Search

Alkylamines with different chain lengths including n-butylamine, n-hexylamine, and n-octylamine, are applied to regulate the CsPbIBr2 perovskite film quality by strain engineering. The status of residual strains is controllably modulated, resulting in improved efficiency and stability of carbon-based hole-transport-material free CsPbIBr2 perovskite solar cells. [ABSTRACT FROM AUTHOR]

The passivation of the defects derived from rapid‐crystallization with electron‐donating molecules is always a prerequisite to obtain desirable perovskite films for efficient and stable solar cells, thus, the in‐depth understanding on the correlations between molecular structure and passivation capacity is of great importance for screening passivators. Here, we introduce the double‐ended amide molecule into perovskite precursor solution to modulate crystallization process and passivate defects. By regulating the intermediate bridging skeletons with alkyl, alkenyl and benzene groups, the results show the passivation strength highly depends on the spin‐state electronic structure that serves as an intrinsic descriptor to determine the intramolecular charge distribution by controlling orbital electron transfer from the donor segment to acceptor segment. Upon careful optimization, the benzene‐bridged amide molecule demonstrates superior efficacy on improving perovskite film quality. As a physical proof‐of‐concept, the carbon‐based, all‐inorganic CsPbI2Br solar cell delivers a significantly increased efficiency of 15.51 % with a remarkably improved stability. Based on the same principle, a champion efficiency of 24.20 % is further obtained on the inverted (Cs0.05MA0.05FA0.9)Pb(I0.93Br0.07)3 solar cell. These findings provide new fundamental insights into the influence of spin‐state modulation on effective perovskite solar cells. [ABSTRACT FROM AUTHOR]

Mixed‐halide perovskites are emerging as excellent photovoltaic candidates because of their tunable bandgaps for semitransparent and tandem perovskite solar cells. However, the notorious film quality originated from the rapidly downward crystallization process susceptibly propagates enormous detrimental defects, which deteriorate the photovoltaic performance and accelerate halide segregation. To address this issue, herein, a multilayer alkalis‐intercalated‐vermiculite is employed as pre‐buried interface modifier to regulate the perovskite lattice property. The matchable lattice structure between perovskite and vermiculite by forming Pb─O bond not only releases the interfacial strain during the film growth but also the embedded alkalis ions can gradually diffuse into perovskite lattice to form a favorable vertical gradient owing to the weak interlamellar van der Waals interaction, playing bis‐roles of atomical lubricant and ion‐reservoir to eliminate detrimental defects. As a result, the film quality and lattice stability is significantly improved with suppressed phase segregation for mixed‐halide perovskites, accompanying a champion efficiency of 11.42% for carbon‐based CsPbIBr2 device, 15.25% for carbon‐based CsPbI2Br device and 23.17% for p‐i‐n inverted (Cs0.05MA0.05FA0.9)Pb(I0.93Br0.07)3 cell. This work provides a new strategy on buried interface engineering for making high‐efficiency and stable perovskite platforms. [ABSTRACT FROM AUTHOR]

Although noble metal-based catalysts are expensive, they are still the most promising oxygen evolution reaction (OER) electrocatalysts. Therefore, it is desirable to reduce the load of the precious metal without affecting the OER performance of the catalyst. In this work, we have innovatively proposed a strategy of interfacial anchoring of Ru atoms and successfully achieve the dispersion of precious metal ruthenium atoms in cross-growing NiS and NiSe multifaceted structures. The dispersion of Ru ensures Ru–NiS/NiSe/NF more active sites and more adequate contact with the electrolyte, which further improves the oxygen production property of the catalyst. As a direct outcome, the target catalyst (Ru–NiS/NiSe/NF) only requires low overpotential of 453 mV to excite a current density of 1000 mA cm−2. Meanwhile, it can remain stable to catalyze the OER for more than 50 h (200 mA cm−2), which gives it great application potential in future large-scale electrolytic water processes. This work provides a new perspective for the efficient utilization of precious metal for designing the efficient and stable OER electrocatalyst. • Staggered growth of NiS and NiSe builds a large number of highly active interfaces. • Highly reactive interface-anchored Ru enables high dispersion at the atomic level. • Ru–NiS/NiSe/NF only requires low overpotential of 453 mV at 1000 mA cm−2 to catalyze OER. • Ru–NiS/NiSe/NF operates stably for at least 50 h at 200 mA cm−2 for OER. [ABSTRACT FROM AUTHOR]

Highly dispersed nickel-platinum alloy with octahedral structure loaded on the surface of the carbon layer (NiPt/C) has been rationally designed and synthesized. The excellent electrical conductivity and small size of the alloy provides rapid electron transport and large electrolyte contact area for OER process. The pre-oxidation of Pt at OER potential contribute to the rapid production of nickel hydroxide, thus promoting the deposition of more iron active sites on its surface. [Display omitted] • An ultra-high dispersion NiPt/C alloy with octahedral structure is prepared. • The OER activity of NiPt/C catalyst is greatly enhanced through the modulation of Fe3+-containing electrolyte. • The oxidation of Pt can effectively contribute to production of more nickel hydroxide, and thus promotes the deposit of more Fe on the surface of NiPt/C. • The NiPt/C catalyst modified by Fe only requires low overpotential of 242 mV to output 1000 mA cm−2 oxygen evolution current. Constructing ultra-high activity, highly efficient and robust oxygen evolution reaction (OER) electrocatalysts, especially at large current density, plays a key role in the development of the electrolytic water industry but remains challenging. Highly dispersed alloy compound with large electrolyte contact area and excellent internal conductivity is considered as a kind of ideal candidate. Here, we have rationally designed and synthesized a nickel-platinum alloy with octahedral structure loaded on the surface of the carbon layer (NiPt/C). Under the in-situ modulation of the iron-containing electrolyte, the Fe modified NiPt/C catalyst displays an amazing OER activity in 1 M KOH, and only requires low overpotentials of 183 and 242 mV to reach 100 and 1000 mA cm−2, respectively. The comprehensive characterization analysis and property measurements reveal that the pre-oxidation of Pt at OER potential contribute to the rapid production of nickel hydroxide, thus promoting the deposition of more iron active sites on its surface. Moreover, the Pt/C/CP(−)//NiPt/C/CP(+) couple embedded in anion-exchange membrane water electrolyser also displays a low cell voltage of 2.03 V at 1000 mA cm−2 with significant electrochemical stability, which endows it a great potential in the field of hydrogen production and electrochemical energy storage. [ABSTRACT FROM AUTHOR]

The integration of SWCNT and WO 3 passivates the defects of perovskite film and simultaneously improves carrier transport, interfacial energy level alignment and hole extraction, which helps the carbon-based all-inorganic CsPbBr 3 PSCs achieve a champion PCE up to 10.47% and excellent humidity-heat stability. [Display omitted] • The SWCNT with oxygen-containing edge groups heals the defects of perovskite film. • The incorporation of SWCNT improves the interfacial carriers transport and contact. • The integration of WO 3 with SWCNT lowers energy barrier for enhanced hole extraction. • The unsealed PSCs achieve a champion PCE of 10.47% and high humidity-heat stability. The construction of efficient interfacial charge transfer and extraction plays an essential role in improving the photovoltaic performance of perovskite solar cells (PSCs). Herein, the single-walled carbon nanotube (SWCNT) and WO 3 are integrated as a robust hole extractor for all-inorganic CsPbBr 3 PSCs. The introduction of SWCNT with high carrier transport behavior and numerous oxygen-containing edge groups not only promotes the hole transport from CsPbBr 3 film to carbon back electrode, but also passivates the metal ion defect states within the CsPbBr 3 film. The further integration of WO 3 hole transport materials compensates for the energy level gap between the perovskite film and the carbon electrode to decrease interfacial energy loss and boosts hole extraction. Benefiting from the collaborative promotion of charge transport and extraction by SWCNT and WO 3 , the tailored CsPbBr 3 PSCs without encapsulation achieve a champion power conversion efficiency of 10.47 % and a long-term stability with 91.3 % retention of the initial efficiency under high temperature and humidity conditions for 800 h. [ABSTRACT FROM AUTHOR]

Manipulating the built-in electric field (BIEF) in the catalyst to regulate the electronic structure and improve the carrier transport is a promising approach, but it is rarely applied in the design of hydrogen evolution reaction (HER) catalysts. In this study, the electrochemical microenvironment of nickel phosphide supported on nickel foam (Ni 2 P/NF) has been modified by introducing tungsten oxide (WO 3) through simple ion group exchange strategy, thereby expanding the BIEF and enhancing the electron transport property. As a direct outcome, the target catalyst (20-WO 3 /Ni 2 P/NF) exhibits ultralow overpotential of 301 mV at high current density of − 1000 mA cm−2. Additional characterization and density functional theory calculations demonstrate that the WO 3 can not only serve as a new hydrogen adsorption active site, but also effectively decrease the dissociation energy of water molecules at the nickel site, which results in rapid production and consumption of protons and enhancing the overall catalytic activity. [Display omitted] • A WO 3 -regulated Ni 2 P/NF has been developed by the method of ion-group exchange and low temperature phosphating strategy. • The modification of WO 3 expands the BIEF of Ni 2 P/NF and promote the rapid dissociation of water molecules on it. • The newly introduced WO 3 can be used as the active site of hydrogen adsorption. • The 20-WO 3 /Ni 2 P/NF exhibits the superior HER activity and only requires low overpotential of 301 mV to reach 1000 mA cm−2. [ABSTRACT FROM AUTHOR]

[Display omitted] A perovskite nanocrystal-molecular hybrid is fabricated to heal the defective perovskite surface. Arising from the role of perovskite nanocrystals as electron and ion reservoirs simultaneously, the soft perovskite lattice is well solidified, significantly improving the efficiency and stability of all-inorganic CsPbI x Br 3-x perovskite solar cells. • An organic molecule bound CsPbBr 3 nanocrystal is fabricated to passivate the perovskite surface. • The passivation ability is enhanced owing to the energy transfer between nanocrystal and organic molecule. • A champion efficiency up to 11.60% for all-inorganic CsPbIBr 2 cell and 14.44% for CsPbI 2 Br cell is achieved. • The unencapsulated device shows excellent tolerance under harsh conditions. Electron cloud density around the functional group of Lewis-base molecule (passivator) highly determines the interaction strength with undercoordinated Pb2+ in perovskite film. With the aim to maximize this scenario, herein, we fabricate a thermally-activated delayed fluorescence molecule (3,4,5,6-tetrakis(3,6-diphenylcarbazol-9-yl)-1,2-dicyanobenzene, 4CzPN-Ph) bound CsPbBr 3 nanocrystal (NC) to heal the defective perovskite surface. Because of the suitable energy alignment, there is a Förster or Dexter triplet energy transfer process from CsPbBr 3 NC donor to 4CzPN-Ph acceptor under light irradiation, leading to the increased electron density within 4CzPN-Ph molecule and thus the enhanced passivation ability. Together with the formation of compositional gradient layer owing to the halide exchange reaction with CsPbBr 3 NCs, the stable perovskite film with reduced defect is obtained, consequently promoting the efficiency up to 11.60 % for CsPbIBr 2 and 14.44 % for CsPbI 2 Br carbon-based devices, with excellent durability under harsh conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Low edge defects of CQDs induced by MBA functionalization improve carrier transport. • The MBA/CQDs with high healing effect holistically passivate the defects of PVK film. • The deeper HOMO of MBA/CQDs reduces energy barrier for increased hole extraction. • The unsealed device achieves a best PCE of 10.40% and high humidity-heat stability. The effective improvement of interfacial charge extraction and inhibition of charge recombination are crucial for promoting the performance of perovskite (PVK) solar cells (PSCs). Here, the N,N'-methylenebisacrylamide-functionalized carbon quantum dots (MBA/CQDs) with defects passivation effect and appropriate energy levels are proposed as a back interface modifier for carbon-based CsPbBr 3 PSCs. The functionalization of MBA molecules not only increases the content of sp 2 hybrid carbon in CQDs, but also expands the passivation effect of CQDs on surface defects of PVK films by introducing carbonyl and amino groups, which improves the carrier transport and reduces the carrier nonradiative recombination. Additionally, the modification of MBA/CQDs provides an intermediate energy level at the PVK/carbon back interface, which boosts hole extraction and lowers energy loss. Finally, a leading-edge power conversion efficiency of 10.40 % is derived for the MBA/CQDs modified champion device, which is significantly improved compared to the 7.02 % efficiency for the original CsPbBr 3 PSCs. Furthermore, the unpackaged CsPbBr 3 PSCs with MBA/CQDs have an excellent stability, maintaining an initial efficiency of 92 % after 30 days of storage at high humidity (85 % relative humidity) and temperature (85 °C) in air. [ABSTRACT FROM AUTHOR]