Riad Nechache

Organic hole‐transporting materials (HTM) are widely used for high‐efficiency solar cells. However, compared with their inorganic counterparts, these materials are often expensive and require complex synthesis methods and the addition of costly dopants to improve their performance. In addition, exposure to the ambient environment affects the chemical stability of some organic materials as well as their device characteristics. Herein, an all‐ambient fabrication method is used to develop a CuSCN layer as an alternative to the conventional Spiro‐OMeTAD HTM. CuSCN thin films are incorporated into both solar cells and photodetectors to study their effect on the optoelectronic properties of these devices. For the solar cells made with CuSCN, a power conversion efficiency of 14.3% is achieved, with remarkable ambient‐stability without encapsulation. Regarding the photodetectors with CuSCN, high‐specific detectivity up to 10¹² Jones is exhibited. Solution‐processed devices exhibit overall impressive performances and represent an essential step toward large‐scale fabrication of efficient, stable, facile, and inexpensive perovskite‐based optoelectronic technologies.

Correction for ‘Ambient condition-processing strategy for improved air-stability and efficiency in mixed-cation perovskite solar cells’ by Ivy M. Asuo et al., Mater. Adv., 2020, DOI: 10.1039/d0ma00528b.

Fabrication of efficient halide perovskite solar cells under ambient conditions and their stability remain a challenge due to the sensitivity of halide perovskites to moisture, oxygen, light, and temperature.

Epitaxial Bi₂FeCrO₆nanoisland arrays with room-temperature multiferroic properties were fabricated by patterned SiO₂template-assisted pulsed laser deposition.

The photoelectric properties of multiferroic double-perovskite Bi2FeCrO6 (BFCO), such as above-bandgap photovoltages, switchable photocurrents and bulk photovoltaic effect, have recently been explored for potential applications in solar technology. Here we report the fabrication of photoelectrodes based on n−type ferroelectric (FE) semiconductor BFCO heterojunctions coated with p−type transparent conducting oxides (TCOs) by pulsed laser deposition, and their application for photoelectrochemical (PEC) water oxidation. The photocatalytic properties of the bare BFCO photoanodes can be improved by controlling the FE polarization state. However, the charge recombination as well as the limited charge transfer kinetics in the photoanode/electrolyte cause major energy loss and thus hinder the PEC performance. We show that this problem may be addressed by the deposition of an ultrathin p−type NiO layer on the photoanode to enhance the charge transport kinetics and reduce charge recombination at surface trapped states for increased surface band bending. A 4−fold enhancement of photocurrent density, up to 0.4 mA cm−2 (at +1.23 V vs. RHE), a best performance of stability over four hours and a high incident photon-to-current efficiency (~3.7%) were achieved under 1 sun illumination in such p-NiO/n-BFCO heterojunction photoanodes. These studies reveal the optimisation of PEC performance by polarization switching of BFCO, as well as the successful achievement of p−TCOs/n−FE heterojunction photoanodes able to sustain multiple hour-stable water oxidation.

Hybrid organic–inorganic perovskites have shown exceptional semiconducting properties and microstructural versatility for inexpensive, solution‐processable photovoltaic and optoelectronic devices. In this work, an all‐solution‐based technique in ambient environment for highly sensitive and high‐speed flexible photodetectors using high crystal quality perovskite nanowires grown on Kapton substrate is presented. At 10 V, the optimized photodetector exhibits a responsivity as high as 0.62 A W⁻¹, a maximum specific detectivity of 7.3 × 10¹² cm Hz^1/2 W⁻¹, and a rise time of 227.2 µs. It also shows remarkable photocurrent stability even beyond 5000 bending cycles. Moreover, a deposition of poly(methyl methacrylate) (PMMA) as a protective layer on the perovskite yields significantly better stability under ambient air operation: the PMMA‐protected devices are stable for over 30 days. This work demonstrates a cost‐effective fabrication technique for high‐performance flexible photodetectors and opens opportunities for research advancements in broadband and large‐scale flexible perovskite‐based optoelectronic devices.

In recent years, hybrid organic-inorganic halide perovskites have been widely studied for the low-cost fabrication of a wide range of optoelectronic devices, including impressive perovskite-based solar cells. Amongst the key factors influencing the performance of these devices, recent efforts have focused on tailoring the granularity and microstructure of the perovskite films. Albeit, a cost-effective technique allowing to carefully control their microstructure in ambient environmental conditions has not been realized. We report on a solvent-antisolvent ambient processed CH₃NH₃PbI_3−xCl_x based thin films using a simple and robust solvent engineering technique to achieve large grains (>5 µm) having excellent crystalline quality and surface coverage with very low pinhole density. Using optimized treatment (75% chlorobenzene and 25% ethanol), we achieve highly-compact perovskite films with 99.97% surface coverage to produce solar cells with power conversion efficiencies (PCEs) up-to 14.0%. In these planar solar cells, we find that the density and size of the pinholes are the dominant factors that affect their overall performances. This work provides a promising solvent treatment technique in ambient conditions and paves the way for further optimization of large area thin films and high performance perovskite solar cells.