RESUMEN
Achieving high solar-to-hydrogen (STH) efficiency concomitant with long-term durability using low-cost, scalable photo-absorbers is a long-standing challenge. Here we report the design and fabrication of a conductive adhesive-barrier (CAB) that translates >99% of photoelectric power to chemical reactions. The CAB enables halide perovskite-based photoelectrochemical cells with two different architectures that exhibit record STH efficiencies. The first, a co-planar photocathode-photoanode architecture, achieved an STH efficiency of 13.4% and 16.3 h to t60, solely limited by the hygroscopic hole transport layer in the n-i-p device. The second was formed using a monolithic stacked silicon-perovskite tandem, with a peak STH efficiency of 20.8% and 102 h of continuous operation before t60 under AM 1.5G illumination. These advances will lead to efficient, durable, and low-cost solar-driven water-splitting technology with multifunctional barriers.
RESUMEN
Understanding and tailoring the physical behaviour of halide perovskites under practical environments is critical for designing efficient and durable optoelectronic devices. Here, we report that continuous light illumination leads to >1% contraction in the out-of-plane direction in two-dimensional hybrid perovskites, which is reversible and strongly dependent on the specific superlattice packing. X-ray photoelectron spectroscopy measurements show that constant light illumination results in the accumulation of positive charges in the terminal iodine atoms, thereby enhancing the bonding character of inter-slab I-I interactions across the organic barrier and activating out-of-plane contraction. Correlated charge transport, structural and photovoltaic measurements confirm that the onset of the light-induced contraction is synchronized to a threefold increase in carrier mobility and conductivity, which is consistent with an increase in the electronic band dispersion predicted by first-principles calculations. Flux-dependent space-charge-limited current measurement reveals that light-induced interlayer contraction activates interlayer charge transport. The enhanced charge transport boosts the photovoltaic efficiency of two-dimensional perovskite solar cells up to 18.3% by increasing the device's fill factor and open-circuit voltage.
RESUMEN
2D perovskites are a class of halide perovskites offering a pathway for realizing efficient and durable optoelectronic devices. However, the broad chemical phase space and lack of understanding of film formation have led to quasi-2D perovskite films with polydispersity in perovskite layer thicknesses, which have hindered device performance and stability. Here, a simple and scalable approach is reported, termed as the "phase-selective method", to fabricate 2D perovskite thin films with homogenous layer thickness (phase purity). The phase-selective method involves the dissolution of single-crystalline powders with a homogeneous perovskite layer thickness in desired solvents to fabricate thin films. In situ characterizations reveal the presence of sub-micrometer-sized seeds in solution that preserve the memory of the dissolved single crystals and dictate the nucleation and growth of grains with an identical thickness of the perovskite layers in thin films. Photovoltaic devices with a p-i-n architecture are fabricated with such films, which yield an efficiency of 17.1% enabled by an open-circuit voltage of 1.20 V, while preserving 97.5% of their peak performance after 800 h under illumination without any external thermal management.
RESUMEN
PURPOSE: To elucidate the relationship between video game (VG) play and interventional radiology (IR) technical skills in medical students. MATERIALS AND METHODS: Twenty medical students recruited at our institution's IR symposium completed a survey to ascertain demographics and prior VG experience, then participated in a 3-part trial of skills assessing IR and VG skill and visuospatial aptitude (VSA). IR skill was evaluated via an endovascular simulation task, VG skill by performance on three separate VGs, and VSA using the Cube Comparison test. Regression analysis was tested the strength of relationship between IR skill and VG experience, VG skill, and VSA, respectively, and participants were stratified by IR skill to top and bottom halves for survey-response comparison. RESULTS: There was no correlation between either VG skill or visuospatial aptitude and IR skill (r = -0.22, p = 0.35; and r = 0.14, p = 0.57). Greater number of years playing VGs correlated with superior IR skill (Spearman's rho=-0.45, p<0.05). Students who selected IR as their specialty of interest had extensive VG experience, playing for > 15 years (n = 4, 80%), at least 10 hours per week at their peak (n = 3, 60%), and reported being either "skilled" or "highly skilled" at VGs (n = 3, 60%). CONCLUSIONS: In our study, though limited by power, number of years playing VGs correlated positively with IR skills in medical students. Prior VG experience may predict an early advanced capacity to learn IR skills and an interest in the specialty.