Yuli Xiong

Enhanced electronic properties in CH3NH3PbI3via LiCl mixing for hole-conductor-free printable perovskite solar cells

By mixing perovskite MAPbI3 (MA = CH3NH3+) with LiCl, an effective one-step drop-coating approach was developed to improve the performance of hole-conductor-free printable perovskite solar cells. The LiCl-mixed perovskite exhibited superior electronic properties because of the improved conductivity of the perovskite layer enabling faster electron transport. LiCl-mixing also improved the crystallinity and morphology of the perovskite layer. As a consequence, perovskite solar cells prepared using the LiCl-mixed perovskite as the light harvester produced higher performances compared with the unmixed perovskite, improving the power conversion efficiency from 10.0% to 14.5%.

Boron-Doped Graphite for High Work Function Carbon Electrode in Printable Hole-Conductor-Free Mesoscopic Perovskite Solar Cells

Work function of carbon electrodes is critical in obtaining high open-circuit voltage as well as high device performance for carbon-based perovskite solar cells. Herein, we propose a novel strategy to upshift work function of carbon electrode by incorporating boron atom into graphite lattice and employ it in printable hole-conductor-free mesoscopic perovskite solar cells. The high-work-function boron-doped carbon electrode facilitates hole extraction from perovskite as verified by photoluminescence. Meanwhile, the carbon electrode is endowed with an improved conductivity because of a higher graphitization carbon of boron-doped graphite. These advantages of the boron-doped carbon electrode result in a low charge transfer resistance at carbon/perovskite interface and an extended carrier recombination lifetime. Together with the merit of both high work function and conductivity, the power conversion efficiency of hole-conductor-free mesoscopic perovskite solar cells is increased from 12.4% for the pristine graphite electrode-based cells to 13.6% for the boron-doped graphite electrode-based cells with an enhanced open-circuit voltage and fill factor.

Efficient Compact-Layer-Free, Hole-Conductor-Free, Fully Printable Mesoscopic Perovskite Solar Cell

A compact-layer-free, hole-conductor-free, fully printable mesoscopic perovskite solar cell presents a power conversion efficiency of over 13%, which is comparable to that of the device with a TiO2 compact layer. The different wettability of the perovskite precursor solution on the surface of FTO and TiO2 possesses a significant effect on realizing efficient mesoscopic perovskite solar cell. This result shows a promising future in printable solar cells by further simplifying the fabrication process and lowering the preparation costs.

Spacer improvement for efficient and fully printable mesoscopic perovskite solar cells

Highly dispersible TiO2@ZrO2 nanoparticles are synthesized to prepare an ultra-flat and crack-free spacer film, leading to an enhanced insulating ability compared to a conventional spacer. The average power conversion efficiency of fully printable mesoscopic perovskite solar cells is improved from 10.2% to 12.5%, and the highest steady output power conversion efficiency is 13.8%.

Mixed (5-AVA)xMA1−xPbI3−y(BF4)y perovskites enhance the photovoltaic performance of hole-conductor-free printable mesoscopic solar cells

We report on a simple one-step solution processing strategy to fabricate new stable mixed cation/mixed halide (5-AVA)xMA1−xPbI3−y(BF4)y perovskite solar cells. The results showed that the power conversion efficiency (PCE) of the optimized mixed (5-AVA)0.034MA0.966PbI2.95(BF4)0.05 perovskite solar cells was substantially increased to 15.5% with a remarkably high VOC of 0.97 V. We have analyzed different mixed perovskites focusing on the characterization of the charge recombination by means of intensity-modulated photovoltage spectroscopy. In addition, our study discloses that the incorporation of MABF4 into the (5-AVA)0.034MA0.966PbI3 perovskite helps to reduce the charge recombination in the mixed perovskite cells, thus improving the open circuit voltage of the device. Furthermore, the new mixed perovskite was demonstrated to produce high-quality perovskite crystals and enhance the conductivity of the mixed perovskite.

Fully printable hole-conductor-free mesoscopic perovskite solar cells based on mesoporous anatase single crystals

Mesoporous anatase singe crystal provides a large surface area and less carrier traps as compared to polycrystals; however, it is generally prepared with a particle size in micrometers by a complex method; this hinders its application as electron transport materials (ETMs) for mesoscopic perovskite solar cells (MPSCs). Herein, we fabricated a small-sized mesoporous anatase single crystal with a large surface area (169 m2 g−1) and an oliver-shape (about 120 nm in length and 60 nm in width) by a simple method and applied it as an ETM into a hole-conductor-free fully printable MPSC. As expected, a high-quality film was formed, and the device showed an obvious increase in efficiency as compared to the P25 (commercial TiO2)-based device due to the faster electron extraction from perovskite to the ETM. This suggests that the mesoporous anatase single crystal is a promising ETM candidate for producing efficient fully-printable hole-conductor-free MPSCs.

N-type metal-oxide electron transport layer for mesoscopic perovskite solar cells

To meet the challenge of continuously increasing global energy demands, organic-inorganic halide based perovskite solar cells (PSCs) have garnered great attention from the photovoltaic research community for their low cost and high efficiency. The efficiency of perovskite-based mesoscopic solar cells increases rapidly, from 3.8% in 2009 to 22.1% in 2016. N-type metal-oxide electron transport layer, as one of the important components in mesoscopic PSCs (MPSCs), acts as not only a scaffold layer for the growth of perovskite crystals, but also a layer to supply transfer pathways for electrons injected from perovskites. In this review, we discussed recent published reports of MPSCs with the focus on n-type metal-oxide electron transport layer in MPSCs. The scaffold materials, scaffold nanostructure, and scaffold/perovskite interface engineering are considered, and the effects of these modifications of scaffolds on the performance of MPSCs are summarized in this review.摘要为了满足日益增长的世界能源需要, 有机-无机卤化物材料制备的钙钛矿太阳能电池因成本低廉和转换效率高, 受到光电材料研究学术领域的高度重视. 其获得公证的光电转换效率在短时间内由2009年的3.8% 提高到2016年的22.1%. n型电子传输层, 作为介观钙钛矿太阳能电池的重要组成部分, 不仅作为钙钛矿晶体生长的骨架层, 还为钙钛矿的激发电子注入提高传输通道. 因此, 本文简要评述了介观钙钛矿太阳能电池的最新进展, 重点介绍了n型金属氧化物电子传输层在介观钙钛矿太阳能电池中的研究近况, 主要包括: 骨架的材料, 骨架的形貌以及骨架同钙钛矿材料层的界面, 同时还探讨了这些n型金属氧化物电子传输层的改性和修饰对介观钙钛矿太阳能电池性能的影响.

A software system for optimum design and trajectory planning of robots

This paper describes an interactive graphic robot-simulation system that has been developed to carry out optimum design and to provide a robot-independent off-line motion-planning tool. The system includes model building, optimum design, trajectory planning and graphic display, and is capable of detecting collisions. Emphasis is given to graphics facilities (translation, scaling, removal of hidden lines, image animation, etc.). The system is highly interactive through a menu technique. It was written in Turbo Pascal and implemented on an IBM PC microcomputer.

Machine intelligence arbitration for geometrical form errors and geometrical adaptive control strategy

Evaluation of form errors is specified by the ISO in terms of the minimum-zone concept. A method is proposed for numerically determining the form errors based on the minimum-zone evaluation, and a general criterion is given for arbitrating the form errors. A general procedure for “machine-intelligent” arbitration is developed for geometrical form errors. A geometrical adaptive control strategy is presented on the basis of machine-intelligent arbitration. The use of the control strategy provides a convenient structure for the control system and produces an optimal control procedure for the cutting and grinding processes.