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In order to mitigate the current global energy and environmental challenges associated with the use of fossil fuels, there is a need for better energy alternatives such as the inexhaustible solar energy. Of great interest is the design and fabrication of low-cost photovoltaic devices which are the epitome of efficient solar energy harvesting. Herein, we report inexpensive hole transport layer (HTL)-free dye-sensitized solar cell architecture with robust photovoltaic (PV) performance. In the proposed solar cell model, expensive hole transport layers, CuI, CuSCN, Spiro-OMeTAD, and PEDOT:PSS, are not required, but instead, a metallic layer is used for dye regeneration. A thorough analysis of the effect of series and shunt resistances, conduction band offset, Schottky barriers, working temperature, the metal work function of the back contact, and the electron affinities of the electron transport layers (ETLs) on the performance of the proposed solar cell is presented. The Solar Capacitance Simulator (SCAPS-1D) is used to perform the numerical simulations of the proposed solar cell design. The study focused on modeling HTL-free dye-sensitized solar cells with the configuration: FTO/ETL/N719 dye/Au. The performance of two ETLs-ZnOS and TiO 2 are critically examined. The optimized model cell performance for the FTO/ZnOS/N719 dye/Au architecture gave an optimal power conversion efficiency (PCE) of 11.54%, 62.71% as the fill factor (FF), short circuit current (Jsc) of 18.50 mAcm −2 , and an open-circuit voltage (Voc) of 0.99 V. On the other hand, the cell architecture FTO/TiO 2 / N719 dye/Au gave an optimized performance of 10.22% as the PCE, 63.58% as the FF, a Voc of 0.97 V, and 16.50 mAcm −2 as the Jsc. Based on these results, ZnOS is a suitable ETL material that has better PV performance of the solar cell device under consideration. ZnOS is earth-abundant, has a tunable band gap, is less toxic, and is, therefore, a promising candidate to replace TiO 2 ETL in future designs and manufacture of HTL-free DSSCs for commercial production.

Background Inhalation of particulate matter (PM) from cigarette smoke is hazardous to smokers and non‐smokers. This contribution simulates the deposition of cigarette PM on the lung surface by trapping tobacco smoke particulates on Croton megalocarpus biochar. This study investigated one commercial cigarette (MM) and one local cigarette (RR). Methodology Biochar was incorporated into the filters of MM and RR cigarettes in order to adsorb PM from mainstream cigarette smoke. A weighed 5 mg of biochar with adsorbed cigarette PM was analyzed using a scanning electron microscope and a Fourier transform infrared spectrometer. The size distribution of cigarette smoke particulates was processed using ImageJ software. Results At 15 s puff time, the mean particulate diameters for the commercial and the local cigarettes, respectively, can be classified as coarse ≈ PM 10 . Conversely, the mean particulate diameter at 2 s puff time for the commercial cigarette falls under the ultrafine classification of ≤PM 2.5 , whereas at the same puff time, the mean particulate diameter for the local cigarette was approximately PM 2.5 . Data from Fourier transform infrared spectroscopy indicate the PM in the two model cigarettes contains aromatic structures that feature the C=C bond characterized by an intense absorption band at δs (1600 cm −1 ). Conclusions This study found that PM in mainstream cigarette smoke depends on puff time. Although cigarette smoking was conducted for two model cigarettes, this study can be extended to any other form of cigarette. Moreover, this study emphasizes the need for comprehensive studies on real‐world cigarette smoking conditions, taking into account cigarette smokers who use larger puff volumes.