Enhancing the Optoelectronic Performance of Perovskite Solar Cells via a Textured CH₃NH₃PbI₃ Morphology

Abstract

Perovskite-based solar cells are generally assembled as planar structures comprising a fl at organoammonium metal halide perovskite layer, or mesoscopic structures employing a mesoporous metal-oxide scaffold into which the perovskite material is infi ltrated. To present, little attention has been directed toward the texturing of the perovskite material itself. Herein, a textured CH 3 NH 3 PbI 3 morphology formed through a thin mesoporous TiO 2 seeding layer and a gas-assisted crystallization method is reported. The textured morphology comprises a multitiered nanostructure, which allows for signifi cant improvements in the light harvesting and charge extraction performance of the solar cells. Due to these improvements, average shortcircuit current densities for a batch of 28 devices are in excess of 22 mA cm −2 , and the maximum recorded power conversion effi ciency is 16.3%. The performance gains concomitant with this textured CH 3 NH 3 PbI 3 morphology provide further insights into how control of the perovskite microstructure can be used to enhance the cell performance.

Structure of Organometal Halide Perovskite Films as Determined with Grazing‐Incidence X‐Ray Scattering Methods

“…[39] While these defects were detrimental for photovoltaic performance in the presented study, films with controlled multitiered surface nanostructures can improve interfacial charge carrier extraction. [40] The first GISAXS investigation on hybrid perovskite films has been conducted by Schlipf et al for a similar 2-step fabrication method (though with lower MAI concentration): [13] It comprises the deposition of a PbI 2 precursor layer from solution by spin-coating at an elevated temperature of 60 °C and the subsequent conversion to perovskite by dipping the crystalline precursor film into a solution containing a mixture of MAI and MACl. This method, developed by Docampo et al, was one of the first successful realizations of the planar PSC architecture.…”

Directing nucleation and growth kinetics in solution-processed hybrid perovskite thin-films

“…The two most widely adopted microstructures are the planar and mesoscopic morphologies. Non-conventional textured perovskite structures have been demonstrated by both one-step [20] and two-step [21] methods, and have been shown to exhibit enhanced light absorption and charge-extraction properties. Yet, one of the most important connections between the perovskite microstructure and the optoelectronic performance is arguably related to the perovskite grain size and charge transport/recombination kinetics.…”

Multi-Scale-Porosity TiO2 scaffolds grown by innovative sputtering methods for high throughput hybrid photovoltaics

“…Using DSC technologies, the light-to-current conversion efficiency was raised up to 13%17. More recently, hybrid solar cells replacing the dye with hybrid Perovskites (PSC) materials1819202122 as sensitizer allowed getting efficiency values as high as 22.1% using advanced mixed perovskites2324. In the standard scheme of the photo-anode of a DSC4 or PSC18, a mesoporous thin film of nanosized TiO 2 crystals is deposited on a Transparent Conductive Oxide (TCO), annealed for grains sintering and anatase crystallization (typically at 500 °C), and subsequently imbued with a photoactive dye2526272829 or infiltrated with perovskite30.…”