Mixed tin/lead (Sn/Pb) perovskites have the potential to achieve higher performances in single junction solar cells compared to Pb-based compounds. The best Sn/Pb based devices are fabricated in a p-i-n structure, and PEDOT:PSS is frequently utilized as the hole transport layer, even if there are many doubts on a possible detrimental role of this conductive polymer. Here, we propose the use of [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz) and [2-(3, 6-dibromo-9H-carbazol-9-yl) ethyl] phosphonic acid (Br-2PACz) as substitutes for PEDOT:PSS. By using Cs_0.25FA_0.75Sn_0.5Pb_0.5I₃ as the active layer, we obtained record efficiencies as high as 19.51% on Br-2PACz, while 18.44% and 16.33% efficiencies were obtained using 2PACz and PEDOT:PSS, respectively. In addition, the implemented monolayers enhance both the shelf lifetime of the device as well as the operational stability. Finally, the Br-2PACz-based devices maintained 80% of their initial efficiency under continuous illumination for 230 h, and after being stored in a N₂ atmosphere for 4224 h (176 days).

Recently, carbazole‐based self‐assembled monolayers (SAMs) have been utilized as hole transport layers (HTLs) in perovskite solar cells. However, their application in Sn or mixed Sn/Pb perovskite solar cells has been hindered by the poor wettability of the perovskite precursor solution on the carbazole surface. Here a self‐assembled bilayer (SAB) comprising a covalent monolayer (Br‐2PACz) and a noncovalent wetting layer (4CzNH₃I) as the HTL in a Cs_0.25FA_0.75Sn_0.5Pb_0.5I₃ perovskite solar cell is proposed. It is demonstrated that the wetting layer completely solves the problem due to the higher polarity of the surface and, furthermore, the ammonium groups help in the passivation of trap states at the buried SAB/perovskite interface. The introduction of the SAB enhances the device reproducibility with an average efficiency of 18.98 ± 0.28% (19.45% for the best device), compared to 11.54 ± 9.36% (19.34% for the best device) for the SAM‐only devices. Furthermore, the improved perovskite processability on the SAB helps to increase the reproducibility of larger size device, where, a 12.5% efficiency for a 0.8 cm² active area device compared to 0.68% for the best SAM‐based solar cell is demonstrated. Finally, the device's operational stability is also improved to 358 hours (T_80%), compared to 220 hours for the SAM‐based solar cell.

The phase‐transfer ligand exchange of PbS quantum dots (QDs) has substantially simplified device fabrication giving hope for future industrial exploitation. However, this technique when applied to QDs of large size (>4 nm) gives rise to inks with poor colloidal stability, thus hindering the development of QDs photodetectors in short‐wavelength infrared range. Here, it is demonstrated that methylammonium lead iodide ligands can provide sufficient passivation of PbS QDs of size up to 6.7 nm, enabling inks with a minimum of ten‐week shelf‐life time, as proven by optical absorption and solution‐small angle X‐ray scattering. Furthermore, the maximum linear electron mobility of 4.7 × 10⁻² cm² V⁻¹ s⁻¹ is measured in field‐effect transistors fabricated with fresh inks, while transistors fabricated with the same solution after ten‐week storage retain 74% of the average starting electron mobility, demonstrating the outstanding quality both of the fresh and aged inks. Finally, photodetectors fabricated via blade‐coating exhibit 76% external quantum efficiency at 1300 nm and 1.8 × 10¹² Jones specific detectivity, values comparable with devices fabricated using ink with lower stability and wasteful methods such as spin‐coating.

Transport layers are of outmost importance for thin‐film solar cells, determining not only their efficiency but also their stability. To bring one of these thin‐film technologies toward mass production, many factors besides efficiency and stability become important, including the ease of deposition in a scalable manner and the cost of the different material's layers. Herein, highly efficient organic solar cells (OSCs), in the inverted structure (n‐i‐p), are demonstrated by using as electron transport layer (ETL) tin oxide (SnO₂) deposited by atomic layer deposition (ALD). ALD is an industrial grade technique which can be applied at the wafer level and also in a roll‐to‐roll configuration. A champion power conversion efficiency (PCE) of 17.26% and a record fill factor (FF) of 79% are shown by PM6:L8‐BO OSCs when using ALD‐SnO₂ as ETL. These devices outperform solar cells with SnO₂ nanoparticles casted from solution (PCE 16.03%, FF 74%) and also those utilizing the more common sol–gel ZnO (PCE 16.84%, FF 77%). The outstanding results are attributed to a reduced charge carrier recombination at the interface between the ALD‐SnO₂ film and the active layer. Furthermore, a higher stability under illumination is demonstrated for the devices with ALD‐SnO₂ in comparison with those utilizing ZnO.

Using diphenyl ether as additive in an environmentally friendly fabrication process for non-fullerene acceptor organic solar cells, the nanostructure of the active layer can be fine-tuned to improve efficiency and stability of the devices.

LSPRs in Ag nanoparticles decay through a highly efficient charge injection into the 4f levels of the cerium oxide matrix.