Abstract:Abstract:In this study, four kinds of structures-[6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM), PCBM/fullerene (C 60 ), C 60 /bathocuproine (BCP), and PCBM/C 60 /BCP-were used as electron transport layers, and the structure, and optical and electronic behaviors of MAPbBr 3 perovskite layers after annealing treatments were observed. The experimental results indicate that PCBM/C 60 bi-layer structure is acceptable for MAPbBr 3 planar perovskite solar cells due to electron step transporting. Low-temperature… Show more
“…In steady‐state PL measurement, the structural relaxation of the crystal lattice increased the optical bandgap, so the lattice expansion in 2D (PEA) 2 PbBr 4 film yielded a blue‐shifted PL spectrum (Figure b and Table S1, Supporting Information) . In UV–vis absorption spectra, 2D (PEA) 2 PbBr 4 and 3D MAPbBr 3 films showed absorption peaks near wavelengths λ = 401 and 525 nm, respectively.…”
Section: Activation Energies For Ion Migration In Halide Perovskitesmentioning
properties of biological synapses and perform parallel operations, they require larger energy than a biological synapse. Therefore, development of an artificial synapse with energy consumption on the level of a biological synapse remains an open problem.Organic-inorganic halide perovskite (OHPs) may provide a material to solve this problem, because of their low activation energy of ion migration. Moreover, various structural modulation of polycrystalline films is possible with facile solution processing so that organic parts in the OHPs can control the ion migration and electrical conduction. OHPs have an ABX 3 crystal structure; the A-site cation is located at the center of a BX 6 octahedral cage, and the B-site metal cation is surrounded by the six nearest-neighbor X-site halide anions. [7] OHPs have a significant hysteresis property that is caused by ion migration or space charges, or both, which may enable gradual modulation of conductance in OHP. [8] Two-terminal artificial synapses based on 3D methylammonium (MA) lead halide perovskite (MAPbX 3 , X = Br, I) films showed synaptic responses that are caused by ion migration in the OHP layer. [9,10] Ion migration in 3D OHP film is induced by relatively low activation energy and a low energy consumption of ≈20 fJ per synaptic event was achieved in the synaptic devices. However, the energy consumption could be further reduced to the energy level of biological synapses when the ion migration was controlled by engineering the structure of OHP films could be optimally done.In this work, we introduce 2D and quasi-2D OHP films into artificial synapses to enable control of ion migration and resultant synaptic responses. For this purpose, we replaced the small MA ion with a bulky phenethylammonium (PEA) ion in their crystalline structures. To prepare 2D, quasi-2D, and 3D OHP films, we controlled the stoichiometric ratio of PEA and MA cations to induce self-assembly of a layered structure. This replacement of an MA cation with PEA cation suppresses ion migration in the out-of-plane direction of the OHP films. [11][12][13] Thereby, the activation energy E A of ion migration is increased, so ion migration and excitatory postsynaptic current (EPSC) can be reduced. Also, energy consumption of the device is reduced to ≈0.7 fJ per synaptic event, which is comparable to that of biological synapses. Memory retention of artificial The hysteretic behavior of organic-inorganic halide perovskites (OHPs) are exploited for application in neuromorphic electronics. Artificial synapses with 2D and quasi-2D perovskite are demonstrated that have a bulky organic cation (phenethylammonium (PEA)) to form structures of (PEA) 2 MA n-1 Pb n Br 3n+1 . The OHP films have morphological properties that depend on their structure dimensionality (i.e., n value), and artificial synapses fabricated from them show synaptic responses such as short-term plasticity, paired-pulse facilitation, and long-term plasticity. The operation mechanism of OHP artificial synapses are also analyzed depending on the dimen...
“…In steady‐state PL measurement, the structural relaxation of the crystal lattice increased the optical bandgap, so the lattice expansion in 2D (PEA) 2 PbBr 4 film yielded a blue‐shifted PL spectrum (Figure b and Table S1, Supporting Information) . In UV–vis absorption spectra, 2D (PEA) 2 PbBr 4 and 3D MAPbBr 3 films showed absorption peaks near wavelengths λ = 401 and 525 nm, respectively.…”
Section: Activation Energies For Ion Migration In Halide Perovskitesmentioning
properties of biological synapses and perform parallel operations, they require larger energy than a biological synapse. Therefore, development of an artificial synapse with energy consumption on the level of a biological synapse remains an open problem.Organic-inorganic halide perovskite (OHPs) may provide a material to solve this problem, because of their low activation energy of ion migration. Moreover, various structural modulation of polycrystalline films is possible with facile solution processing so that organic parts in the OHPs can control the ion migration and electrical conduction. OHPs have an ABX 3 crystal structure; the A-site cation is located at the center of a BX 6 octahedral cage, and the B-site metal cation is surrounded by the six nearest-neighbor X-site halide anions. [7] OHPs have a significant hysteresis property that is caused by ion migration or space charges, or both, which may enable gradual modulation of conductance in OHP. [8] Two-terminal artificial synapses based on 3D methylammonium (MA) lead halide perovskite (MAPbX 3 , X = Br, I) films showed synaptic responses that are caused by ion migration in the OHP layer. [9,10] Ion migration in 3D OHP film is induced by relatively low activation energy and a low energy consumption of ≈20 fJ per synaptic event was achieved in the synaptic devices. However, the energy consumption could be further reduced to the energy level of biological synapses when the ion migration was controlled by engineering the structure of OHP films could be optimally done.In this work, we introduce 2D and quasi-2D OHP films into artificial synapses to enable control of ion migration and resultant synaptic responses. For this purpose, we replaced the small MA ion with a bulky phenethylammonium (PEA) ion in their crystalline structures. To prepare 2D, quasi-2D, and 3D OHP films, we controlled the stoichiometric ratio of PEA and MA cations to induce self-assembly of a layered structure. This replacement of an MA cation with PEA cation suppresses ion migration in the out-of-plane direction of the OHP films. [11][12][13] Thereby, the activation energy E A of ion migration is increased, so ion migration and excitatory postsynaptic current (EPSC) can be reduced. Also, energy consumption of the device is reduced to ≈0.7 fJ per synaptic event, which is comparable to that of biological synapses. Memory retention of artificial The hysteretic behavior of organic-inorganic halide perovskites (OHPs) are exploited for application in neuromorphic electronics. Artificial synapses with 2D and quasi-2D perovskite are demonstrated that have a bulky organic cation (phenethylammonium (PEA)) to form structures of (PEA) 2 MA n-1 Pb n Br 3n+1 . The OHP films have morphological properties that depend on their structure dimensionality (i.e., n value), and artificial synapses fabricated from them show synaptic responses such as short-term plasticity, paired-pulse facilitation, and long-term plasticity. The operation mechanism of OHP artificial synapses are also analyzed depending on the dimen...
“…obtained [80] . The other fullerene derivative, [6,6]-phenyl C 61 butyric acid methyl ester (PCBM), inherits the high electron mobility of fullerenes and shows good solubility due to the introduction of organic groups. As a result, poly (3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) and PCBM are also widely used as the HTL material and the ETL material in PSC devices, respectively.…”
“…3b). Thus, the optimized annealing temperature helped in obtaining highly crystalline films without pinholes and cracks, which can promote the separation and transportation processes of photo-excited carriers [45, 46]. Fig.…”
Due to their outstanding performance, low cost, ease of fabrication, diverse photonic, and optoelectronic applications, metal halides perovskite have attracted extensive interest in photodetector applications. Currently, devices made by metal oxides, metal sulfides, and 2D materials had achieved good responsivity, but suffered from high dark current, slow response speed, small on-off ratio, and poor stability. Whole performances of these photodetectors are not satisfactory. Here, a lateral perovskite (CH3NH3PbBr3)/Ethanolamine/TiO2 (in ethanol) trilayer photodetector is designed for achieving high performance. EA treatment enhances electron extraction and reduces undesired recombination. This trilayer device shows good performances with low dark current of 1.5 × 10−11 A, high on-off ratio of 2700, high photodetectivity of 1.51 × 1012 Jones, high responsivity of 0.13 A W−1, and high stability, comparative to conventional single layer devices. This work provides the way to improve the performance of metal halide perovskite photodetectors.
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