51�������

Abstract:

The site-selective functionalization of C(sp²)−H bonds has emerged as powerful tools for molecular synthesis. The challenge in the field is to achieve different site selectivity reverse to electron-controlled electrophilic substitution under mild conditions. Herein, we report a mild Ru-catalyzed meta-selective C(sp²)−H alkylation of aniline derivatives. Mechanistic studies revealed a distinct Ru catalytic species ligated by two κ²-bound aminopyrimidine in an octahedral geometry. This ruthenium species is generated from dissociation of p-cymene to trigger the metallaphotoredox catalysis.

Abstract:

ABSTRACT Reducing non‐radiative charge‐carrier recombination at both p‐ and n‐side interfaces of the perovskite layer is crucial for realizing high‐voltage single‐ and multi‐junction solar cells. Herein, it is demonstrated that co‐depositing a mixture of ethane‐1,2‐diammonium iodide and different oleyl‐based amphiphiles renders a passivator‐insulator modification at the perovskite–C 60 interface, which suppresses n‐side contact losses in narrow‐bandgap (∼1.26 eV) Sn–Pb perovskite solar cells. Interestingly, a cationic oleyl‐based amphiphile introduced concurrently with the poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate hole‐transport‐layer, deposited from an aqueous dispersion in 1‐propanol, also reduces the p‐side energy loss by providing a substrate for high‐quality perovskite films and limiting the contact between the doped hole‐transport‐layer and the perovskite layer atop. This double‐sided interface modification strategy enables open‐circuit voltage ( V oc ) values of up to 0.91 V—over 91% of the detailed‐balance limit—for 22.6% efficient single‐junction Sn–Pb perovskite solar cells. Monolithic all‐perovskite tandem solar cells show V oc and efficiency values of up to 2.16 V and 26.1%, respectively. The results demonstrate that insulating‐passivating interface modifications between the perovskite and charge transport layers represent an effective strategy for reducing energy losses in emerging perovskite solar cell technologies.

Abstract:

ABSTRACT Perovskite solar cells have achieved high efficiencies but remain limited by instabilities. For the opaque metal rear electrode, Au is commonly used to achieve stable operation but is impractical for scalable photovoltaics due to cost. We investigate the effect of a 5 nm chromium (Cr) interlayer beneath low‐cost metals (Al, Ag, Cu) to inhibit metal interdiffusion. Cr/Al electrodes yield devices with high efficiencies (up to 24.7%) and operational stability comparable to reference devices using Au rear electrodes under heat and light stress, with raw material costs reduced by five orders of magnitude. At the front semi‐transparent electrode, through which sunlight will be incident, we identify indium diffusion from indium tin oxide (ITO) as a key degradation mechanism, revealed via depth‐resolved mass spectrometry. We demonstrate that replacing ITO with fluorine‐doped tin oxide (FTO) substantially improves stability. Combining both improvements, FTO with Cr/Al contacts, produces devices retaining >66% of the initial efficiency after >1000 h ageing at 75 °C under simulated sunlight. These results highlight the critical role of electrode selection on perovskite solar cell durability and provide a practical route toward stable and cost‐effective perovskite photovoltaics.

Abstract:

Vacuum-based deposition is a scalable, solvent-free industrial method ideal for uniform coatings on complex substrates. However, all vacuum-deposited perovskite solar cells fabricated by thermal evaporation trail solution-processed counterparts in efficiency and stability due to film quality challenges, necessitating advancement and improved understanding. Here, we report a co-evaporation route for 1.67-eV wide-bandgap perovskites by introducing a PbCl2 co-source to optimize film quality. We promote perovskite formation with pronounced (100) “face-up” orientation and deliver a certified all vacuum-deposited solar cell with 18.35% efficiency (19.3% in the lab) for 0.25-cm2 devices (18.5% for 1-cm2 cells). These cells retain 80% of peak efficiency after 1,080 hours under the ISOS-L-2 protocol. Leveraging operando hyperspectral imaging, we provide spatiotemporal spectral insight into halide segregation and trap-mediated recombination, correlating microscopic luminescence features with macroscopic device performance while distinguishing radiative from non-ideal recombination channels. We further demonstrate 27.2%-efficient 1-cm2 evaporated perovskite-on-silicon tandems and outdoor stability of all vacuum-deposited tandems in Italy, retaining ~80% initial performance after 8 months.

Abstract:

Raw data for 'Homogenized optoelectronic properties in perovskites: achieving high-efficiency solar cells with common chloride additives'