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Organic lead halide perovskite solar cells (PSCs) have become a viable alternative for next‐generation photovoltaic systems. The significance of reproducibly processing perovskite with less defects comes from the fact that imperfections have a major impact on the solar cell's performance and long‐term stability. Although it is well known that cautious precursor processing has a significant influence on perovskite defect generation, there haven't been extensive investigations on the serial associations between precursor processing, perovskite orientation, and defect generation in PSCs. Making use of a unique precursor chemistry treatment technique that facilitates uniaxially oriented perovskite growth, it is aimed to mitigate defects of sequentially spin‐coated perovskite. Through the temperature‐dependent configurational entropic effect on coordination between iodoplumbate and dimethylsulfoxide (DMSO), a DMSO de‐intercalation processing method is developed. This method enables the induction of uniaxially‐oriented α‐FA0.9MA0.1PbI3‐xBrx (FA: formamidnium, MA: methylammomnium, x < 0.13) perovskite growth parallel to substrates. As a result, this processing delivered significant advances in power conversion efficiency (24.02%) and ambient operational stability under light. This straightforward technique provides a accesible process for producing efficient and stable perovskite solar cells, enabling uniaxially oriented perovskite fabrication without complicated procedures or additional substances. [ABSTRACT FROM AUTHOR]

Quasi‐2D Ruddlesden–Popper perovskite (RPP) have surfaced as a promising candidate for light emitting diodes (LEDs) due to its outstanding optoelectronic properties. However, a reliable approach for patterning RPPs remains elusive due to the use of polar solvents in lithographic processes, which can damage the RPP. Here, a reliable and damage‐free dry micropatterning method of RPPs is reported, which also offers a cost/time advantage compared to conventional patterning methods. The sharp edges of high aspect ratio silicon micropillars are used to cut RPPs to a pre‐defined shape and then the cut RPPs are delaminated to obtain a patterned array of RPPs. The resultant patterned array exhibits no sign of degradation or discernable difference between adjacent pixels, achieving a ≈100% yield. The obtained array is utilized to fabricate a pixelated LED where a sharp electroluminescence (EL) spectrum peaking at 410 nm with full‐width‐at‐half‐maximum (FWHM) of 10 nm is observed. The pixelated devices demonstrate the potential to suppress EQE drops as the pixel size decreases, attributed to both the damage‐free micropatterning process and the defect tolerance of RPPs. Moreover, further improvements of the patterning method are demonstrated to avoid parasitic emission and suggest a promising strategy to fabricate pixel‐accessible micro‐LEDs. [ABSTRACT FROM AUTHOR]

In 2004, K. S. Novoselov and A. K. Geim et al. have used sellotape to peel off the layered 2D graphite, and successfully obtained few‐layer thin graphene. Inspired by this, herein, the sellotape is initially used to exfoliate the layered Ruddlesden–Popper (RP) quasi‐2D perovskite film for efficient light‐emitting diodes application. The top surface layer of quasi‐2D perovskite film is mechanically peeled off by the sellotape without damaging the crystalline region below, which minimizes the poor conductivity issue of quasi‐2D perovskite film owing to the decreased defect density. Moreover, the exfoliated quasi‐2D film exhibits low charge traps density and enhanced energy transfer from low‐dimensional to high‐dimensional domains due to the elimination of surface defective layer and the recrystallization of quasi‐2D perovskite crystal, leading to high photoluminescence quantum yield (PLQY) up to 83.2%. Subsequently, an efficient perovskite light‐emitting diode based on the exfoliated quasi‐2D perovskite thin film is achieved with high current efficiency of 46.0 cd m−2 and excellent external quantum efficiency (EQE) up to 14.8%. [ABSTRACT FROM AUTHOR]

Although there have been significant advances in the stability of perovskite solar cells through encapsulation techniques to remove extrinsic degradation factors, such as moisture and oxygen, irreversible photo‐degradation originating from intrinsic defects is still challenging and remains elusive. Herein, the photo‐aging mechanism due to intrinsic defects is investigated in nitrogen‐filled conditions, excluding extrinsic degradation factors. Devices with similar power conversion efficiencies (PCE) of 21%, but with different Fermi levels in the perovskite films, via controlling the self‐doping effect, have been investigated. Opto‐electronic investigations and depth profiles of the elemental constituents show that after photo‐aging, strain relaxation in the perovskite lattice and a Fermi level shift towards conduction band edge are observed, implying the formation of new defect states in Pb‐rich devices. Furthermore, thermal admittance spectroscopy measurement of the devices suggests that the formation of the deep‐traps in the perovskite leads to irreversible degradation. Thin‐film solar cells that are relatively Pb‐deficient (FA‐rich) exhibit improved long‐term stability, retaining over 90% of their initial PCE during 500 h of continuous 1‐Sun illumination. This study suggests passivation of the Pb‐I related antisite defects near the grain boundaries and the interface is crucial for the fabrication of solar cells with enhanced long‐term stability. [ABSTRACT FROM AUTHOR]

In situ control of perovskite absorber properties enables a record‐efficiency two‐terminal monolithic perovskite‐CIGS tandem thin‐film solar cell. [ABSTRACT FROM AUTHOR]

Keywords: long term stability; organic-inorganic hybrid halide perovskites; self-doping; solar cells; thermal admittance spectroscopy EN long term stability organic-inorganic hybrid halide perovskites self-doping solar cells thermal admittance spectroscopy 1 1 1 05/08/21 20210506 NES 210506 In article number 2100555, Mansoo Choi, Yun Seog Lee, and co-workers systematically investigate the self-doping effect on the light stability of perovskite solar cells (PSCs). Long term stability, organic-inorganic hybrid halide perovskites, self-doping, solar cells, thermal admittance spectroscopy Perovskite Solar Cells: Investigation of Defect-Tolerant Perovskite Solar Cells with Long-Term Stability via Controlling the Self-Doping Effect (Adv. [Extracted from the article]

Recent progress in commercial single-junction photovoltaic (PV) technologies has brought device efficiency closer to their practical limits. Module prices are dropping rapidly and solar energy has already reached grid parity in many areas. Solar module costs now constitute a small fraction of the total systems costs and to continue system cost reduction, increasing efficiency becomes even more critical. Multi-junction solar cells are the most logical path to increase PV module performance beyond 25%, but the varieties available today are still are out-performed in efficiency or cost by the main stream single-junction technologies: crystalline Si, CdTe and CIGS. Finding a solution for this problem is attracting a growing research interest. We review the latest developments in the field with particular focus on thin-film high band gap candidates such as perovskites on commercial bottom cells including silicon, CdTe and CIGS. We also review the current state of all-chalcopyrite tandems, and promising concepts using CdTe-alloys as a top cell on silicon. [ABSTRACT FROM AUTHOR]