Browsing by Author "Peng, Xiaojin"
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Item Open Access Controlling homogenous spherulitic crystallization for high-efficiency planar perovskite solar cells fabricated under ambient high-humidity conditions(Wiley-VCH Verlag, 2019-10-25) Angmo, Dechan; Peng, Xiaojin; Seeber, Aaron; Zuo, Chuantian; Gao, Mei; Hou, Qicheng; Yuan, Jian; Zhang, Qi; Cheng, Yi‐Bing; Vak, DoojinThe influence of precursor solution properties, fabrication environment, and antisolvent properties on the microstructural evolution of perovskite films is reported. First, the impact of fabrication environment on the morphology of methyl ammonium lead iodide (MAPbI3) perovskite films with various Lewis‐base additives is reported. Second, the influence of antisolvent properties on perovskite film microstructure is investigated using antisolvents ranging from nonpolar heptane to highly polar water. This study shows an ambient environment that accelerates crystal growth at the expense of nucleation and introduces anisotropies in crystal morphology. The use of antisolvents enhances nucleation but also influences ambient moisture interaction with the precursor solution, resulting in different crystal morphology (shape, size, dispersity) in different antisolvents. Crystal morphology, in turn, dictates film quality. A homogenous spherulitic crystallization results in pinhole‐free films with similar microstructure irrespective of processing environment. This study further demonstrates propyl acetate, an environmentally benign antisolvent, which can induce spherulitic crystallization under ambient environment (52% relative humidity, 25 °C). With this, planar perovskite solar cells with ≈17.78% stabilized power conversion efficiency are achieved. Finally, a simple precipitation test and in situ crystallization imaging under an optical microscope that can enable a facile a priori screening of antisolvents is shown.Item Open Access Environmental blue CoAl2O4 pigment co-doped by Zn2+ and Mg2+: synthesis, structure and optical properties(Taylor & Francis, 2017-12-09) Peng, Xiaojin; Cheng, Jinshu; Yuan, Jian; Jin, Na; Kang, Junfeng; Hou, Yansheng; Zhang, QiNano-sized blue solid solutions ZnxMg0.5−xCo0.5Al2O4 (x = 0–0.5) have been synthesised by the Pechini method. Single-phase ZnxMg0.5−xCo0.5Al2O4 with crystallite size of ∼40 nm was identified by XRD measurement. The TG-DSC results indicated that the phase formation temperature of ZnxMg0.5−xCo0.5Al2O4 increased with the substitution of Zn2+/Mg2+ → Co2+ proceeding. The UV–vis spectra illustrated that the Zn0.3Mg0.2Co0.5Al2O4 pigment displayed the most intensive blue colour with the strongest absorbance appearing within the visible region. The FT-IR spectra suggested that the inversion degree of ZnxMg0.5−xCo0.5Al2O4 pigment reduces with the increase of Zn2+ rather than Mg2+, enabling to control the pigment colour by tuning the Zn2+ content. The FE-SEM images showed an irregular shaped morphology of ZnxMg0.5−xCo0.5Al2O4 crystal, different from the cubic-like morphology of CoAl2O4 crystal. The XPS results illustrated that the inversion of pure CoAl2O4 pigment is larger than that of Zn0.3Mg0.2Co0.5Al2O4. Both Zn0.2Mg0.3Co0.5Al2O4 and Zn0.3Mg0.2Co0.5Al2O4 show commercial potential in pigments application.Item Open Access Perovskite and organic solar cells fabricated by inkjet printing: progress and prospects(Wiley, 2017-09-27) Peng, Xiaojin; Yuan, Jian; Shen, Shirley; Gao, Mei; Chesman, Anthony S. R.; Yin, Hong; Cheng, Jinshu; Zhang, Qi; Angmo, DechanInkjet printing (IJP) technology, adapted from home and office printing, has proven to be an essential research tool and industrial manufacturing technique in a wide range of printed electronic technologies, including optoelectronics. Its primary advantage over other deposition methods is the low-cost and maskless on-demand patterning, which offers unmatched freedom-of-design. Additional benefits include the efficient use of materials, contactless high-resolution deposition, and scalability, enabling rapid translation of learning from small-scale, laboratory-based research into large-scale industrial roll-to-roll manufacturing. In the development of organic solar cells (OSCs), IJP has enabled the printing of many of the multiple functional layers which comprise the complete cell as part of an additive printing scheme. Although IJP is only recently employed in perovskite solar cell (PeSC) fabrication, it is already showing great promise and is anticipated to find broader application with this class of materials. As OSCs and PeSCs share many common functional materials and device architectures, this review presents a progress report on the IJP of OSCs and PeSCs in order to facilitate knowledge transfer between the two technologies, with critical analyses of the challenges and opportunities also presented.Item Open Access Preparation and Characterization of a Stable Nano-Sized ZnxCo1 – xAl2O4 Ink for Glass Decoration by Ink-jet Printing(MAIK Nauka/Interperiodica (МАИК Наука/Интерпериодика), 2017-06) Peng, Xiaojin; Zhang, Qi; Cheng, Jinshu; Yuan, Jian; Wu, Ya; Jie, JunnanA stable inorganic glass ink was prepared by mechanically grinding a mixture of a blue pigment(ZnxCo1 – xAl2O4) and low-melting-point glass powders in a specific organic solvent, which possesses a lower annealing temperature compared with ceramic ink. The ZnxCo1 – xAl2O4 based pigment was synthesized by solid-state reaction and the best sintering temperature should be at 1300°C or above according to the observation of XRD. ZnxCo1 – xAl2O4 shows blue color both in a powder form and coating. The average particle size of pigments and glass powders mixture decreases with the increase of glass powders and milling time. SEM cross-sectional images of annealed coating samples illustrate that the pigments are well dispersed in the ink layer and the glass adhesive binds well on the surface of glass plate, enhancing the mechanical strength of the ink layer. All the obtained results collectively revealed that the prepared nano-sized ZnxCo1 – xAl2O4 ink can be applied in glass decoration.