Understanding the Impact of SAM Fermi Levels on High Efficiency p-i-n Perovskite Solar Cells.

Completing the picture of the underlying physics of perovskite solar cell interfaces that incorporate self-assembled molecular layers (SAMs) will accelerate further progress in p-i-n devices. In this work, we modified the Fermi level of a nickel oxide-perovskite interface by utilizing SAM layers with a range of dipole strengths to establish the link between the resulting shift of the built-in potential of the solar cell and the device parameters. To achieve this, we fabricated a series of high-efficiency perovskite solar cells with no hysteresis and characterized them through stabilize and pulse (SaP), JV curve, and time-resolved photoluminescence (TRPL) measurements.

CO Laser Crystallization in Ambient for Highly Efficient FAPbI Perovskite Solar Cells.

Metal halide perovskite solar cells have achieved tremendous progress and have attracted enormous research and development efforts since the first report of demonstration in 2009. Due to fabrication versatility, many heat treatment methods can be utilized to achieve perovskite film crystallization. Herein, 10.

Piperidine and Pyridine Series Lead-Free Dion-Jacobson Phase Tin Perovskite Single Crystals and Their Applications for Field-Effect Transistors.

Two-dimensional (2D) organic-inorganic metal halide perovskites have gained immense attention as alternatives to three-dimensional (3D) perovskites in recent years. The hydrophobic spacers in the layered structure of 2D perovskites make them more moisture-resistant than 3D perovskites. Moreover, they exhibit unique anisotropic electrical transport properties due to a structural confinement effect.

The first demonstration of entirely roll-to-roll fabricated perovskite solar cell modules under ambient room conditions.

The rapid development of organic-inorganic hybrid perovskite solar cells has resulted in laboratory-scale devices having power conversion efficiencies that are competitive with commercialised technologies. However, hybrid perovskite solar cells are yet to make an impact beyond the research community, with translation to large-area devices fabricated by industry-relevant manufacturing methods remaining a critical challenge. Here we report the first demonstration of hybrid perovskite solar cell modules, comprising serially-interconnected cells, produced entirely using industrial roll-to-roll printing tools under ambient room conditions.

Performance Enhancement of Lead-Free 2D Tin Halide Perovskite Transistors by Surface Passivation and Its Impact on Non-Volatile Photomemory Characteristics.

Two-dimensional (2D) tin (Sn)-based perovskites have recently received increasing research attention for perovskite transistor application. Although some progress is made, Sn-based perovskites have long suffered from easy oxidation from Sn to Sn , leading to undesirable p-doping and instability. In this study, it is demonstrated that surface passivation by phenethylammonium iodide (PEAI) and 4-fluorophenethylammonium iodide (FPEAI) effectively passivates surface defects in 2D phenethylammonium tin iodide (PEA SnI ) films, increases the grain size by surface recrystallization, and p-dopes the PEA SnI film to form a better energy-level alignment with the electrodes and promote charge transport properties.

Recent progress in layered metal halide perovskites for solar cells, photodetectors, and field-effect transistors.

Metal halide perovskite materials demonstrate immense potential for photovoltaic and electronic applications. In particular, two-dimensional (2D) layered metal halide perovskites have advantages over their 3D counterparts in optoelectronic applications due to their outstanding stability, structural flexibility with a tunable bandgap, and electronic confinement effect. This review article first analyzes the crystallography of different 2D perovskite phases [the Ruddlesden-Popper (RP) phase, the Dion-Jacobson (DJ) phase, and the alternating cations in the interlayer space (ACI) phase] at the molecular level and compares their common electronic properties, such as out-of-plane conductivity, crucial to vertical devices.

Thermal-Radiation-Driven Ultrafast Crystallization of Perovskite Films Under Heavy Humidity for Efficient Inverted Solar Cells.

Fabricating perovskite solar cells (PSCs) in air is conducive to low-cost commercial production; nevertheless, it is rather difficult to achieve comparable device performance as that in an inert atmosphere because of the poor moisture toleration of perovskite materials. Here, the perovskite crystallization process is systematically studied using two-step sequential solution deposition in an inert atmosphere (glovebox) and air. It is found that moisture can stabilize solvation intermediates and prevent their conversion into perovskite crystals.

Inorganic-Cation Pseudohalide 2D Cs Pb(SCN) Br Perovskite Single Crystal.

Most of the reported 2D Ruddlesden-Popper (RP) lead halide perovskites with the general formula of A B X (n = 1, 2, …) comprise layered perovskites separated by A-site-substituted organic spacers. To date, only a small number of X-site-substituted RP perovskites have been reported. Herein, the first inorganic-cation pseudohalide 2D phase perovskite single crystal, Cs Pb(SCN) Br , is reported.

Homologous Bromides Treatment for Improving the Open-Circuit Voltage of Perovskite Solar Cells.

The power conversion efficiency (PCE) of solution-processed organic-inorganic mixed halide perovskite solar cells has achieved rapid improvement. However, it is imperative to minimize the voltage deficit (W  = E /q - V ) for their PCE to approach the theoretical limit. Herein, the strategy of depositing homologous bromide salts on the perovskite surface to achieve a surface and bulk passivation for the fabrication of solar cells with high open-circuit voltage is reported.

Magnetic optical rotary dispersion and magnetic circular dichroism in methylammonium lead halide perovskites.

Large magnetic optical rotary dispersion (Faraday rotation) has been demonstrated recently in methylammonium lead bromide. Here, we investigate the prospect of extending the active spectral range by altering the halogen. We also investigate the origins of large Faraday rotation in these diamagnetic materials using magnetic circular dichroism (MCD) spectroscopy and the Kramers-Kronig relations.

Immediate and Temporal Enhancement of Power Conversion Efficiency in Surface-Passivated Perovskite Solar Cells.

This work reports strategies for improving the power conversion efficiency (PCE) by capitalizing on temporal changes through the storage effect and immediate improvements by interface passivation. It is demonstrated that both strategies can be combined as shown by PCE improvement in passivated perovskite solar cells (PSCs) upon ambient storage because of trap density reduction. By analyzing the dominant charge recombination process, we find that lead-related traps in perovskite bulk, rather than at the surface, are the recombination centers in both as-fabricated and ambient-stored passivated PSCs.

Flexible and efficient perovskite quantum dot solar cells via hybrid interfacial architecture.

All-inorganic CsPbI perovskite quantum dots have received substantial research interest for photovoltaic applications because of higher efficiency compared to solar cells using other quantum dots materials and the various exciting properties that perovskites have to offer. These quantum dot devices also exhibit good mechanical stability amongst various thin-film photovoltaic technologies. We demonstrate higher mechanical endurance of quantum dot films compared to bulk thin film and highlight the importance of further research on high-performance and flexible optoelectronic devices using nanoscale grains as an advantage.

High-performance solar flow battery powered by a perovskite/silicon tandem solar cell.

The fast penetration of electrification in rural areas calls for the development of competitive decentralized approaches. A promising solution is represented by low-cost and compact integrated solar flow batteries; however, obtaining high energy conversion performance and long device lifetime simultaneously in these systems has been challenging. Here, we use high-efficiency perovskite/silicon tandem solar cells and redox flow batteries based on robust BTMAP-Vi/N-TEMPO redox couples to realize a high-performance and stable solar flow battery device.

Gas chromatography-mass spectrometry analyses of encapsulated stable perovskite solar cells.

Although perovskite solar cells have produced remarkable energy conversion efficiencies, they cannot become commercially viable without improvements in durability. We used gas chromatography-mass spectrometry (GC-MS) to reveal signature volatile products of the decomposition of organic hybrid perovskites under thermal stress. In addition, we were able to use GC-MS to confirm that a low-cost polymer/glass stack encapsulation is effective in suppressing such outgassing.

Solution-Processed Faraday Rotators Using Single Crystal Lead Halide Perovskites.

Lead halide perovskites (LHPs) have become a promising alternative for a wide range of optoelectronic devices, thanks to their solution-processability and impressive optical and electrical properties. More recently, LHPs have been investigated in magneto-optic studies and have exhibited spin-polarized emission, photoinduced magnetization, and long spin lifetimes. Here, the viability of methylammonium lead bromide (MAPbBr) single crystals as solution-processed Faraday rotators is demonstrated.

Acetic Acid Assisted Crystallization Strategy for High Efficiency and Long-Term Stable Perovskite Solar Cell.

Improving the quality of perovskite poly-crystalline film is essential for the performance of associated solar cells approaching their theoretical limit efficiency. Pinholes, unwanted defects, and nonperovskite phase can be easily generated during film formation, hampering device performance and stability. Here, a simple method is introduced to prepare perovskite film with excellent optoelectronic property by using acetic acid (Ac) as an antisolvent to control perovskite crystallization.

Unveiling the Relationship between the Perovskite Precursor Solution and the Resulting Device Performance.

For the fabrication of perovskite solar cells (PSCs) using a solution process, it is essential to understand the characteristics of the perovskite precursor solution to achieve high performance and reproducibility. The colloids (iodoplumbates) in the perovskite precursors under various conditions were investigated by UV-visible absorption, dynamic light scattering, photoluminescence, and total internal reflection fluorescence microscopy techniques. Their local structure was examined by in situ X-ray absorption fine structure studies.

Application of polydimethylsiloxane surface texturing on III-V//Si tandem achieving more than 2 % absolute efficiency improvement.

Silicon based multi-junction solar cells are a promising approach for achieving high power conversion efficiencies using relatively low-cost substrates. In recent years, 2-terminal triple-junction solar cells using GaInP/GaAs as top cells and Si bottom cell have achieved excellent efficiencies. Epitaxial growth or wafer bonding has been used for the integration of the cells.

Visualizing the Impact of Light Soaking on Morphological Domains in an Operational Cesium Lead Halide Perovskite Solar Cell.

The dynamics of photogenerated carriers and mobile ions in operational cesium lead halide (CsPbI) perovskite solar cells (PSCs) under working conditions are studied using nanoscale-resolved fluorescence lifetime imaging microscopy (FLIM). The temporally and spatially resolved photoluminescence (PL) changes in the perovskite film during and after bias light soaking are dynamically monitored. Through the analysis of the dynamic variations of PL intensity and PL lifetime of an open-circuit PSC, the impacts of light soaking are revealed by a dynamic model of photogenerated charge carrier and mobile ions.

Light-activated inorganic CsPbBrI perovskite for room-temperature self-powered chemical sensing.

Halide perovskite materials are excellent light harvesters that have generated enormous interest for photovoltaic technology and an increasing number of other optoelectronic applications. Very recently, their use for miniaturized chemical sensors has shown a promising room-temperature response. Here, we present some insights on the use of CsPbBr2I (CPBI) perovskites for self-powered room-temperature sensing of several environmentally and medically relevant compounds demonstrating rapid detection of down to concentrations of 1 ppm.

Mutual Insight on Ferroelectrics and Hybrid Halide Perovskites: A Platform for Future Multifunctional Energy Conversion.

An insight into the analogies, state-of-the-art technologies, concepts, and prospects under the umbrella of perovskite materials (both inorganic-organic hybrid halide perovskites and ferroelectric perovskites) for future multifunctional energy conversion and storage devices is provided. Often, these are considered entirely different branches of research; however, considering them simultaneously and holistically can provide several new opportunities. Recent advancements have highlighted the potential of hybrid perovskites for high-efficiency solar cells.

The Impact of a Dynamic Two-Step Solution Process on Film Formation of Cs (MA FA ) PbI Perovskite and Solar Cell Performance.

This paper provides deep understanding of the formation mechanism of perovskite film fabricated by sequential solution-based methods. It compares two sequential spin-coating methods for Cs (MA FA ) PbI perovskite. First is the "static process," with a stoppage between the two spin-coating steps (1st PbI -CsI-dimethyl sulfoxide (DMSO)-dimethylformamide (DMF) and 2nd methylammonium iodide (MAI)-formamidinium iodide (FAI)-isopropyl alcohol).

Light- and bias-induced structural variations in metal halide perovskites.

Organic-inorganic metal halide perovskites have gained considerable attention for next-generation photovoltaic cells due to rapid improvement in power conversion efficiencies. However, fundamental understanding of underlying mechanisms related to light- and bias-induced effects at the nanoscale is still required. Here, structural variations of the perovskites induced by light and bias are systematically investigated using scanning probe microscopy techniques.