Characteristics of Perovskite Solar Cells (PSCs) with Various Metal Electrode Deposited Using Thermal Evaporators

Organic material-based solar cell devices such as perovskite solar cells (PSCs) have attracted attention as renewable energy resources with low production cost, lightweight, wearable device applications, and large-area processability. To enhance device performance, many research groups have attempted to develop new materials and structures. Metal electrode materials play an important role in solar energy conversion in PSCs, owing to the ohmic contact and contact resistance between metal negative electrodes and photoactive layers. Until recently, conventional metal sources such as Ag, Au, or Cu have been used as electrodes. In this study, PSCs were employed in various metal negative electrodes using a thermal evaporator. The authors investigated the effect of metal negative electrodes on PSCs.

Characteristics of GZO-based multilayer transparent conducting films

Ga-doped ZnO (GZO)/metal/GZO structures were fabricated on glass substrates to be the transparent conducting layers in this study. GZO films and metal films were deposited at room-temperature by a radio-frequency sputter and a thermal evaporator, respectively. The GZO/Ag/GZO (GAG) structures had poor electrical and optical properties due to the formation of Ag islands on the GZO layer. A 1-nm Cu seed layer was deposited on the GZO layer to fabricate the GZO/Ag/Cu/GZO (GACG) structure to improve its electrical and optical properties. The GACG structure had sheet resistance of 9 [Formula: see text], average visible transmittance of 86% and figure of merit of [Formula: see text] [Formula: see text]. In addition, the sheet resistance of the GACG structure kept almost the same after annealing at [Formula: see text]C in atmosphere for more than 5 h, which showed good thermal stability.

The Effect of Vacuum Pressure During Fabrication of Zinc Sulphide Thin Film Using Thermal Evaporator

Zinc sulphide is a remarkable semiconductor material, with its highly demanded optical, electrical properties and its availability, it is used in the field of photovoltaic applications. The objectives are to investigate the effect of vacuum pressure on the glass substrate and the study different cluster models based on its crystal size. The ZnS thin films were fabricated using a thermal evaporator at the pressure of 10-5 Torr, 10-6 Torr, and 10-7 Torr. Four different size cluster models have been characterized theoretically. Each model was built based on the size of crystal structures, optimized to the lowest energy level, and evaluated as realistic clusters. The structural and optical properties of the thin films were studied using X-ray diffractometry, absorption, and photoluminescence spectroscopy respectively. Significant differences were observed in the crystal structure and optical properties of fabricated MoS2 thin films at different pressures.

Intrinsically Stable Wide Band Gap Br-Free CsxFA1-xPbI3 (x=0.5-0.9) Perovskites Overcoming Phase Segregation

<p>A ~20 nm thick compact TiO₂ was deposited on patterned FTO (TEC-7) by spray pyrolysis of 0.2 M Ti (IV) bis(ethylacetoacetate)-diisopropoxide 1-butanol solution at 450 ºC followed by annealing at 450 ºC for one hour. The perovskite precursor solution was prepared by dissolving CsI, FAI, PbI₂ and DMAI in 1 mL DMF and was deposited on 70 ℃ preheated c-TiO₂/FTO substrate by spin coating at 3000 rpm for 30 s. The obtained precursor film was annealed at 170℃ for 40 min. A hole-transport material (HTM) solution containing 0.1 M spiro-OMeTAD, 0.035 M Li-TFSi, and 0.12 M 4-tert-butylpyridine (tBP) in chlorobenzene solution was then spin coated onto the perovskite film at 4000 rpm for 20 s. Finally, a 100 nm thick Ag was deposited as contact layer via thermal evaporator.</p>

Intrinsically Stable Wide Band Gap Br-Free CsxFA1-xPbI3 (x=0.5-0.9) Perovskites Overcoming Phase Segregation

<p>A ~20 nm thick compact TiO₂ was deposited on patterned FTO (TEC-7) by spray pyrolysis of 0.2 M Ti (IV) bis(ethylacetoacetate)-diisopropoxide 1-butanol solution at 450 ºC followed by annealing at 450 ºC for one hour. The perovskite precursor solution was prepared by dissolving CsI, FAI, PbI₂ and DMAI in 1 mL DMF and was deposited on 70 ℃ preheated c-TiO₂/FTO substrate by spin coating at 3000 rpm for 30 s. The obtained precursor film was annealed at 170℃ for 40 min. A hole-transport material (HTM) solution containing 0.1 M spiro-OMeTAD, 0.035 M Li-TFSi, and 0.12 M 4-tert-butylpyridine (tBP) in chlorobenzene solution was then spin coated onto the perovskite film at 4000 rpm for 20 s. Finally, a 100 nm thick Ag was deposited as contact layer via thermal evaporator.</p>

Photovoltaic thermal collector assisted heat pumps using environment-friendly working fluids

In this research, a photovoltaic-thermal collector assisted heat pump has been developed and tested its performance under the tropical climatic conditions of Malaysia. The refrigerants such as, R134a and R1234yf were selected based on its thermodynamic and thermo-physical properties. The temperature of the photovoltaic module was theoretically predicted under the influence of tube diameter, tube spacing and refrigerant mass flow rate. Further, the energy performance of the photovoltaic-thermal evaporator and the heat pump system are investigated experimentally. Finally, the economical feasibility of the photovoltaic-thermal collector evaporator was assessed for the period of 20 years. The results showed that, the tube spacing and diameter of the copper tubes used in the photovoltaic-thermal evaporator/collector using R134a and R1234yf were optimized to 80 mm and 12.7 mm, respectively. It was observed that, during the clear sunny day, the average photovoltaic module temperature was reduced to 30.9 °C under the influence of panel cooling using refrigerant. The output of the panel was enhanced by 21%–44% with increase in solar radiation from 400 W/m2 to 1000 W/m2. The coefficient of performance of the heat pump was varied from 4.8 to 6.84 with an average coefficient of performance of 5.8 during clear sunny days. The life cycle economic analysis indicated that, the photovoltaic-thermal collector evaporator assisted heat pump has a payback period of 3 years, whereas the reference photovoltaic system has a payback period of 8 years.

A Chip-Scale, Low Cost PVD System

Standard physical vapor deposition systems are large, expensive, and slow. As part of an on-going effort to build a fab-on-a-chip, we have developed a chip-scale, low cost, fast physical vapor deposition system consisting of two MEMS devices: a chip-scale thermal evaporator and a mass sensor that serves as a film thickness monitor. Here, we demonstrate the functionality of both devices by depositing Pb thin-films. The thermal evaporator was made by fabless manufacturing using the SOIMUMPs processs (MEMSCAP, inc). It turns on in 1.46s and reaches deposition rates as high as 7.2 ˚ As−1 with ∼1mm separation from the target. The mass sensor is a re-purposed quartz oscillator (JTX210) that is commercially available for less than one dollar. Its resolution was measured to be 2.65fg or 7.79E-5 monolayers of Pb.

Role of Oxygen Pressure on the Surface Properties of Polycrystalline Cu2O Films Deposited By Thermal Evaporator

<p>Polycrystalline cuprous oxide (P-Cu2O) films are deposited on Cu substrates for various (0.2, 0.3 and 0.4 mbar) oxygen pressures (OP) by thermal evaporator. The XRD pattern shows the development of Cu (200), Cu2O (200) and Cu2O (311) diffraction planes which confirms the deposition of P-Cu2O films. The intensity of Cu2O (200) and Cu2O (311) planes is associated with the increase of OP. The crystallite size and microstrains developed in (200) and (311) planes are found to be 19.31, 21.18, 11.32 nm; 22.04, 23.11, 12.08 nm and 0.113, 0.103, 0.193; 0.099, 0.096, 0.181 with increasing OP respectively. The d-spacing and lattice constant are found to be 0.210, 0.128 nm and 0.421, 0.425 nm respectively. The bond length of P-Cu2O film is found to be 0.255 nm. The crystallites/unit area of these planes is found to be 12.21, 7.46, 45.16 nm-2 and 8.21, 5.75, 37.16 nm-2 respectively. The texture coefficients of these planes are found to be 1.22, 1.26, 1.11 and 0.78, 0.74 and 0.56 with increasing OP respectively. The O and Cu contents are found to be 5.31, 5.92, 6.94 wt % and 83.01, 82.44, 80.65 wt % respectively. The thickness and growth rate of P-Cu2O films are found to be 87.9, 71.9, 65.5 nm and 17.6, 14.2, 13.1 (nm/min) with increasing OP respectively. The SEM micro-structures reveal the formations of patches of irregular shapes, rounded nano-particles, clouds of nano-particles and their distribution depend on the increasing OP. The refractive index and energy band gap of P-Cu2O films are found to be 1.96, 1.89, 1.92 and 2.47, 2.44 and 2.25 eV with increasing OP respectively.<br /><br /></p>

Carrot-inspired solar thermal evaporator

A carrot-inspired solar thermal evaporator exhibits a water evaporation rate of 2.04 kg m−2 h−1 and an outstanding durability and stability.