In this study, we used two types of materials as working electrode of DSSC, commercial TiO2 (P25) nanoparticle and ZnO nanotip. First part, we sintered TiO2 electrode in nitrogen and treat TiO2 electrode by UV light irradiation, in order to increase dye adsorption onto TiO2. Second part, we used three different buffer layers to grow ASD-ZnO nanotip as working electrode, sputtered-ZnO, sputtered-AZO and spin-coating TiO2. The hetrojuction is formed at the interface of ZnO nanotip/TiO2 buffer layers due to the different materials between ZnO and TiO2, which is beneficial for electron-hole separation. The morphology was measured by field emission scanning electron microscope (FE-SEM, Philip XL-40FEG). The sheet resistivity was measured by four-point probe. The crystallinity was examined by X-Ray diffraction (XRD, Simens D5000). Structural and spectral properties are characterized by ultraviolet-visible spectroscopy (UV-Vis) spectroscopy. The fourier transform infrared spectroscopy (FT-IR spectroscopy, BRUKER 66v/s) deals with the infrared region of absorption spectroscopy. And the Angilent B1500A is used for current-voltage (I-V) characterization of solar cells. In our results, we enhance the performance of TiO2 electrode DSSC, the open circuit voltage can reach to 0.56 V, the short circuit current density can reach to 16.65 mA/cm2, the conversion efficiency can reach to 4.6 % and the fill factor can reach to 49.2 %. On ZnO electrode, the open circuit voltage can reach to 0.57 V, the short circuit current density can reach to 4.43 mA/cm2, the conversion efficiency can reach to 1.21 % and the fill factor can reach to 47.9 %.

Polycrystalline Cu(In,Al)Se2 films were deposited by four-source evaporation of Cu, In, Al, and Se using Knudsen type sources in which the elemental fluxes were coincident onto soda lime glass substrates. The single-phase films with composition of Cu:In:Al:Se = 28:15:9:48 which were confirmed by X-ray diffraction and micro-Raman spectroscopy were deposited at substrate temperature of 560¢J. Secondary phases were observed when temperature of substrate is below 560¢J due to incompletely reaction. Under fixed effusion flux, the value of Cu/(In+Al) becomes larger as temperature of substrate increase. However, the value of Al/(In+Al) keeps nearly constant as temperature increase. The band gap is 1.53 eV derived from the result of spectrophotometer. The room temperature resistivity, Hall mobility and carrier concentration of the films are 0.28 £[cm, 24.63 cm2V-1s-1 and 1.27x1019 cm-3 respectively. And the conductive type is p-type. By the way, we try to grow Cu(In,Al)Se2 film in the presence of an Sb beam at substrate temperature of 440¢J. After the addition of an Sb beam, surface morphology become smooth and compact, but there is no significant grain growth. No matter an Sb beam adds or not, secondary phases were observed in both case due to the low temperature of substrate.

To accommodate the crisis of global warming and fossil fuel shortage, the world starts to value continual development and application of all sorts of green energy. Among various renewable sources of energy, solar energy is distinct for its low pollution and renewability. Under the standard of zero harm to the environment and low-carbon emission, solar energy is deemed the new green energy to replace fossil fuel. Consequently, governments around the world, one after the other, invest in research and development, and make solar energy the highest potential energy industry in industrial development by means of governmental policy and subsidy. This research focuses on the development and current status of solar cell industry in Greater China and other developed countries, and sets out to identify the co-opetition of current solar energy development of solar cell industry in Greater China in light of analysis based on Michael Porter diamond model and industry life cycle with the secondary data gathered in relation to solar photovoltaic industry chain. This research discovers that, in recent years, the solar cell industry has phenomenon of hasty expansion, intensive competition, petty profit at the middle range of industry chain, and manufacture switching to regions with low production cost. It is suggested in this research that to combine strength of industrially connected parties, make the economic industry more open, create a win-win situation, and embrace the upcoming of low-carbon economy, a series of actions may be considered. They are (1) strategic alliance of vertical integration and division by profession, (2) enhance industrial technology communication and cooperation to solve problem of technology and manufacturer, (3) elaborate complementary strengths and optimize integration of industry chain, (4) combine with comprehensive policy and actuate the solar photovoltaic market of Greater China.

In this research, hills-like hierarchical structured TiO2 photoanodes for dye-sensitized solar cells (DSSCs) have been prepared. We expected these appropriately aggregated TiO2 clusters in photoanode layer could cause stronger light scattering and higher dye loading that increased efficiency of photovoltaics. For detailed light-harvesting study, different molecular weight of polyvinyl alcohol (PVA) polymers were used as binders for TiO2 nanoparticles (P-25 Degussa) aggregation. After preparing a series of TiO2 films with dissimilar morphology, the reflection of TiO2 films, absorbance of attached dye, amount of dye loading, and performance of fabricated DSSC devices were measured and investigated. An optimized device had higher dye loading and well light harvesting at the same time that induced a 23% increase of short-circuit current Jsc in DSSCs. Moreover, we found that electrolyte could penetrate or diffuse easily in this higher porous structure. We fabricated dye-sensitized solar cells with MPN-based liquid electrolyte and gel polymer electrolyte. From this structure, the short-circuit current Jsc was increased around 16% and 19% respectively compared to conventional layers with liquid electrolyte and gel polymer electrolyte devices. The increase in highly viscous system of gel polymer electrolyte is due to easier penetration by such hills-like hierarchical structure.

In this thesis, silicon oxide thin films fabricated on silicon substrates by reactive radio frequency (rf) magnetron sputtering and supercritical CO2 (SCCO2) treatment at room temperature were investigated. The electrical properties including I-V and C-V of the films prepared at different processing conditions were discussed. Using the Transmission Electron Microscope (TEM), the thickness of silicon oxide thin films were measured. The results suggested that the film quality can be significantly improved by the SCCO2 treatment after reactive sputtering. The leakage current of the films at an electrical field of 1 MV/cm is 1¡Ñ10-8A/cm2 with a hysteresis voltage of 0.01V. The silicon oxide thin films can be used as a barrier layer for Al/SiO2/Si silicon solar cells. The energy conversion efficiency of a single crystal silicon solae cell is 10.2% under AM1.5 (965W/m2) radiation. After rapid thermal annealing(RTA) at 500¢J, the measured short-circuit current, open- circuit voltage, fill factor are 53mA, 0.54V and 0.53, respectively.

In organic solar cell, the surface characteristic plays an important role in the power conversion efficiency of solar cell device. According to the literatures, the increased roughness can increase the contact area at the interface between PEDOT:PSS and active layer, improving hole extraction to the anode. Furthermore, a rough interface may cause a scattering effect on the incident light, which can reflect the out-lost-light back into the active layer and leads an efficient light absorbed. There are many ways to change the morphology of hole transporting layer, such as solvent-treated, or additives adding. However, the above process methods are easily affected by the external environmental conditions. It¡¦s difficult to get the surface morphology been well controlled, resulting in a process instability and low reproducibility. In this research, we will create regular grooves on hole transporting layer by rubbing method. By changing baking temperature and rubbing pressure adjustment of PEDOT:PSS layer; we can precisely control the groove depth and surface morphology. This method makes the process simple and high stability. We found that the PEDOT:PSS hole transporting layer with a suitable depth grooves can enhance the power conversion efficiency. The power conversion efficiency of samples were measured under AM 1.5G 100mW/cm2 illumination. In our results, we found that the device possess about 14.52nm-depth of groove structure, the power conversion efficiency of devices can be increased from 2.03% to 2.36% (which is 17.6% improved). This consequence can be attributed to a short current density increasing from 5.67mA/cm2 to 6.67mA/cm2 based on the device structure is ITO(1500Å)/Rubbing-PEDOT:PSS(500Å)/P3HT:PCBM(800Å)/Al(2000Å).

This research plans the power capacities of the obstacle lighting on the power transmission towers, which are located in the areas where the utility cannot reach. The obstacle lighting is formed by light emitting diodes (LEDs), which are powered mainly by solar cells and subordinately by rechargeable batteries. The solar cells charge the batteries during the sunny daytime with plenty sunlight. When the sunlight is insufficient and the obstacle lamp is turned on, batteries and solar cells supply the obstacle lighting simultaneously. The power capacities of the solar cells and batteries are designated to keep the obstacle lighting system uninterruptible either under the drastic weather variation or a long period of insufficient sunlight. Under the specified operation rules of the obstacle lighting, a more economical and precise method is proposed for planning the power capacities of solar cells and batteries based on the weather data from Central Weather Bureau in recent 6 years following. The power planning method is implemented in the areas of Kaohsiung, Chiayi and Ali mountain to demonstrate the feasibility and the accuracy in reality.

This thesis investigates the effect of the ripple current on the output power of solar cells. A solar panel with several metal halide lamps is set up to emulate the photovoltaic power system, which is cascaded by a boost converter and a buck-boost converter to extract triangular and trapezoidal currents, respectively. All experiments are operated under the room temperature with different current ripples and frequencies. The measured current and voltage waveforms at the output powers indicate that the dynamic characteristics are very different from static ones obtained from the dc loads. It is found that the output voltage lags the current when the peak of the rippled current goes beyond the maximum power point (MPP), leading to a declination in the average output power. This phenomenon becomes more severe for a higher peak, lower frequency, and larger charge of the rippled current exceeding the MPP. In addition, the declination in the average power may cause a shift of the MPP.

In this study, we prepare the zinc oxide nanotip with aqueous solution deposited on ZnO nucleation layer. The thermal annealing with N2 ambiance at 300 oC for 1 hr increase the UV emission and decrease the defects. We use ZnO nanotip as an anti-reflection layer because of surface roughness and optical interference. ZnO nanotip with rough surface decreases reflection, so we use ZnO nanotip as an anti-reflection layer, after grown ZnO nanotip on solar cell the efficiency of solar cell was enhancement. The coordination modes were measured by Fourier-transform infrared spectrometer (FTIR). The physical properties were characterized by X-ray diffraction (XRD). The optical properties were measured by Micro-photoluminescence (Micro-PL). The morphology was observed by field emission scanning electron microscope (FE-SEM). The performance of the cells was measured by a semiconductor device analyzer. In our results, we grow the high performance of ZnO nanotip on solar cell to increase the efficiency. The short-circuit current increased from 42 to 51 mA, and the efficiency increased from 15.7 to 18.8 %.

We have investigated the polarization effect of optical process in the vertically coupled InGaAs quantum dots (QDs) triple layers by varying the thickness of GaAs spacer layer. The TE/TM ratio for the ground state emission decreases from near 4 to 1.5 as the spacer thickness (d) decreases from 40 nm to 5 nm. And, the TE polarization (in-plane polarization) is anisotropic with a stronger component along [01-1] direction. P-type modulation doping further decreases the TE/TM ratio to r = 1.2 for the strong vertical coupling QDs structure of 5-nm spacer. Then, using a cross-sectional transmission electron microscopy directly reveals the InGaAs QDs of 5-nm spacer well aligned along the growth direction. From the electroluminescence (EL) and differential absorption (£G£\) experiments, the higher optical gain and absorption change for the excited state suggest that the e2-hh transition has higher oscillator strength for the vertically coupled QDs. We also investigate for the triple-layer InGaAs vertically coupled quantum dots (VCQDs) by adding modulation doping (MD) in the 5-nm GaAs spacer layers. In addition to the QDs fundamental and excited transitions, a coupled-state transition is observed for the VCQDs. For the VCQDs of p-type MD, the optical transitions at ground state and coupled state are enhanced by the improvement of hole capture for the valence subbands. For the VCQDs of n-type MD, the main absorption change occurs at the coupled state, consistent with the dominant emission peak observed in EL spectra. For GaAs-based solar cells application, in order to enhance absorption at infrared range for GaAs-based solar cells, multi-stack InGaAs VCQDs of 5-nm GaAs spacers are grown in the active region. Due to the strong vertical coupling between QDs would promote quantum efficiency. We have investigated the photovoltaic response for the solar cells by increasing the layer numbers of VCQDs. The device of nine-layer InGaAs VCQDs shows an enhanced short-circuit current density (Jsc) of 10.5 mA/cm2. The value is increased by 42% compared to GaAs reference device. However, the open-circuit voltage (Voc) is reduced from 0.88 V to 0.54 V. Then, we change the GaAs spacer thickness of coupled In0.75Ga0.25As QDs, and investigated the effects on photovoltaic response. For the sample of d =10 nm shows the best performance of current density (Jsc~24 mA/cm2) and efficiency (h~10.6%). The Jsc and h are increases by 55% and 112% more than the device without QDs, respectively.