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Perovskite solar cells (PSC) with efficiencies > 20% have only been realized with highly expensive archetype organic hole transporting materials that can impede the large-scale deployment of PSC. Here we demonstrate PSCs achieving stabilized efficiencies of 20.3% with CuSCN as hole electron extraction layer. We developed a new method for the solution deposition of compact and highly conformal CuSCN layers that afford fast carrier extraction and collection. We also show that the notorious instability of CuSCN based PSCs is not associated with the CuSCN/perovskite interface but rather originates from the CuSCN/Au contact. By introducing a thin spacer layer between CuSCN and gold layers, the PSCs retained >95% of their initial efficiency after aging for 500 h under full-sun illumination at 60 °C, and >85% of their initial efficiency after aging at 85 °C for 1000 h. Importantly, under both continuous illumination and thermal stress, CuSCN based devices surpass the stability of spiro-OMeTAD based PSCs.One Sentence Summary: A record performance displayed by operationally stable perovskite solar cells employing all-inorganic charge extraction layers was realized after introducing a simple dynamic approach for the deposition of thin and conformal CuSCN layer onto perovskite layer and a thin spacer layer between CuSCN and gold layers, which will foster their large scale deployment.The prominence of organic-inorganic perovskite solar cells (PSC) can be credited to the unprecedented advancement in the power conversion efficiencies (PCEs), realized mostly by tailoring the formation and composition of the absorber layer (1,2). Certified PCEs >20% have been obtained while retaining the electron selective TiO 2 layer and by using either spiroOMeTAD [2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9′-spirobifluorene] or a polymerbased PTTA (poly-triarylamine) as the hole-transporting material (HTM) (2,3). However, the cost of these HTMs is prohibitively high for large-scale applications and the long-term operational and thermal instability seems to be associated with the archetype organic HTMs or their ingredients (4). One of the strategies to combat the issues of cost and instability could be the use of inexpensive inorganic hole extraction layers similar to the use of TiO 2 as an electron transporting material (5). However, obtaining stable PCEs >20% with PSCs using inorganic 2 HTMs, such as NiO, CuI, Cs 2 SnI 6 , and CuSCN when subjected to light soaking under realistic operational conditions, i.e., at maximum power point and 60°C has remained a challenge (6-9).The realization of efficiencies > 20% using PSCs with inorganic HTMs remains undoubtedly a key goal to foster the large-scale deployment of PSC. Among various inorganic hole transporting materials, CuSCN is an extremely cheap, abundant p-type semiconductor, that exhibits high hole mobility, a good thermal stability and a well-aligned work function (10). The CuSCN is intrinsically p-doped and transmits light across the entire visible and near infrared spect...

Using a novel layer-by-layer approach we have deposited metal−organic open frameworks (MOFs) based on benzenetricarboxylic acid ligands and Cu(II)-ions on a COOH-terminated organic surface. The deposited layers were characterized using a number of surface analysis techniques. XRD measurements show that the MOFs deposited using this method have the same bulk structure of HKUST-1.

Preventing the degradation of metal perovskite solar cells (PSCs) by humid air poses a substantial challenge for their future deployment. We introduce here a two-dimensional (2D) A2PbI4 perovskite layer using pentafluorophenylethylammonium (FEA) as a fluoroarene cation inserted between the 3D light-harvesting perovskite film and the hole-transporting material (HTM). The perfluorinated benzene moiety confers an ultrahydrophobic character to the spacer layer, protecting the perovskite light-harvesting material from ambient moisture while mitigating ionic diffusion in the device. Unsealed 3D/2D PSCs retain 90% of their efficiency during photovoltaic operation for 1000 hours in humid air under simulated sunlight. Remarkably, the 2D layer also enhances interfacial hole extraction, suppressing nonradiative carrier recombination and enabling a power conversion efficiency (PCE) >22%, the highest reported for 3D/2D architectures. Our new approach provides water- and heat-resistant operationally stable PSCs with a record-level PCE.

We review recent developments in the area of self-assembled monolayers (SAMs) and their applications. First, we discuss issues related to the structure, the phase transitions, the phase diagram, and the growth dynamics. We explain how the internal degrees of freedom and the multiple interactions involved can lead to a fairly rich phase behaviour even for systems which are commonly considered 'simple' model systems. Then we discuss selected problems for more complex SAM-based systems, including SAMs as substrates for growth, SAMs and molecular electronics, electrochemical applications, and 'switchable' SAMs, as well as the use of SAMs for biofunctionalized surfaces and lateral structuring.