Bismuth (Bi) based solar cells have recently attracted significant attention in line with lead-free perovskite solar cells development. In this study, 2-aminothiazolium iodide (ATI) is used to prepare highly crystalline...

Thin film ceramics and semiconductors play an important role in energy- and environment- related areas such as photovoltaics, energy storage and water purification. The morphology and structure of materials significantly...

Indoor light-energy-harvesting solar cells have long-standing history with perovskite solar cells (PSCs) recently emerging as potential candidates with high power conversion efficiencies (PCEs). However, almost all of the reported studies on indoor light-harvesting solar cells utilize white light in the visible wavelength. Low wavelength near-ultraviolet (UV) lights used under indoor environments are not given attention despite their high photon energy. In this study, perovskite solar cells have been investigated for the first time for harvesting energy from a commercially available near-UV (UV-A) indoor LED light (395–400 nm). Also called black lights, these near-UV lights are commonly used for decoration (e.g., in bars, pubs, aquariums, parties, clubs, body art studios, neon lights, and Christmas and Halloween decorations). The optimized perovskite solar cells with the n–i–p architecture using the CH3NH3PbI3 absorber were fabricated and characterized under different illumination intensities of near-UV indoor LEDs. The champion devices delivered a PCE and power output of 20.63% and 775.86 μW/cm2, respectively, when measured under UV illumination of 3.76 mW/cm2. The devices retained 84.10% of their initial PCE when aged under near-UV light for 24 h. The effects of UV exposure on the device performance have been comprehensively characterized. Furthermore, UV-stable solar cells fabricated with a modified electron transport layer retained 95.53% of its initial PCE after 24 h UV exposure. The champion devices delivered enhanced PCE and power output of 26.19% and 991.21 μW/cm2, respectively, when measured under UV illumination of 3.76 mW/cm2. This work opens up a novel direction for energy harvesting from near-UV indoor light sources for applications in microwatt-powered electronics such as internet of things sensors.

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Renewable solar energy has attracted much attention and is an essential alternative energy supply to address the increasing energy demand and environmental concerns. In this aspect, photovoltaic (PV) technology is a good candidate for utilization of solar energy. One of the promising emerging PV technologies is dye-sensitized solar cells (DSSCs), where dye molecules, socalled photosensitizers, are used as the light absorber. In this regard, dyes can be considered among the most important components in DSSCs. The very first dyes used for high-performance DSSCs were based on Ru-polypyridyl complexes. [1][2][3][4] However, they usually show relatively low extinction coefficient and involve difficult synthesis and purification steps. [5] Thus, a new group of dyes called metal-free organic dyes subsequently emerged for DSSC applications. The organic dyes provide high extinction coefficient and flexibility in design and tuning of their electronic properties. [6] The structures of organic dyes are usually based on the state-of-the-art donor-π-acceptor (D-π-A) design. Unlike Ru-polypyridyl complexes whose excitation process is based on metal-to-ligand charge transfer (MLCT), the relevant electronic transition upon photoexcitation in the organic dyes is intramolecular charge transfer (ICT). [7] The electron density moves from the donor part to the acceptor part, leading to efficient charge separation.A great deal of research in DSSCs has focused on the dye design and modification to tune the dye properties. In general, the structures of organic dyes usually contain a large extended conjugated system from the donor and π-spacer units to give broad and intense spectral absorption in visible light. The molecular design for the organic dyes normally relies on linking conjugated units via C─C or C─N bond formation. The reactions involved inevitably are Pd cross-coupling reactions, such as the Suzuki-Miyaura, Stille, and Buchwald-Hartwig reactions. These reactions involve the use of Pd-based catalysts including a specific coupling partner, for example, organoborons for the Suzuki-Miyaura reaction and organostannanes for the Stille reaction. Notwithstanding their versatility, the Pd catalysts are normally expensive as Pd is a rare metal and they need additional ligands added to perform the catalysis. The high cost of the catalysts can increase the total cost of dye synthesis, making the dyes more expensive. Moreover, some starting materials, such as organostannanes, cause toxicity concerns and possible tin contamination in the products. [8] The organostannanes have been acknowledged to cause toxicity to a range of neurological and liver systems. [9] Therefore, more sustainable alternative reactions must be sought to address the toxicity concerns and lower the cost of dye production. One of the promising alternative reactions is the Wittig or Horner-Wadsworth-Emmons (HWE) reaction.As mentioned earlier, the organic dye architecture is based on D-π-A design and the modification of the dye structure is normally carried out by changi...