Oriented wide-bandgap perovskites for monolithic silicon-based tandems with over 1000 hours operational stability.

The instability of hybrid wide-bandgap (WBG) perovskite materials (with bandgap larger than 1.68 eV) still stands out as a major constraint for the commercialization of perovskite/silicon tandem photovoltaics, yet its correlation with the facet properties of WBG perovskites has not been revealed. Herein, we combine experiments and theoretical calculations to comprehensively understand the facet-dependent instability of WBG perovskites.

Highly passivated TOPCon bottom cells for perovskite/silicon tandem solar cells.

Tunnel oxide passivated contact (TOPCon) silicon solar cells are rising as a competitive photovoltaic technology, seamlessly blending high efficiency with cost-effectiveness and mass production capabilities. However, the numerous defects from the fragile silicon oxide/c-Si interface and the low field-effect passivation due to the inadequate boron in-diffusion in p-type polycrystalline silicon (poly-Si) passivated contact reduce their open-circuit voltages (Vs), impeding their widespread application in the promising perovskite/silicon tandem solar cells (TSCs) that hold a potential to break 30% module efficiency. To address this, we have developed a highly passivated p-type TOPCon structure by optimizing the oxidation conditions, boron in-diffusion, and aluminium oxide hydrogenation, thus pronouncedly improving the implied V (iV) of symmetric samples with p-type TOPCon structures on both sides to 715 mV and the V of completed double-sided TOPCon bottom cells to 710 mV.

Eliminating Resistance-Capacitance Coupling Shielding for Depicting the Defect Landscape in Perovskite Solar Cells by Capacitance Spectroscopy.

Capacitance spectroscopy techniques have been widely utilized to evaluate the defect properties in perovskites, which contribute to the efficiency and operation stability development for perovskite solar cells (PSCs). Yet the interplay between the charge transporting layer (CTL) and the perovskite on the capacitance spectroscopy results is still unclear. Here, they show that a pseudo-trap-state capacitance signal is generated in thermal admittance spectroscopy (TAS) due to the enhanced resistance capacitance (RC) coupling caused by the carrier freeze-out of the CTL in PSCs, which could be discerned from the actual defect-induced trap state capacitance signal by tuning the series resistance of PSCs.

Visualizing the Structure-Property Nexus of Wide-Bandgap Perovskite Solar Cells under Thermal Stress.

Wide-bandgap perovskite solar cells (PSCs) toward tandem photovoltaic applications are confronted with the challenge of device thermal stability, which motivates to figure out a thorough cognition of wide-bandgap PSCs under thermal stress, using in situ atomic-resolved transmission electron microscopy (TEM) tools combing with photovoltaic performance characterizations of these devices. The in situ dynamic process of morphology-dependent defects formation at initial thermal stage and their proliferations in perovskites as the temperature increased are captured. Meanwhile, considerable iodine enables to diffuse into the hole-transport-layer along the damaged perovskite surface, which significantly degrade device performance and stability.

Tandem Electro-Oxidative C-C and C-N Coupling and Aromatization for the Construction of Pyrazine-Fused Bisaza[7]helicene.

Repeated tandem electro-oxidative C-C and C-N coupling and aromatization were employed for the efficient construction of aza[7]helicene () as a key intermediate and the targeted pyrazine-fused bisaza[7]helicene () derivatives in 90.0-93.2% isolated yields under a controlled potential.

Phase-Stable Wide-Bandgap Perovskites for Four-Terminal Perovskite/Silicon Tandem Solar Cells with Over 30% Efficiency.

Wide-bandgap perovskite solar cells (PSCs) with an optimal bandgap between 1.7 and 1.8 eV are critical to realize highly efficient and cost-competitive silicon tandem solar cells (TSCs).

Stabilizing Fullerene for Burn-in-Free and Stable Perovskite Solar Cells under Ultraviolet Preconditioning and Light Soaking.

It is crucial to make perovskite solar cells sustainable and have a stable operation under natural light soaking before they become commercially acceptable. Herein, a small amount of the small molecule bathophenanthroline (Bphen) is introduced into [6,6]-phenyl-C -butyric acid methyl ester and it is found that Bphen can stabilize the C -cage well through formation of much more thermodynamically stable charge-transfer complexes. Such a strengthened complex is used as an interlayer at the in-light perovskite/SnO side to achieve a champion device with efficiency of 23.