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Multimodal x-ray microscopy is key to assessing the property-functionality relationships of semiconductor devices with the utmost sensitivity and spatial resolution. Here, we report on a novel setup—the “Analyzer of X-ray excited Optical Luminescence Offering Temporal and spectraL resolution” (AXOLOTL)—and demonstrate its use by investigating a series of triple-cation mixed-halide perovskite solar cells (PSCs) with varying Cs content. These PSCs exhibit spatially varying performance and are thus ideally probed by multimodal x-ray microscopy to elucidate the origin of the performance variations. Specifically, our nanoscale characterization of the wrinkled perovskite photoabsorber unveils a segregation of I and Br, which is accompanied by a narrowed band gap and an increased charge-carrier lifetime in thick absorber areas. Overall, we demonstrate with this technique the spatial correlation of compositional inhomogeneities, topography, electrical performance, and optical performance, which is of highest interest for identifying loss mechanisms at the nanoscale in high-performance electronic device development, including solar cells.

Metal-halide perovskite based tandem solar cells are appealing but making a high efficiency device is not trivial. Here Chen et al. increase the carrier collection in the perovskite layer and largely enhance the efficiency in tandem cells when combined with colloidal quantum dot or silicon layers.

Light-ray tracing (RT) and the transfer matrix method (TMM) allow detailed optical simulation of single-junction silicon and perovskite solar cells, which critically aids device design towards record performance. However, their accuracy is compromised when simulating monolithic perovskite/silicon tandem devices built from textured silicon substrates, due to the resulting complex top-cell morphologies. The associated front surfaces of such tandem devices are typically either roughly conformal to the textured silicon underneath (for thermally evaporated or hybrid-deposited perovskites) or flattened (for solution-processed perovskites). Here, we develop accurate optical models for each configuration. For the conformal-like morphology, we apply a texture-on-texture model to accommodate for local imperfect conformalities. Contrastingly, for the flattened morphology, we develop a multi-subcell model to solve the limitation that films must be conformal in one-step RT + TMM simulations. We verify our models with experimental light absorption and quantum efficiency data for photovoltaic cells and modules in both morphological configurations and identify primary sources of parasitic light absorption. Finally, we extend our simulations to module-scale optics and find that textured module glass can effectively suppress photon escape for both tandem-device morphologies, improving their module performance.

Slot‐die coating is highly promising for scaled deposition of metal halide perovskite thin films. However, the power conversion efficiencies (PCEs) of slot‐die‐prepared perovskite solar cells (PSCs) still lag behind their spin‐casted counterparts. To resolve this issue, the crystal size and quality of slot‐die‐coated methylammonium lead triiodide (MAPbI3) perovskite films are dramatically improved via additive engineering using potassium thiocyanate (KSCN). The modified micrometer‐thick films have an average grain size of ≈11 μm and charge‐carrier parameters that are comparable with single‐crystal perovskites, such as a 1.89 μs lifetime, 136.65 ± 31.52 cm2 V−1 s−1 mobility, and 25.15 ± 3.55 μm diffusion length. Exploiting these enhanced properties, planar inverted PSCs with negligible hysteresis are fabricated and an average and a maximum PCE of 20.14% and 21.38%, respectively, are achieved which are among the highest reported values for slot‐die‐coated PSCs. Notably, our devices have a narrow PCE distribution along the slot‐die coating axis, highlighting slot‐die coating's promise to fabricate large‐scale, high‐performance PSCs.

Abstract Large‐scale manufacturing of polysilicon‐based passivating contacts for high‐efficiency crystalline silicon (c‐Si) solar cells demands simple fabrication of thermally stable SiOx films with well controlled microstructure and nanoscale thickness to enable quantum‐mechanical tunneling. Here, plasma‐dissociated CO2 is investigated to grow in situ thin (

We have fabricated CH3NH3PbI3−xClx perovskite thin films crystallized in situ on substrates of different natures (e.g., porosity, wettability) and investigated their photoluminescence properties. We observe that the crystallization time and thin film structure are strongly influenced by the chemical nature and porosity of the substrate. Moreover, we find that the mesoporous scaffold can tune the emissive properties of the semiconducting compound both in terms of spectral region and dynamics. In particular, perovskite crystallites grown in the nanometre size porous scaffold present a shorter-living and blue-shifted emission with respect to the perovskite crystals which are free to grow without any constraints.