Restoring quantum dot solar cells as if ‘flattening crumpled paper’

Nanowerk  October 4, 2024
All-inorganic CsPbI3 perovskite quantum dots (PQDs) hold significant potential for next-generation photovoltaics due to their unique optoelectronic properties. Initially used long-chain ligands in PQDs synthesis stabilized the black phase but hindered charge transport when employed to solar cells, necessitating their replacement with shorter ones leading to the formation of surface defects and loss of tensile strain, resulting in the transition to the undesired orthorhombic phase and compromising PQD solar cell performance. To address these issues researchers at the Republic of Korea developed an efficient ligand-exchange process utilizing a multifaceted anchoring ligand, 2-thiophenemethylammonium iodide (ThMAI). The larger ionic size of ThMA+ compared to Cs+ facilitated the restoration of surface tensile strain in PQDs, while its thiophene and ammonium groups enabled effective passivation of surface defects. Because of these advantages the thin films exhibited improved carrier lifetime, uniform PQD orientation, and increased ambient stability, the solar cells demonstrated an improved power conversion efficiency (PCE) of 15.3 % and enhanced device stability… read more. TECHNICAL ARTICLE