Gefitinib-Induced Interface Engineering Enhances the Defect Formation Energy for Highly Efficient and Stable Perovskite Solar Cells

TL;DR

This paper demonstrates that gefitinib modification of PEDOT:PSS and SnO2 interfaces in perovskite solar cells reduces defects, improves energy level alignment, and enhances both efficiency and stability, leading to record performance improvements.

Contribution

It introduces a novel interface engineering strategy using gefitinib to passivate defects and optimize energy levels in PSCs, significantly boosting their efficiency and stability.

Findings

Open-circuit voltage increased from 1.077V to 1.110V.

Power conversion efficiency improved from 17.01% to 19.63%.

PCE of SnO2/perovskite interface increased from 22.46% to 23.89%.

Abstract

Poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) has been widely used as a hole transport layer in perovskite solar cells (PSCs). However, the high interface defect density and energy level mismatch between PEDOT:PSS and perovskite can lead to significant open-circuit voltage loss. Additionally, the free PSS chains on the surface of PEDOT:PSS can absorb water molecules, promoting the degradation of perovskite at the PEDOT:PSS/perovskite interface. Here, gefitinib is used to modify the surface of PEDOT:PSS, removing a portion of the free PSS chains from the surface, reducing the PSS/PEDOT ratio, and enhancing the conductivity of PEDOT:PSS. Gefitinib has altered the energy level structure of PEDOT:PSS, facilitating hole transport at the interface. The Cl, F, and NH groups in gefitinib also passivated defects in the perovskite, reducing the defect density at the interface and significantly enhancing the stability of PSCs. This modification increased the open-circuit voltage from 1.077 to 1.110 V and the power conversion efficiency (PCE) from 17.01% to 19.63%. When gefitinib was used to modify the interface between SnO2 and perovskite, the PCE of PSCs (ITO/SnO2/perovskite/Spiro-OMETAD/Au) increased from 22.46% to 23.89%. This approach provides new perspectives and strategies for improving the efficiency and stability of PSCs.