The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST, also called the Guo Shou Jing Telescope) is a special reflecting Schmidt telescope. LAMOST's special design allows both a large aperture (effective aperture of 3.6 m-4.9 m) and a wide field of view (FOV) (5 • ). It has an innovative active reflecting Schmidt configuration which continuously changes the mirror's surface that adjusts during the observation process and combines thin deformable mirror active optics with segmented active optics. Its primary mirror (6.67 m×6.05 m) and active Schmidt mirror (5.74 m×4.40 m) are both segmented, and composed of 37 and 24 hexagonal sub-mirrors respectively. By using a parallel controllable fiber positioning technique, the focal surface of 1.75 m in diameter can accommodate 4000 optical fibers. Also, LAMOST has 16 spectrographs with 32 CCD cameras. LAMOST will be the telescope with the highest rate of spectral acquisition. As a national large scientific project, the LAMOST project was formally proposed in 1996, and approved by the Chinese government in 1997. The construction started in 2001, was completed in 2008 and passed the official acceptance in June 2009. The LAMOST pilot survey was started in October 2011 and the spectroscopic survey will launch in September 2012. Up to now, LAMOST has released more than 480 000 spectra of objects. LAMOST will make an important contribution to the study of the large-scale structure of the Universe, structure and evolution of the Galaxy, and cross-identification of multiwaveband properties in celestial objects.

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Large-size crystals of organic-inorganic hybrid perovskites (e.g., CH 3 NH 3 PbX 3 , X = Cl, Br, I) have gained wide attention since their spectacular progress on optoelectronic technologies. Although presenting brilliant semiconducting properties, a serious concern of the toxicity in these lead-based hybrids has become a stumbling block that limits their wide-scale applications. Exploring lead-free hybrid perovskite is thus highly urgent for high-performance optoelectronic devices. Here, a new lead-free perovskite hybrid (TMHD)BiBr 5 (TMHD = N,N,N,N-tetramethyl-1,6-hexanediammonium) is prepared from facile solution process. Emphatically, inch-size high-quality single crystals are successfully grown, the dimensions of which reach up to 32 × 24 × 12 mm 3 . Furthermore, the planar arrays of photodetectors based on bulk lead-free (TMHD)BiBr 5 single crystals are first fabricated, which shows sizeable on/off current ratios (≈10 3 ) and rapid response speed (τ rise = 8.9 ms and τ decay = 10.2 ms). The prominent device performance of (TMHD)BiBr 5 strongly underscores the lead-free hybrid perovskite single crystals as promising material candidates for optoelectronic applications.