Johann Bouclé

Reducing surface and bulk defect densities is a key process to achieve high performance perovskite solar cells (PSCs). However, simultaneously enhancing interfacial losses and minimizing non-radiative recombination remains a critical challenge. In this study, we present a detailed investigation into an interfacial engineering strategy aimed at optimizing device performance through improved charge extraction and defect passivation. This approach involves integrating TiO2/graphene nanoplatelets (GNP) nanocomposites synthesized in a single step by laser pyrolysis as electron transport layers (ETLs) in mesoporous PSCs. The introduction of GNP improves the interfacial properties of the ETL, thereby facilitating charge collection. Simultaneously, the perovskite layer is passivated using n-octylammonium iodide (OAI) to minimize surface trap states and promote high crystalline films. The synergistic effect of GNP-modified TiO2 and OAI surface passivation improves film quality, minimizes voltage losses and reduces recombination at the interfaces. Consequently, the optimized device exhibits substantial improvements in open-circuit voltage (up to 1.06 V), fill factor (up to 68%), and overall device efficiency achieving 18.6%. Our findings highlight the potential of combined interface engineering as a promising approach to achieve high performance devices.

Chloride-based additive engineering has become nearly indispensable in the development of high-efficiency perovskite solar cells (PSCs), with the majority of record-setting devices achieving power conversion efficiencies (PCE) exceeding 25% using methylammonium chloride (MACl) as a processing additive. However, the extreme process sensitivity and consequent irreproducibility associated with MACl incorporation are rarely addressed. Here, we systematically investigate MACl-processed FA0.9Cs0.1Pb(I0.9Br0.1)3 films and show that MACl–assisted processing can act as a double-edged strategy. Under nominally identical processing conditions, a minority of samples exhibit strong photoluminescence (PL) enhancement, whereas the majority display PL quenching despite their larger grain sizes. Using complementary techniques such as X-ray diffraction (XRD), line-profile analysis, atomic force microscopy (AFM), and time-resolved PL (TRPL), we attribute this bimodal response to compositional and structural heterogeneity, including halide-segregated domains and nonuniform microstrain that increase trap-assisted nonradiative recombination. To mitigate this instability, we replace volatile MACl with a reduced-volatility chloride additive derived from a stoichiometric MACl/PbCl2 precursor (1:1 molar ratio, hereafter MCP chloride additive). At optimal additive concentration (5 mol %), the MCP-5 yields single-phase diffraction signatures, homogenized PL, and substantially extended carrier lifetimes, increasing the average lifetime by a factor of ∼7–9 (from ∼180 ns to ∼1.3–1.6 μs). In n–i–p PSCs, MCP-5-based devices yield modest but representative efficiencies, with a best PCE of 12.03%, a ∼20% relative efficiency gain, and a 30 mV increase in open-circuit voltage compared to MACl-20-treated devices, together with reduced device-to-device variability. Short-term humidity tests on unencapsulated cells (70–75% relative humidity, 24 h) further show improved PCE retention for MCP–5 compared to MACl–20 and control devices. Overall, these results identify MACl-assisted processing-induced heterogeneity as a key source of irreproducibility and establish MCP chloride additive processing routes as a promising approach to more reproducible mixed-halide PSCs, while highlighting the need for future long-term stability studies.

Understanding the impact of the aluminum zinc oxide (AZO) seed layer thickness on zinc oxide nanowires (ZnO NWs) growth is decisive in attaining high‐quality NWs with higher transparency and without cracking issues when using flexible substrates, especially for optoelectronic applications. Therefore, herein, ZnO NWs have been grown on various thicknesses of AZO films deposited onto flexible substrates (PET, PET/ITO (60 Ω sq⁻¹) and (200 Ω sq⁻¹)) through a simple, low‐temperature hydrothermal growth process. Based on AZO layer thickness, structural, optical, morphological, and topographical properties have been systematically investigated. The results demonstrate that 1) thicker AZO films (≈250 nm) increase the crystallinity of the ZnO NWs than thinner AZO films (≈200 and 100 nm). 2) ZnO NWs on the thicker AZO films with different ITO grades (60 or 200 Ω sq⁻¹) provide an optical bandgap value of 3.24–3.27 eV and offer good transmittance (>80%) in the visible range. 3) The AZO film thickness strongly influences ZnO NWs growth, especially NWs’ average diameter and density. 4) Annealing the samples at 100 °C after NW growth is pointless. Overall, the findings demonstrate efficient tuning of the ZnO NW properties that exhibit promising potentiality for perovskite solar cells, which have also been preliminarily tested.

The massive deployment of IoT connected devices brings up different modern problems, such as radiofrequency spectrum saturation and energetic requirements. Organic photovoltaics are good candidates for indoor energy harvesting and data reception in a simultaneous lightwave information and power transfer scenario applied for IoT, at which the non-directive channel significantly contributes to the optical system performance. However, achieving the channel impulse response of diffuse links requires complex numerical approaches. This article presents the first ever OPV model used in a Monte-Carlo ray-tracing simulation, associated to theoretical and experimental validation. Finally, for the first time, an optical simulation with an OPV receiver is realized in a cubic environment, from which the received optical power and generated current distributions were obtained. Results show that the employed OPV is suited for indoor energy harvesting to supply low power IoT nodes, and with proper dedicated front-end, could manage to receive optical data in a SLIPT scenario.

Layered halide perovskites have emerged as a promising contender in solid-state lighting; however, the fabrication of perovskite light-emitting devices in laboratories usually experiences low device-to-device reproducibility since perovskite crystallization is highly sensitive to ambient conditions. Although device processing inside gloveboxes is primarily used to reduce the influence of oxygen and moisture, several extraneous variables, including thermal fluctuations in the inert atmosphere or contaminations from residual solvents, can destabilize the crystallization process and alter the properties of the emissive layers. Here, we examine typical experimental configurations used in research laboratories to deposit layered perovskite films in inert atmospheres and discuss their crucial influences on the formation of polycrystalline thin films. Our results demonstrate that fluctuations in the glovebox properties (concentrations of residual O₂ and H₂O or solvent traces), even in very short timescales, can negatively impact the consistency of the perovskite film formation, while thermal variation plays a relatively minor role in this phenomenon. Furthermore, the careful storage of chemical species inside the workstation is critical for reproducing high-quality perovskite layers. Consequently, when applying our most controlled environment for perovskite deposition, the photoluminescence lifetime of perovskite thin films shows a standard deviation of only 3%, whereas the reference set-up yields a 15% standard deviation. Regarding complete perovskite light-emitting diodes, the uncertainties in statistical luminance and EQE data are significantly reduced from 230% and 140% to 38% and 42%, respectively.

Layered halide perovskites have emerged as a promising contender in solid-state lighting thanks to their tunable bandgap, high luminescence quantum yield, and high color purity. However, the fabrication of perovskite light-emitting devices in laboratories usually experiences low de-vice-to-device reproducibility since perovskite crystallization is highly sensitive to ambient condi-tions, such as humidity and temperature. Although device processing inside gloveboxes is primarily used to reduce the influence of oxygen and moisture, several extraneous variables, including gas-eous pollution traces and thermal fluctuations in the inert atmosphere or contaminations from re-sidual solvents confined in the enclosed environment, can destabilize the crystallization process and alter the properties of the emissive layers. Here, we examine different experimental set-ups for spin-coating deposition of layered perovskites in inert atmospheres and their influences on the formation of polycrystalline thin films. Our results demonstrate that fluctuations in the glovebox properties (concentrations of residual O2 and H2O or solvent traces), even in very short timescales, can negatively impact the consistency of the perovskite film formation, while thermal variation plays a relatively minor role in this phenomenon. Furthermore, careful storage of chemical species inside the workstation is critical for reproducing high-quality perovskite layers. Consequently, when applying our most controlled environment for perovskite deposition, the photoluminescence life-time of perovskite thin films shows a standard deviation of only 3%, whereas the reference set-up yields a 15% standard deviation. Regarding complete perovskite light-emitting diodes, the uncer-tainties in statistical luminance and EQE data are significantly reduced from 230% and 140% to 38% and 42%, respectively.