Vacancy healing for stable perovskite solar cells via bifunctional potassium tartrate

Perovskite solar cell has gained widespread attention as a promising technology for renewable energy.However, their commercial viability has been hampered by their long-term stability and potential Pb leakage. Herein, we demonstrate a bifunctional passivator of the potassium tartrate(PT) to address both challenges. PT minimizes the Pb leakage in perovskites and also heals cationic vacancy defects, resulting in improved device performance and stability. Benefiting from PT modification, the power conversion efficiency(PCE) is improved to 23.26% and the Pb leakage in unencapsulated films is significantly reduced to 9.79 ppm. Furthermore, the corresponding device exhibits no significant decay in PCE after tracking at the maximum power point(MPP) for 2000 h under illumination(LED source, 100 mW cm^(-2)).

Fabrication and Modification Strategies of Metal Halide Perovskite Absorbers

Due to the long carrier lifetime,high carrier mobility,and high absorption coefficient of perovskite materials,the power conversion efficiency(PCE)of perovskite solar cells(PSCs)has increased from 3.8%in 2009 to 25.7%in 2021,which have already surpassed the PCE of thin-film solar cells and closes to the efficiency of Si-based photovoltaics(26.7%).Therefore,PSCs have become a promising clean energy technology for commercialization.However,the low defect formation energy of perovskite leads to a higher defect density than other conventional photovoltaic materials.It results in severe non-radiative recombination,limiting its further development and the commercialization.In this review,we summarize the mechanism and strategies for high-quality perovskite absorber fabrications to minimize the bulk and surface/interface defects of halide perovskite,including film quality development and interface modification.Strategies are proposed for further promoting the film quality and the corresponding device performance.Finally,we highlight the challenges that need to be overcome to control over the defect properties of halide perovskite.

Balancing Energy-Level Difference for Efficient n-i-p Perovskite Solar Cells with Cu Electrode

Developing low cost and stable metal electrode is crucial for mass production of perovskite solar cells(PSCs).As an earthabundant element,Cu becomes an alternative candidate to replace noble metal electrodes such as Au and Ag,due to its comparable physiochemical properties with simultaneously good stability and low cost.However,the undesirable band alignment associated with the device architecture impedes the exploration of efficient Cu-based n-i-p PSCs.Here,we demonstrated the ability of tuning the Fermi level(E_(F))of hole transport layer(HTL)to reduce the energy level difference(Schottky barrier)between HTLs and Cu.Further,we identified that the balance of energy level difference between HTL and adjacent layers(including perovskite and Cu)is crucial to efficient carrier transportation and photovoltaic performance improvement in the PSCs.Under the optimized condition,we achieve a device power conversion efficiency(PCE)of 20.10%,which is the highest on the planar n-i-p PSCs with Cu electrode.Meanwhile,the Cu-based PSCs can maintain 92%of their initial efficiency after 1000 h storage,which is comparable with Au-based devices.The present work not only extends the understanding on the band alignment of neighboring semiconductor functional layer in the device architecture to improve the resulting performance but also suggests great potential of Cu electrode for application in PSCs community.