Antisolvent Method Research Articles

Regulation of phase arrangement in 2D ruddlesden-popper perovskite films via anti-solvent method for efficient solar cells

Recently, quasi-two-dimensional RP(Ruddlesden-Popper)-based perovskite solar cells have attracted a wide range of research interest. However, two-dimensional layered perovskites have disordered phase distribution and multi-quantum well structure that are adversely to charge transport and extraction, resulting in the inability to obtain relatively satisfactory photoelectric conversion efficiency (PCE). Here, we fabricated an 2D RP perovskite solar cell with reversely graded phase arrangement by friendly antisolvent method, and obtained the PCE of 14.45%. The dependence of efficiency on device architecture according to the vertical growth direction is further revealed and discussed. To investigate the effect of different antisolvents on crystal orientation and phase arrangement of GA-based 2D RP perovskites, we applied IPA as antisolvent and found that IPA not only significantly improved the surface roughness, quality and crystallinity of 2D perovskites but also reduce or even eliminate lower-n (n = 1, 2) phases and improve the vertical orientation of 2D phases in perovskites films, thereby improving charge transport and extraction. In the end, we achieved a champion PCE of 15.80%. These findings provide an effective guidance for developing GA-based organic spacers toward highly efficient and stable 2D PSCs with less quantum confinement.

Synthesis of lignin nanoparticle‑manganese dioxide complex and its adsorption of methyl orange

Lignin nanoparticles (LNPs) were synthesized using an anti-solvent method and subsequently loaded with manganese dioxide (MnO2) via potassium permanganate treatment, resulting in the formation of MnO2@LNPs. An extensive investigation was conducted to elucidate the influence of MnO2@LNPs on the decolorization of methyl orange solution. The LNPs were successfully obtained by adjusting the preparation parameters, yielding particles exhibited average sizes ranging from 300 to 600 nm, and the synthesis process exhibited a high yield of up to 87.3% and excellent dispersion characteristics. Notably, LNPs size was reduced by decreasing initial concentration, increasing stirring rate, and adding water. In the acetone-water two-phase system, LNPs self-assembled into spherical particles driven by π-π interactions and hydrogen bond forces. Oxidation modification using potassium permanganate led to the formation of nanoscale MnO2, which effectively combined with LNPs. Remarkably, the resulting MnO2@LNPs demonstrated a two-fold increase in methyl orange adsorption capacity (227 mg/g) compared to unmodified LNPs. The process followed the Langmuir isotherm model and was exothermic.

Rapid synthesis of two photoluminescent pyridinium manganese-based halides by an anti-solvent method

The zero-dimensional Mn2+-based halides have efficient emission and good stability due to their unique crystal and electronic structures. Herein, a rapid anti-solvent method was used to prepare two lead-free manganese-based metal halides, (PP)3MnBr5 and (CP)2MnBr4, where PPB (1-phenacylpyridinium bromide) and CPB (cetylpyridinium bromide) were used as organic ion sources. Single crystal of (PP)3MnBr5 was grown and its structure was solved by XRD. In both compounds, (MnBr4)2- is isolated by organic molecules to form a 0-dimensional structures, exhibiting different fluorescent thermal stability and photoluminescence lifetimes. (PP)3MnBr5 shows a strong narrow emission band at 510 nm with a high photoluminescence quantum yield of 73 % and high environmental and thermal stability. (CP)2MnBr4 has a yellow-green emission band at 525 nm with a photoluminescence quantum yield of 28 %. (PP)3MnBr5 has a higher atmosphere and thermal stability than (CP)2MnBr4. After exposure in air for 1000 h, the luminescence intensity of (PP)3MnBr5 is 95 % of the initial value. At 423.15 K, the luminescence intensity of (PP)3MnBr5 is 79 % of the initial value.

A non-thermal modification method to promote the interaction of zein-alginate oligosaccharides composites for better encapsulation and stability—Cold plasma

This current research explored the application of cold plasma (CP) treatment to modify zein-alginate oligosaccharide (zein-AOS) composites in an ethanol-water solution. Anti-solvent method was used to prepare zein-AOS nanoparticles (NPs), and the objective was to investigate the mechanism by which CP promotes interaction between protein and saccharides. Characterization results indicated that CP treatment improved hydrogen bonding and electrostatic interaction between zein and AOS. The CP zein-AOS NPs underwent dispersion and rearrangement, resulting in smaller aggregates with better dispersibility. Among the various induction conditions tested, the zein-AOS85 NPs (induced at 85 W for 2 min) exhibited superior performance as delivery wall materials, with smaller particle size (234.67 nm), larger specific surface area (9.443 m2/g), and higher surface charge (−35.43 mV). In addition, zein-AOS85 showed high stability when used as delivery wall material, providing more binding sites and self-assembly dynamics for nutrients. Curcumin was used as the nutrient model in this study, and CP was found to enhance hydrogen bonding, electrostatic interaction, and hydrophobic interaction between zein, AOS, and nutrients, resulting in increased encapsulation efficiency (EE) from 63.80 % to 85.17 %. The delivery system also exhibited good pH, ionic strength, storage, and dispersion stability.

Low-Temperature Emission Dynamics of Methylammonium Lead Bromide Hybrid Perovskite Thin Films at the Sub-Micrometer Scale.

We study the low-temperature (T = 4.7 K) emission dynamics of a thin film of methylammonium lead bromide (MAPbBr3), prepared via the anti-solvent method. Using intensity-dependent (over 5 decades) hyperspectral microscopy under quasi-resonant (532 nm) continuous wave excitation, we revealed spatial inhomogeneities in the thin film emission. This was drastically different at the band-edge (∼550 nm, sharp peaks) than in the emission tail (∼568 nm, continuum of emission). We are able to observe regions of the film at the micrometer scale where emission is dominated by excitons, in between regions of trap emission. Varying the density of absorbed photons by the MAPbBr3 thin films, two-color fluorescence lifetime imaging microscopy unraveled the emission dynamics: a fast, resolution-limited (∼200 ps) monoexponential tangled with a stretched exponential decay. We associate the first to the relaxation of excitons and the latter to trap emission dynamics. The obtained stretching exponents can be interpreted as the result of a two-dimensional electron diffusion process: Förster resonant transfer mechanism. Furthermore, the non-vanishing fast monoexponential component even in the tail of the MAPbBr3 emission indicates the subsistence of localized excitons. Finally, we estimate the density of traps in MAPbBr3 thin films prepared using the anti-solvent method at n∼1017 cm-3.

Zein-Based Nanoparticles Improve the Therapeutic Efficacy of a TrkB Agonist toward Alzheimer's Disease.

The brain-derived neurotrophic factor (BDNF)/TrkB pathway plays a crucial role in neural plasticity and neuronal survival but is often deficient in neurodegenerative diseases like Alzheimer's disease (AD). CF3CN acts as a specific TrkB agonist that displays therapeutic effects in the AD mouse model, but its brain/plasma ratio (B/P ratio) distribution is not satisfactory. To increase its brain exposure, we synthesized several derivatives and employed nanoparticle (NP) formulation to optimize the most potent #2 derivative's in vivo PK profiles. We generated stable #2-loaded zein/lactoferrin composite NPs (#2/zein/LF) using the antisolvent co-precipitation method. In vivo PK studies revealed that nanoencapsulation improved #2's oral bioavailability by approximately 2-fold and significantly enhanced its plasma Cmax and t1/2, but the brain profiles were comparable. Pharmacodynamics showed that #2/zein/LF activates TrkB signaling that phosphorylates asparagine endopeptidase (AEP) T322 and decreases its enzymatic activity, resulting in reduced AEP-cleaved amyloid precursor protein and Tau fragments in the brains of AD mice, correlating with its PK profiles. After 3 months of treatment in 3xTg mice, #2/zein/LF decreased AD pathologies and alleviated cognitive dysfunction. Hence, zein/LF composite nanoencapsulation is a promising drug delivery method for improving the PK profiles of a potential preclinical candidate for treating neurodegenerative diseases.

Improvement of delivery properties of soybean 7S protein by high-pressure homogenization: In the case of curcumin

In this study, curcumin@high-pressure homogenization-soybean 7S protein/nanoparticles (CUR@HPH-7S-NPs) were prepared by an anti-solvent method. The physicochemical properties results showed at a CUR concentration of 4 mg/mL, CUR@HPH-7S-NPs had better size, encapsulation efficiency (EE), and zeta-potential values of 151.9 nm, 88.80 %, and −23.1 mV, respectively. Fourier transforms infrared (FTIR) and endogenous fluorescence spectroscopy results indicated CUR bound to HPH-7S through hydrophobic interactions, and the force between HPH-7S and CUR molecules was greater than that between untreated 7S protein and CUR. Furthermore, the pH stability results showed the size of CUR@HPH-7S-NPs was barely affected by pH away from adjacent area of the isoelectric point of 7S protein. The physical thermal stability and bio-accessibility results suggested that HPH-7S was more effective in delaying the degradation, had more physical thermal stability, and had a significant improvement in the bio-accessibility of CUR than that of untreated 7S protein. What's more, the antioxidant activity results showed at a CUR equivalent concentration of 40 μg/mL, the DPPH and ABTS radical scavenging activity of CUR@HPH-7S-NPs was 85.10 % and 96.64 %, respectively, both of which were significantly higher than that of free CUR. Finally, this study aimed to provide a theoretical basis for the delivery of other hydrophobic bioactive substances.

Integrating Synthesis, Physicochemical Characterization, and In Silico Studies of Cordycepin-Loaded Bovine Serum Albumin Nanoparticles.

Cordycepin gets rapidly metabolized in the body into inactive form due to its structural similarity to adenosine, thus inhibiting its development as a medicinal agent. This study was aimed to improve the solubility and stability of cordycepin, a potential drug with known antiproliferative activity, by encapsulating it in bovine serum albumin: β-cyclodextrin nanoparticles. Cordycepin-loaded nanoparticles (CLNPs) were synthesized using the antisolvent method and characterized thoroughly using various techniques. Our dynamic light scattering measurement showed a particle size and zeta potential of 160 ± 2.75 nm and -20.21 ± 2.1 mV, respectively, for CLNPs. Transmission electron microscopy studies revealed that particles were spherical in morphology. These CLNPs showed sustained release of cordycepin with encapsulation and loading efficiency of 81.62 ± 1.5 and 27.02 ± 2.0%, respectively, based on high-performance liquid chromatography and UV-vis studies. Based on differential scanning calorimetry and zeta potential studies, CLNPs improve cordycepin stability and solubility. Our molecular simulations and binding energy calculation also showed favorable protein interaction between cordycepin, bovine serum albumin, and β-cyclodextrin, further supporting the notion of improved stability. In vitro cytotoxicity, apoptosis, and cellular uptake studies on breast cancer cells showed that the synthesized nanoparticles had greater cytotoxicity as compared to free cordycepin.

Preparation of disodium terephthalate/multi-walled carbon nanotube composite as an anode material for sodium-ion batteries: Performance and mechanism

Compared with the scarce resources of lithium-ion batteries (LIBs), sodium-ion batteries have been attracting research attentions as an ideal carrier for large-scale energy storage systems due to their abundant raw material resources. Organic materials are gaining importance as SIB anodes due to their advantages of simple preparation method, recyclability, and multi-electron reactions. In this work, disodium terephthalate/multi-walled carbon nanotube (Na2TP/MWCNT) organic composite was prepared as SIB anode material by an anti-solvent method. Experimental results indicated that the optimum sodium storage can be achieved with 10 wt% MWCNT dosage, where reversible capacities reached 229.9 and 93.2 mA h/g at current densities 0.1 and 2C, respectively. The capacity remained 124.9 mA h/g after 50 cycles at 1C current density, which suggested that the composite could act as a candidate for sodium ion battery anodes.

Ultrafast Antisolvent Growth of Single-Crystal CsPbBr3 Microcavity for Whispering-Gallery-Mode Lasing.

In recent years, all-inorganic cesium lead bromide (CsPbBr3) perovskites have garnered considerable attention for their prospective applications in green photonics and optoelectronic devices. However, the development of efficient and economical methods to obtain high-quality micron-sized single-crystalline CsPbBr3 microplatelets (MPs) has become a challenge. Here, we report the synthesis of CsPbBr3 MPs on Si/SiO2 substrate by optimizing the ultrafast antisolvent method (FAS). This technique is able to produce well-dispersed, uniformly sized, and morphologically regular tetragonal phase single crystals, which can give strong green emission at room temperature, with excellent stability and excitonic character. Moreover, the crystals demonstrated lasing with a whispering gallery mode with a low threshold. These results suggest that the single-crystalline CsPbBr3 MPs synthesized by this method are of high optical quality, holding vast potential for future applications in photonic devices.

In-situ construction of FAPbBr3-wrapped MoS2 heterostructure for photocatalytic H2 evolution from dehydrogenation of aromatic alcohols

Photocatalytic H2 evolution from organics dehydrogenation has sparked tremendous research attention. Metal halide perovskites (MHPs) with unique photoelectrical properties are deemed as a promising new-generation photocatalysts. Here, FAPbBr3-wrapped MoS2 heterostructure photocatalysts are in-situ constructed by an anti-solvent method for photocatalytic dehydrogenation of aromatic alcohols, which realizes a co-production of clean H2 fuel and value-added aldehydes. Experimental characterizations and theoretical calculations disclose that the introduction of MoS2 decreases the size of the FAPbBr3, and forms a built-in electric field in the composite, which synergistically inhibit the electron-hole pairs recombination and enhance the charge separation. Meanwhile, the MoS2 with low hydrogen binding energy provides abundant reduction sites to accelerate the kinetic of H2 evolution. As a consequence, the optimal FAPbBr3/MoS2-7 composite exhibits a H2 evolution rate of 1150 μmol g−1 h−1 and a benzyl aldehyde (BAD) generation rate of 1040 μmol g−1 h−1 under visible light irradiation, which is about 6 times of blank FAPbBr3. The activity is comparable to the reported value of H2 production from photocatalytic haloid acid splitting using MHPs-based catalysts. Electron paramagnetic resonance (EPR) measurement reveals that carbon-centered radical of •CH(OH)Ph is the primary intermediate for the photocatalytic dehydrogenation of aromatic alcohols.

DEVELOPMENT AND EVALUATION OF CREAM PREPARATION CONTAINING PHYTOSOME FROM AMLA FRUIT EXTRACT (PHYLLANTHUS EMBLICA L.)

Objective: This study aims to develop and evaluate the phytosome of Phyllanthus emblica L. fruit extract. Methods: The formation of phytosome was performed by using three methods, namely solvent evaporation, antisolvent, and thin layer formation method. The phytosome was evaluated for its entrapment efficiency, particle size, polydispersity index, Fourier Transform Infra-Red (FTIR), and Transmission Electron Microscope (TEM) methods. The phytosome was made into cream with a concentration of 1%. The cream stability was evaluated at a room temperature of 40 °C for 28 d. The permeation of the total phenolic content of cream-containing phytosome and cream-containing extract without phytosome technology was evaluated by diffusion studies. Results: The best method to prepare phytosome was an antisolvent method with the efficiency of entrapment, particle size, and polydispersity index equal to 66.99±0.01%, 298.53 nm±12.04, and 0.323±0.01 respectively. Evaluation by using TEM and FTIR spectroscopy also confirmed the formation of spherical phytosome. There were no significant changes in the cream's organoleptic, pH, and viscosity during storage at room temperature. The permeation test through skin snake and Spangler’s membrane showed that cream containing phytosome had a better diffusion percentage than cream containing extract without phytosome technology. Conclusion: The results of this study showed that the antisolvent method was a potential method to develop phytosome of Phyllanthus emblica L. fruit extract and cream containing phytosome was effective in increasing the permeation.

Suppressing Excess Lead Iodide Aggregation and Reducing N-Type Doping at Perovskite/HTL Interface for Efficient Perovskite Solar Cells.

Excess lead iodide (PbI2 ) aggregation at the charge carrier transport interface leads to energy loss and acts as unstable origins in perovskite solar cells (PSCs). Here, a strategy is reported to modulate the interfacial excess PbI2 by introducing π-conjugated small-molecule semiconductors 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] (TAPC) into perovskite films through an antisolvent addition method. The coordination of TAPC to PbI units through the electron-donating triphenylamine groups and π-Pb2+ interactions allows for a compact perovskite film with reduced excess PbI2 aggregates. Besides, preferred energy level alignment is achieved due to the suppressed n-type doping effect at the hole transport layer (HTL) interfaces. As a result, the TAPC-modified PSC based on Cs0.05 (FA0.85 MA0.15 )0.95 Pb(I0.85 Br0.15 )3 triple-cation perovskite achieved an improved PCE from 18.37% to 20.68% and retained ≈90% of the initial efficiency after 30 days of aging under ambient conditions. Moreover, the TAPC-modified device based on FA0.95 MA0.05 PbI2.85 Br0.15 perovskite produced an improved efficiency of 23.15% compared to the control (21.19%). These results provide an effective strategy for improving the performance of PbI2 -rich PSCs.

Advances in Starch Nanoparticle for Emulsion Stabilization.

Starch nanoparticles (SNPs) are generally defined as starch grains smaller than 600-1000 nm produced from a series of physical, chemical, or biologically modified starches. Many studies have reported the preparation and modification of SNPs, which are mostly based on the traditional "top-down" strategy. The preparation process generally has problems with process complexity, long reaction periods, low yield, high energy consumption, poor repeatability, etc. A "bottom-up" strategy, such as an anti-solvent method, is proven to be suitable for the preparation of SNPs, and they are synthesized with small particle size, good repeatability, a low requirement on equipment, simple operation, and great development potential. The surface of raw starch contains a large amount of hydroxyl and has a high degree of hydrophilicity, while SNP is a potential emulsifier for food and non-food applications.

Voriconazole-syringic acid co-crystals reduced voriconazole-induced hepatotoxicity: In vitro and in vivo studies

Voriconazole (VOR) is recommended for the management of Invasive Aspergillosis. However, hepatotoxicity is one of the most common adverse-effects of VOR. Therefore, the current study explored solid-phase modification of VOR by co-crystallization with hepatoprotective co-former, namely, syringic acid (SYR) to address hepatotoxicity concerns. The co-former was selected based on Molecular complementarity and Hydrogen bond propensity via the Mercury 2.0 software and based on Δpka rule. Consequently, the anti-solvent crystallization method was used to generate the VOR-SYR (2:1) co-crystals. Various analytical and spectral techniques were used to characterize co-crystals. The change in endotherm of VOR-SYR (2:1) co-crystal to the lower value (112.08 °C) than VOR (131.1 °C) and SYR (209 °C) indicated the possibility of a new solid form co-crystal. The alterations in characteristic peaks in the powder x-ray diffraction pattern confirmed the synthesis of VOR-SYR (2:1) co-crystals. The FT-IR (Fourier-Transform Infrared) spectroscopy results revealed the generation of a new peak at 3470 cm−1 and the reduced intensity of peak observed at 3197 cm−1 for VOR-SYR (2:1) co-crystals. This suggested the formation of inter molecular hydrogen bonds. The solubility of the VOR-SYR (2:1) co-crystals was similar to that of the pure drug. Dissolution of the VOR-SYR (2:1) co-crystals demonstrated 99.41% ± 2.58% release in 1 h, whereas the VOR displayed 100.28 ± 1.26% release in 4 h. The in vivo study revealed a significant decrease in hepatotoxicity in the C57bL/6 mice treated with VOR-SYR (2:1) co-crystals (∼40 mg kg−1/day) as compared to VOR (40 mg kg−1/day) treated mice. The reduction in hepatoxicity post administration of VOR-SYR (2:1) co-crystals may be attributed to slow down of metabolism owing to critical role of pyrimidine ring of VOR in co-crystal synthesis in addition to hepatoprotective, antioxidant and anti-inflammatory mechanisms of SYR. Thus, the VOR-SYR (2:1) co-crystals may be a potential dosage form for further pharmacodynamic analysis in experimental Invasive Aspergillosis infection.

Electrophoretic Deposition of Rochelle Salt Nanocrystals on Aluminum Plate

A straightforward and inexpensive electrophoretic method for obtaining environment-friendly nanocrystalline piezo layers from Rochelle salt (RS) is presented here. The electrophoretic deposition process includes the formation of nanocrystals by precipitation of Rochelle salt/water solutions in ethanol (anti-solvent method) under the influence of a high electric field. A nanoporous anodic aluminum oxide membrane is used to separate the electrochemical cell into two chambers. The composition of the RS:H2O:EtOH mixture and the spatial separation of the process of precipitation from electrophoretic deposition allow control of the nanocrystal size and the uniformity of the layer. The reaction kinetics, the morphology, and the piezo response to the resulting layers are all investigated. The best samples were obtained at RS:H2O:EtOH ratio 1:22.5:37.5. Under these conditions, the nanocrystals are preferentially oriented on the aluminum substrate and form a dense and homogeneous layer. Although the obtained structure is polycrystalline, the resulting piezo effect is 1120 pC/N, which is comparable to inorganic monocrystals and piezoceramics. This allows the use of electrophoretically deposited polycrystalline piezo layers in applications such as energy harvesting.

Efficient blue emission from stable silver-based metal halide single crystals

In this paper, the one-dimensional Cs2AgI3 and Cu+-doped Cs2AgI3 single crystals had been synthesized by antisolvent infiltration method. A blue-emission with peak at 473 nm and a large Stokes shift was observed in the Cs2AgI3 single crystals, which might originate from the self-trapped excitons (STEs). Experimental studies revealed that appropriate Cu+ dopant greatly enhanced the Cs2AgI3 photoluminescence quantum yield (PLQY). Theoretical calculation confirmed that the optimized Cu+ concentration could effectively modulate the electronic band structure, and the electronic states highlighted in CuI4 tetrahedron showed strong localized characteristic, which was beneficial to improve the luminescence efficiency of the blue band. In addition, this kind of metal halides exhibited strong stability in air ambient. This work supplies a feasible strategy to improve the optoelectronic performance by extrinsic chemical doping and could prompt the commercial application of lead-free metal halides.

Improvement of physicochemical stability and digestive properties of quercetagetin using zein-chondroitin sulfate particles prepared by antisolvent co-precipitation

Zein-quercetagetin-chondroitin sulfate (Zein-Que-CS) composite nanoparticles with different compositions were successfully fabricated using a novel antisolvent co-precipitation method. The mean particle diameter (97.5 to 219.4 nm), negative surface potential (−29.9 to −51.1 mV), and turbidity (265 to 370 NTU) of suspensions of Zein-Que nanoparticles increased after the addition of CS. Electrostatic attraction, hydrogen bonding, and hydrophobic attraction were the main driving forces for the formation of the composite nanoparticles. The encapsulation efficiency and loading capacity of the quercetagetin within the Zein-Que-CS (100:10:30) nanoparticles were 91.6 % and 6.1 %, respectively. The photostability and thermal stability of the encapsulated quercetagetin were 3.4- and 3.2- fold higher than that of the free form. The nanoparticles had good resistance to sedimentation and exhibited slow-release properties under simulated gastrointestinal conditions. The Zein-Que-CS nanoparticles developed in this study may therefore be useful for the encapsulation, protection, and delivery of quercetagetin.

(111)-Dominated Perovskite Films by Antisolvent Engineering.

Fabricating perovskite films with a dominant crystal orientation is an effective path to realizing quasi-single-crystal perovskite film, which can eliminate the fluctuation of the electrical properties in films arising from grain-to-grain variations, and improve the performance of perovskite solar cells (PSCs). Perovskite (FAPbI3 ) films based on one-step antisolvent methods usually suffer from chaotic orientations due to the inevitable intermediate phase conversion from intermediates of PbI2 •DMSO, FA2 Pb3 I8 •4DMSO, and δ-FAPbI3 to α-FAPbI3 . Here, a high-quality perovskite film with (111) preferred orientation ((111)-α-FAPbI3 ) using a short-chain isomeric alcohol antisolvent, isopropanol (IPA) or isobutanol (IBA), is reported. The interaction between IPA and PbI2 leads to a corner-sharing structure instead of an edge-sharing PbI2 octahedron, sidestepping the formation of these intermediates. With the volatilization of IPA, FA+ can replace IPA in situ to form α-FAPbI3 along the (111) direction. Compared to randomly orientated perovskites, the dominantly (111) orientated perovskite ((111)-perovskite) exhibits improved carrier mobility, uniform surface potential, suppressed film defects and enhanced photostability. PSCs based on the (111)-perovskite films show 22% power conversion efficiency and excellent stability, which remains unchanged after 600h continuous working at maximum power point, and 95% after 2000h of storage in atmosphere environment.

Synthesis, crystal growth, electronic structures and optical properties of wide bandgap semiconductor (CH3NH3)2HgI4

The synthesis, crystal growth and electronic structures, as well as optical properties of Hg-based hybrid organic-inorganic compound (CH3NH3)2HgI4 are reported. Single crystal was grown through the anti-solvent method, yielding the faint yellow (CH3NH3)2HgI4 flake crystals. The structural analysis revealed that (CH3NH3)2HgI4 crystallized in the orthorhombic space group Pbca with a 0D crystal structure featuring anionic [HgI4]2- units that were surrounded by CH3NH3+ cations. Furthermore, (CH3NH3)2HgI4 does not decompose when being exposed to air, but the crystallinity slowly decays over time in air at room temperature. TGA and DSC show that it is stable for (CH3NH3)2HgI4 from room temperature to 223 °C. It shows that (CH3NH3)2HgI4 is a slightly indirect nature with 3.276 eV of band gap based on density functional theory calculations, which is close to 3.18 eV derived from UV–vis–NIR spectra of (CH3NH3)2HgI4 crystal. In addition, room temperature photoluminescence (PL) spectra of (CH3NH3)2HgI4 yields broad peaks at 540 nm with full width at half maximum (FWHM) values of 201 nm. These PL peaks are tentatively assigned to self-trapped excitons following the crystal and electronic structure considerations. The bands around the Fermi level have small dispersions, which is indicative of high charge localization with significant exciton binding energies in (CH3NH3)2HgI4. PL analysis indicates that (CH3NH3)2HgI4 may have potential research value as white-light-emitting phosphors and scintillator.