Controllable Growth of Centimeter-Sized 2D Perovskite Heterostructures for Highly Narrow Dual-Band Photodetectors

Abstract

Two-dimensional (2D) organic-inorganic perovskites have recently attracted increasing attention due to their great environmental stability, remarkable quantum confinement effect and layered characteristic. Heterostructures consisting of 2D layered perovskites are expected to exhibit new physical phenomena inaccessible to the single 2D perovskites and can greatly extend their functionalities for novel electronic and optoelectronic applications. Herein, we develop a novel solution method to synthesize (C 4 H 9 NH 3 ) 2 PbI 4 /(C 4 H 9 NH 3 )(CH 3 NH 3 )Pb 2 I 7 single-crystals with the centimeter size, high phase purity, controllable junction depth, high crystalline quality and great stability for highly narrow dual-band photodetectors. On the basis of the different lattice constant, solubility and growth rate between (C 4 H 9 NH 3 ) 2 PbI 4 and (C 4 H 9 NH 3 )(CH 3 NH 3 )Pb 2 I 7 , the newly designed synthesis method allows to first grow the (C 4 H 9 NH 3 ) 2 PbI 4 guided by the self-assembled layer of the organic cations at the water-air interface and subsequently the (C 4 H 9 NH 3 )(CH 3 NH 3 )Pb 2 I 7 layer is formed via diffusion process. Such growth process provides an efficient away for us to readily obtain the (C 4 H 9 NH 3 ) 2 PbI 4 /(C 4 H 9 NH 3 )(CH 3 NH 3 )Pb 2 I 7 single-crystals with various thickness and junction depth by controlling the concentration, reaction 2 temperature and time. The formation of heterostructures has been verified by X-ray diffraction, cross-section photoluminescence and reflection spectroscopy with the estimated junction width below 70 nm. Photodetectors based on such heterostructural single crystal plates exhibit extremely low dark current (∼10 −12 A), high on/off current ratio (∼10 3 ), and highly narrow dual-band spectral response with a full-width at half-maximum of 20 nm at 540 nm and 34 nm at 610 nm due to the high crystalline quality of the synthesized heterostructures and extremely large resistance in the out-of-plane direction leading to the efficient control of photogenerated carrier collection. In particular, the synthetic strategy is general for other 2D perovskites and the narrow dual-band spectral response with all full-width at half-maximum <40 nm can be continuously tuned from red to blue by properly changing the halide compositions. Our findings not only provide an efficient synthetic approach with great simplicity to create 2D perovskite based heterostructural single crystals for investigating the physical processes in those heterostructures, but also offer an alternative strategy to achieve optical-filterless narrow dual-band photodetectors in the entire visible range for multicolor optical sensing.

Giant Nonlinear Optical Response in 2D Perovskite Heterostructures

“…2D perovskite heterostructures with centimeter size were synthesized according to our previous report . As shown in Figure a, in contrast to 3D MAPbI 3 ( n = ∞) which crystallizes in the tetragonal I4/mcm space group at room temperature, 2D perovskites exhibit the orthorhombic space groups Pcab for (BA) 2 PbI 4 ( N = 1) and Ccmm for (BA) 2 MAPb 2 I 7 ( N = 2), respectively (Table S1, Supporting Information) .…”

“…Synthesis of Centimeter‐Size 2D Perovskite Heterostructure Plates : 2D perovskite heterostructure single‐crystal with different thickness was synthesized according to the previous work . 0.45 g PbO powder was dissolved in a mixture of 3.5 mL HI (57% w/w aqueous) and 0.5 mL H 3 PO 2 (50% w/w aqueous) by heating at 150 °C under constant magnetic stirring.…”

“…Synthesis of Centimeter-Size 2D Perovskite Heterostructure Plates: 2D perovskite heterostructure single-crystal with different thickness was synthesized according to the previous work. [12] 0.45 g PbO powder was dissolved in a mixture of 3.5 mL HI (57% w/w aqueous) and 0.5 mL H 3 PO 2 (50% w/w aqueous) by heating at 150 °C under constant magnetic stirring. Then 1.75 mol L −1 BAI solution was added into the resultant solution and slowly cooled down to 75 °C while 0.15 g MAI powder was successively injected into the solution for the synthesis of (BA) 2 (MA)PbI 4 /(BA) 2 (MA)Pb 2 I 7 plates.…”

Three-Dimensional Lead Iodide Perovskitoid Hybrids with High X-ray Photoresponse

“…Alternative materials based on double perovskites [12][13][14][15] and low-dimensional perovskites [15][16][17][18][19][20] are also being explored as they enrich the structural diversity and property repertoire of the perovskite framework. The 3D perovskite structure which forms by the corner-sharing motif of the MX 6 octahedra of Pb 2+ and Sn 2+ creates a favorable electronic band structure with very broad valence and conduction bands which facilitate photo-excited charge transport.…”

Ultrathin Ruddlesden–Popper Perovskite Heterojunction for Sensitive Photodetection

“…In contrast to their 3D counterparts, the emerging 2D Ruddlesden–Popper perovskites have received increasing attention due to their better ambient stability . Up to now, 2D Ruddlesden–Popper perovskites have been demonstrated to exhibit abundant and adjustable optoelectronic properties, high quantum efficiency, and large specific surface area . Furthermore, the synthetic routes of layered perovskites which depend on self‐assemble with low cost and efforts are facial and economically .…”