Pengyun Zhang,Jie Xiong,Wei-Hsiang Chen,Pingfan Du,Lixin Song
In recent years, air-processed MAPbI3 perovskite solar cells (PSCs) have attracted widespread interest from researchers worldwide because of their simple and low-cost fabrication process. Nonetheless, the ambient conditions usually bring about many adverse effects, such as imperfect crystallization and numerous defects in perovskite films, which seriously impact both the photoelectric performance and stability of the device. Therefore, in this work, a polymer dual-passivation strategy was employed by introducing ammonium polyphosphate (APP) as an additive to the green anti-solvent to accurately modify the perovskite layer. APP, which has abundant phosphate and ammonium groups, could simultaneously fill the I/Pb vacancies by Lewis acid–base reactions to restrain defect formation and improve the power conversion efficiency (PCE) of the ultimate device. On the other hand, the long molecular chains of the polymer with a certain flexural ability were easily congregated at the grain boundaries of the perovskite grains, thus enhancing the bending resistance. Consequently, high-quality perovskite films with a dense morphology and large grain size were obtained. Because of the reduced defect density and suppressed non-radiative recombination, the optimal PSC attained a champion PCE of 20.87% with negligible hysteresis. Furthermore, the non-encapsulated APP-modified flexible device also exhibited excellent bending resistance. Only 20% of its normalized PCE was lost after 150 bending cycles at room temperature. This simple, green, low-cost, and reliable strategy for preparing high-efficiency PSCs with good stability can facilitate its commercialization.
Yunfan Li,Zhiwang Yang,Jie Guan,Qibin Yan,Ziqiang Lei
Epoxy resin (EP) is an industrially essential polymer widely used in electronic packaging, adhesives, and construction. Despite its utility, the high flammability of EP poses a significant safety risk. In this study, a novel chitosan-derived organic-inorganic hybrid flame retardant (CPMM) was synthesized, which was then combined with ammonium polyphosphate (APP) and added to epoxy resin (EP) to produce high-performance flame-retardant epoxy thermosets. Samples containing 7.5 wt% CPMM and 7.5 wt% APP reached a limiting oxygen index (LOI) of 30.5 % and a V-0 rating, along with a marked decrease in peak heat release rate from 1447.0 kW/m 2 to 267.1 kW/m 2 compared to pure EP. Thermogravimetric analysis indicated that the synergistic effect of CPMM and APP promotes the formation of more complete intumescent char structures, thereby enhancing the flame-retardant properties of the epoxy thermosets. Furthermore, mechanical performance tests showed improvements in both tensile and flexural strengths due to the robust interaction between CPMM and the matrix. This study provides a promising strategy for the design of bio-based organic-inorganic hybrid flame retardants and epoxy thermosets with enhanced performance.
危险品化学品经营许可证（带存储）