Issue 2


Editorial

Hydrogen Leading the Green Energy Future

Ashutosh Tiwari

Advanced Materials Letters, 2022, Volume 13, Issue Issue 2, Pages 2202-1690
DOI: 10.5185/aml.2022.17896

Climate change demonstrates erratic weather conditions, heavy rains drought floods, landslides, soil erosion, tsunami, and extreme cold and warm weather which severely impact the livelihoods of the public. Attaining the substance by reducing carbon pollution and other greenhouse gases is the best way to control climate change. The world requires drastic action against global warming. At present, the energy crisis is a prominent challenge across the globe. The creation of energy selections that advance public health, the environment, and economics through energy is essential. Considering the suitable climate, habitat variation, and their adverse effects such as glaciers, heatwave, sea levels rise, etc., it is important to understand the climate control and framing combat policy. 

Review Article

Dye Enhanced Quantum Dot Sensitized Solar Cell

Shawqi Al Dallal; Khalil Ebrahim Jasim

Advanced Materials Letters, 2022, Volume 13, Issue Issue 2, Pages 2202-1691
DOI: 10.5185/amlett.2022.021691

Third generation solar cells, such as dye and quantum dot sensitized solar cells are attracting attention of many research groups. In this investigation we explore the role of dye extract on the enhancement of the photovoltaic properties of quantum dot sensitized solar cells (QDSSCs). Lead sulfide quantum dots of different sizes have been used to sensitize a nanostructured titanium oxide electrode. We compare the open circuit voltage, the short circuit current, and power conversion efficiency of QDSSCs with the same quantities as obtained for dye-enhanced system using pomegranate dye extract. An open circuit voltage of 166 mV, a short circuit current of 0.1 mA, and an efficiency of 0.32% were obtained for 2.4 nm radius lead sulfide quantum dot sensitized solar cells. Using pomegranate dye extract reveals a considerable enhancement of the above characteristics. The combined dye-quantum dot system produces an open circuit voltage of 300 mV, a short circuit current of 0.55 mA, and an efficiency of 3.4%. For 3.2 nm radius QDs, the efficiency is substantially higher, reaching about 7%. A model describing the structure and processes leading to the above enhancement of the assembled solar cell characteristics is presented. In this model we explain the interplay between the transfer of electrons between the dye, quantum dots, and subsequent injection in the wide band gap titanium dioxide semiconductor. 

Research Article

Investigation of Thermal behaviour of Swelling Anti-Fire Composite Materials Identified with RFID Technology

Kamil Janeczek; Mateusz Kosyl; Aneta Araźna; Michał Czaiński; Krzysztof Lipiec; Wojciech Stęplewski; Marek Kościelski

Advanced Materials Letters, 2022, Volume 13, Issue Issue 2, Pages 2202-1692
DOI: 10.5185/amlett.2022.021692

Passive fire protections are one of the safety systems which are installed commonly in buildings. As every kind of such systems these protections have to controlled according to legal regulations. To facilitate periodic checks RFID technology can be successfully used. In this paper, thermal behaviour of produced swelling materials suitable for passive fire protection was examined and thermal endurance of RFID tags used to identify these protections was analysed as well. The results achieved in this study showed expected thermal behaviour of the swelling materials which fulfilled the whole space of the protections blocking spreading fire and smoke. Further, it was noticed that a gasket sealant and a high-temperature silicone allowed to decrease temperature affecting RFID tags. Paper-face and hard RFID tags withstood the applied thermal exposure and their readability was restored after cooling down the tags to about 120°C. This means that it is likely that these tags can resist small fire incidents on condition that temperature affecting the tags does not exceed a decomposition temperature of materials used for their production.  

Fabrication of n+-poly-Si/p+-c-Si tunnel diode using Low-pressure Chemical Vapor Deposition for Photovoltaic Applications

Vineet Kumar Singh

Advanced Materials Letters, 2022, Volume 13, Issue Issue 2, Pages 2202-1693
DOI: 10.5185/amlett.2022.021693

In this paper, an n+-poly-silicon/p+-crystalline-silicon tunnel diode has been fabricated and characterized. The n+ poly-silicon layer is deposited by the low-pressure chemical vapor deposition method, while a diffusion furnace is used for boron diffusion in crystalline silicon. Scanning electron microscopy and X-ray diffraction pattern have been used for structural characterization. Hall measurement and current-voltage characteristics have been used for carrier density, mobility, current density, and contact resistance measurement. Hall measurement reveals the carrier density of ~1019 cm-3 in phosphorus-doped poly-silicon tunnel layer with mobility of  ~5.4 cm2   V-1-s-1. The current-voltage characteristics of the tunnel diode show the current density of ~103 Ampere/cm2 at a voltage of 0.1 Volt. Using tunnel diode, an n+-poly-Si/p+-c-Si/n-c-Si/n+-c-Si structure has been fabricated for photovoltaic application. This structure generates a current density of  ~17.9 mA/cm2 and a voltage of 601 mV for a 195±10 nm thick doped poly-silicon layer. Further, to improve the solar cell’s performance, a thin layer of poly-silicon has been used. 

Microstructural Evolution for Super304H Austenite Steel used in China Plants

Chang Che; Shaohai Ma; Qingchuan Pan; Kai Yan; Gong Qian

Advanced Materials Letters, 2022, Volume 13, Issue Issue 2, Pages 2202-1694
DOI: 10.5185/amlett.2022.021694

Super304H (18Cr-9Ni-3Cu-Nb-N) austenite steel has high creep strength and has been used as the material of tubes in 600 class supercritical power plants in China. Many Super304H materials have run for more than 100,000 hours. Long-time service feature of these austenitic stainless steels has not been understood. An understanding of the long-term microstructural evolution under actually used conditions is a key for the improvement of these heat resistant steels. In this article, creep behavior of Super304H used in China plants was analyzed, microstructural evolution of Super304H materials after different service conditions were studied involving in optical microscope, TEM and SAXS. The results show, M23C6, Cu-rich particles, and σ phase were found to precipitate. A quantitative assessment of microstructure evolution was given during long-term creep.

Structural and Optical Studies of Quaternary Glass System

G. Upender; V. Chandra Mouli; V. Sreenivasulu; Praveena Kuruva; M. Prasad

Advanced Materials Letters, 2022, Volume 13, Issue Issue 2, Pages 2202-1695
DOI: 10.5185/amlett.2022.021695

The new tellurite glasses with chemical composition 64TeO2-15CdO-(20-x) ZnO-xLi2O-1V2O5 (x= 0, 5, 10, 15 and 20 mol %) were synthesized by traditional melt quench hardening method. The glass samples showed broad humps of typical amorphous phase in the X- ray diffraction patterns. The physical properties of glass samples such as density (ρ), molar volume (Vm), oxygen packing density (OPD), refractive index (n), molar refractivity (Rm) and metallization parameter (M) were estimated. The Fourier transform infrared spectroscopy (FTIR) studies exhibited that replacement of ZnO by Li2O forms significantly some basic structural units of TeO4, TeO3/TeO3+1 and ZnO4. Differential scanning calorimetry (DSC) was employed to find out the glass transition temperature (Tg) and thermal stability ( ). The optical enthrallment studies exhibited that the cut-off wavelength (λ) decreases while optical energy gap (Eopt) and Urbach energy ( ) values increases with an increase an escalation of Li2O content. This tellurite glasses possess an important use such as sensor devices, storage of data system and industrial applications etc.