enhanced activity both under λ > 420 nm and λ > 475 nm light irradiation and to long-term stability. The H 2 production rate of BP/g-C 3 N 4 (384.17 µmol g −1 h −1 ) is comparable to, and even surpasses that of the previously reported, precious metal-loaded photocatalyst under λ > 420 nm light. The efficient charge transfer between BP and g-C 3 N 4 (likely due to formed NP bonds) and broadened photon absorption (supported both experimentally and theoretically) contribute to the excellent photocatalytic performance. The possible mechanisms of H 2 evolution under various forms of light irradiation is unveiled. This work presents a novel, facile method to prepare 2D nanomaterials and provides a successful paradigm for the design of metal-free photocatalysts with improved chargecarrier dynamics for renewable energy conversion. solar fuel technology. For acquiring the above listed beneficial features, visible light-responsive graphitic carbon nitride (g-C 3 N 4 ), a 2D metal-free photocatalyst, has been extensively explored in photocatalysis. Though g-C 3 N 4 was discovered to be feasible for photocatalytic water splitting, obtaining a relatively high efficiency of H 2 production still largely relies on the loading of noble metal cocatalysts because of the high recombination rate of the charge carriers in g-C 3 N 4 . [2] Furthermore, the relatively wide bandgap (2.7 eV) confines its light response mainly into the ultraviolet (UV) range and only slightly into a narrow region of the visible light range (λ < 460 nm). [3] To solve these problems, numerous strategies have been developed, mainly including morphology tuning, doping with metal/nonmetal ions, and heterojunction creation. [4] However, quite limited progresses have been achieved thus far. Aiming to enhance the harvesting of solar light efficiently and economically, the development of novel g-C 3 N 4 -based metal-free photocatalysts with a broader photoresponse range is of great significance.Black phosphorus (BP), a layered material that consists of corrugated atomic planes with strong intralayer chemical bonding and weak interlayer van der Waals interactions, has attracted tremendous interest of material scientists. Since the PhotocatalysisThe ORCID identification number(s) for the author(s) of this article can be found under https://doi.

Two-dimensional perovskites are an attractive alternative to 3D perovskites for solar cell application as they directly address a critical issue of stability of 3D perovskite solar cells, while achieving similarly high power conversion efficiencies.

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Abstract:The unique optical properties possessed by plasmonic noble metal nanostructures in consequence of localized surface plasmon resonance (LSPR) are useful in diverse applications like photovoltaics, sensing, nonlinear optics, hydrogen generation, and photocatalytic pollutant degradation. The incorporation of plasmonic metal nanostructures into solar cells provides enhancement in light absorption and scattering cross-section (via LSPR), tunability of light absorption profile especially in the visible region of the solar spectrum, and more efficient charge carrier separation, hence maximizing the photovoltaic efficiency. This review discusses about the recent development of different plasmonic metal nanostructures, mainly based on Au or Ag, and their applications in promising third-generation solar cells such as dye-sensitized solar cells, quantum dot-based solar cells, and perovskite solar cells.

Three‐dimensional (3D) perovskite solar cells are prone to degradation in the presence of moisture, heat, and light. Recently, two‐dimensional (2D) perovskites are synthesized by isolating metal halide perovskite layers using aliphatic or aromatic alkylammonium spacer cation, which can retain their performance under ambient humidity levels due to the hydrophobic property of the spacer cation. However, the best 2D perovskite thus far, using aliphatic short butylammonium (BA) cation as spacer cation, shows only a modest tolerance against moisture and heat due to the inferior hydrophobicity as well as the relatively smaller size of the BA cation. Here, a bulkier aromatic phenylethylammonium (PEA) used as a spacer cation to synthesis 2D perovksite in order to achieve highly stable solar cells. By modifying the crystallization process, an average power conversion efficiency (PCE) of 5.50% is achieved, which is the highest reported PCE for aromatic alkylammonium‐based lower dimensional perovskite solar cells. Importantly, unencapsulated (PEA)2(MA)3Pb4I13 devices show enhanced moisture stability compared to other reported perovskite solar cells in harsh moisture environment (72 ± 2% relative humidity). Moreover, the use of organic materials in p‐i‐n type device, instead of metal oxides, as electron and hole extraction layers also paves the way toward constructing flexible perovskite solar cells.

Direct conversion X-ray detectors operate by directly converting X-ray photons into an electrical signal, while indirect conversion detectors (also called scintillators) first convert X-ray photons to visible light. Subsequently, this light is converted to an electrical signal using visible light detectors. Direct conversion detectors are simpler in configuration and offer higher spatial resolution than scintillators. [2] Among traditional semiconductors, amorphous selenium (a-Se), [3] and Cd 1−x Zn x Te (CZT, x < 20%)-based materials [4] dominate the market of commercial X-ray detectors. a-Se has a low device dark current and stable device performance; however, it possesses low X-ray absorptivity. On the other hand, CZT offers excellent absorptivity, but requires high-temperature processing conditions (>900 °C), [5] and suffers from structural imperfections [5,6] and compositional inhomogeneity. [6,7] These limitations demand the development of novel semiconductors for direct X-ray detectors.Solution-processed metal halide perovskites have recently emerged as a family of unique semiconductors for X-ray detectors. [2b,8] Due to their elemental constitution of heavy atoms such as lead and iodine, metal halide perovskites have a high X-ray attenuation coefficient. [2b,8b,9] However, conventional perovskites suffer from long-term instability, and high dark current (determines noise level). [10] Early diagnoses of diseases requires high spatial resolution, which is measured by recording the resolving power of a line-pair (lp) phantom. [11] For radiology, a minimum spatial resolution of 5.7 lp mm −1 is required for adequate resolution of small objects. [12] Imaging becomes more challenging when it comes to mammographic applications, where a resolution of 10 lp mm −1 is needed to resolve small microcalcifications. [13] Unfortunately, conventional direct conversion X-ray detectors have low resolution as they are integrated into transistor arrays with limited pixel dimensions. [14] Here we report a strategy to grow aligned orthorhombic δ-CsPbI 3 microwires offering one of the highest X-ray absorption coefficients. The crystals show a record-low dark current density of 12 pA mm −2 under 600 V mm −1 electric field. A Schottky junction with δ-CsPbI 3 is able to sense dose rates as low as 33.3 nGy air s −1 . We also show an X-ray spatial resolution of ≈12.4 lp mm −1 , which is one of the highest values reported to date (Table S1, Supporting Information). The fabricated X-ray detectors are used widely, but they suffer from short operational stability and insufficient absorptivity of X-ray photons. Here, a strategy for roomtemperature, solution-grown δ-CsPbI 3 monocrystalline microwires exhibiting one of the highest linear X-ray absorption coefficients among known semiconductors is reported. In a metal-semiconductor-metal architecture, δ-CsPbI 3 demonstrates one of the lowest detectable X-ray dose rates at 33.3 nGy air s −1 , enabled by its exceptionally low dark current density of 12 pA mm −2 . The detector remains stab...

The performance of perovskite solar cells (PSCs) has seen rapid growth in the last decade due to the meticulous optimization of device fabrication procedures and material compositions. Most reports focus on device fabrication protocols in an inert atmosphere. Only a few offer reproducible methods to fabricate PSCs in ambient air, and even fewer report the stable maximum power point (MPP) operation of devices. This methods/ protocol article presents detailed protocols for fabricating 20% milestone PSCs in ambient air and their encapsulation toward a stable 500+ h MPP operation. We also developed a simple encapsulation testing protocol: we found that if an encapsulated device withstands 120 °C heat stress for 5 min in ambient air, it likely withstands long-term MPP conditions.

Multijunction tandem solar cells offer a promising route to surpass the efficiency limit of single-junction solar cells. All-perovskite tandem solar cells are particularly attractive due to their high power conversion efficiency, now reaching 28% despite being made with relatively easy fabrication methods. In this review, we summarize the progress in all-perovskite tandem solar cells. We then discuss the scientific and engineering challenges associated with both absorbers and functional layers and offer strategies for improving the efficiency and stability of all-perovskite tandem solar cells from the perspective of chemistry.