Perovskite solar cells (pero-SCs) have undergone rapid development in the past decade. However, there is still a lack of systematic studies investigating whether the empirical rules of working lifetime assessment used for silicon solar cells can be applied to pero-SCs. It is believed that pero-SCs show enhanced stability under day/night cycling owing to the reported self-healing effect in the dark^1,2. Here we find that the degradation of highly efficient FAPbI₃ pero-SCs is much faster under a natural day/night cycling mode, bringing into question the widely accepted approach to estimate the operational lifetime of pero-SCs based on continuous-mode testing. We reveal the key factor to be the lattice strain caused by thermal expansion and shrinking of the perovskite during operation, an effect that gradually relaxes under the continuous-illumination mode but cycles synchronously under the cycling mode^3,4. The periodic lattice strain under the cycling mode results in deep trap accumulation and chemical degradation during operation, decreasing the ion-migration potential and hence the device lifetime⁵. We introduce phenylselenenyl chloride to regulate the perovskite lattice strain during day/night cycling, achieving a certified efficiency of 26.3 per cent and a 10-fold improvement in the time required to reach 80% of peak efficiency (T₈₀) under the cycling mode after the modification.

The twisted spiro-type SAM 4PA-spiro effectively suppresses molecular aggregation and ensures appropriate energy levels, providing an efficiency of 25.28 and 21.87% for the p–i–n PSCs (0.05 cm²) and modules (29.0 cm²).

The most cost-effective electrical energy is produced by photovoltaic (PV) systems, and with the smallest carbon footprint, making it a sustainable renewable energy. They provide an excellent alternative to the existing fossil fuel-based energy systems, while providing 4% of global electricity demand. PV system efficiency is significantly reduced by the intrinsic non-linear model, maximum power point (MPP), and partial shading (PS) effects. These two problems cause major power loss. To devise the maximum power point tracking (MPPT) control of the PV system, a novel group teaching optimization algorithm (GTOA) based controller is presented, which effectively deals with the PS and complex partial shading (CPS) conditions. Four case studies were employed that included fast-changing irradiance, PS, and CPS to test the robustness of the proposed MPPT technique. The performance of the GTOA was compared with the latest bio-inspired techniques, i.e., dragon fly optimization (DFO), cuckoo search (CS), particle swarm optimization (PSO), particle swarm optimization gravitational search (PSOGS), and conventional perturb and observe (P&O). The GTOA tracked global MPP with the highest 99.9% efficiency, while maintaining the magnitude of the oscillation <0.5 W at global maxima (GM). Moreover, 13–35% faster tracking times, and 54% settling times were achieved, compared to existing techniques. Statistical analysis was carried out to validate the robustness and effectiveness of the GTOA. Comprehensive analytical and statistical analysis solidified the superior performance of the proposed GTOA based MPPT technique.

Substitutional alloying can enhance the stability and improve the optoelectronic properties of vacancy-ordered double perovskite A₂BX₆ for potential photovoltaic application.

COVID-19 is a pandemic disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This virus is mainly spread by droplets, respiratory