Perovskite solar cells (PSCs) have reshaped the thin-film photovoltaic technology owning to their exceptional high power conversion efficiency (PCE) in conjunction with their low-cost and facile production. PSCs are fabricated...

The peculiar ions and carriers heterogeneity observed in hybrid organic / inorganic materials is the source of their emergent cross-coupled light and electric field tuneable functions with potential utility in...

Organic–Inorganic Halide Perovskites (OIHP) have attracted tremendous research interest due to their exceptional semiconducting properties in combination with their facile, solution-based manufacturing performed at low temperatures. Their device applications cover a wide range of domains, while amongst them, photovoltaics is one of the most promising paths towards industrialization. The complex ionic character of perovskites offers a gigantic playground of new dynamic phenomena such as migration of ionic species and vacancies that are strongly coupled to electronic carriers. The interactions between ions and charge carriers are commonly tunable by electrical fields, light, and strain, opening the path for novel device concepts with emerging functionalities. Here, we study the synaptic properties of a four–cation RbCsFAMA perovskite device deployed across an inverted solar cell geometry, as an expansion of Rogdakis et al. Mater. Adv., 2022, 3, 7002 investigations. The device exhibits stable bipolar resistive switching behavior and operates in a low voltage window <  ± 1 V, with a high resistance to low resistance state ratio of up to 105. We show that our device can emulate a wide variety of synaptic functions such as paired-pulse facilitation, long-term potentiation, long-term depression, spiking-rate-dependent plasticity, and spike-timing-dependent plasticity.

Effective passivation of defects is an important step toward achieving highly efficient and stable Perovskite Solar Cells (PSCs). In this work, we introduce the incorporation of two different octylammonium based spacer cations as 2D perovskite passivation layers, namely Octylammonium Bromide (OABr) and octylammonium iodide. PSCs with OABr as a 2D passivation layer demonstrated an enhanced Power Conversion Efficiency (PCE) of 21.40% (the control device has a PCE of 20.26%), resulting in a higher open circuit voltage of 40 mV. The 2D perovskite passivation layers lead to a smoother interface and a better contact with the hole transport layer, while transient photoluminescence and transient photovoltage measurements indicated reduced non-radiative recombination. Unencapsulated devices retained almost 90% of their initial PCE after 500 h of exposure under high ambient humidity conditions, confirming that the surface passivation treatment has led to improved device stability.

Herein, an azulene–pyridine molecule (AzPy) is implemented in inverted perovskite solar cells (PSCs) for increasing the power conversion efficiency (PCE) and the stability of the devices. The first goal is achieved by depositing a thin layer of AzPy on top of the hole charge transport layer (HTL). The surface engineering of HTL with AzPy improves the perovskite layer formation, thus increasing light absorption and reducing bulk nonradiative recombination while protecting the perovskite from degradation species from the HTL. This approach increases the mean PCE by approximately 6%. The second goal of improving the stability of the devices is mainly achieved by replacing the hydrophilic bathocuproine (BCP) with the more hydrophobic AzPy. By the development of an AzPy layer over the electron transport layer (ETL), the stability of the PSCs is increased under ambient conditions and thermal or light stress, without affecting the PCE. The two proposed interface engineering approaches are both implemented in the device in conjunction with the perovskite surface treatment with n‐hexylammonium bromide, resulting in devices that deliver a PCE of 20.42% and increased thermal and light stability, thus retaining 90% of their initial PCE for more than 1200 h under ambient conditions.