Shaozhen Xiong

Effects of oxygen incorporation in solar cells with a-SiOx:H absorber layer

The effects of oxygen incorporation on layer properties and cell performance were investigated in thin film solar cells with a-SiOx:H absorber layers. Besides the widened optical band gap and increased defect densities, a doping effect is observed upon oxygen incorporation even for the layers with wide band gap. From comparison of solar cells illuminated from either p- or n-side, we conclude that overall hole carrier collection is strongly deteriorated by increasing the oxygen concentration. The donor-like states induced by oxygen reform the electric field in the absorber. The intensified electric field near the p/i interface improves the quantum efficiency (QE) around 400 nm, which is attributed to the better carrier collection in the p-layer. The maximum of QE shows a blue shift with both p- and n-side illumination. It is consistent with the enhanced optical band gap of the absorber layer and shows the potential of usage in multi-junction solar cells.

A simple and flexible driver for OLED

A microcontroller-based driver was designed and developed for dot-matrix displays made with organic light emitting diodes (OLEDs). It was made by modifying driver designed for dot matrix LEDs made with inorganic semiconductors. The driver was designed with adjustable driving frequency, pulse-width, polarity and pulse-amplitude. It is a generalized driver suitable for operating OLED dot matrices made with different electroluminescent organic materials or in different device structures. A driver system was fabricated to drive an OLED panel in 40/spl times/7 format.

Effect of pretreatment on PET films and its application for flexible amorphous silicon solar cells

We proposed a low cost solution of flexible amorphous silicon solar cells on Polyethylene terephthalate(PET) polymer substrates deposited at low temperatures. PET films were firstly annealed both in the air and in vacuum at different temperatures, and the properties of PET films after annealing were evaluated. Then PET films were exposed to glow discharge Argon plasma in a standard PECVD system to improve their surface properties. The relationship between glow discharge parameters and the energy of Ar plasma were investigated by OES. After Ar plasma treatment, not only the surface morphology of PET but also the adhesion of the solar cell thin films to the PET substrates were improved. Finally, single junction a-Si solar cells with a p-i-n superstrate type were fabricated on PET/ITO substrates at low temperature of Ts=125°C, and an initial efficiency of 4.8% was obtained.

35.4: A 2.1-inch AMOLED Display Based on Metal-Induced Laterally Crystallized Polycrystalline Silicon Technology

A 2.1-inch color active-matrix organic light-emitting diode display based on an improved metal-induced laterally crystallized polycrystalline silicon technology is demonstrated. Leakage current was reduced with the active islands of polycrystalline silicon transistors patterned after nickel-based metal-induced lateral crystallization. Color was obtained by combining whitelight organic light-emitting diodes with micro-fabricated color filters.

Design on a Novel a-Si PIN/OLED Image Sensor & Display Device

A novel PIN/OLED image sensor & display device is proposed. Each pixel contains an a-Si PIN diode and an OLED in serial connection but in opposite polarity. The a-Si PIN diode acts as input sensor element and converts input light intensity into electric current strength. When the pixel is biased in the forward direction to that of the OLED, the electric current controls the output light intensity of the OLED. A theoretic simulation was carried out and compared with experimental results.

Structure design of nano-TiO 2 electrode in dye-sensitized solar cells #

In dye-sensitized solar cells (DSSCs), the physical properties and microstructure of nano-titanium dioxide film electrode are the key factors to influence the photo-electric characters greatly and they are also determined by the preparation techniques. A new electrode of double-layer TiO2 with different structure was designed and prepared by spin-coating and screen-printing techniques alternately. Such two types of layers have different contribution to the photo-electric conversion functions. Compact TiO2 film made by spin-coating only absorbs little dyes, but it works as a barrier layer between ITO and electrolyte. The porous TiO2 film made by screen-printing will absorb more dyes, and results in higher photocurrent. At the end, the effect of the compact layer on I-V properties of the DSSCs was discussed.

The key factors on silicon-based tandem thin film solar cells

The key factor for high efficiency of tandem Si-based thin film solar cells is to optimize the whole configuration for improving its utilization of solar energy besides the active layers of device-quality level. Several aspects reached in our lab are discussed in this paper. A double structure of P+ window layer was proposed and studied. An interlayer between top-cell and bottom-cell in the tandem structure for forming a micro-cavity in top-cell was simulated by the software programmed by ourselves. Finally, the results of two types of tandem solar cells, namely, a-Si/a-Si and a-Si/μc-Si with the light trapping back-reflection structure are reported.

H-plasma-assisted aluminum induced crystallization of amorphous silicon

A technique to improve and accelerate aluminum induced crystallization (AIC) by using hydrogen plasma is proposed. Raman spectroscopy and secondary ion mass spectrometry of crystallized poly-Si thin films show that hydrogen plasma radicals reduce the crystallization time of AIC. This technique shortens the annealing time from 10 to 4 h and increases the Hall mobility from 22.1 to 42.5 cm2/(V?s). The possible mechanism of AIC assisted by hydrogen radicals is also discussed.

P-67: Investigation on the Hydrogen-Assisted Al Induced Metal Crystallization Poly-Si

The hydrogen plasma-assistant Al induced crystallization (HAIC) technology has been proposed in this paper. This technology integrates the crystallization and passivation into one process. The annealing time has been reduced by almost half of the traditional AIC technology. Additionally, the HAIC technology can also improve the resulted poly-Si performance obviously. This technology makes the AIC technology more suitable for the industrial application.

Controllable light utilization in silicon-based thin film solar cells

Controllable light utilization in silicon-based-thin-film solar cells with a DBR structure have been simulated. A experimental model cells constructed by a-Si pin/ZnO (~70 nm)/P+muc-Si(20 nm) were verified. The ratio of Isc increment can be reached to 14.1%.