Browsing by Author "Liao, Liang-Sheng"

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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.
Graphdiyne-modified cross-linkable fullerene as an efficient electron-transporting layer in organometal halide perovskite solar cells
(2018-01-01)
Li, Meng
;
Wang, Zhao-Kui
;
Kang, Tin
;
Yang, Yingguo
;
Gao, Xingyu
Interface engineering resulting in good contact, enhanced transport capability, and matched energy levels is indispensable and critical for the development of high-performance planar perovskite solar cells (PSCs). Here, we report an excellent electron-transporting layer (ETL) that can simultaneously enhance the stability and efficiency of n-i-p planar PSCs. Large pi-conjugated graphdiyne (GD) was introduced into cross-linkable fullerene [6,6]-phenyl-C61-butyric styryl dendron ester (PCBSD) to improve the film orientation. Raman spectroscopy and 2D grazing incidence X-ray diffraction (GIXRD) measurements revealed that a strong pi-pi stacking interaction occurred between GD and cross-linkable PCBSD (C-PCBSD), generating a face-on stacked composite film. The orientated C-PCBSD: GD films was favorable for the growth and crystallization of the subsequent perovskite films and provided the merits of superior electron mobility, efficient charge extraction and energy-level tailoring. In addition, the thermally annealed C-PCBSD: GD film provided an adhesive film network with sufficient solvent resistance. Consequently, the perovskite devices delivered a power conversion efficiency of 20.19% with obviously improved cell stability. This indicates a potential application of GD-modified cross-linkable fullerene as an ETL in n-i-p structure PSCs. The finding opens a new route to deposit the fullerene films with ordered orientation by 2D materials with large pi-conjugation, and thus to control the subsequent perovskite crystallization.
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.