The crystallization evolution in solution-processed films is critical to the performance and stability of perovskite solar cells. However, the crystallization kinetics of all-inorganic perovskites remain poorly understood due to experimental challenges in observing polycrystalline cluster kinetics during annealing. Using temperature-controlled laser scanning confocal microscopy, we performed in situ monitoring during annealing. Results show that enhanced dicoumarol (DIC)-perovskite precursor interactions promote spontaneous formation of DIC-Cs+[PbI3-x Br x ]- (delta-phase) heterogeneous seeds. This suppresses solvent-dominated intermediate phases and promotes solvent volatilization. The effective diffusion activation energy increased from 24.5 to 26.9 kJ mol-1, significantly retarding crystal growth. The average cluster growth rate decreased from 320 to 237 nm s-1. The resulting CsPbI3-x Br x films exhibit high crystallinity, reduced trap density, and extended carrier lifetime, enabling a power conversion efficiency of 22.14% and improved environmental stability. This work provides direct in situ insights into cluster growth, guiding the use of heterogeneous seeds for high-quality all-inorganic perovskite films.
The traditional electro-Fenton (EF) process is limited by the generation and activation of hydrogen peroxide (H2O2). The electrochemical three-electron oxygen reduction reaction (3e- ORR) could directly activate molecular oxygen to form hydroxyl radicals (center dot OH), which opens up a path for the development of ecofriendly water treatment technologies. However, the main limitation of the 3e- ORR reaction at present is the lack of low-cost and high-selectivity catalytic current collectors. Herein, through coupling the 2e- active Ni sites with the common Fe and Mn sites in the Fenton reaction, the amorphous NiFeMn alloy catalytic film (A-NFM) was successfully deposited onto the current collector via a high-efficiency, reproducible, and self-developed filtering cathode vacuum arc (FCVA) codeposition system. The A-NFM could successfully selectively reduce O2 to center dot OH through the 3e- pathway, thereby avoiding the generation and activation of H2O2 in the Fenton process. The A-NFM can rapidly and completely remove ciprofloxacin within 30 min, achieving an apparent rate constant of 0.132 min-1, which is comparable to the most advanced oxidation processes currently available. Moreover, after 100 cycles, the degradation efficiency remains stable, indicating that this system has good stability in practical applications. This strategy can efficiently generate in situ center dot OH, opening up a path for the development of green water treatment technologies.
The simultaneous generation of clean H2 fuel and high-value compounds will improve the utilization efficiency of solar energy. However, conventional photocatalysts often exhibit slow dynamics of photogenerated charge carriers and insufficient utilization of visible light. Herein, the hollow cage CoS x modified asymmetric Zn0.5Cd0.5S (ZCS) nanoparticles of CoS x /ZCS samples are effectively synthesized, and they exhibit the synergistic effects of the bulk electric field (BEF) and local surface electric field (LSEF). Thus, the photogenerated electrons in the [Zn-S] region are guided through the [Cd-S] region, ultimately migrating directionally to the hollow cage CoS x . Notably, the catalyst of 1.6%-CoS x /ZCS exhibits yields of 20.1 mmolg-1h-1 for hydrogen production and 35.2 mmolg-1h-1 for benzaldehyde (BAD), which are 3.79-fold and 4.57-fold, respectively, compared to the original ZCS catalyst. This advancement marks a significant improvement in directing charge flow and facilitating the utilization of visible light to enhance photocatalytic efficacy.
Low-dimensional perovskites have emerged as a possible method for enhancing the performance of perovskite solar cells (PSCs). Nevertheless, cation migration across 2D and 3D layers disrupts octahedral networks, resulting in a loss of efficiency over time. This article reports the use of 1D@3D perovskite induced by a large 2-diethylaminoethyl chloride cation template. The one-dimensional solar cell capacitance simulator is employed to propose and calculate the photovoltaic (PV) merits of the 1D@3D-structured PSC with tin oxide (SnO2) and Spiro-OMeTAD charge-transporting materials. The designed FTO/SnO2/1D@3D perovskite/Spiro-OMeTAD/Au structure showed a proper energy-level frontier at interfaces with the appropriate material characteristics. The PV parameters of the PSCs are explored by changing the thickness, p-type doping level, and bulk defect density of the perovskite film. In addition, the SnO2 and Spiro-OMeTAD layers are optimized in terms of doping concentration and effective density of states. Moreover, we have assessed the thermal stability of the proposed PSC by altering the operating temperature. With this approach, high-performance and stable 1D@3D-structured cells with good thermal stability, demonstrating an impressive power conversion efficiency of 28.398% at 280 K, are achieved.
Molecular weight optimization is crucial for high-performance stretchable conjugated polymer films. However, an in-depth understanding of molecular weight distribution on solution assembly, film microstructures, and electrical/mechanical properties of conjugated polymers is lacking. Herein, a model conjugated polymer, poly(indacenodithiophene-co-benzothiadiazole) (IDTBT), with a similar weight-average molecular weight but different polydispersity indexes (PDIs) of 3.2, 2.4, and 1.6 is investigated. The low-PDI polymer, containing a high content of homogeneous long chains, facilitates sufficient interchain aggregation caused by the enhanced chain entanglement and prolonged aggregation dynamics, which creates a low-crystallinity film containing long-chain well-connected aggregates and chain entanglement networks. Consequently, the charge mobility increases from 2.1 to 3.1 cm2 V-1 s-1 as PDI decreases from 3.2 to 1.6. During stretching, the polymer chains align more effectively along the strain direction in the low-PDI film, which creates more dynamic sliding sites and short-range aggregates to dissipate the strain energy. Thus, the low-PDI polymer film exhibits a high charge mobility of 1.0 +/- 0.1 cm2 V-1 s-1 at 100% strain and 0.9 +/- 0.1 cm2 V-1 s-1 after 100 cycles of stretching-releasing at 25% strain, which significantly outperforms the high-PDI film. This work demonstrates the significance of polydispersity optimization for developing mechanically robust polymer semiconductor films in stretchable electronics.
