Origin and Fundamentals of Perovskite Solar Cells

In the last few decades, the energy demand has been increased dramatically. Different forms of energy have utilized to fulfill the energy requirements. Solar energy has been proven an effective and highly efficient energy source which has the potential to fulfill the energy requirements in the future. Previously, various kind of solar cells have been developed. In 2013, organic–inorganic metal halide perovskite materials have emerged as a rising star in the field of photovoltaics. The methyl ammonium lead halide perovskite structures were employed as visible light sensitizer for the development of highly efficient perovskite solar cells (PSCs). In 2018, the highest power conversion efficiency of 23.7% was achieved for methyl ammonium lead halide based PSCs. This obtained highest power conversion efficiency makes them superior over other solar cells. The PSCs can be employed for practical uses, if their long term stability improved by utilizing some novel strategies. In this chapter, we have discussed the optoelectronic properties of the perovskite materials, construction of PSCs and recent advances in the electron transport layers for the fabrication of PSCs

Fabrication of an Azithromycin Sensor

Azithromycin (AZY) is a well-known top-prioritized antibiotic and is used by humans in strong concentrations. However, the side effects of the AZY antibiotic may cause some serious and significant damage to humans and the environment. Thus, there is a need to develop effective and sensitive sensors to monitor accurate concentrations of AZY. In the last decade, electrochemistry-based sensors have received enormous attention from the scientific community because of their high sensitivity, selectivity, cost-effectiveness, fast response, rapid detection response, simple fabrication, and working principle. It is important to mention that electrochemical sensors rely on the properties of electrode modifiers. Hence, the selection of electrode materials is of great significance when designing and developing efficient and robust electrochemical sensors. In this study, we fabricated an AZY sensor by utilizing a molybdenum disulfide/titanium aluminum carbide (MoS2@Ti3AlC2) composite as the electrode material. The MoS2@Ti3AlC2 composite was synthesized via a simple sonication process. The synthesized MoS2@Ti3AlC2 composite was characterized using a powder X-ray diffraction (XRD) method to examine the phase purity and formation of the MoS2@Ti3AlC2 composite. Scanning electron microscopy (SEM) was used to study the surface morphological features of the prepared MoS2@Ti3AlC2 composite, whereas energy dispersive X-ray spectroscopy (EDAX) was adopted to determine the elemental composition of the prepared MoS2@Ti3AlC2 composite. The glassy carbon (GC) electrode was modified with the prepared MoS2@Ti3AlC2 composite and applied as the AZY sensor. The sensing performance of the MoS2@Ti3AlC2 composite-modified GC electrode was studied using linear sweep voltammetry. The sensor demonstrated excellent performance when determining AZY and showed a good detection limit of 0.009 µM with a sensitivity of 6.77 µA/µM.cm2

Fabrication of Sulfur-Doped Reduced Graphene Oxide Modified Glassy Carbon Electrode (S@rGO/GCE) Based Acetaminophen Sensor

In the past few years, the design and fabrication of highly sensitive and selective electrochemical sensors have received enormous attention from electrochemists. Acetaminophen is an important drug that is used as an antipyretic and analgesic drug throughout the world. It is important to monitor the accurate amount of acetaminophen. Herein, we have prepared sulfur-doped reduced graphene oxide (S@rGO) using simple strategies. The morphological feature of the S@rGO was characterized by using scanning electron microscopy whereas phase purity and formation of S@rGO were authenticated by X-ray diffraction. Further, the glassy carbon electrode was modified using S@rGO as an electrode modifier and employed as an acetaminophen sensor (S@rGO/GCE). This modified sensor (S@rGO/GCE) demonstrates a reasonable detection limit of 0.07 µM and a sensitivity of 0.957 µA/µMcm2

Hydrothermal Synthesis of MnO₂/Reduced Graphene Oxide Composite for 4-Nitrophenol Sensing Applications

Recently, the electrochemical sensing approach has attracted materials/electrochemical scientists to design and develop electrode materials for the construction of electrochemical sensors for the detection of para-nitrophenol (4-NP). In the present study, we have prepared a hybrid composite of MnO2 and rGO (MnO2/rGO) using a hydrothermal approach. The morphological features of the prepared MnO2/rGO composite were studied by scanning electron microscopy, whereas the phase purity and formation of the MnO2/rGO composite were authenticated via the powder X-ray diffraction method. Energy-dispersive X-ray spectroscopy was also employed to analyze the elemental composition of the prepared MnO2/rGO composite. In further studies, a glassy carbon electrode (GCE) was modified with MnO2/rGO composite (MnO2/rGO/GCE) and explored as 4-nitrophenol (4-NP) sensor. The fabricated MnO2/rGO/GCE exhibited a reasonably good limit of detection of 0.09 µM with a sensitivity of 0.657 µA/µMcm2. The MnO2/rGO/GCE also demonstrates good selectivity, stability and repeatability in 50 cycles

Design and Fabrication of α-MnO₂-Nanorods-Modified Glassy-Carbon-Electrode-Based Serotonin Sensor

Serotonin is a very important monoamine neurotransmitter, which takes part in biological and psychological processes. In the present scenario, design and fabrication of a serotonin electrochemical sensor is of great significance. In this study, we have synthesized α-MnO2 via a hydrothermal synthesis method using potassium permanganate as a precursor. The physiochemical properties, such as structural and phase-purity of the prepared α-MnO2, were investigated by various characterization techniques and methods (powder X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy). Furthermore, the serotonin sensor was fabricated using α-MnO2 as an electrode modifier or electro-catalyst. The bare glassy carbon electrode (GCE) was adopted as a working substrate, and its active carbon surface was modified with the synthesized α-MnO2. This modified GCE (α-MnO2/GCE = MGCE) was explored as a serotonin sensor. The electrochemical investigations showed that the MGCE has excellent electro-catalytic properties towards determination of serotonin. The MGCE exhibits an excellent detection limit (DL) of 0.14 µM, along with good sensitivity of 2.41 µAµM−1 cm−2. The MGCE also demonstrated excellent selectivity for determination of serotonin in the presence of various electro-active/interfering molecules. The MGCE also exhibits good cyclic repeatability, stability, and storage stability

Hydrothermal Synthesis of MnO2/Reduced Graphene Oxide Composite for 4-Nitrophenol Sensing Applications

Recently, the electrochemical sensing approach has attracted materials/electrochemical scientists to design and develop electrode materials for the construction of electrochemical sensors for the detection of para-nitrophenol (4-NP). In the present study, we have prepared a hybrid composite of MnO2 and rGO (MnO2/rGO) using a hydrothermal approach. The morphological features of the prepared MnO2/rGO composite were studied by scanning electron microscopy, whereas the phase purity and formation of the MnO2/rGO composite were authenticated via the powder X-ray diffraction method. Energy-dispersive X-ray spectroscopy was also employed to analyze the elemental composition of the prepared MnO2/rGO composite. In further studies, a glassy carbon electrode (GCE) was modified with MnO2/rGO composite (MnO2/rGO/GCE) and explored as 4-nitrophenol (4-NP) sensor. The fabricated MnO2/rGO/GCE exhibited a reasonably good limit of detection of 0.09 µM with a sensitivity of 0.657 µA/µMcm2. The MnO2/rGO/GCE also demonstrates good selectivity, stability and repeatability in 50 cycles

Fabrication of Sulfur-Doped Reduced Graphene Oxide Modified Glassy Carbon Electrode (S@rGO/GCE) Based Acetaminophen Sensor

In the past few years, the design and fabrication of highly sensitive and selective electrochemical sensors have received enormous attention from electrochemists. Acetaminophen is an important drug that is used as an antipyretic and analgesic drug throughout the world. It is important to monitor the accurate amount of acetaminophen. Herein, we have prepared sulfur-doped reduced graphene oxide (S@rGO) using simple strategies. The morphological feature of the S@rGO was characterized by using scanning electron microscopy whereas phase purity and formation of S@rGO were authenticated by X-ray diffraction. Further, the glassy carbon electrode was modified using S@rGO as an electrode modifier and employed as an acetaminophen sensor (S@rGO/GCE). This modified sensor (S@rGO/GCE) demonstrates a reasonable detection limit of 0.07 µM and a sensitivity of 0.957 µA/µMcm2

Hydrothermally Synthesized MoS₂ as Electrochemical Catalyst for the Fabrication of Thiabendazole Electrochemical Sensor and Dye Sensitized Solar Cells

In this work we reported the hydrothermal preparation of molybdenum disulfide (MoS2). The phase purity and crystalline nature of the synthesized MoS2 were examined via the powder X-ray diffraction method. The surface morphological structure of the MoS2 was examined using scanning electron microscopy and transmission electron microscopy. The specific surface area of the MoS2 was calculated using the Brunauer-Emmett-Teller method. The elemental composition and distribution of the Mo and S elements were determined using energy-dispersive X-ray spectroscopy. The oxidation states of the Mo and S elements were studied through employing X-ray photoelectron spectroscopy. In further studies, we modified the active surface area (3 mm) of the glassy carbon (GC) electrode using MoS2 as an electrocatalyst. The MoS2 modified GC electrode (MSGC) was used as an electrochemical sensor for the detection of thiabendazole (TBZ). Linear sweep voltammetry (LSV) was used as the electrochemical sensing technique. The MSGC exhibited good performance in the detection of TBZ. A limit of detection of 0.1 µM with a sensitivity of 7.47 µA/µM.cm2 was obtained for the detection of TBZ using the LSV method. The MSGC also showed good selectivity for the detection of TBZ in the presence of various interfering compounds. The obtained results showed that MoS2 has good electrocatalytic properties. This motivated us to explore the catalytic properties of MoS2 in dye sensitized solar cells (DSSCs). Thus, we have fabricated DSSCs using MoS2 as a platinum-free counter electrode material. The MoS2 counter electrode-based DSSCs showed good power conversion efficiency of more than 5%. We believe that the present work is beneficial for the scientific community, and especially for research surrounding the design and fabrication of catalysts for electrochemical sensing and DSSC applications

Fabrication of CeO₂/GCE for Electrochemical Sensing of Hydroquinone

Hydroquinone is a widely used derivative of phenol which has a negative influence on human beings and the environment. The determination of the accurate amount of hydroquinone is of great importance. Recently, the fabrication of an electrochemical sensing device has received enormous attention. In this study, we reported on the facile synthesis of cerium dioxide (CeO2) nanoparticles (NPs). The CeO2 NPs were synthesized using cerium nitrate hexahydrate as a precursor. For determining the physicochemical properties of synthesized CeO2 NPs, various advanced techniques, viz., powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS), were studied. Further, these synthesized CeO2 NPs were used for the modification of a glassy carbon electrode (CeO2/GCE), which was utilized for the sensing of hydroquinone (HQ). A decent detection limit of 0.9 µM with a sensitivity of 0.41 µA/µM cm2 was exhibited by the modified electrode (CeO2/GCE). The CeO2/GCE also exhibited good stability, selectivity, and repeatability towards the determination of HQ

Enhanced mechanism to prioritize the cloud data privacy factors using AHP and TOPSIS: a hybrid approach

Abstract Cloud computing is a new paradigm in this new cyber era. Nowadays, most organizations are showing more reliability in this environment. The increasing reliability of the Cloud also makes it vulnerable. As vulnerability increases, there will be a greater need for privacy in terms of data, and utilizing secure services is highly recommended. So, data on the Cloud must have some privacy mechanisms to ensure personal and organizational privacy. So, for this, we must have an authentic way to increase the trust and reliability of the organization and individuals The authors have tried to create a way to rank things that uses the Analytical Hieratical Process (AHP) and the Technique for Order Preference by Similarity to the Ideal Solution (TOPSIS). Based on the result and comparison, produce some hidden advantages named cost, benefit, risk and opportunity-based outcomes of the result. In this paper, we are developing a cloud data privacy model; for this, we have done an intensive literature review by including Privacy factors such as Access Control, Authentication, Authorization, Trustworthiness, Confidentiality, Integrity, and Availability. Based on that review, we have chosen a few parameters that affect cloud data privacy in all the phases of the data life cycle. Most of the already available methods must be revised per the industry’s current trends. Here, we will use Analytical Hieratical Process and Technique for Order Preference by Similarity to the Ideal Solution method to prove that our claim is better than other cloud data privacy models. In this paper, the author has selected the weights of the individual cloud data privacy criteria and further calculated the rank of individual data privacy criteria using the AHP method and subsequently utilized the final weights as input of the TOPSIS method to rank the cloud data privacy criteria