Highly Stable Thin Films Based on Novel Hybrid 1D (PRSH)PbX3 Pseudo-Perovskites.

Gabriele Calabrese,Francesco Giannici,Candida Pipitone,Antonino Martorana,Norberto Masciocchi,Silvia Milita,Caterina Summonte,Luisa Barba,Diego Marini

doi:10.3390/nano11102765

Abstract

In this study, the structure and morphology, as well as time, ultraviolet radiation, and humidity stability of thin films based on newly developed 1D (PRSH)PbX3 (X = Br, I) pseudo-perovskite materials, containing 1D chains of face-sharing haloplumbate octahedra, are investigated. All films are strongly crystalline already at room temperature, and annealing does not promote further crystallization or film reorganization. The film microstructure is found to be strongly influenced by the anion type and, to a lesser extent, by the DMF/DMSO solvent volume ratio used during film deposition by spin-coating. Comparison of specular X-ray diffraction and complementary grazing incidence X-ray diffraction analysis indicates that the use of DMF/DMSO mixed solvents promotes the strengthening of a dominant 100 or 210 texturing, as compared the case of pure DMF, and that the haloplumbate chains always lie in a plane parallel to the substrate. Under specific DMF/DMSO solvent volume ratios, the prepared films are found to be highly stable in time (up to seven months under fluxing N2 and in the dark) and to highly moist conditions (up to 25 days at 78% relative humidity). Furthermore, for representative (PRSH)PbX3 films, resistance against ultraviolet exposure (λ = 380 nm) is investigated, showing complete stability after irradiation for up to 15 h at a power density of 600 mW/cm2. These results make such thin films interesting for highly stable perovskite-based (opto)electronic devices.

Highlights

Perovskites have recently emerged as the holy grail of photovoltaics, reaching in a decade of research a solar cell certified efficiency of 25.5% for a single-junction device, rivaling the performance of well-established technologies [1]
The top-view SEM images of the (PRSH)PbBr3 and (PRSH)PbI3 films (Figures 1 and 2, respectively), taken at low and high magnification, allow us to establish the morphology of the as-prepared films at different length scales, and their dependence on the solvent composition
The (PRSH)PbBr3 film prepared by using diagrams for more (DMF) as the only solvent exhibits disconnected regions (Figure 1a,e) due to the presence of cracks all over the surface, which are suppressed by adding DMSO to DMF [Figure 1b–d,f–h]

Summary

Introduction

Perovskites have recently emerged as the holy grail of photovoltaics, reaching in a decade of research a solar cell certified efficiency of 25.5% for a single-junction device, rivaling the performance of well-established technologies [1]. Despite their excellent performances [2,3,4], which have been exploited in a large number of (opto)electronic devices well beyond solar cells (such as gas sensors [5], transistors [6], thermoelectric [7] and piezoelectric [8] generators, light-emitting diodes [9], lasers [10], and photodetectors [11]), the reduced long-term stability of the large majority of inorganic and hybrid perovskites still represents the main obstacle preventing their commercialization and, their optimization is one of the main research topics in the field [12,13]. In the search for an optimized strategy, devices based on hybrid 2D/3D composites have been proposed (showing impressive results) [18,19]

Methods

Results

Conclusion