Vapor Phase Infiltration Improves Thermal Stability of Organic Layers in Perovskite Solar Cells

Andrés-Felipe Castro-Méndez, Jamie P. Wooding, Selma Fairach, Carlo A. R. Perini, Emily K. McGuinness, Jacob N. Vagott, Ruipeng Li, Sanggyun Kim, Vivek Brahmatewari, Nicholas Dentice, Mark D. Losego, and Juan-Pablo Correa-Baena

ACS Energy Lett. 2023, 8, 1, 844–852

Publication Date: January 3, 2023

https://doi.org/10.1021/acsenergylett.2c02272

This study investigates the use of vapor phase infiltration (VPI) to improve the stability of organic charge transport layers, such as hole-selective spiro-OMeTAD in perovskite solar cells (PSCs) and other organic electronic devices.

By using X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and grazing incident wide-angle X-ray scattering (GIWAXS), the study identifies that infiltration of TiOx via VPI hinders the crystallization of the spiro-OMeTAD layer. The infiltrated PSCs retained over 80% of their original efficiency after an operando stability test of 200 hours at 75°C, double the efficiency retained by devices without infiltration. This study suggests VPI can be used to stabilize organic charge transport layers and prolong device lifetimes.

Device stability measurements were carried out by tracking the maximum power point (MPP) of the devices while keeping constant the temperature of the films (by Peltier pads) at 75 °C using the stability measurement platform Litos from Fluxim.