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Metal halide perovskites have attracted considerable attention for light‐emitting diode (LED) applications due to their desirable optoelectronic properties including high brightness and color purity. However, the performance of blue perovskite LEDs (PeLEDs) remains inferior to their red and green counterparts. Herein, an ionic liquid (IL), specifically 1‐butyl‐3‐methylimidazolium tetrafluoroborate is introduced as the interlayer on the hole transport layer (HTL). This IL demonstrates a strong interaction with the perovskite emissive layer, resulting in effective defect passivation and a shallower valence band maximum. Consequently, nonradiative recombination is reduced, and hole injection is enhanced. Additionally, a soft lithography method employing a transfer process is successfully developed that enables precise micropatterning of the perovskite light‐emitting layer. Through these advancements, the IL‐modified PeLED exhibits pure blue emission at 470 nm with a maximum luminance of 891 cd m−2 and an impressive maximum EQE of 8.3%. Furthermore, the micro PeLED with an IL interlayer achieves a maximum luminance of 400 cd m−2 and a maximum EQE of 3.9%. [ABSTRACT FROM AUTHOR]

Propylammonium lead iodide (C3H7NH3PbI3), a promising hybrid perovskite, is successfully synthesized by a solgel technique. Structural, optical, and dielectric properties have been studied in detail. The dielectric constant, loss factor, electric modulus, and AC and DC conductivity of this hybrid perovskite exhibit strong temperature dependence over the frequency range of 10 Hz ≤ f ≤ 8 MHz. The Nyquist plot reveals the distinct contributions of grain and grain boundary to the total impedance. The dielectric constant is found to increase with temperature in the high frequency region. The modified Cole–Cole plot shows that the space charge and free charge conductivity increase with the elevation of temperature, whereas the relaxation time decreases with the rise in temperature. From the modified Kohlrausch–Williams–Watts equation, we perceived asymmetrical nature in electric modulus spectra at various temperatures, which corresponds to the non-Debye type nature of perovskite. It has also been found that, with the elevation of temperature, the imaginary part of electric modulus spectra shifts from the non-Debye type toward the Debye type nature, though failing to acquire exact Debye type response, and emerges as a semiconductor material. AC conductivity of PAPbI3 is illustrated on the basis of the correlated barrier hopping (CBH) mechanism. Activation energy estimated from both modulus spectra and DC conductivity matches well, affirming the similarity between relaxation behavior and conduction mechanism. Along with all these, PAPbI3 possesses a high dielectric constant associated with a small dielectric loss, making it a potential candidate for energy harvesting devices. [ABSTRACT FROM AUTHOR]

In this work, CsPbBr3 has been successfully synthesized via sol-gel technique. The orthorhombic phase of the material has been verified by X-ray diffraction measurement followed by Rietveld refinement analysis. Morphological study has revealed the cubic shape of particles with dimension ∼3 μm. Electrical properties are characterized by Complex impedance (Z*), dielectric permittivity (ɛ*), and ac conductivity within the frequency range 10 Hz–5 MHz for different temperatures between 313K and 673 K. The dielectric behavior of CsPbBr3 is found to be thermally activated and frequency dependent. The ascensive nature of ɛ′(ω) at lower frequency is assigned to the Maxwell-Wagner type interfacial polarization. ɛ′(ω) has been fitted using Kramers-Kronig relation by including the dielectric constant at infinite frequency. Variation of ɛ″(ω) with frequency has been explained by the hopping of charge carrier over a potential barrier between charge defects. AC conductivity has also been fitted by Jonscher's power law to find the real component of conductivity and it has been described by using the Jump relaxation model. Activation energy has been calculated by fitting the dc conductivity using Arrhenius relation and found to have a value of 0.517 eV. Grain resistance (rg), grain capacitance (cg), grain boundary resistance (rgb), and grain boundary capacitance (cgb) have been accounted by fitting Z′ vs log(f) plot with equivalent circuit and existing theoretical model. [ABSTRACT FROM AUTHOR]

Lead-free hybrid halide perovskite (CH3NH3)3Bi2Br9 has been successfully synthesised by mechano-chemical method. The microstructure analysis by Rietveld's refinement method revealed that the crystal belongs to trigonal system with space group P 3 ˉ m1. The obtained microstructural parameters are well in agreement with the previously published data. Temperature-dependent AC conductivity, impedance spectroscopy and complex dielectric properties have been investigated in detail. The negative temperature coefficient of resistance behaviour reveals the semiconducting nature of the materials. The complex impedance spectroscopy also supports the semiconducting nature of the sample with activation energy for conduction ~0.38 eV. [ABSTRACT FROM AUTHOR]

CsPbBr3 has been synthesized via a wet chemical technique instead of colloidal hot injection route. Crystalline structure and chemical composition of the material have been assured by Rietveld refinement and energy dispersive X-ray spectroscopy. Photoresponse capability of CsPbBr3 nanocrystal in cubic phase has been already explored. Here, intrinsic optoelectronic properties of orthorhombic CsPbBr3 have been investigated in detail. A prototype photodetector has been fabricated on a transparent conducting oxide-coated glass by using silver as the other electrode material. The photo-responsibility of CsPbBr3 arises due to the combined effect of electron–hole pair generation and trapping within material and recombination. The non-linearity of I–V characteristics clearly reveals the formation of well-established Schottky contact at perovskite–ITO junction. Responsivity of the detector increases from 1.4 to 1.73 mA W−1 after enhancing the irradiance from 25 to 100 mW cm−2 at 8 V bias voltages. Linear dynamic range has been accounted to study the linear photosensitivity of the device. In order to investigate the stability and reversibility, photocurrent has been measured under ON/OFF condition of frequency 20 s. The quantitative contribution of polycrystalline grain and grain boundary to charge mobilization has been evaluated by fitting the Cole–Cole plot under different solar intensities. [ABSTRACT FROM AUTHOR]

MAPbX3(MA = CH3NH3, X = Br, I) are synthesized by the chemical route. The Rietveld refinement of the room temperature X-ray diffraction pattern of the materials shows that MAPbBr3is crystallized in the cubic Pm3m crystal symmetry whereas MAPbI3crystallizes in the tetragonal phase with space group I4/mcm. The dielectric relaxation of MAPbX3has been studied in the frequency range from 42 Hz to 0.2 MHz in the electric modulus formalism. The relaxation time is determined by the reciprocal of the frequency where the maximum of the imaginary part of the electric modulus is centred. The relaxation mechanism of the samples is investigated by the Cole-Cole model. The complex impedance plane plots are analyzed by an electrical equivalent circuit consisting of a resistance and a capacitance. The frequency dependent conductivity spectra follow the power law. [ABSTRACT FROM AUTHOR]

In this work, CsPbBr3 has been successfully synthesized via sol-gel technique. The orthorhombic phase of the material has been verified by X-ray diffraction measurement followed by Rietveld refinement analysis. Morphological study has revealed the cubic shape of particles with dimension ∼3 μm. Electrical properties are characterized by Complex impedance (Z*), dielectric permittivity (ɛ*), and ac conductivity within the frequency range 10 Hz–5 MHz for different temperatures between 313K and 673 K. The dielectric behavior of CsPbBr3 is found to be thermally activated and frequency dependent. The ascensive nature of ɛ′(ω) at lower frequency is assigned to the Maxwell-Wagner type interfacial polarization. ɛ′(ω) has been fitted using Kramers-Kronig relation by including the dielectric constant at infinite frequency. Variation of ɛ″(ω) with frequency has been explained by the hopping of charge carrier over a potential barrier between charge defects. AC conductivity has also been fitted by Jonscher's power law to find the real component of conductivity and it has been described by using the Jump relaxation model. Activation energy has been calculated by fitting the dc conductivity using Arrhenius relation and found to have a value of 0.517 eV. Grain resistance (rg), grain capacitance (cg), grain boundary resistance (rgb), and grain boundary capacitance (cgb) have been accounted by fitting Z′ vs log(f) plot with equivalent circuit and existing theoretical model. [ABSTRACT FROM AUTHOR]