Lead-free single crystal perovskite materials exhibit impressive characteristics, such as high carrier mobility, low trap density, and long diffusion length. Herein, the high-performance blue light photodetectors are reported based on lead-free all-inorganic Cs 3 Sb 2 Br 9 perovskite single crystals. These millimeter-sized Cs 3 Sb 2 Br 9 single crystals have small thermal activation energy of 56.8 meV estimated by temperature-dependent photoluminescence study. There is no obvious structural phase transition of the as-obtained Cs 3 Sb 2 Br 9 single crystals since no Raman peak shift is observed with temperature increasing from 80 to 300 K. The as-constructed high quality Cs 3 Sb 2 Br 9 single crystals photodetectors have an excellent performance of a responsivity of 2.29 A W −1 , a sharp detectivity of 3.77 × 10 12 Jones, and an external quantum efficiency (EQE) peak of 1.8 × 10 3 %. Moreover, the photodetectors exhibit a fast response time (<0.2 ms) and the full width at half maximum (FWHM) of the sharp EQE peak is as narrow as 15 nm. This work provides a promising strategy in the design of lead-free, stable, and high-performance perovskites for photodetector devices.
Kunlun Jiang,Wenjian Yang,Zhaobing Zhang,Yongli Zhang,Jing Lan,Dehao Chen,Wenzhe Li,Jiandong Fan
Cs3Sb2Br9, as a sort of novel lead-free perovskite single crystal, has the merits of high carrier mobility and a long diffusion length. However, the large-sized and high-crystallized Cs3Sb2Br9 single crystals are not easily obtained. Herein, we apply the vertical Bridgman method to grow centimeter-sized Cs3Sb2Br9 single crystal. The temperature-dependent crystal structure of Cs3Sb2Br9 is in situ characterized in the temperature range of 100–400 K. A novel crystallographic and electronic structure anisotropy of the as-grown Cs3Sb2Br9 single crystal along the transmission directions of [100] and [001] is experimentally and theoretically proved. Owing to the layered two-dimensional (2D) structure of Cs3Sb2Br9, quantum confinement effects prolong the lifetime of hot carriers, leading to their accumulation within the Sb–Br plane along the [100] direction, thereby resulting in a higher density of electronic states. Accordingly, the [100] device exhibits a carrier mobility higher than that of the [001] device, with the [100] device mobility being 4 orders of magnitude higher than that of the [001] device at 423 K, showing a remarkable anisotropy. The [100] device also shows responsivity ∼10 times higher than that of the [001] device.
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