Large-Area Heterojunction Photodetectors Based on Nanometer-Thick CH₃NH₃PbI₃ Films Modified with Poly(methyl methacrylate) Nanofilms

Abstract

The metal halide organic−inorganic perovskite material provides a broad prospect for the development of highperformance photoelectric detectors due to its extraordinary optical and electrical properties. In this work, a nanometer-thick CH 3 NH 3 (MA)PbI 3 heterojunction photodetector (PD) with an ultralarge scale of 1.0 cm × 1.0 cm is prepared and a facile approach is proposed to enhance the performance of the heterojunction PDs by introducing a poly(methyl methacrylate) (PMMA) nanolayer to modify the MAPbI 3 film. The heterojunction PD achieves a broadband photoresponse from 300 to 800 nm and can work well without any external bias. Moreover, after the modification with a suitable concentration of the nanometer-thick PMMA, the crystal quality of the MAPbI 3 layer, as well as the performance of the heterojunction PD, is greatly enhanced, and the photosensitivity, responsivity, specific detectivity, and response times are as high as 2.09 × 10 4 , 0.46 A/W, 3.18 × 10 10 Jones, and 0.21/0.12 s, respectively. In addition, the ambient and thermal stabilities of the MAPbI 3 heterojunction PD are largely improved, which can also be attributed to the protection and passivation of the PMMA nanolayer. This work definitely demonstrates a cost-effective method for designing large-scale, stable, high-performance, self-powered photodetectors and also opens great opportunities for developing low-cost and broadband perovskite-based photoelectric devices.

Interfacial Passivation and Energy Level Alignment Regulation for Self‐Powered Perovskite Photodetectors with Enhanced Performance and Stability

“…The PMMA was directly spin-coated on the surface of the annealed perovskite, which can passivate the surface defects and prevent the erosion of water molecule. [27] However, the Fe 3 O 4 and PMMA in the above reports only improve the perovskite film quality and have no effect on other layers. It is also crucial to improve the energy level structure between the perovskite layer and charge transport layer.…”

Polymer‐Assisted Phase Stable γ‐CsPbI3 Perovskite Film for Self‐Powered and Ultrafast Photodiodes

“…Cross-sectional scanning electron microscopy (SEM) images of the obtained photodiode, except for Ag layer, are shown in Figure S2 (Supporting Information), indicating a clearly sandwiched structure with a thin perovskite layer thickness of 32 nm, much thinner than those reported in other works. [31][32][33][34][35][36] Optoelectronic characterizations are conducted and exhibited in Figure 2. Responsivity (R), detectivity (D*), and external quantum efficiency (EQE) are three critical parameters for evaluating photodetection performance.…”

“…Cross‐sectional scanning electron microscopy (SEM) images of the obtained photodiode, except for Ag layer, are shown in Figure S2 (Supporting Information), indicating a clearly sandwiched structure with a thin perovskite layer thickness of 32 nm, much thinner than those reported in other works. [ 31–36 ]…”

Transfer-Printed Nanoscale Poly(3-hexylthiophene-2,5-diyl) Layers for Organic Photodetectors

“…10−13 In particular, photomultiplication-type (PM-type) OPDs with external quantum efficiencies (EQEs) greater than 100% show excellent weak light detection ability. 14 The EQE at 620 nm of PM-type OPDs based on poly(3-hexylthiophene)/ [6,6]-phenylC61butyric acid methyl ester (PCBM) reached 1250% under a −10 V applied voltage. 15 However, the photoresponse speed of PM-type OPDs is slower than that of conventional photodiode-type OPDs.…”

“…Photodetectors that convert incident light into electrical signals have been applied in many electronic systems, including in optical communications, bioimaging, and security fields. − However, the complicated manufacturing, poor flexibility, and low coefficient of conventional detectors based on inorganic semiconductors (Si, Ge, and GaInAs) hamper their widespread use. − Solution-processed organic photodetectors (OPDs) with organic layers on the order of nanometers have received tremendous attention due to their advantages of low cost, light weight, flexibility, and simple fabrication. − In particular, photomultiplication-type (PM-type) OPDs with external quantum efficiencies (EQEs) greater than 100% show excellent weak light detection ability . The EQE at 620 nm of PM-type OPDs based on poly­(3-hexylthiophene)/[6,6]-phenylC61-butyric acid methyl ester (PCBM) reached 1250% under a −10 V applied voltage .…”