One of the reasons for decreasing the efficiency of Sn PVK PV is the charge injection unbalance between the electron injections from the PVK to fullerenes and hole injections from the PVK to hole transporting layers. The charge unbalance causes charge accumulation in the perovskite layers and decreases the efficiency. Our project is aiming at optimizing the charge balance. Namely, the hole injection rate is equal to the electron injection rate by optimizing hole transporting layer. We have achieved 13.6 % for Pb free Sn PVK PV and 23,3% for SnPb alloyed PVK PV, whose efficiencies are top levels in each devices. In this proposal, the relationship between the molecular structures and the hole injection has to be discussed in detail. Therefore, we use self-assembled monolayers with p type characters. The design and the syntheses will be done in Lithuania side and the materials will be sent to Japan side. In Japan side, solar cells will be fabricated and these photovoltaic performances are evaluated.
Project funding:
Intergovernmental programme administrated by Research Council of Lithuania: Lithuania –Japan
Project results:
The band gap of the Sn perovskite solar cell (Sn PVK PV) is 1.2-1.4 eV and 33 % efficiency is expected from Sheckley-Qieisser limit curve. This is higher than that of Pb PVK PV which band gap is 1.6 eV and 30 % efficiency is expected. However, at the present stage, the efficiency of Sn PVK PV is from 14.6 % to 23.3 %, which is lower than that of 25.5%. The objective of this proposal is on the efficiency enhancement of Sn PVK PV, which is expected to exceed the efficiency of the Si solar cells.
Period of project implementation: 2022-04-01 - 2023-12-31
Project coordinator: Kaunas University of Technology
Project partners: The University of Electro-Communications, Kyushu Institute of Technology
