Various target samples were prepared by adhering 20μm thick Al foils to sapphire substrates. 0.2mm thick steel barrels with Φ0.6mm and Φ0.8mm diameter were attached to the surface of Al foils. A diffractive beam homogenizer was used to modify the laser pulse emitted from a Q-switched Nd:YAG laser. The unmodified beams presented a multi-ringed nonuniform energy profile, while numerous small energy spikes randomly distributed over the homogenized laser beam. The unmodified and homogenized beams at 80mJ were used to ablate the target samples, and the flight trajectories of Al flyers were visualized by a time-resolved shadowgraph technique. The images showed that more debris and fragments were formed at the radiation of the homogenized laser pulse, while a reverse results were obtained when barrels were employed. Moreover, the laser induced crater silhouettes presented differently in sizes and morphologies resulting from the change in the energy profiles pre- and post-homogenization. The flyer velocities were ~1300m/s regardless of the barrel parameters for unmodified laser ablation. While for homogenized lasers, the flyer velocity was up to ~1500m/s for free surface foils, and much lower velocities (~700m/s and ~1000m/s) were observed for Al foils covered with Φ0.6mm and Φ0.8mm barrel.
Organic-inorganic hybrid perovskite solar cells have been widely recognized as an excellent candidate for next-generation photovoltaic devices because of their easy processing and rapidly developing power conversion efficiency (PCE). Owing to the fact that the interface is sensitive to photoelectric conversion properties, many strategies are used to improve the interface wettability between perovskite precursor solution and the hole transport layer (HTL). In this study, we report a method of argon plasma treatment on the poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) layer which could effectively enhance the wettability because of the improvement in the chemical compositions and film morphologies of PEDOT:PSS. In contrast to untreated films, the wettability of PEDOT:PSS is increased by 3.3, 3.6 and 3.7 times based on the optimization of plasma power, treating time, and pressure, respectively. We also systematically described the timeliness of wettability from 0 to 8 hours after plasma treatment. The interface wettability shows a down trend with increasing storage time.