Engineering of the interface between perovskite absorber thin films and charge transport layers has fueled the development of perovskite solar cells (PSCs) over the past decade. For p‐i‐n PSCs, the development and adoption of hole transport layers utilizing self‐assembled monolayers (SAM‐HTLs) based on carbazole functional groups with phosphonic acid anchoring groups has enabled almost lossless contacts, minimizing interfacial recombination to advance power conversion efficiency in single‐junction and tandem solar cells. However, so far these materials have been deposited exclusively via solution‐based methods. Here, for the first time, vacuum‐based evaporation of the most common carbazole‐based SAM‐HTLs (2PACz, MeO‐2PACz, and Me‐4PACz) is reported. X‐ray photoelectron spectroscopy and infrared spectroscopy demonstrate no observable chemical differences in the evaporated SAMs compared to solution‐processed counterparts. Consequently, the near lossless interfacial properties are either preserved or even slightly improved as demonstrated via photoluminescence measurements and an enhancement in open‐circuit voltage. Strikingly, applying evaporated SAM‐HTLs to complete PSCs demonstrates comparable performance to their solution‐processed counterparts. Furthermore, vacuum deposition is found to improve perovskite wetting and fabrication yield on previously non‐ideal materials (namely Me‐4PACz) and to display conformal and high‐quality coating of micrometer‐sized textured surfaces, improving the versatility of these materials without sacrificing their beneficial properties.

Monolithic two-terminal (2T) perovskite/CuInSe 2 (CIS) tandem solar cells (TSCs) combine the promise of an efficient tandem photovoltaic (PV) technology with the simplicity of an all-thin-film device architecture that is compatible with flexible and lightweight PV. In this work, we present the first-ever 2T perovskite/CIS TSC with a power conversion efficiency (PCE) approaching 25% (23.5% certified, area 0.5 cm 2 ). The relatively planar surface profile and narrow band gap (∼1.03 eV) of our CIS bottom cell allow us to exploit the optoelectronic properties and photostability of a low-Br-containing perovskite top cell as revealed by advanced characterization techniques. Current matching was attained by proper tuning of the thickness and bandgap of the perovskite, along with the optimization of an antireflective coating for improved light in-coupling. Our study sets the baseline for fabricating efficient perovskite/CIS TSCs, paving the way for future developments that might push the efficiencies to over 30%.

Vacuum‐assisted growth (VAG) control is one of the most promising methods for controlling nucleation and crystallization of printed and coated large area lead halide perovskite‐based layers for optoelectronics. To coat or print homogeneous high‐quality perovskite thin‐films at high fabrication yield, real‐time process monitoring of the VAG is pivotal. In response, a 2.1‐megapixel multichannel photoluminescence (PL) and reflection imaging system is developed and employed for the simultaneous spatial in situ analysis of drying, nucleation, and crystal growth during VAG and subsequent thermal annealing of inkjet‐printed and blade‐coated perovskite thin‐films. It is shown that the VAG process, for example, evacuation rate and time, affects the film formation and provide detailed insight into traced PL and reflection transients extracted from sub‐second videos of each channel. Based on correlative analysis between the transients and, for example, perovskite ink composition, wet‐film thickness, or evacuation time, key regions which influence crystal quality, film morphology, and are base for prediction of solar cell performance are identified.

Perovskite/silicon tandem photovoltaics have attracted enormous attention in science and technology over recent years. In order to improve the performance and stability of the technology, new materials and processes need to be investigated. However, the established sequential layer deposition methods severely limit the choice of materials and accessible device architectures. In response, a novel lamination process that increases the degree of freedom in processing the top perovskite solar cell (PSC) is proposed. The very first prototypes of laminated monolithic perovskite/silicon tandem solar cells with stable power output efficiencies of up to 20.0% are presented. Moreover, laminated single‐junction PSCs are on par with standard sequential layer deposition processed devices in the same architecture. The numerous advantages of the lamination process are highlighted, in particular the opportunities to engineer the perovskite morphology, which leads to a reduction of non‐radiative recombination losses and and an enhancement in open‐circuit voltage (Voc). Laminated PSCs exhibit improved stability by retaining their initial efficiency after 1‐year aging and show good thermal stability under prolonged illumination at 80 °C. This lamination approach enables the research of new architectures for perovskite‐based photovoltaics and paves a new route for processing monolithic tandem solar cells even with a scalable lamination process.

Light management is key to high-performance solar cells, particularly to monolithic perovskite/Si tandem solar cells and in real field applications. Random pyramidal textures of commercial Si solar cells (height ∼2–5 μm) allow for efficient light harvesting; however, solution processing of conventional perovskite thin films (thickness ∼0.5 μm) over these large textures exhibits bad coverage, resulting in shunting paths. In response to this challenge, we present high-efficiency perovskite solar cells (PSCs) processed on replicated industry-applicable random pyramidal textures with a smaller pyramid size of ∼1–2 μm. As a first step, we develop planar PSCs with close to micrometer thick perovskite absorber layers that maintain efficient charge carrier extraction by using a Lewis base additive and exhibit a power conversion efficiency of up to 18%. Employing these thick films in textured PSCs with inverted pyramids improves the light management as compared to the planar reference, with the AM 1.5G weighted reflectance being reduced from 9.9 to 5.2%. The reduced broadband reflectance in conjunction with enhanced light trapping increases the current generation by 7.7% relative, which corresponds to 87.3% of the maximum attainable short-circuit current density. In addition, we maintain a high fill factor and open-circuit voltage comparable to that of the planar reference PSC despite the increased surface area of the texture. Thereby, our champion textured PSC exhibits a stabilized power output of 18.7% at maximum power point tracking for 5 min. Finally, the textured PSCs also exhibit improved current generation for all angles of incidence, emphasizing their advantages at realistic irradiation conditions and for bifacial applications.