Organic-inorganic hybrid perovskite is a class of direct-bandgap semiconductors that can be processed as thin films from solutions by low-temperature methods. Among various solution-processable semiconductor materials, the hybrid perovskites exhibit unique combination of low bulk-trap densities, remarkable ambipolar transport properties, good broadband absorption characteristics and long charge carrier diffusion lengths, making them ideal for photovoltaic applications. Furthermore, as direct bandgap semiconductors with low bulk trap densities, the hybrid perovskite films possess remarkable luminescent properties. The bandgap of the hybrid perovskites can be tuned by crystal engineering, i.e. tuning the composition at molecular levels. These intriguing properties indicate that the hybrid perovskites may also find applications in light-emitting diodes and lasing. This paper reviews the unique properties and current research progresses of this class of dream material and provides our perspective of future directions.

Magnetic field effects (MFEs) are used to describe the changes of the photophysical properties (including photoluminescence, electroluminescence, injected current, photocurrent, and etc.) when materials and devices are submitted to the external magnetic field. The MFEs in non-magnetic luminescent materials and devices was first observed in organic semiconductor. In the past two decades, the effects have not only attracted extensive research as an emerging physical phenomenon, but also has been used as a unique experimental method to explore the processes such as charge transport, carrier recombination, and spin polarization in organic semiconductors. Recent studies have found that MFEs can also be observed in metal halide perovskites with strong spin-orbital coupling. Besides expanding the research domain of MFEs, these findings can also be utilized to study the physical mechanism in metal halide perovskites, and then provide insights to improve the performance of perovskite devices. In this review, we focus on the magnetic field effects on the electroluminescence and photoluminescence changes of organic semiconductors and halide perovskites. We review the mainstream theoretical models and representative experimental phenomena to date, and comparatively analyzed the luminescence behavior of organic semiconductors and halide perovskites under magnetic fields. It is hoped that this review can provide some ideas for the research on the MFEs of organic semiconductors and halide perovskites, and contribute to the research of luminescence in organic materials and halide perovskites.

To explore new constituents in two‐dimensional materials and to combine their best in van der Waals heterostructures, are in great demand as being unique platform to discover new physical phenomena and to design novel functionalities in interface‐based devices. Herein, PbI2 crystals as thin as few‐layers are first synthesized, particularly through a facile low‐temperature solution approach with the crystals of large size, regular shape, different thicknesses and high‐yields. As a prototypical demonstration of flexible band engineering of PbI2‐based interfacial semiconductors, these PbI2 crystals are subsequently assembled with several transition metal dichalcogenide monolayers. The photoluminescence of MoS2 is strongly enhanced in MoS2/PbI2 stacks, while a dramatic photoluminescence quenching of WS2 and WSe2 is revealed in WS2/PbI2 and WSe2/PbI2 stacks. This is attributed to the effective heterojunction formation between PbI2 and these monolayers, but type I band alignment in MoS2/PbI2 stacks where fast‐transferred charge carriers accumulate in MoS2 with high emission efficiency, and type II in WS2/PbI2 and WSe2/PbI2 stacks with separated electrons and holes suitable for light harvesting. Our results demonstrate that MoS2, WS2, WSe2 monolayers with very similar electronic structures themselves, show completely distinct light‐matter interactions when interfacing with PbI2, providing unprecedent capabilities to engineer the device performance of two‐dimensional heterostructures. 1 图 1 异质结中 PbI2引起的MoS2发光增强与WSe2发光 淬灭