Perovskite solar cells (PSCs) are among the most promising photovoltaic technologies owing to their exceptional optoelectronic properties1,2. However, the lower efficiency, poor stability and reproducibility issues of large-area PSCs compared with laboratory-scale PSCs are notable drawbacks that hinder their commercialization3. Here we report a synergistic dopant-additive combination strategy using methylammonium chloride (MACl) as the dopant and a Lewis-basic ionic-liquid additive, 1,3-bis(cyanomethyl)imidazolium chloride ([Bcmim]Cl). This strategy effectively inhibits the degradation of the perovskite precursor solution (PPS), suppresses the aggregation of MACl and results in phase-homogeneous and stable perovskite films with high crystallinity and fewer defects. This approach enabled the fabrication of perovskite solar modules (PSMs) that achieved a certified efficiency of 23.30% and ultimately stabilized at 22.97% over a 27.22-cm2 aperture area, marking the highest certified PSM performance. Furthermore, the PSMs showed long-term operational stability, maintaining 94.66% of the initial efficiency after 1,000 h under continuous one-sun illumination at room temperature. The interaction between [Bcmim]Cl and MACl was extensively studied to unravel the mechanism leading to an enhancement of device properties. Our approach holds substantial promise for bridging the benchtop-to-rooftop gap and advancing the production and commercialization of large-area perovskite photovoltaics.
27 March 2019 in Journal of the American Chemical Society
Targeted modification of electronic structure is an important step in the optimization of Metal-Organic Frameworks (MOF) for photovoltaic, sensing and photocatalytic applications. The key parameters to be controlled include the band gap, the absolute energy position of band edges, the excited state charge separation and degree of hybridization between metal and ligand sites. Partial metal replacement, or metal doping, within secondary building units is a promising, yet relatively unexplored route to modulate these properties in MOFs. Therefore, in the present study, a general method for selecting metal dopant is worked out in theory and validated by experiment, retaining MIL-125 and UiO-66 as the model systems. Metal mixing enables targeted optimization of key electronic structure parameters. This method is applicable to any MOF architecture and can serve as a roadmap for future synthesis of MOFs with pre-defined properties.
11 July 2020 in Journal of the American Chemical Society
Electrocatalytic reduction of carbon monoxide into fuels or chemicals with two or more carbons is very attractive due to their high energy density and economic value. Herein we demonstrate the synthesis of a hydrophobic Cu/Cu2O sheet catalyst with hydrophobic n-butylamine layer and its application in CO electroreduction. The CO reduction on this catalyst produces two or more carbon products with a Faradaic efficiency of 93.5% and partial current density of 151 mA cm−2 at the potential of −0.70 V versus a reversible hydrogen electrode. A Faradaic efficiency of 68.8% and partial current density of 111 mA cm−2 for ethanol were reached, which is very high in comparison to all previous reports of CO2/CO electroreduction with a total current density higher than 10 mA cm−2. The as-prepared catalyst also showed impressive stability that the activity and selectivity for two or more carbon products could remain even after 100 operating hours. This work opens a way for efficient electrocatalytic conversion of CO2/CO to liquid fuels.
28 February 2017 in The Journal of Physical Chemistry Letters
With the fast-growing accumulation of electronic waste and rising demand for rare metals, it is compelling to develop technologies that can promotionally recover targeted metals, like gold, from waste, a process referred to as urban mining. Thus, there is increasing interest in the design of materials to achieve rapid, selective gold capture while maintaining high adsorption capacity, especially in complex aqueous-based matrices. Here, a highly porous metal-organic framework (MOF)–polymer composite, BUT-33–poly( para -phenylenediamine) (PpPD), is assessed for gold extraction from several matrices including river water, seawater, and leaching solutions from CPUs. BUT-33–PpPD exhibits a record-breaking extraction rate, with high Au 3+ removal efficiency (>99%) within seconds (less than 45 s), a competitive capacity (1600 mg/g), high selectivity, long-term stability, and recycling ability. Furthermore, the high porosity and redox adsorption mechanism were shown to be underlying reasons for the material’s excellent performance. Given the accumulation of recovered metallic gold nanoparticles inside, the material was also efficiently applied as a catalyst.