Bifunctional hole-shuttle molecule for improved interfacial energy level alignment and defect passivation in perovskite solar cells

Abstract Perovskite solar cells have reached a power conversion efficiency over 25%, and the engineering of the interface between the perovskite and hole transport layer (HTL) has been crucial to achieve high performance. Here we design a bifunctional molecule CBz-PAI with carbazole-triphenylamine and phenylammonium iodide units to passivate defects at the perovskite/HTL interface. Owing to a favourable energy level alignment with the perovskite, the CBz-PAI acts as a hole shuttle between the perovskite layer and the HTL. This minimizes the difference between the quasi-Fermi level splitting of the perovskite, or ‘internal’ V oc , and the external device V oc , thus reducing voltage losses. As a result, solar…

• ÉP
  École Polytechnique Fédérale de Lausanne
• CS
  China Scholarship Council