MAPbCl₃ Light Absorber for Highest Voltage Perovskite Solar Cells

Abstract

Perovskite solar cells (PSCs) excel in achieving high open-circuit voltages (V OC ) for narrow bandgaps (∼1.6 eV) but face challenges with wide-bandgap perovskites, like methylammonium lead trichloride (MAPbCl 3 ) with a 3.03 eV bandgap. These materials are transparent in visible absorbing ultraviolet (UV) light. However, achieving uniform film crystallization remains a hurdle. Here, we enhance MAPbCl 3 crystallization by manipulating annealing atmospheres (nitrogen, air, and MACl vapor). Excess MACl vapor improves surface coverage, which is crucial for film stability. We demonstrate that the microstructure of the perovskite film, including surface morphology, grain boundaries, and interfaces, can affect the photovoltaic properties. The subsequently obtained V OC of 1.78 V is the highest recorded for singlejunction PSCs to the best of our knowledge. Surprisingly, the conventional holetransport layer spiro-OMeTAD, optimized for narrow bandgaps, sustains such high voltages. Photoluminescence measurements reveal a trap-assisted recombination peak at 1.65 eV, indicating deep traps as significant to voltage loss in MAPbCl 3 .

The Effect of Cesium Incorporation on the Vibrational and Elastic Properties of Methylammonium Lead Chloride Perovskite Single Crystals

“…Furthermore, Zia et al developed perovskite solar cells (PSCs) that were annealed in a MACl vapor atmosphere, which demonstrated superior performance compared to those that were annealed in nitrogen and air atmospheres. PSCs treated with MACl vapor exhibited the highest open-circuit voltage (V oc ) of 1.78 V with consistent short-circuit current density (J sc ), fill factors (FFs), and PCE values of 0.87% [ 11 ]. Nevertheless, despite the exceptional attributes of the pure perovskite compounds MAPbX 3 , FAPbX 3, and CsPbX 3 (X = Br, Cl or I), challenges remain in ensuring the moisture and thermal stability critical to prolonging the lifetime of perovskite photovoltaic devices [ 12 , 13 ].…”

Defect Engineering and Emission Tuning of Wide-Bandgap MAPbCl3 Perovskite

“…In parallel, lead-chloride perovskites with wide bandgap are promising candidates in applications such as visible-blind UV photodetection. − Due to shorter Pb-halide bond lengths and wider band gaps, transition energy levels of defects in lead-chloride perovskites shift deeper into the bandgap, and the established defect tolerance of lead-bromide and iodide perovskites is not preserved anymore. , The deep defects of lead-chloride perovskites not only increase the nonradiative recombination rates but also introduce extra radiative recombination channels which often give rise to sub-bandgap emission features. For instance, all-inorganic CsPbCl 3 single crystal was found to exhibit an additional minor emission peak near its main emission peak. , Similarly, organic–inorganic MAPbCl 3 single crystal displayed additional emissions near − or far apart from its intrinsic peak. The emergence of sub-bandgap emissions provides an avenue for studying the defect property and carrier recombination dynamics through optical spectroscopy.…”