The recent success of organometallic halide perovskites (OHPs) in photovoltaic devices has triggered lots of corresponding research and many perovskite analogues have been developed to look for devices with comparable performance but better stability. Upon the preparation of all inorganic halide perovskite nanocrystals (IHP NCs), research activities have soared due to their better stability, ultrahigh photoluminescence quantum yield (PL QY), and composition dependent luminescence covering the whole visible region with narrow line-width. They are expected to be promising materials for next generation lighting and display, and many other applications. Within two years, a lot of interesting results have been observed. Here, the synthesis of IHPs is reviewed, and their progresses in optoelectronic devices and optical applications, such as light-emitting diodes (LEDs), photodetectors (PDs), solar cells (SCs), and lasing, is presented. Information and recent understanding of their crystal structures and morphology modulations are addressed. Finally, a brief outlook is given, highlighting the presently main problems and their possible solutions and future development directions.

Intrinsically high mobility and large absorption coefficient endow inorganic halide perovskites (IHPs) with great promise for high-performance photodetectors (PDs), which, however, are being hindered by the low carrier extraction and transport efficiency of the solution assembled films. Here, we report on a general strategy to enhance the perovskite film conductivity that carbon nanotubes (CNTs) conductive nanonets are constructed from to provide fast carrier tracks. Resultantly, the CsPbBr nanosheet/CNT composite films exhibit both high light harvesting and high conductivity, such advantages are demonstrated by the high performances of corresponding planar PDs. Specifically, the highest external quantum efficiency (EQE) of 7488% and the highest responsivity of 31.1 A W under a bias of 10 V among IHP PDs with planar structure are achieved, which are almost 125-fold over the previous best results. Besides, the efficient charge extraction and transport also remarkably contribute to the fast response speed where a rise time of 16 μs is achieved, which is also superior to state-of-the-art IHP PDs. Furthermore, the composite films exhibit impressive flexibility due to the ultrathin 2D and 1D structural characteristic of perovskites and CNTs. By deploying the PD as a point-like detector, we acquire clear images. The results indicate the promising potentials of the perovskite/CNT composites for solution and ambient condition processed flexible devices, and this strategy is general for all kinds of perovskite optoelectronic devices including photodetectors, phototransistors, and even LEDs.

Lead-free Bi-based perovskite FA3Bi2X9 (X = Cl, Br, and I) quantum dots (QDs) are synthesized for the first time at room temperature. The ligand-passivated FA3Bi2Br9 QDs exhibit blue emission at 437 nm with photoluminescence quantum yield (PLQY) up to 52%.