• Energy Research

Abstract A series La-doped WO3/SrTiO3 heterojunctions photocatalyst were successfully prepared using solvothermal method. The as-fabricated heterostructures composite included La-doped WO3 fluff spheres tightly grew on the surface of SrTiO3 cubic particles. The crystallanity, structural, morphological and optical features of the catalysts were characterized using several techniques including XRD, XPS, SEM, TEM UV−vis and HRTEM. The photocatalytic activity of the heterojunction was evaluated by the photocatalytic degradation of methyl orange (MO) under visible-light irradiation. The influence of La doping and SrTiO3 molar ratio on heterojunctions photocatalysts was investigated. Among the as-prepared photocatalysts, the LWS50 sample exhibited the highest photocatalytic activity, almost 100% MO were completely decomposed within 75 min under visible light irradiation (λ > 420 nm). Compared with the pure WO3 and SrTiO3, the enhancement of photocatalytic activity was mainly attributed to the three-dimensional hierarchical structure and the effectively transfer and separation of photogenerated electron–hole pairs in La doped WO3 and SrTiO3 heterojunctions

Wide‐bandgap (WBG) perovskite solar cells (PSCs) are acknowledged as promising candidates for tandem solar cells and building photovoltaics. It is well known that cesium‐based all‐inorganic halide WBG perovskites possess the comparable optoelectronic properties as the organic–inorganic counterparts, but exhibit superior thermal stability. Among them, CsPbIBr2 is considered a feasible material for tandem solar cells after balancing the bandgap and stability of the inorganic perovskite. However, CsPbIBr2 PSCs are often subjected to drastic interfacial charge recombination especially in carbon‐based device structure derived from the chemical bonding defects (i.e., uncoordinated Pb2+) naked on CsPbIBr2 soft lattice, which dramatically limits overall efficiency of CsPbIBr2 WBG PSCs. Herein, a trimethyl ammonium salt hexyltrimethylammonium bromide is presented for CsPbIBr2/carbon interfacial modification. Benefiting from the −N+(CH3)3 passivation effect and −C6H13 hydrophobic alkyl chain, the optimal device with highly smooth morphology and sufficient charge extraction exhibits a champion power conversion efficiency of 11.24% and improved long‐term stability with 99.7% and 79.7% efficiency retention under dry air atmosphere and continuous 85 °C thermal stress, indicating the valuable potential application of the lattice solidified CsPbIBr2 WBG PSCs.

AbstractBandgap‐tunable mixed‐halide perovskite materials have attracted considerable interest because of their indispensability as top counterparts in tandem solar cells. However, the soft and disordered lattice always suffers from severe phase segregation under illumination, which is particularly susceptible to residual lattice strain. Herein, we report a strain regulation strategy by using alkenamides terminated Ti3C2Tx MXenes as an additive into perovskite precursor. Apart from the role of a template for grain growth to obtain high‐quality films, the stretchable alkyl chain promotes lattice shrinkage or expansion to form an elastic grain boundary to eliminate the spatially distributed stain and shut down ion migration channels. As a result, the all‐inorganic perovskite solar cells based on CsPbIBr2 and CsPbI2Br halides achieve prolonged device stability under harsh conditions and the best power conversion efficiencies up to 11.06% and 14.30%, respectively.

Abstract To improve the photovoltaic performance of the perovskite solar cells, it is necessary to reduce the density of surface defect for perovskite film with smooth surface. In this paper, we demonstrate a DMSO/CB mixed vapor annealing process to fabricate high-performance planar perovskite solar cells. The mixed vapor annealing treatment can significantly enhance the crystallization of perovskite film, leading to less crystal surface defects, effective charge-separation and the electron transport rate at the perovskite interface. Finally, the efficiency and reproducibility of the cells has been greatly improved. The power conversion efficiency (PCE) improved from 16.6% to 18.4% under AM 1.5G 100 mW·cm−2 irradiation. We anticipate that the mixed vapor annealing treatment will become a promising crystallization method for the fabrication of high performance PSCs in the future commercialization.

AbstractA high‐performance electron transport layer (ETL)‐free planar fluorine‐doped tin oxide (FTO)/perovskite/hole‐transport material/Au solar cell was prepared. We revealed that a plasma‐cleaning pretreatment for FTO substrates could significantly improve the quality of perovskite films, leading to the promotion of charge separation, an increase in the electron‐transport rate, and a decrease in the recombination reaction at the FTO/perovskite interface. Finally, the efficiency of the cells was greatly improved. A power conversion efficiency of over 15 % and a fill factor of 0.68 were achieved under AM 1.5G 100 mW cm−2 irradiation without the use of a compact n‐type metal‐oxide blocking layer.

All‐inorganic CsPbIBr2 perovskite solar cells (PSCs) recently demonstrated great superiority for application in tandem and semitransparent photovoltaics because of their excellent phase stability. However, compared to state‐of‐the‐art PSCs, the inferior film quality is harmful for the photovoltaic performance improvement. Herein, a novel ionic additive, tetrabutylammonium hexafluorophosphate (TBAPF6), is employed to improve the all‐inorganic CsPbIBr2 perovskite film quality and passivate detrimental defects. By assembly into carbon–electrode‐based solar cells, a champion efficiency as high as 10.57% is achieved, which is much higher than that of a control device with 8.30% efficiency, mainly attributed to the suppressed non‐radiative recombination. More importantly, the presence of alkyl chains and fluorine atoms in TBAPF6 significantly increases the hydrophobicity of perovskite films and therefore improves the long‐term stability under harsh conditions without encapsulation.