces are the main drawbacks solution-processed CIGS absorbers resulting in lower power conversion efficiencies when compared to vacuum-based solar cells. Therefore, promoting absorber grain growth is key further improve solution-based cell performance. The effect alkali elements such as Na generally recognised have beneficial effects not only on opto-electronic properties but also growth. In this work, thermal evaporation a thin layer NaCl prior selenisation resulted with significantly larger grains than previously seen diffusing directly from soda-lime glass substrate. non-toxic, abundant readily available compound that has been typically used an source, rather additive into precursor solution. these devices was primarily observed spectacular morphological changes leading improved carrier collection minority lifetimes, less doping. Transmission electron microscopy (TEM) revealed voids forming around large upon addition had negative inter-grain transport. Nonetheless, device performance doubled 5% 10% using doping approach; however, compromise between optimum electronic be made. This study demonstrates novel, simple effective Na-doping strategy for reveals current limitations atmospherically deposited