UV- and NIR-Protective Semitransparent Smart Windows Based on Metal Halide Solar Cells

In this study, a solution-processable lead iodide semiconductor having a wide band gap was investigated as a light absorbing material for various organic electron transport materials, in a search for low-cost semiconductor materials allowing the facile fabrication of efficient photovoltaic devices. A Tauc plot suggested a wide intrinsic optical band gap of 2.4 eV for a thin film of PbI₂, while X-ray diffraction revealed that the spin-coated PbI₂ thin film had a hexagonal crystalline structure with preferable orientation along the (001) plane. The effect of the light intensity on the values of <i>V</i>_oc and <i>J</i>_sc was studied to investigate the charge recombination mechanism of fabricated devices. An efficient bifacial solar cell was prepared featuring a thin Ag film sandwiched between BCP and MoO₃ layers as a transparent rear electrode. The whole device featuring the BCP/Ag/MoO₃ electrode exhibited a maximum transmittance of approximately 60% in the visible region, less than 15% in the UV region, and less than 25% in the NIR region. A power conversion efficiency of 2.19% was achieved for a device featuring an opaque electrode (Ca/Al), while the corresponding device featuring the transparent electrode (BCP/Ag/MoO₃) provided values of 0.75% and 0.67% when illuminated from the front and rear, respectively. Thus, wide band gap metal halide materials potentially open up a new path for fabricating efficient and transparent photovoltaic devices having applications as building-integrated smart windows. It also effectively prevents the penetration of UV and NIR light, which is harmful for human health, into the building

Photovoltaic Performance of Vapor-Assisted Solution-Processed Layer Polymorph of Cs₃Sb₂I₉

The presence of toxic lead (Pb) remains a major obstruction to the commercial application of perovskite solar cells. Although antimony (Sb)-based perovskite-like structures A₃M₂X₉ can display potentially useful photovoltaic behavior, solution-processed Sb-based perovskite-like structures usually favor the dimer phase, which has poor photovoltaic properties. In this study, we prepared a layered polymorph of Cs₃Sb₂I₉ through solution-processing and studied its photovoltaic properties. The exciton binding energy and exciton lifetime of the layer-form Cs₃Sb₂I₉ were approximately 100 meV and 6 ns, respectively. The photovoltaic properties of the layered polymorph were superior to those of the dimer polymorph. A solar cell incorporating the layer-form Cs₃Sb₂I₉ exhibited an open-circuit voltage of 0.72 V and a power conversion efficiency of 1.5%the highest reported for an all-inorganic Sb-based perovskite

Pollutant Soot for Pollutant Dye Degradation: Soluble Graphene Nanosheets for Visible Light Induced Photodegradation of Methylene Blue

The findings presented here offer a new approach for the environmental application of pollutant soot somewhat like utilizing a pollutant material for degrading the other pollutant material. Herein, a simpler approach is described for the isolation of two-dimensional graphitic materials as water-soluble graphene nanosheets (wsGNS) from the globally identified dirty–dangerous black pollutant particulate matter as black carbon (BC) from the petrol soot. The as-isolated wsGNS are further employed for the photocatalytic degradation of toxic dye such as methylene blue (MB) under the influence of visible light irradiation. The photodegradation performance of wsGNS compared to insoluble graphene nanosheets (GNS) showed ∼11 times faster degradation rate within ∼90 min of visible light exposure (60 W tungsten bulb). The insights of the aqueous phase photodegradation of MB by the system of MB-wsGNS were studied by different chemical characterization techniques including nuclear magnetic resonance spectroscopy, high-performance liquid chromatography, Raman, and fourier transform infrared spectroscopy. Furthermore, we have checked the regeneration efficiency of wsGNS, which was still at its higher value even after five cycles of recycling testing

Sunlight-Induced Selective Photocatalytic Degradation of Methylene Blue in Bacterial Culture by Pollutant Soot Derived Nontoxic Graphene Nanosheets

Herein, a potential approach is described for assessing the ecological importance of the graphitic nanocarbons isolated from dirty, dangerous black pollutant particulate material. A simple experiment of photodegradation and a toxicological test were done using the natural sunlight as a source of energy and the pollutant petrol soot derived water-soluble graphene nanosheets (wsGNS) as photocatalyst to achieve complete degradation of pollutant organic dye as methylene blue (MB). Compared to the artificial source of visible light (60W tungsten bulb), the sunlight-induced photodegradation using wsGNS show ∼1.5 times higher rate of photodegradation. The toxicological test confirmed the nontoxic behavior of wsGNS against the two different types of bacterial strains: Gram-negative and Gram-positive cells, <i>Escherichia coli</i> and <i>Staphylococcus aureus</i>, respectively. Moreover, wsGNS are precisely used for the selective photodegradation of MB without harming the bacterial growth from the pool of MB-bacterial strains. Nontoxicity and selectivity along with the improved in photodegradation efficiencies by wsGNS under the influence of sunlight are the most significant and sustainable perspectives of the present finding

Rapid Real-Time Antimicrobial Susceptibility Testing with Electrical Sensing on Plastic Microchips with Printed Electrodes

Rapid antimicrobial susceptibility testing is important for efficient and timely therapeutic decision making. Due to globally spread bacterial resistance, the efficacy of antibiotics is increasingly being impeded. Conventional antibiotic tests rely on bacterial culture, which is time-consuming and can lead to potentially inappropriate antibiotic prescription and up-front broad range of antibiotic use. There is an urgent need to develop point-of-care platform technologies to rapidly detect pathogens, identify the right antibiotics, and monitor mutations to help adjust therapy. Here, we report a biosensor for rapid (<90 min), real time, and label-free bacteria isolation from whole blood and antibiotic susceptibility testing. Target bacteria are captured on flexible plastic-based microchips with printed electrodes using antibodies (30 min), and its electrical response is monitored in the presence and absence of antibiotics over an hour of incubation time. We evaluated the microchip with <i>Escherichia coli</i> and methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) as clinical models with ampicillin, ciprofloxacin, erythromycin, daptomycin, gentamicin, and methicillin antibiotics. The results are compared with the current standard methods, i.e. bacteria viability and conventional antibiogram assays. The technology presented here has the potential to provide precise and rapid bacteria screening and guidance in clinical therapies by identifying the correct antibiotics for pathogens