Plasmonic‐Functionalized Broadband Perovskite Photodetector

Abstract

of these perovskite-based photodetectors decreases to almost zero when the incident light wavelength is in the nearinfrared range due to the threshold of the material bandgap width at 760 nm. To improve the optical response of the perovskites in the near-infrared range, many chemical processings were explored, such as mixing of different perovskites [19][20][21][22] and doping of other materials. [23][24][25] Unfortunately, these chemical methods might induce the distortion of perovskite lattice and damage the device performance. [26] Metal nanostructures under light illumination can give rise to localized surface plasmon resonance (LSPR), [27,28] which induces strong light scattering and absorption. [29][30][31][32][33] Randomly inserting metal nanostructures into perovskite-based devices, such as solar cells [34][35][36][37] and photodetectors, [38,39] can improve photoresponse ability at the visible range. However, the response of these perovskite-based devices at the near-infrared range is still very weak.Here, we report a perovskite-based photodetector with high photoresponsivity in the near-infrared range that was fabricated on a well-defined plasmonic-functionalized multilayer substrate that was composed of arrays of Au nanosquares/SiO 2 spacer/ Au film. Due to the strong plasmonic coupling between the substrate and the incident light, a great amount of free carriers are generated in the perovskite film. As a consequence, a wider optical spectrum response and a better external quantum efficiency (EQE) in the near-infrared range were achieved, compared with the perovskite film on a usual Si/SiO 2 substrate. In addition, a sequentially tunable spectral response range of our device can be realized by varying the size of Au nanosquares.The schematic of our photodetector device is shown in Figure 1a, where the plasmonic substrate was designed to consist of three functional layers, arrays of Au nanosquares at the top, a SiO 2 dielectric spacer in the middle, and an Au film at the bottom. The perovskite (CH 3 NH 3 PbI 3 ) and hole-transporting medium (2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F 4 -TCNQ)-doped poly [bis(4-phenyl) (2,4,6-trimethylphenyl) amine] (PTAA) solution, abbreviated as HTM) were spin-coated onto the substrate. The HTM layer, incorporated between the substrate and CH 3 NH 3 PbI 3 layer, serves two functions: harvesting holes from the CH 3 NH 3 PbI 3 layer and insulating the transfer of hot electrons from the decay of LSPR. The incident Organic-inorganic hybrid perovskite photodetectors have been reported to possess superior optoelectronic properties, such as high sensitivity, ultrafast response, and capability of strongly absorbing the light in the visible range. While in the near-infrared range, the performances of these photodetectors deteriorate seriously, originating from the weak coupling of infrared light to the perovskites. In this study, an organic-inorganic hybrid perovskite photodetector on arrays of Au nanostructures is fabricated, which exhibits a remarkable photocur...

Two-step vapor deposition of self-catalyzed large-size PbI2 nanobelts for high-performance photodetectors

“…It is well known that the measured data can be well fitted by Equation of Ip = αΦ β , where Ip is the photocurrent, α and β are the fitting parameters, and Φ is the light intensity. [46][47][48][49][50][51] As a result, the asfabricated photodetector reveals a power dependence of Ip = 0.23Φ 0.799 from the fitting of the measured data, depicting the sublinear relationship between the photocurrent and light intensity, which is often observed in layered-material based photoconductors due to the complex processes of electron-hole generation, trapping, and recombination in the semiconductors. [46][47][48] It is worth to point out that the value of β is higher than the reported 2D nanosheets in literatures, 19,21,22 indicating the high crystallinity of the as-prepared PbI2 nanobelts.…”

Localized surface plasmon effects on the photophysics of perovskite thin films embedding metal nanoparticles

“…[10][11][12][13][14] In particular, numerous experimental works report the photovoltaic or photodetection performance enhancement that results from coupling metallic nanostructures to organic metal halide perovskite films. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] However, the origin of the improvement reported remains, in most cases, unclear. In some cases, inclusion of metallic nanoparticles has led to an increase of the cell efficiency without affecting the optical absorption of the perovskite, which remains unchanged, hence discarding light trapping as the mechanism behind the improvement.…”

Edge‐State‐Enhanced Ultrahigh Photoresponsivity of Graphene Nanosheet‐Embedded Carbon Film/Silicon Heterojunction

“…Heterojunction photodetector becomes an indispensable part in the electronic components and optoelectronic products. Plane graphene–silicon junction attracts growing attentions in various applications such as solar cells, tunable Schottky barrier triodes, complementary metal‐oxide‐semiconductor (CMOS)‐compatible optical modulator, gas sensors, and photodetectors . Particularly, plane graphene–silicon photodetectors are suitable for weak light detection (approximately picowatt incidences' detection), which is crucial for wide applications including taking high‐quality photos under insufficient light, infrared monitoring, and optical spectroscopic analysis.…”