Applied Materials Today
Self-aligned CH3NH3PbBr3 perovskite nanowires via dielectrophoresis for gas sensing applications
Graphical abstract
Single-crystalline MAPbBr3 and MAPbCl3 NWs with high surface area and characteristic surface moieties provide not only distinct optoelectronic properties but also strong and abundant analyte adsorption sites. Self-alignment of single-crystalline MAPbBr3 nanowires via dielectrophoresis provides a potential platform for chemiresistive gas sensors with high selectivity owing to their atmosphere-dependent electrical properties associated with the intermolecular interactions in the reversible adsorption and desorption process.
Introduction
Metal halide perovskite (MHP) materials hold a promising potential for optoelectronic applications such as solar cells, light-emitting diodes, and photodetectors owing to a wide range of tunability in their energy band structures and the relevant light absorption and luminescence [1], [2], [3], [4], [5]. For the past few years, significant efforts have been devoted to understanding and improving their optoelectronic properties based on their diverse structural and chemical variability in a perovskite framework with a general formula of ABX3, where A+ cation is Cs+, MA+ (MA+ = CH3NH3+), and FA+ (FA+ = HC(NH2)2+), B2+ cation is mainly Pb2+, X− halide is Cl−, Br−, and I− [6], [7], [8], [9], [10], [11]. Moreover, low dimensional nanostructures such as nanocrystals (NCs) and nanoplatelets of MHPs have been adopted to achieve the physical properties (e.g. quantum confinement) unattainable using bulk MHPs due to the characteristic features in their morphologies [12], [13], [14], [15], [16], [17], [18]. However, uncontrolled formation of surface defects in MHP NCs has shown to introduce undesired trap states capturing mobile charge carriers, which have a great influence on the stability and performance of MHPs-based devices [19], [20], [21], [22], [23]. Therefore, a precise control of the surface charge recombination plays a crucial role in further optimization of MHPs-based devices relying on their electronic and optical properties.
While the surface passivation of MHP NCs has been widely performed using organic molecules containing amine-end groups, a few reports also showed that the environmental gas molecules can effectively interact with the ionic components such as metal cations and halogen vacancies at the MHP surface, resulting in a modulation of their photoluminescence (PL) and photostability as well as electrical resistance [24], [25], [26], [27]. For example, Loi and co-workers reported that the physisorption of oxygen and water molecules in MAPbBr3 single crystals can significantly enhance their PL intensity by over two orders of magnitude [24]. Bao et al. reported a resistive variation of MAPbI3 thin films when exposed to NH3 atmosphere [25]. These results indicate that the adsorption of environmental gas molecules can considerably affect the concentration of surface charge carriers and their transporting properties in the MHP materials. Furthermore, the MHP materials are a crystalline semiconductor with high carrier mobility and long carrier diffusion length, which give rise to efficient channels for charge carriers [28,29]. Thus, nanostructured MHPs with high surface area and versatile surface chemistry can provide a new platform for highly sensitive, active gas sensor materials.
Recently, Zhuang et al. demonstrated that polycrystalline MAPbI3-x(SCN)x film responds to acetone vapour and NO2 gases [30]. Xu and coworkers reported that gold-loaded MASnI3-SnO2 based gas sensor exhibited 240% of response for NO2 gas at 5 ppm with a recovery time of 12 s [31]. However, most of recent studies were focused on polycrystalline MAPbI3 and mixed halide MAPbI3-xClx thin films to detect O2, O3, or NH3 gas molecules although they are known to exhibit a permanent degradation against moisture and polar solvents accompanied by chemical decomposition and morphological changes [32], [33], [34]. Since this decomposition preferentially initiates at grain boundaries of MHP thin films, their electronic properties are significantly determined by their microstructure quality such as polycrystallinity, grain size, and defects, limiting the access to the intrinsic response of MHP materials to various environmental molecules [35,36]. Therefore, the fabrication of single-crystalline MHPs with enhanced stability and well-controlled nanostructure is important to understand how the environmental molecules interact with their surface moieties.
Herein, for the first time, we demonstrate alignment of single-crystalline MAPbCl3 and MAPbBr3 nanowires (NWs) via dielectrophoresis (DEP) on Au interdigitated electrodes (IDEs) as an ideal platform for chemiresistive gas sensors with high selectivity. The single-crystalline MHP NWs with a length of ∼25 μm could be grown in a liquid phase with excess organic ligands by kinetically controlled supersaturation of the precursor solution in the crystallization process. Under an electric field, DEP force exerted on the NWs allows a precise deposition of MHP NWs with respect to IDEs, resulting in a uniform and controlled alignment of NWs. The interaction mechanism of MHPs with the gas molecules could be understood by adsorption and desorption of oxygen molecules that manipulate the effective concentration of charge carriers along the MHP NWs. This concept is also supported by the presence of abundant O2 molecules at the surface of aligned MAPbBr3 NWs array that exhibited much higher selectivity in contrast to MAPbCl3 NWs array.
Section snippets
Materials
Lead(II) bromide (PbBr2, 99%), lead(II) chloride (PbCl2, 99%), methylammonium chloride (MACl, ≥ 98%), methylammonium bromide (MABr, ≥ 99%) n-octylamine (≥ 99%), and oleic acid (≥ 90%) were purchased from Sigma-Aldrich and used as received. Toluene (≥ 99%), N,N-dimethylformamide (DMF, ≥ 99.5%), and dimethyl sulfoxide (DMSO, ≥ 99.5%) were purchased from Daechung Chemicals & Metals and used as received.
Synthesis of MAPbCl3 nanowires
First, 10.72 mg (0.16 mmol) of MACl and 55.6 mg (0.2 mmol) of PbCl2 were dissolved in 2 mL of
Results and discussion
Single-crystalline MHP NWs were successfully synthesized by a modified reverse ligand-assisted reprecipitation (LARP) method, in which the preferential growth of crystals is attributed to the prolonged duration for the growth of the initially formed crystals under excess surface ligands (i.e. n-octylamine and oleic acid), as illustrated in Fig. 1a [37,38]. First, relatively uniform MHP cubes with an edge length of ∼2.5 μm were obtained by fast addition of toluene into the precursor solution. In
Conclusions
In conclusion, single-crystalline MAPbBr3 and MAPbCl3 NWs with high surface area and characteristic surface moieties provide not only distinct optoelectronic properties but also strong and abundant analyte adsorption sites. We demonstrated that the DEP process allows for a high level of control over the spatial distribution and orientation of single-crystalline MHP NWs that provide new opportunities as a new platform for highly sensitive, active gas sensor materials. MAPbBr3 NWs array sensors
CRediT authorship contribution statement
Artavazd Kirakosyan: Conceptualization, Methodology. Moon Ryul Sihn: Resources, Investigation, Data curation. Min-Gi Jeon: . Rezaul M.D. Kabir: . Jihoon Choi: Conceptualization, Writing – review & editing, Supervision, Funding acquisition.
Declaration of Competing Interest
The authors declare no competing financial interests.
Acknowledgements
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (No. NRF-2019R1I1A2A01060608, 2020R1I1A1A01062138).
References (54)
- et al.
Printable organometallic perovskite enables large-area, low-dose X-ray imaging
Nature
(2017) - et al.
Detection of volatile organic compounds (VOCs), aliphatic amines using highly fluorescent organic-inorganic hybrid perovskite nanoparticles
Dyes. Pigm.
(2017) - et al.
Spectroscopic study on the interaction of organic-inorganic hybrid perovskite nanoparticles with linear aliphatic alcohols
Dyes. Pigm.
(2017) - et al.
Light enhanced room temperature resistive NO2 sensor based on a gold-loaded organic–inorganic hybrid perovskite incorporating tin dioxide
Microchim. Acta
(2019) - et al.
Highly sensitive and selective gas sensors using p-type oxide semiconductors: overview
Sensor Actuator B-Chem.
(2014) - et al.
Metal-halide perovskites for photovoltaic and light-emitting devices
Nat. Nanotechnol.
(2015) - et al.
Understanding the physical properties of hybrid perovskites for photovoltaic applications
Nat. Rev. Mater.
(2017) - et al.
Perovskite light-emitting diodes with external quantum efficiency exceeding 20 percent
Nature
(2018) - et al.
Overcoming the electroluminescence efficiency limitations of perovskite light-emitting diodes
Science
(2015) - et al.
Electron-hole diffusion lengths exceeding 1 micrometer in an organometal trihalide perovskite absorber
Science
(2013)
Long-range balanced electron and hole-transport lengths in organic-inorganic CH3NH3PbI3
Science
Reversible halide exchange reaction of organometal trihalide perovskite colloidal nanocrystals for full-range band gap tuning
Nano Lett.
Excitons versus free charges in organo-lead tri-halide perovskites
Nat. Commun.
Suppressed Mn2+ doping in organometal halide perovskite nanocrystals by formation of two-dimensional (CH3NH3)2MnCl4
Chem. Comm.
Scale-up synthesis of organometal halide perovskite nanocrystals (MAPbX3, X = Cl, Br, and I)
ACS Sustain. Chem. Eng.
Quantum dot light-emitting diodes based on inorganic perovskite cesium lead halides (CsPbX3)
Adv. Mater.
Bright light-emitting diodes based on organometal halide perovskite nanoplatelets
Adv. Mater.
50-Fold EQE improvement up to 6.27% of solution-processed all-inorganic perovskite CsPbBr3 QLEDs via surface ligand density control
Adv. Mater.
Dimensionality engineering of hybrid halide perovskite light absorbers
Nat. Commun.
Metal halide perovskite nanocrystals: synthesis, post-synthesis modifications, and their optical properties
Chem. Rev.
Optical properties of colloidal CH3NH3PbBr3 nanocrystals by controlled growth of lateral dimension
Cryst. Growth Des.
Scalable synthesis of exfoliated organometal halide perovskite nanocrystals by ligand-assisted ball milling
ACS Sustain. Chem. Eng.
Genesis, challenges and opportunities for colloidal lead halide perovskite nanocrystals
Nat. Mater.
Highly efficient perovskite nanocrystal light-emitting diodes enabled by a universal crosslinking method
Adv. Mater.
Efficient perovskite light-emitting diodes featuring nanometre-sized crystallites
Nat. Photon.
Amine-based passivating materials for enhanced optical properties and performance of organic–inorganic perovskites in light-emitting diodes
J. Phys. Chem. Lett.
Surface engineering for improved stability of CH3NH3PbBr3 perovskite nanocrystals
Nanoscale
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These authors contributed equally to the presented work.