Exploring the Charge Dynamics and Energy Loss in Printable Mesoscopic Perovskite Solar Cells

Printable mesoscopic perovskite solar cells (p-MPSCs) show great potential for commercialization, but little research has been devoted to understanding the dynamics of photogenerated carriers in this type of cell, limiting their further performance improvements. Herein, two techniques with complementary time scales were used, namely transient absorption spectroscopy (TAS) and time-resolved photoluminescence spectroscopy (TRPL), to quantify the processes of carrier recombination, diffusion, and extraction in p-MPSCs. It is found that the carrier diffusion in mesoscopic samples should not be neglected at the time scale monitored by TRPL, and thus the diffusion-recombination model is more suitable compared to the simplified carrier recombination model usually used in interpreting the data of TAS and TRPL. As a result, the calculated carrier diffusion length within the perovskite filled in the mesoscopic scaffold is up to 5.48 mu m. This also demonstrates that the hole transport layer is not necessary for p-MPSCs. In addition, the relationship between the maximum quasi-Fermi energy level splitting and the bulk recombination coefficient within perovskite is determined through calculations. This study takes an important step toward establishing the relationship between the mesoscopic structure, carrier dynamics, and device performance of p-MPSCs.

Automated summary

This study uses transient absorption spectroscopy and time-resolved photoluminescence spectroscopy to quantify the processes of carrier recombination, diffusion, and extraction in p-MPSCs, revealing the importance of carrier diffusion in mesoscopic samples and establishing a new diffusion-recombination model for interpreting data.