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The spin degree of freedom in hybrid organic–inorganic perovskites (HOIPs) has become a rapidly growing research topic in both HOIPs and spintronics fields due to its fundamental scientific significance and tight relevance with optoelectronics. The flourishing achievements of HOIP spintronics call for a timely review to summarize the key progress and guide future developments. In this review, classical spintronic phenomena based on spin‐orbit coupling (SOC) are discussed, especially Rashba splitting and related applications such as spin‐charge conversion. Owing to the unique chirality‐spin coupling, spintronics in chiral HOIPs are particularly focused on, including chirality‐induced spin selectivity (CISS). Based on the complex band structure and carrier/exciton, spin dynamics is also widely investigated and constitutes an indispensable part of HOIP spintronics. Aside from the three main threads, other spintronic phenomena such as magneto‐optical coupling and device exploration are involved as promising opportunities. Despite the continuous breakthroughs in HOIP spintronics, more efforts are required to expand material systems, explore new physics, and optimize device configurations for enhanced performance and high integration. A deep understanding of spin behaviors in HOIPs will create a new platform beyond conventional optoelectronic and photovoltaic applications. [ABSTRACT FROM AUTHOR]

Colorless‐to‐black switching has attracted widespread attention for smart windows and multifunctional displays because they are more useful to control solar energy. However, it still remains a challenge owing to the tremendous difficulties in the design of completely reverse absorptions in transmissive and colored states. Herein, we report on an electrochemical device that can switch between colorless and black by using the electrochemical process of hybrid organic–inorganic perovskite MAPbBr3, which shows a high integrated contrast ratio of up to 73% from 400 to 800 nm. The perovskite solution can be used as the active layer to assemble the device, showing superior transmittance over the entire visible region in neutral states. By applying an appropriate voltage, the device undergoes reversible switching between colorless and black, which is attributed to the formation of lead and Br2 in the redox reaction induced by the electron transfer process in MAPbBr3. In addition, the contrast ratio can be modulated over the entire visible region by changing the concentration and the applied voltage. These results contribute toward gaining an insightful understanding of the electrochemical process of perovskites and greatly promoting the development of switchable devices. [ABSTRACT FROM AUTHOR]

Crystalline materials have governed the development of hybrid organic‐inorganic perovskites (HOIPs), giving rise to a variety of fascinating applications such as solar cells and optoelectronic devices. With increasing interest in non‐crystalline systems, the glassy state of HOIPs has recently been identified. Here, the basic building blocks of crystalline HOIPs appear to be retained, though their glasses lack long‐range periodic order. The emerging family of glasses formed from HOIPs exhibits diverse properties, complementary to their crystalline state. This mini review describes the chemical diversity of both three‐dimensional and two‐dimensional crystalline HOIPs and demonstrates how glasses are produced from these materials. Specifically, current achievements in melt‐quenched glasses formed from HOIPs are highlighted. We conclude with our perspective on the future of this new family of materials. [ABSTRACT FROM AUTHOR]

Crystalline materials have governed the development of hybrid organic‐inorganic perovskites (HOIPs), giving rise to a variety of fascinating applications such as solar cells and optoelectronic devices. With increasing interest in non‐crystalline systems, the glassy state of HOIPs has recently been identified. Here, the basic building blocks of crystalline HOIPs appear to be retained, though their glasses lack long‐range periodic order. The emerging family of glasses formed from HOIPs exhibits diverse properties, complementary to their crystalline state. This mini review describes the chemical diversity of both three‐dimensional and two‐dimensional crystalline HOIPs and demonstrates how glasses are produced from these materials. Specifically, current achievements in melt‐quenched glasses formed from HOIPs are highlighted. We conclude with our perspective on the future of this new family of materials. [ABSTRACT FROM AUTHOR]

The development of digital technology has made our lives more advanced as a society familiar with the Internet of Things (IoT). Solar cells are among the most promising candidates for power supply in IoT sensors. Perovskite photovoltaics (PPVs), which have already attained 25% and 40% power conversion efficiencies for outdoor and indoor light, respectively, are the best candidates for self-powered IoT system integration. In this review, we discuss recent research progress on PPVs under indoor light conditions, with a focus on device engineering to achieve high-performance indoor PPVs (Id-PPVs), including bandgap optimization and defect management. Finally, we discuss the challenges of Id-PPVs development and its interpretation as a potential research direction in the field. [ABSTRACT FROM AUTHOR]

This article describes a machine learning guided framework for screening the potential toxicity impact of amine chemistries used in the synthesis of hybrid organic–inorganic perovskites. Using a combination of a probabilistic molecular fingerprint technique that encodes bond connectivity (MinHash) coupled to non‐linear data dimensionality reduction methods (Uniform Manifold Approximation and Projection), we develop an "Amine Atlas." We show how the Amine Atlas can be used to rapidly screen the relative toxicity levels of amine molecules used in the synthesis of 2D and 3D perovskites and help identify safer alternatives. Our work also serves as a framework for rapidly identifying molecular similarity guided, structure–function relationships for safer materials chemistries that also incorporate sustainability/toxicity concerns. [ABSTRACT FROM AUTHOR]

MAPbBr3 (MA = CH3NH3+) doping with bismuth increases electric conductivity, charge carrier density and photostability, reduces toxicity, and expands light absorption. However, Bi doping shortens excited-state lifetimes due to formation of DY− charge recombination centers. Using nonadiabatic molecular dynamics and time-domain density functional theory, we demonstrate that the DY− center forms a deep, highly localized hole trap, which accelerates nonradiative relaxation ten-fold and is responsible for 90% of carrier losses. Hole trapping occurs by coupling between the valence band and the trap state, facilitated by the Br atoms surrounding the Bi dopant. Passivation of the DY− center with chlorines heals the local geometry distortion, eliminates the trap state, and makes the carrier lifetimes longer than even in pristine MAPbBr3. The decreased charge recombination arises from reduced nonadiabatic coupling and shortened coherence time, due to diminished electron-hole overlap around the passivated defect. Our study demonstrates accelerated nonradiative recombination in Bi-doped MAPbBr3, suggests a strategy for defect passivation and reduction of nonradiative energy losses, and provides atomistic insights into unusual defect properties of metal halide perovskites needed for rational design of high-performance perovskite solar cells and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Recent experiments report the rotation of FA (FA=HC[NH2]2+) cations significantly influence the excited-state lifetime of FAPbI3. However, the underlying mechanism remains unclear. Using ab initio nonadiabatic (NA) molecular dynamics combined with time-domain density functional simulations, we have demonstrated that reorientation of partial FA cations significantly inhibits nonradiative electron-hole recombination with respect to the pristine FAPbI3 due to the decreased NA coupling by localizing electron and hole in different positions and the suppressed atomic motions. Slow nuclear motions simultaneously increase the decoherence time, which is overcome by the reduced NA coupling, extending electron-hole recombination time scales to several nanoseconds and being about 3.9 times longer than that in pristine FAPbI3, which occurs within sub-nanosecond and agrees with experiment. Our study established the mechanism for the experimentally reported prolonged excited-state lifetime, providing a rational strategy for design of high performance of perovskite solar cells and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Two-dimensional semiconductors are considered intriguing materials for photonic applications, thanks to their stunning optical properties and the possibility to manipulate them at the nanoscale. In this review, we focus on transition metal dichalcogenides and low-dimensional hybrid organic-inorganic perovskites, which possess the same characteristics related to planar confinement of their excitons: large binding energies, wide exciton extension, and high oscillator strength. We describe their optoelectronic properties and their capability to achieve strong coupling with light, with particular attention to polariton-polariton interactions. These aspects make them very attractive for polaritonic devices working at room temperature, in view of the realization of all-optical logic circuits in low-cost and easy-to-synthesize innovative materials. [ABSTRACT FROM AUTHOR]

Hybrid organic–inorganic perovskites, while well examined for photovoltaic applications, remain almost completely unexplored in the terahertz (THz) range. These low-cost hybrid materials are extremely attractive for THz applications because their optoelectronic properties can be chemically engineered with relative ease. Here, we experimentally demonstrate the first attempt to apply solution-processed polycrystalline films of hybrid perovskites for the development of photoconductive terahertz emitters. By using the widely studied methylammonium-based perovskites MAPbI3 and MAPbBr3, we fabricate and characterize large-aperture photoconductive antennas. The work presented here examines polycrystalline perovskite films excited both above and below the bandgap, as well as the scaling of THz emission with the applied bias field and the optical excitation fluence. The combination of ultrafast time-resolved spectroscopy and terahertz emission experiments allows us to determine the still-debated room temperature carrier lifetime and mobility of charge carriers in halide perovskites using an alternative noninvasive method. Our results demonstrate the applicability of hybrid perovskites for the development of scalable THz photoconductive devices, making these materials competitive with conventional semiconductors for THz emission. [ABSTRACT FROM AUTHOR]