Synergistic Optimization of Buried Interface by Multifunctional Organic-Inorganic Complexes for Highly Efficient Planar Perovskite Solar Cells

For the further improvement of the power conversion efficiency(PCE)and stability of perovskite solar cells(PSCs),the buried interface between the perovskite and the electron transport layer is crucial.However,it is challenging to effectively optimize this interface as it is buried beneath the perovskite film.Herein,we have designed and synthesized a series of multifunctional organic-inorganic(OI)complexes as buried interfacial material to promote electron extraction,as well as the crystal growth of the perovskite.The OI complex with BF4−group not only eliminates oxygen vacancies on the SnO_(2) surface but also balances energy level alignment between SnO_(2) and perovskite,providing a favorable environment for charge carrier extraction.Moreover,OI complex with amine(−NH_(2))functional group can regulate the crystallization of the perovskite film via interaction with PbI2,resulting in highly crystallized perovskite film with large grains and low defect density.Consequently,with rational molecular design,the PSCs with optimal OI complex buried interface layer which contains both BF4−and−NH_(2) functional groups yield a champion device efficiency of 23.69%.More importantly,the resulting unencapsulated device performs excellent ambient stability,maintaining over 90%of its initial efficiency after 2000 h storage,and excellent light stability of 91.5%remaining PCE in the maximum power point tracking measurement(under continuous 100 mW cm−2 light illumination in N2 atmosphere)after 500 h.

Molybdenum-doped ordered L1_(0)-PdZn nanosheets for enhanced oxygen reduction electrocatalysis

Ultrathin Pd-based two-dimensional(2D)nanosheets(NSs)with tunable physicochemical properties have emerged as promising candidate for oxygen reduction reaction(ORR).Unfortunately,structurally ordered Pd-based NSs can be hardly prepared as high temperature annealing(>600℃)is necessary for disorder to order phase transition,making it a considerable challenge for morphology control.Herein,a new class of ultrathin structurally ordered Mo-doped L1_(0)-PdZn NSs with curved geometry and abundant defects/lattice distortions is reported as an efficient oxygen reduction electrocatalyst in alkaline solution.It is found that Mo(CO)_(6) serves as reducing agent and Mo source to generate the unique ordered 2D morphology,which leads to the significantly modified electronic structure.The developed L1_(0)-Mo-PdZn NSs exhibit excellent ORR mass activity of 2.6 A mg_(Pd)^(−1) at 0.9 V versus reversible hydrogen electrode,31.5 and 17.6 times higher than those of Pd/C and Pt/C,respectively,outperforming most of the reported Pdbased ORR electrocatalsyts.Impressively,L1_(0)-Mo-PdZn NSs is extremely stable for ORR,with only 2.3% activity loss after 10000 potential cycles.Density functional theory study suggests that ordered L1_(0) structure and Mo doping can raise the vacancy formation energy of Pd atom and thus promote the ORR stability.