The Role of SnO2 Processing on Ionic Distribution in Double-Cation-Double Halide Perovskites

Moving toward a future of efficient, accessible, andless carbon-reliantenergy devices has been at the forefront of energy research innovationsfor the past 30 years. Metal-halide perovskite (MHP) thin films havegained significant attention due to their flexibility of device applicationsand tunable capabilities for improving power conversion efficiency.Serving as a gateway to optimize device performance, considerationmust be given to chemical synthesis processing techniques. Therefore,how does common substrate processing techniques influence the behaviorof MHP phenomena such as ion migration and strain? Here, we demonstratehow a hybrid approach of chemical bath deposition (CBD) and nanoparticleSnO(2) substrate processing significantly improves the performanceof (FAPbI(3))(0.97)(MAPbBr(3))(0.03) by reducing micro-strain in the SnO2 lattice, allowingdistribution of K+ from K-Cl treatment of substrates topassivate defects formed at the interface and produce higher currentin light and dark environments. X-ray diffraction reveals differencesin lattice strain behavior with respect to SnO2 substrateprocessing methods. Through use of conductive atomic force microscopy(c-AFM), conductivity is measured spatially with MHP morphology, showinghigher generation of current in both light and dark conditions forfilms with hybrid processing. Additionally, time-of-flight secondaryionization mass spectrometry (ToF-SIMS) observed the distributionof K+ at the perovskite/SnO2 interface, indicatingK(+) passivation of defects to improve the power conversionefficiency (PCE) and device stability. We show how understanding therole of ion distribution at the SnO2 and perovskite interfacecan help reduce the creating of defects and promote a more efficientMHP device.

Automated summary

Moving towards a future of efficient, accessible, and less carbon-reliant energy devices has been a major focus of energy research innovations for the past three decades.The use of metal-halide perovskite (MHP) thin films has garnered significant attention due to their flexible device applications and tunable capabilities to enhance power conversion efficiency. A hybrid approach of chemical bath deposition (CBD) and nanoparticle SnO2 substrate processing has been found to greatly improve the performance of (FAPbI(3))(0.97)(MAPbBr(3))(0.03) by reducing micro-strain in the SnO2 lattice and allowing for the distribution of K+ ions to passivate defects at the interface. This results in higher current generation in both light and dark environments. Understanding the ion distribution at the SnO2 and perovskite interface can effectively reduce the formation of defects and promote more efficient MHP devices.