光スーパーキャパシターのためのキャパシターとペロブスカイト太陽電池の作製に関する研究

九州工業大学博士学位論文（要旨）学位記番号：生工博甲第308号 学位授与年月日：平成30年3月23

Preparation of Perovskite Films under Liquid Nitrogen Atmosphere for High Efficiency Perovskite Solar Cells

High quality perovskite film with high coverage and tight grain arrangement is critical for achieving high-efficiency and high-stability perovskite solar cells (PSCs). In this work, high quality perovskite films were successfully prepared by liquid nitrogen assisted method (LN method). Here, the vaporization of liquid nitrogen reduces the ambient temperature and absorb thermal energy from the substrate surface to accelerate the nucleation of perovskite. The results of scanning electron microscopy (SEM) shows that the perovskite films prepared by liquid nitrogen assisted method were dense and pinhole-free. The devices prepared by the LN method leads to a high-efficiency upto 16.53%, and the high efficiency device could maintain over 89% of the initial power conversion efficiency (PCE) even after 30 days storage in a desiccator at room temperature

Tunable Open Circuit Voltage by Engineering Inorganic Cesium Lead Bromide/Iodide Perovskite Solar Cells

Perovskite solar cells based on series of inorganic cesium lead bromide and iodide mixture, CsPbBr3-xI x , where x varies between 0, 0.1, 0.2, and 0.3 molar ratio were synthesized by two step-sequential deposition at ambient condition to design the variations of wide band gap light absorbers. A device with high overall photoconversion efficiency of 3.98 % was obtained when small amount of iodide (CsPbBr2.9I0.1) was used as the perovskite and spiro-OMeTAD as the hole transport material (HTM). We investigated the origin of variation in open circuit voltage, Voc which was shown to be mainly dependent on two factors, which are the band gap of the perovskite and the work function of the HTM. An increment in Voc was observed for the device with larger perovskite band gap, while keeping the electron and hole extraction contacts the same. Besides, the usage of bilayer P3HT/MoO3 with deeper HOMO level as HTM instead of spiro-OMeTAD, thus increased the Voc from 1.16 V to 1.3 V for CsPbBr3 solar cell, although the photocurrent is lowered due to charge extraction issues. The stability studies confirmed that the addition of small amount of iodide into the CsPbBr3 is necessarily to stabilize the cell performance over time

Resolve deep-rooted challenges of halide perovskite for sustainable energy development and environmental remediation

Metal halide perovskite (ABX3) has become a new class of fascinating nanomaterial that has attracted extensive interdisciplinary attention as a low-cost and easy to manufacture photocatalyst in the platform of solar energy conversion and environmental remediation. This is due to its appealing optimal band gaps, long carrier diffusion length, high carrier mobility, defect tolerance, unique chemical and optoelectronic properties. Nevertheless, their ionic crystal structures are unstable, therefore hindering practical application. In this review, we first introduce the unique structural and physical properties of metal halide perovskites. Subsequently, we examine the critical challenges faced by present halide perovskites, including (1) material instability, (2) Pb-toxicity, and (3) material defective structures. Next, we highlight the practical approaches being taken to resolve the bottlenecks of metal halide perovskites, particularly the adoption of (1) protonic solvents (i.e., HX; X = I or Br) for water splitting reaction, (2) mild protonic solvents for CO2 photoreduction, (3) functionalizing and encapsulation of perovskites, (4) engineering Pb-less/Pb-free material, and (5) defect remediation, followed by several methods to evaluate and quantify defect states. Then, we summarize a panorama of the latest progression of halide perovskites either in its pristine formed or hybridized formed used in photocatalysis, photoelectrochemical, and photovoltaic-photoelectrochemical systems. Lastly, this review is ended with a summary and some revitalized perspectives on the future directions for stable and efficient metal halide perovskite-based photocatalysis research. It is anticipated that this review provides a new research direction for future metal halide perovskite-based photocatalysis development

Methoxy-functionalized mesostructured stable carbon catalysts for effective biodiesel production from non-edible feedstock

The nano-architectured Ca(OCH3)2/AC catalyst was prepared through hydrothermal process. In this work, the controlled structural growth and morphology of nano-architectured Ca(OCH3)2/AC catalyst were reported and their conversion activity from non-edible oil source (crude jatropha oil) to biodiesel production was also evaluated in this study. Remarkable difference in catalytic activity for biodiesel production among these samples was observed. It shows that the catalytic properties of the hydrothermal synthesized catalyst was improved by exposing the catalytic active OCH3 predominantly on the surface of catalyst. The 0.4-OMe/AC catalyst with methanol/oil molar ratio of 12:1, agitation speed of 600 rpm and 3 wt% of catalyst provided maximum biodiesel yield of 98.65% at 60 °C for 1 h reaction time. The catalyst exhibited outstanding stability where negligible Ca2+ leaching was detected and the recovered catalyst was reused in 8 successive cycles without significant loss in activity. Therefore, this kind of bimodal porosity catalyst is said to exhibit very high activity, stability, and recyclability, which entailed potential saving and affordable biodiesel production possibilities

Performance Enhancement of Mesoporous TiO2-Based Perovskite Solar Cells by SbI3 Interfacial Modification Layer

TiO2 is commonly used as an electron-transporting material in perovskite photovoltaic devices due to its advantages, including suitable band gap, good photoelectrochemical stability, and simple preparation process. However, there are many oxygen vacancies or defects on the surface of TiO2 and thus this affects the stability of TiO2-based perovskite solar cells under UV light. In this work, a thin (monolayer) SbI3 modification layer is introduced on the mesoporous TiO2 surface and the effect at the interface between of TiO2 and perovskite is monitored by using a quartz crystal microbalance system. We demonstrate that the SbI3-modified TiO2 electrodes exhibit superior electronic properties by reducing electronic trap states, enabling faster electron transport. This approach results in higher performances compared with electrodes without the SbI3 passivation layer. CH3NH3PbI3 perovskite solar cells with a maximum power conversion efficiency of 17.33% in air, accompanied by a reduction in hysteresis and enhancement of the device stability, are reported

Magnesium-Doped MAPbI3 Perovskite Layers for Enhanced Photovoltaic Performance in Humid Air Atmosphere

Despite the high efficiency of MAPbI3 perovskite solar cells, the long term stability and degradation in humid atmosphere are issues that still needed to be addressed. In this work, magnesium iodide (MgI2) was first successfully used as a dopant into MAPbI3 perovskite prepared in humid air atmosphere. Mg doping decreased the valence band level, which was determined from photoelectron yield spectroscopy. Compared to the pristine MAPbI3 perovskite film, the 1.0% Mg-doped perovskite film showed increased crystal grain size and formation of pinhole-free perovskite film. Performance of the solar cell was increased from 14.2% of the doping-free solar cell to 17.8% of 1.0% Mg-doped device. Moreover, 90% of the original power conversion efficiency was still retained after storage in 30–40% relative humidity for 600 h

Melamine Hydroiodide Functionalized MAPbI3 Perovskite with Enhanced Photovoltaic Performance and Stability in Ambient Atmosphere

Despite the remarkable performance of organometallic halide perovskite solar cells (PSCs), their ultimate stability is still a major issue that inhibits the commercialization of this eminent technology. Herein, melamine hydroiodide (MLAI) is added to function methyl ammonium (CH3NH3+, MA+) lead iodide perovskite for fabricating structured perovskite with enhanced photovoltaic performance and stability in the harsh ambient atmosphere (35 °C, 60–70% relative humidity). Nearly no new phase formed even incorporated 25 mol.% MLAI induces the strain in the perovskite crystal structure. The MLAI‐structured perovskite film shows a denser and smoother surface than the pristine MAPbI3 perovskite. Planar PSCs based on 2 mol.% MLAI‐functionalized perovskite show 17.2% power conversion efficiency with nearly no hysteresis which is much higher than pristine MAPbI3 PSCs. Most importantly, the solar cell devices based on 2 mol.% MLAI‐functionalized perovskite still retain over 90% of the initial performance after being kept in ambient atmosphere for more than 560 h without encapsulation

All‐Inorganic CsPb1−xGexI2Br Perovskite with Enhanced Phase Stability and Photovoltaic Performance

01 August Compared with organic‐inorganic perovskites, all‐inorganic cesium‐based perovskites without volatile organic compounds have gained extensive interests because of the high thermal stability. However, they have a problem on phase transition from cubic phase (active for photo‐electric conversion) to orthorhombic phase (inactive for photo‐electric conversion) at room temperature, which has hindered further progress. Herein, novel inorganic CsPb1−xGexI2Br perovskites were prepared in humid ambient atmosphere without a glovebox. The phase stability of the all‐inorganic perovskite was effectively enhanced after germanium addition. In addition, the highest power conversion efficiency of 10.8 % with high open‐circuit voltage (VOC) of 1.27 V in a planar solar cell based on CsPb0.8Ge0.2I2Br perovskite was achieved. Furthermore, the highest VOC up to 1.34 V was obtained by CsPb0.7Ge0.3I2Br perovskite, which is a remarkable record in the field of all‐inorganic perovskite solar cells. More importantly, all the photovoltaic parameters of CsPb0.8Ge0.2I2Br perovskite solar cells showed nearly no decay after 7 h measurement in 50–60 % relative humidity without encapsulation

Plastic waste and microplastic issues in Southeast Asia

Plastic pollution on land and in oceans is currently a pressing environmental issue. The accumulation of waste has caused severe, irreversible impacts and consequences on marine life, ecosystems, and the environment due to the lack of good waste collection, treatment, and management systems. Limited resources and infrastructure constantly challenge waste management in Southeast Asia. Therefore, we will examine the current plastic situation and issues in Southeast Asia and gain an understanding of the issues of the existing waste management systems in those countries. Then, we will examine the current practices applied in tackling plastic pollution and review the collective commitment and actions of governments, private sectors, social organizations, stakeholders, and consumers, as the key players in ending plastic pollution