Session Index

To improve the parasitic absorption problem, we tried to change the wide band gap material molybdenum oxide (MoOx) to the silicon heterojunction (SHJ) solar cell structure, thereby replacing the a-Si in the p-type doped amorphous silicon a-Si:H(p) of the layer. We compared the optical properties of MoO¬x with different thickness settings, and proved that MoOx has good carrier transport effect by changing the metal electrode at 180°C hot plate annealing temperatures. Preliminary results show that the Si HJT cell with a 15 nm-thick MoOx layer achieves a power conversion efficiency (PCE) of 21.2% and an open-circuit voltage (Voc) of 640.6mV.

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There is a fundamental trade-off between the resolution and the field of view in traditional imaging systems. Recently, Fourier ptychography (FP) based image reconstruction has shown excellent capability to produce sub-micron resolution images from wide field microscope without any moving parts. In this work, we demonstrate the possibility of generating high-resolution microscopic images using cost-effective consumer parts. The imaging system consists of an evolution board of raspberry Pi4, LED array module and a 5-mega pixels camera. By using FP to reconstruct the captured image at different angles, we demonstrate transforming low-resolution images to high-resolution giga-pixel images with large field-of-view.

 

In this work, we propose an electron-selective buffer layer (ES-BL) in fullerene-based organic photovoltaics (OPVs) by blending fullerene (C60) with a tris(8-hydroxyquinoline)aluminum(III) (Alq3). Compared to neat Alq3 for exciton blocking purposes, the proposed Alq3:C60 buffer layer shows higher power conversion efficiency (PCE) of 1.15%. In addition, insignificant PCE loss is observed after more than 1 day of continuous operation under AM1.5G solar illumination at 100 mW/cm2 by replacing BCP (τ84 ~25 hours) with Alq3:C60 buffer layer (τ98 ~25 hours). This can be attributed to the suppression of C60 photo-oligomerization process by the robust Alq3 molecule.

 

In this work, we propose a charge carrier selective structure by inserting an electron-transporting material (Bathophenanthroline; BPhen) between MoOx and the photoactive blend. The device shows an improved hole extraction process with a 10% enhancement of Jsc. In addition, the device shows an extended operational lifetime of 160 hours after 10% decay of the initial PCE, which is much durable compared to the one using standard MoOx neat film as hole extraction layer.

 

X-ray Photoelectron Spectroscopy (XPS) has been used to investigate the composition and chemical states of films in semiconductor industry. The purpose of adding Al2O3 passivation layer is to facilitate carrier lifetime and passivate intrinsic defects of photovoltaics. In this study, TEM was used to confirm the thickness of Al2O3 layer and SiOx interlayer formed by different annealing temperatures. To verify the chemical state of SiOx layer, XPS combined with Ar+ sputtering was used to reconstruct the elemental distribution of Si/SiOx/Al2O3 samples in different depths. The results show that the thickness of the SiOx layer is increasing with higher annealing temperature.

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This study proposed a chemical-modified polymer air-gap fiber Fabry–Pérot interferometer (PAGFFPI) with coating an Ag-film by silver mirror reaction (SMR) for achieving hot-wire anemometry (HWA). Experimental results demonstrate that the sensor can be effectively heated by LD with high responses and good sensitivity.

 

A new vertical structure LED is proposed recently to solve the uneven current spreading density problem of Y-shaped vertical structure LED. In this paper, we investigate current density and near-field light intensity distribution of the Y-shaped and the new vertical structure LED at different wavelengths. Five wavelengths are chosen for comparison: deep ultraviolet light (365nm~375nm), ultraviolet light (380nm~400nm), violet light (420nm~430nm), blue light (440nm~460nm), and green light (520nm~530nm). We find that the current distributions are distinct for different wavelengths. The new structure exhibits superior current spreading and light emitting uniformity at all wavelengths.

 

Organic-inorganic hybrid perovskites have become one of the most promising photoelectric materials for generating solar cells in recent years. However, their instability to environment remains a tough issue. Thermal degradation is one of the most important problems hindering their commercialization. This study investigates three kinds of perovskite films (MAPbI3, MAPbI3-xBrx, MAPbI3-xClx), conducting thermal induced stability experiments. Several surface analysis techniques, such as X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometer (TOF-SIMS) are used to provide a deeper understanding into materials decomposition. In summary, it is found that bromine-doped perovskite films have better stability upon exposure to heat.

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By finite-difference time-domain (FDTD) simulations, we design tungsten absorber for Solar Thermophotovoltaics (STPV) system. In this study, periodic pyramid structures with Tungsten material modeled by complex-conjugate multiple-pole model and convolutional
perfectly matched layers (CPML) are adapted to simulate the optimal structure with almost unity absorptivity in solar spectrum region.

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In this study, perovskite solar cells (PSCs) based on three different annealing temperatures are fabricated in a low humidity glove box by using two-step method. With the improvement of surface morphology and crystallinity of perovskite layer, an optimal photoelectric conversion efficiency (PCE) of 12.19 % is achieved.

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This paper proposed a tire pressure sensor based on fiber Bragg grating (FBG). The operating mechanism is that the tire pressure squeezes the polymer of sensor to stretch the grating and to cause the grating center wavelength to be shifted. By changing the size of the pressure-receiving opening, the sensitivity can be improved.

 

We proposed a hydrophone based on a fiber Bragg grating for detecting acoustic-wave signals of underwater. The hydrophone consists of fiber Bragg grating, silicon thin-film, and 3D print structure.