Structural, Photophysical, and Electrical Properties of Methylamine-Treated Perovskite Thin Films

• Main Authors: Chiao, Guan-Haw, 喬冠豪
• Other Authors: Sun, Kien-Wen
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/pzwcc9

碩士 === 國立交通大學 === 應用化學系碩博士班 === 107 === Organic-inorganic hybrid perovskites (OIHP) have many novel properties and have been applied to the light absorbing material of solar cells, as well as been successfully demonstrated in optoelectronics, such as light-emitting diodes and lasers. Easy fabrication of polycrystalline perovskite thin films with high crystallinity has been essential to the rapid advancement of the photovoltaic and optoelectronic performance. However, there still remain much demands for further improvement since there exists significant inhomogeneity in the polycrystalline films, and little is known about the defect physics. Herein, we demonstrated that, with treatment of methylamine (MA) vapor to the spin-coated perovskite film, quality of the film was significantly improved structurally, topologically and electronically, which can possibly lead to more efficient and reproducible photovoltaic and optoelectronic devices. Our XRD and SEM results clearly indicated increase inthe homogeneity, grain size and crystallinity of the spin-coated MAPbI3 and MAPbBr3thin films after treated with the MA vapor. The influence of MA vapor treatment in the emission, absorption, energy gap, and carrier lifetime were also investigated using the absorption, steady-state, and time-resolved photoluminescence spectroscopy. The carrier concentrations, mobility, electrical resistivity, and photoconductivity of the treated MAPbI3and MAPbBr3thin film were also studied using the Hall coefficient and current-voltage measurements. The improvement in morphology and crystallinity of theMA-treatedMAPbI3 and MAPbBr3 thin films was clearly reflected in the observed enhanced carrier mobility, lifetime, and electrical conductivity. The bandgaps of the MA-treated films were found slightly blue-shifted due to the reduced defect states in the band tail.