Browsing by Author "Yang, Ying-Guo"

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Enhanced crystallization and stability of perovskites by a cross-linkable fullerene for high-performance solar cells
(2016)
Li, Meng
;
Chao, Yi-Hsiang
;
Kang, Tin
;
Wang, Zhao-Kui
;
Yang, Ying-Guo
Organic-inorganic halide perovskite solar cells (PSCs) still suffer from the issues of poor reproducibility and inferior stability despite their considerable increase in efficiency. Here, we demonstrate planar PSCs with simultaneously improved device characteristics and stability by introducing a cross-linkable [6,6]-phenyl-C-61-butyric styryl dendron ester (PCBSD) into CH3NH3PbIxCl3-x perovskites. The cross-linkable merit of C-PCBSD can enhance the crystallization of perovskites and address the issue of low electron extraction efficiency. In addition, the anti-solvent network of C-PCBSD facilitates the sequential solution process and prevents washing by the solvent used in the upper layer. The C-PCBSD network resisted the moisture incursion and protected the interfaces from erosion, and it passivated the voids or pinholes generated in the bulk active layer. As a result, an outstanding PSC with a power conversion efficiency of 17.21% is achieved with evidently improved cell stability.
Perovskite Grains Embraced in a Soft Fullerene Network Make Highly Efficient Flexible Solar Cells with Superior Mechanical Stability
(2019-06-01)
Li, Meng
;
Yang, Ying-Guo
;
Wang, Zhao-Kui
;
Kang, Tin
;
Wang, Qiong
Halide perovskite films processed from solution at low-temperature offer promising opportunities to make flexible solar cells. However, the brittleness of perovskite films is an issue for mechanical stability in flexible devices. Herein, photo-crosslinked [6,6]-phenylC(61)-butyric oxetane dendron ester (C-PCBOD) is used to improve the mechanical stability of methylammonium lead iodide (MAPbI(3)) perovskite films. Also, it is demonstrated that C-PCBOD passivates the grain boundaries, which reduces the formation of trap states and enhances the environmental stability of MAPbI(3). Thus, MAPbI(3) perovskite solar cells are prepared on solid and flexible substrates with record efficiencies of 20.4% and 18.1%, respectively, which are among the highest ever reported for MAPbI(3) on both flexible and solid substrates. The result of this work provides a step improvement toward stable and efficient flexible perovskite solar cells.