Defects in Hybrid Perovskites: The Secret of Efficient Charge Transport. (1st September 2021)

• Record Type: Journal Article
• Authors: Musiienko, Artem; Ceratti, Davide Raffaele; Pipek, Jindřich; Brynza, Mykola; Elhadidy, Hassan; Belas, Eduard; Betušiak, Marián; Delport, Geraud; Praus, Petr
• Is Part Of: Advanced functional materials. Volume 31:Number 48(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-09-01
• Subjects: charge transport -- defects -- halide perovskites -- nature of defects -- perovskites -- perovskites stability -- solar cells; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202104467
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: The interaction of free carriers with defects and some critical defect properties are still unclear in methylammonium lead halide perovskites (MHPs). Here, a multi‐method approach is used to quantify and characterize defects in single crystal MAPbI3, giving a cross‐checked overview of their properties. Time of flight current waveform spectroscopy reveals the interaction of carriers with five shallow and deep defects. Photo‐Hall and thermoelectric effect spectroscopy assess the defect density, cross‐section, and relative (to the valence band) energy. The detailed reconstruction of free carrier relaxation through Monte Carlo simulation allows for quantifying the lifetime, mobility, and diffusion length of holes and electrons separately. Here, it is demonstrated that the dominant part of defects releases free carriers after trapping; this happens without non‐radiative recombination with consequent positive effects on the photoconversion and charge transport properties. On the other hand, shallow traps decrease drift mobility sensibly. The results are the key for the optimization of the charge transport properties and defects in MHP and contribute to the research aiming to improve perovskite stability. This study paves the way for doping and defect control, enhancing the scalability of perovskite devices with large diffusion lengths and lifetimes. Abstract : Time of flight currents shed light on the interaction of free electrons and holes with defects in MAPbI3 perovskite. Reconstruction of carrier transport dynamics reveals the effect of defects on diffusion length, lifetime, and mobility. Photo‐Hall and thermoelectric spectroscopies assess parameters of defects. Advanced characterization of charge transport and defects can stimulate new device architectures and material modification pathways.