Interfacial Treatment by 1,4-Phenyldiammonium Diiodide to Significantly Improve the Performance of Carbon-Based CsPbI₂Br Solar Cells

Abstract

Herein, a facile treatment to the interface of the CsPbI 2 Br layer and the carbon electrode using 1,4-phenyldiammonium diiodide (PhDADI) is reported for significantly improving the power conversion efficiency (PCE) of the corresponding CsPbI 2 Br solar cells based on a carbon electrode without a hole transport material. Owing to the positive contribution of the PhDADI treatment including the reduced defect density, improved crystallinity, and decreased surface roughness of CsPbI 2 Br, all key device parameters such as the open-circuit voltage, short-circuit current density, and fill factor are improved, thus leading to the PCE promotion from 11.80% for the control device without the PhDADI modification to 14.20%. Moreover, the stability test indicates that the PhDADI-modified device has the superior stability to the control device without PhDADI.