http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/8900 Sun, 19 Apr 2026 09:56:29 GMT 2026-04-19T09:56:29Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/8918 Title: Voice controlled automatic hand sanitizer dispenser with thermometer Authors: Mirudula, S.; Jeyaram, S.; Loheeswaran, S. Abstract: Recent days, the whole world is struggling with COVID-19 pandemic. As one of the preventive measures, people’s body temperatures are measured and hands are sanitized while they enter into most of the organizations. Usually this is manually performed by security personals. Since nowadays we have to fight with Omicron which is the new variant of COVID 19 and highly transmissible, it is better to perform the temperature screening and sanitizing by reducing or without human-human interaction. This is the main motivation and scope of this project. Many automatic hand sanitizing devices are available at the market at present, but the novelty of this project is voice enabling feature with low cost. The system welcomes the person and instructs him to measure his body temperature by voice while he is entering. Then it measures the body temperature and displays as well as reads out the measured temperature. If the person’s body temperature is within the allowable range, then it will dispense the hand sanitizer, else it will instruct him to go for manual screening. The circuit for the system comprises an Arduino microcontroller, OLED display, relay module, ultrasonic sensors, temperature sensor, 5 V DC pump, LED lights, audio modulator and speaker. The temperature sensor (MLX90614) senses the body temperature. Microcontroller verifies that the value is within the specified range as controlled by its ultrasonic sensor and displays the temperature on the OLED display and voice play also. Thereafter, the relay module controls the 5 V DC pump to dispense the sanitizer. The language of the voice can be set according to the user’s preference. The device helps to maintain personal preventive measures as well as detecting a possible symptomatic person, since fever with high temperature is one of the major symptoms of COVID-19. The device has been tested and ensured its working effectiveness. It will be very useful for any organization even with more buildings/sections. It can be positioned at the entrance of the buildings for temperature screening and hand sanitize all the staff and visitors against COVID-19. Sat, 01 Jan 2022 00:00:00 GMT http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/8918 2022-01-01T00:00:00Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/8917 Title: Natural dyes extracted from Catharanthus flower petals for dye-sensitized solar cells application Authors: Senevirathna, H.M.C.U. Abstract: Dye-Sensitized Solar Cells (DSSCs) are one of the most studied cost-efficient solar cells with commercially available Ru-based dyes as the photosensitizer[1]. There has been a considerable interest to utilise natural dyes due to being environmentally friendly and economically superior to the commercially available Ru-based dyes [2]. This study focuses on utilising natural dyes extracted from Catharanthus flower petals as a photosensitizer for fabricating TiO2 based DSSC. Fresh flower petals were washed with deionized water before drying them to make a powder sample. Dyes were then extracted by soaking the power with ethanol and DI-water. The UV-Visible spectroscopy study reveals the presence of Chlorophyll and Anthocyanin in the ethanol extract. However, no distinguished peaks were observed for the dye-coated TiO2 films due to the interference of the TiO2 absorbance. Moreover, the uniform distribution of the dye molecules in the dye-coated TiO2 films was confirmed by the AFM study. DSSCs were then fabricated by doctor-blade method with the effective area of 0.25 cm2 utilising natural dye, 𝐼 − / 𝐼3 − redox couple and Pt electrode as a sensitizer, electrolyte and counter electrode, respectively. Finally, the photovoltaic performance of the fabricated devices was investigated under simulated irradiation of intensity 100 mW/cm2 with AM 1.5 filter. The device with ethanol extract of Catharanthus flower sensitized photoanode pronounced photovoltaic properties with short circuit current density, open circuit voltage and fill factor, 0.39 mAcm-2 , 0.56 V and 0.50, respectively. Sat, 01 Jan 2022 00:00:00 GMT http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/8917 2022-01-01T00:00:00Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/8916 Title: Influence of post-annealing temperature on the properties of thermally evaporated CuI thin film Authors: Gunasekara, M.S.S.; Thivakarasarma, T.; Dhayalan, V.; Ravirajan, P. Abstract: Copper Iodide (CuI) has been widely used in various optoelectronic applications including solar cells, light-emitting diodes owing to the high hole mobility, high electrical conductivity, wide direct bandgap, high transparency, and high chemical stability. In this work, the effect of the post-annealing treatment on the structural, optical, and electrical properties of the thermally evaporated CuI thin film (100 nm) was investigated by using X-ray diffraction (XRD), UV visible spectrometer, and four-point probe method, respectively. The prepared films were annealed in air at different temperatures from 50°C to 300 °C. XRD pattern of CuI film well matched with standard values and no phase change was observed with the heat treatment. The heat-treated CuI films have a lattice parameter decrease from 6.06Å to 6.03Å due to the decrement of unit cell volume. An optical band gap was found in the range of 2.98 -3.00 eV. Therefore, thermally evaporated CuI films are optically stable in the temperature range of 50 - 300°C. And the electrical resistivity of thermally evaporated CuI film was found at 0.20 Ωcm. The study suggests that changing the annealing temperature as a post deposition treatment affects structural, optical, and electrical properties of thermally evaporated CuI films slightly. These results indicate that thermally evaporated p-type CuI film is stable and is promising hole-transporting material for opto-electronic devices. Sat, 01 Jan 2022 00:00:00 GMT http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/8916 2022-01-01T00:00:00Z http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/8915 Title: Optical and Electronic properties of greener synthesized colloidal semiconducting CdS nanoparticles Authors: Suvanya, A.; Niluja, S.; Elilan, Y.; Shivatharsiny, Y. Abstract: The utilization of toxic chemicals for the synthesis of nanoparticles has limited its application in the field of nanotechnology. The use of natural precursors in the nanoparticle synthesis has opened new paths in the field of nanotechnology to overcome the above strategy. Semiconducting nanoparticles, such as CdS, ZnS and CdSe are prominent materials in optoelectronic applications due to their dimension and photostability. Among these materials CdS Nanoparticles are highly preferred due to their excellent thermal and chemical stability and tunable bandgap. Generally, CdS Nanoparticles can be synthesized by micro emulsion, ultrasonic irradiation, sol-gel, and photo-itching methods. However, these methods are not cost-effective and environmentally friendly. Therefore, there is a need to synthesize these colloidal nanoparticles using greener approach. In this report, we report a green method for the synthesis of cadmium sulphide (CdS) nanoparticles and its optical and electronic properties. CdS nanoparticles were synthesized by natural resources, such as garlic, onion and tobacco. Garlic and Onion were used as the Sulfur source and tobacco was used as Cadmium source. Both onion and tobacco used in this work are grown in Jaffna peninsula, Sri Lanka. The UV-Vis-NIR spectroscope, X-ray diffractometry (XRD) techniques were used to characterize the CdS nanoparticles. Moreover, the current-voltage (I-V) characteristics of CdS thin films were also studied to unveil the electrical conduction of the synthesized CdS films. Finally, the semiconducting property of both of these colloidal CdS Nanoparticles were compared by fabricating a colloidal thin film field effect transistor on a 100 nm SiO2 coated Si substrate using Pt as source and drain electrodes. The channel length of the fabricated was 2 µm and widths is 2 mm. The electrical properties of FETs were studied using computer interfaced source measure unit. The non-linearity in the I-V curves is observed in all the colloidal thin film FETs. This confirmed that the greener synthesized CdS colloidal nanoparticles are semiconducting and hence, they could be used for several optoelectronic applications. Sat, 01 Jan 2022 00:00:00 GMT http://repo.lib.jfn.ac.lk/ujrr/handle/123456789/8915 2022-01-01T00:00:00Z