Crystal Systems and Lattice Parameters of CH3NH3Pb(I1-xBrx)3 Determined Using Single Crystals: Validity of Vegard's Law.

Metal halide perovskites are promising materials for light absorbers in solar cell applications. Use of the Br/I system enables us to control band gap energy and improves the efficiency of solar cells. Precise knowledge of lattice parameters and band gap energies as functions of compositions are crucially important for developing the devices using those materials. In this study, we have determined lattice parameters and band gap energies of CH3NH3Pb(I1-xBrx)3, one of the most intensively studied mix-halide perovskites, as functions of Br content x. We measured accurate Br contents and lattice parameters of CH3NH3Pb(I1-xBrx)3 (0 ≤ x ≤ 1) using single-crystalline samples by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) measurements, respectively. The CH3NH3Pb(I1-xBrx)3 crystal system is tetragonal for x ≤ 0.06 and cubic for x ≥ 0.08 at 300 K. Lattice parameters of CH3NH3Pb(I1-xBrx)3 strictly follow Vegard's law; i.e., they are linearly dependent on x. We give linear expressions of x of lattice parameters for the tetragonal and cubic phases of CH3NH3Pb(I1-xBrx)3 at 300 K. We have shown that these expressions can be used for determining the Br contents of CH3NH3Pb(I1-xBrx)3 polycrystalline thin-film samples based on XRD measurements and, in addition, demonstrated that XPS measurements on polycrystalline samples may be erroneous because of impure ingredients in the samples. Furthermore, we determined band gap energies of CH3NH3Pb(I1-xBrx)3 (0 ≤ x ≤ 1) at room temperature using absorption spectra of polycrystalline thin films taking account of excitonic effects.

Controlled Photodynamic Action of Axial Fluorinated DiethoxyP(V)tetrakis(p-methoxyphenyl)porphyrin through Self-Aggregation.

DiethoxyP(V)tetrakis(p-methoxyphenyl)porphyrin (EtP(V)TMPP) and its fluorinated derivative (FEtP(V)TMPP) were synthesized to examine their photodynamic action. These P(V)porphyrins were aggregated in an aqueous solution, resulting in the suppression of their photodynamic activity. In the presence of human serum albumin (HSA), a water-soluble protein, the aggregation states were resolved and formed a binding complex between P(V)porphyrin and HSA. These P(V)porphyrins photosensitized the oxidation of the tryptophan residue of HSA under the irradiation of long-wavelength visible light (>630 nm). This protein photodamage was explained by the electron transfer from tryptophan to the photoexcited state of P(V)porphyrins and singlet oxygen generation. The axial fluorination reduced the redox potential of the one-electron reduction of P(V)porphyrin and increased the electron transfer rate constant. However, this axial fluorination decreased the binding constant with HSA, and the quantum yield of photosensitized HSA damage through electron transfer was decreased. The photocytotoxicity of these P(V)porphyrins to HaCaT cells was also confirmed, and FEtP(V)TMPP demonstrated stronger phototoxicity than EtP(V)TMPP. In summary, a self-aggregation of porphyrin photosensitizers and resolving by targeting biomacromolecules may be used to target selective photodynamic action. The redox potential and an association with a targeting biomolecule are the important factors of the electron transfer-mediated mechanism, which is advantageous under hypoxic tumor conditions.

Highly Efficient 17.6% Tin-Lead Mixed Perovskite Solar Cells Realized through Spike Structure.

Frequently observed high Voc loss in tin-lead mixed perovskite solar cells is considered to be one of the serious bottle-necks in spite of the high attainable Jsc due to wide wavelength photon harvesting. An amicable solution to minimize the Voc loss up to 0.50 V has been demonstrated by introducing an n-type interface with spike structure between the absorber and electron transport layer inspired by highly efficient Cu(In,Ga)Se2 solar cells. Introduction of a conduction band offset of ∼0.15 eV with a thin phenyl-C61-butyric acid methyl ester layer (∼25 nm) on the top of perovskite absorber resulted into improved Voc of 0.75 V leading to best power conversion efficiency of 17.6%. This enhancement is attributed to the facile charge flow at the interface owing to the reduction of interfacial traps and carrier recombination with spike structure as evidenced by time-resolved photoluminescence, nanosecond transient absorption, and electrochemical impedance spectroscopy measurements.

Photosensitized Protein-Damaging Activity, Cytotoxicity, and Antitumor Effects of P(V)porphyrins Using Long-Wavelength Visible Light through Electron Transfer.

Photodynamic therapy (PDT) is a less-invasive treatment for cancer through the administration of less-toxic porphyrins and visible-light irradiation. Photosensitized damage of biomacromolecules through singlet oxygen (1O2) generation induces cancer cell death. However, a large quantity of porphyrin photosensitizer is required, and the treatment effect is restricted under a hypoxic cellular condition. Here we report the phototoxic activity of P(V)porphyrins: dichloroP(V)tetrakis(4-methoxyphenyl)porphyrin (CLP(V)TMPP), dimethoxyP(V)tetrakis(4-methoxyphenyl)porphyrin (MEP(V)TMPP), and diethyleneglycoxyP(V)tetrakis(4-methoxyphenyl)porphyrin (EGP(V)TMPP). These P(V)porphyrins damaged the tryptophan residue of human serum albumin (HSA) under the irradiation of long-wavelength visible light (>630 nm). This protein photodamage was barely inhibited by sodium azide, a quencher of 1O2. Fluorescence lifetimes of P(V)porphyrins with or without HSA and their redox potentials supported the electron-transfer-mediated oxidation of protein. The photocytotoxicity of these P(V)porphyrins to HeLa cells was also demonstrated. CLP(V)TMPP did not exhibit photocytotoxicity to HaCaT, a cultured human skin cell, and MEP(V)TMPP and EGP(V)TMPP did; however, cellular DNA damage was barely observed. In addition, a significant PDT effect of these P(V) porphyrins on a mouse tumor model comparable with the traditional photosensitizer was also demonstrated. These findings suggest the cancer selectivity of these P(V)porphyrins and lower carcinogenic risk to normal cells. Electron-transfer-mediated oxidation of biomacromolecules by P(V)porphyrins using long-wavelength visible light should be advantageous for PDT of hypoxic tumor.

First-principles investigation of the Lewis acid-base adduct formation at the methylammonium lead iodide surface.

We have here performed a campaign of ab initio calculations focusing on the anchoring mechanism and adduct formation of some Lewis bases, both aliphatic and aromatic, on a PbI2-rich flat (001) methylammonium lead iodide (MAPI) surface. Our goal is to provide theoretical support to the recently reported experimental techniques of MAPI surface passivation via Lewis acid-base neutralization and similarly of MAI·PbI2·(Lewis base) adduct formation. We tested several X-donor bases (X = :N, :O, :S), paying attention to the thermodynamic stability of the final MAPI·base adducts and to their electronic properties. Factors that impact on the passivation mechanism are the directionality of the Lewis base lone pair and its enhanced/reduced overlap with MAPI Pb p orbitals, the dipole moment of the base and, similarly, the electronegativity of the X donor atom. Also non-covalent interactions, both at the surface side (intra, MAPI) and at the very interface (inter, MAPI·Lewis base), seem to contribute to the stability of the final adducts. Here we show that the thermodynamic stability does not necessarily correspond to the most effective base → acid dative bond formation. Starting from a low coverage (12.5% of the undercoordinated Pb atoms available at the surface are passivated) this paper paves the way towards the study of cooperative and steric effects among Lewis bases at higher coverages representing, to the best of our knowledge, one of the very first studies focusing on the molecular anchoring on the surfaces of this very important class of materials.

Material challenges for solar cells in the twenty-first century: directions in emerging technologies.

Photovoltaic generation has stepped up within the last decade from outsider status to one of the important contributors of the ongoing energy transition, with about 1.7% of world electricity provided by solar cells. Progress in materials and production processes has played an important part in this development. Yet, there are many challenges before photovoltaics could provide clean, abundant, and cheap energy. Here, we review this research direction, with a focus on the results obtained within a Japan-French cooperation program, NextPV, working on promising solar cell technologies. The cooperation was focused on efficient photovoltaic devices, such as multijunction, ultrathin, intermediate band, and hot-carrier solar cells, and on printable solar cell materials such as colloidal quantum dots.

Regioregular Phthalocyanines Substituted with Bulky Donors at Non-Peripheral Positions.

Three regioregular phthalocyanines (1-3) were synthesized selectively by the cyclic tetramerization of phthalonitriles bearing a bulky diarylamine substituent at the next position of nitrile. The steric repulsion at the tetramerization of bulky phthalonitriles allowed for the selective formation of regioregular phthalocyanines as confirmed by NMR and single crystal X-ray structural analyses. The absorption spectrum of 1 substituted with di(4-tert-butylphenyl)amine groups at the non-peripheral positions showed a non-split Q-band at 764 nm, which was redshifted by 83 nm compared with that of metal free phthalocyanine (H2 Pc). The TD-DFT calculation and electrochemical studies prove that the substitution of diarylamine groups at the α-positions effectively destabilizes the HOMO energy level, which causes a large redshift of the Q-band. Moreover, 1 can generate a one-electron oxidation species through chemical oxidation. The Q-band position of 2 bearing 4,4'-dimetoxyphenylamine units was further shifted by 10 nm compared with that of 1. In addition, 3 having carbazole units showed a small redshift of the Q-band relative to H2 Pc. The hole-mobility of 2 in thin film was determined to be 1.1×10-5  cm V-1 s-1 by using a space charge limited current method. A perovskite solar cell employing 2 as a hole-transporting layer gave an efficiency of 5.1 % under standard global 100 Wcm-2 AM 1.5 G illumination.

Determination of Singlet Oxygen and Electron Transfer Mediated Mechanisms of Photosensitized Protein Damage by Phosphorus(V)porphyrins.

The mechanism of photosensitized protein damage byphosphorus(V) tetraphenylporphyrin derivatives (P(V)TPPs) wasquantitatively clarified. P(V)TPPs bound to human serum albumin(HSA), a water-soluble protein, and damaged its tryptophan residueduring photoirradiation. P(V)TPPs photosensitized singlet oxygen ((1)O(2))generation, and the contribution of (1)O(2) to HSA damage was confirmedby the inhibitory effect of sodium azide, a (1)O(2) quencher. However,sodium azide could not completely inhibit HSA damage, suggesting thecontribution of an electron transfer mechanism to HSA damage. Thedecrement in the fluorescence lifetime of P(V)TPPs by HSA supportedthe electron transfer mechanism. The contribution of these processes could be determined by the kinetic analysis of the effect ofsodium azide on the photosensitized protein damage by P(V)TPPs.

Theoretical studies on the absorption spectra of cis-[Ru(4,4'-COO-2,2'-bpy)2(X)2](4-), (X = NCS, Cl) and panchromatic trans-terpyridyl Ru complexes including strong spin-orbit coupling.

In this paper, we theoretically and experimentally investigate the photophysical and chemical characteristics and absorption spectra of various ruthenium complexes in solution used as efficient dye-sensitized solar cells. The target molecules are two well-known complexes, cis-[Ru(4,4'-COO-2,2'-bpy)2(X)2](4-), (X = NCS, Cl) and trans-terpyridyl Ru. The experimental absorption spectra of these molecules, which show strong spin-orbit (SO) coupling, are simulated using first-order perturbation theory based on time-dependent density functional theory and quantum chemistry calculations. It turns out that the theory can simulate the experimental data very well, which indicates that SO coupling is very important and the mixing between singlet and triplet states is strong in these molecules because of the large SO coupling constant of the Ru atom. The exact absorption spectra can only be reproduced by including the perturbation by SO coupling. The physical and chemical differences between cis-[Ru(4,4'-COO-2,2'-bpy)2(X)2](4-), (X = NCS, Cl) and trans-terpyridyl Ru complexes are elucidated by natural bond orbital and natural transition orbital analyses. From these analyses, we have found that the two kinds of Ru complexes are quite different in terms of photoexcitation response and chemical bonding between the central Ru atom and the surrounding ligands.

Visible light absorption and photoelectrochemical activity of colorless molecular 1,3-bis(dicyanomethylidene)indane (BDMI) by surface complexation on TiO2.

Adsorption of the colorless 1,3-bis(dicyanomethylidene)indane (BDMI) onto a nanocrystalline TiO2 surface unusually turned the BDMI a deep blue color. Upon contact of the BDMI-adsorbed TiO2 (BDMI-TiO2) with an iodide-based redox electrolyte, a photocurrent density as high as 14.9 mA cm(-2) was generated with a photovoltage of 0.42 V, leading to a power conversion efficiency of 3.63%. This unprecedented photovoltaic performance was simultaneously investigated by spectroscopic studies of BDMI-TiO2 films and density functional theory (DFT)/time-dependent DFT (TD-DFT) computational approaches for [BDMI](-)[Ti(OH)3·H2O](+) (1) as a simple model compound to inspect the light to current conversion abilities. All these results established that the color change from colorless to deep blue and the highly efficient photocurrent generation through binding on the TiO2 surface originates from interfacial charge transfer transitions from anionic BDMI to TiO2.

Theoretical Verification of Photoelectrochemical Water Oxidation Using Nanocrystalline TiO2 Electrodes.

Mesoscopic anatase nanocrystalline TiO2 (nc-TiO2) electrodes play effective and efficient catalytic roles in photoelectrochemical (PEC) H2O oxidation under short circuit energy gap excitation conditions. Interfacial molecular orbital structures of (H2O)3 &OH(TiO2)9H as a stationary model under neutral conditions and the radical-cation model of [(H2O)3&OH(TiO2)9H]+ as a working nc-TiO2 model are simulated employing a cluster model OH(TiO2)9H (Yamashita/Jono's model) and a H2O cluster model of (H2O)3 to examine excellent H2O oxidation on nc-TiO2 electrodes in PEC cells. The stationary model, (H2O)3&OH(TiO2)9H reveals that the model surface provides catalytic H2O binding sites through hydrogen bonding, van der Waals and Coulombic interactions. The working model, [(H2O)3&OH(TiO2)9H]+ discloses to have a very narrow energy gap (0.3 eV) between HOMO and LUMO potentials, proving that PEC nc-TiO2 electrodes become conductive at photo-irradiated working conditions. DFT-simulation of stepwise oxidation of a hydroxide ion cluster model of OH-(H2O)3, proves that successive two-electron oxidation leads to hydroxyl radical clusters, which should give hydrogen peroxide as a precursor of oxygen molecules. Under working bias conditions of PEC cells, nc-TiO2 electrodes are now verified to become conductive by energy gap photo-excitation and the electrode surface provides powerful oxidizing sites for successive H2O oxidation to oxygen via hydrogen peroxide.

Identification of possible downstream genes required for the extension of peripheral axons in primary sensory neurons.

The LIM-homeodomain transcription factor Islet2a establishes neuronal identity in the developing nervous system. Our previous study showed that Islet2a function is crucial for extending peripheral axons of sensory neurons in zebrafish embryo. Overexpressing a dominant-negative form of Islet2a significantly reduced peripheral axon extension in zebrafish sensory neurons, implicating Islet2a in the gene regulation required for neurite formation or proper axon growth in developing sensory neurons. Based on this, we conducted systematic screening to isolate genes regulated by Islet2a and affecting the development of axon growth in embryonic zebrafish sensory neurons. The 26 genes selected included some encoding factors involved in neuronal differentiation, axon growth, cellular signaling, and structural integrity of neurons, as well as genes whose functions are not fully determined. We chose four representative candidates as possible Islet2a downstream functional targets (simplet, tppp, tusc5 and tmem59l) and analyzed their respective mRNA expressions in dominant-negative Islet2a-expressing embryos. They are not reported the involvement of axonal extension or their functions in neural cells. Finally, knockdown of these genes suggested their direct actual involvement in the extension of peripheral axons in sensory neurons.

Dye-sensitized solar cells using ethynyl-linked porphyrin trimers.

Toward the extension of the light-harvesting region of sensitizers in dye-sensitized solar cells (DSSCs), two ethynyl-linked porphyrin trimers were synthesized and investigated. The zinc­freebase­zinc trimer (Zn­FbA­Zn) showed an absorption maximum at a longer wavelength than the all-zinc trimer (Zn­ZnA­Zn), although the energy level of Zn­FbA­Zn was lower than that of Zn­ZnA­Zn. The DSSCs using these trimers showed spectral sensitivities up to 900 nm. Reflecting the energy levels of these trimers, the DSSC using Zn­ZnA­Zn showed better performance than that using Zn­FbA­Zn. After the optimization of cell fabrication conditions, the photoelectric conversion efficiency η of the DSSC using Zn­ZnA­Zn reached 3.17%. The larger TiO2 nanoparticles (ca. 37 nm) than the conventional cases (ca. 13 nm) were found to be preferable in this case, due to high molar extinction coefficients of the porphyrin trimers.

Spectral Splitting Solar Cells Consisting of a Mesoscopic Wide-Bandgap Perovskite Solar Cell and an Inverted Narrow-Bandgap Perovskite Solar Cell.

In comparison to monolithic perovskite/perovskite double-junction solar cells, a four-terminal spectrum-splitting system is a simple method to obtain a higher power conversion efficiency (PCE) because it has no constraints of unifying the structures of the top and bottom cells. In this work, utilizing the fact that low-bandgap Sn-Pb bottom cells work the best in p-i-n while Pb-based wide-bandgap top cells work better in an n-i-p architecture, a wide-bandgap (Eg = 1.61 eV) perovskite solar cell with a mesoscopic structure and a narrow-bandgap (Eg = 1.27 eV) perovskite solar cell with an inverted structure were combined to fabricate a double-junction four-terminal spectral splitting solar cell. The double-junction solar cell with the 801 nm spectral splitting with an active area of 0.18 cm2 was found to work with a PCE of 25.3%, which is the highest reported so far for a 4-T all-perovskite double-junction spectral splitting solar cell.

Effect of nuclear vibrations, temperature, co-adsorbed water, and dye orientation on light absorption, charge injection and recombination conditions in organic dyes on TiO2.

We study the effect of nuclear motions at different temperatures, including the effect of a dye molecule's orientation with respect to the oxide surface, on factors determining the performance of dye sensitized solar cells: light absorption, electron injection, and back-donation. We perform ab initio molecular dynamics simulations of aminophenyl acid dyes NK1 and NK7, differing by the electron donating group, in a vacuum and adsorbed in mono- and bi-dentate modes on a dry and a water-covered anatase (101) surface of TiO(2), at 300 and 350 K. Nuclear vibrations and an increase of temperature cause a red shift in the absorption spectra of free dyes. This effect is preserved in dyes on dry TiO(2) but largely disappears in the presence of water. Averaged over nuclear vibrations, the driving force to injection, ΔG, differs from the static estimate. It depends on the adsorption mode and the presence of H(2)O but is almost the same for 300 and 350 K. Recombination to the dye cation is expected to be much enhanced by the approach of the dye oxidation equivalent hole to the surface during dye wagging around TiO(2). This effect is somewhat mitigated by the co-adsorbed water. The dynamics of ΔG(t) are explained by uncorrelated evolution of the energies of the dye excited state and the conduction band minimum of the oxide due to their respective vibrations, and are almost independent of dye orientation. It may therefore be possible to independently control the conditions of recombination and of injection.

Unraveling the adsorption mechanism of aromatic and aliphatic diols on the TiO2 surface: a density functional theory analysis.

Understanding the adsorption mechanism of organic molecules on inorganic semiconductors is of great importance for generating and control functions in organic-inorganic materials. Here we have comprehensively investigated, by means of the density functional theory, the adsorption structure and energetic stability of aliphatic and aromatic diols on TiO2 using ethylene glycol, 1,2-n-decanediol, and catechol. Our calculations clearly show that the non-dissociative bidentate adsorption is more stable than the dissociative one for the aliphatic diol, both at low and high coverage conditions, result far differently from many other chemical anchor cases for which the dissociative mechanism usually prevails. On the other hand, for catechol the dissociative bidentate is the most stable at low coverage conditions, whereas, surprisingly, increasing the coverage with catechol makes the non-dissociative mechanism the most stable one, revealing possible coexistence of a dissociative and non-dissociative anchoring at high coverage. This work unraveled a variety of adsorption fashions of the diol compounds in conjunction with the impact of the coverage effect, highly dependent on the nature of the lateral chain of the anchor group.

The origin of the strong interfacial charge-transfer absorption in the surface complex between TiO2 and dicyanomethylene compounds.

Interfacial charge transfer transitions between organic and inorganic materials are expected to be a potential photoinduced charge separation mechanism for photoenergy conversions. Recently, we reported that the hybrid material formed from TiO2 nanoparticles and an organic electron acceptor, 7,7,8,8-tetracyanoquinodimethane (TCNQ), shows strong interfacial charge transfer absorption in the visible region. In this work, we have theoretically studied the structure, and electronic and absorption properties in order to clarify the formation mechanism and the origin of the strong interfacial charge transfer absorption. Density functional theory (DFT) calculations employing an anatase Ti14O28H2(OH)2(H2O)2 nano-cluster unraveled that the surface complex is formed by a nucleophilic addition reaction between a surface hydroxyl group of TiO2 and the carbon atom of the methylene moiety in TCNQ with the drastic changes in the structure and electronic properties of TCNQ. In the formation process, owing to the high electron affinity of TCNQ, a negative charge of the surface oxygen atom is transferred to the TCNQ moiety. This leads to a significant electronic hybridization between TiO2 and TCNQ, which is the origin of interfacial charge transfer transitions.

A donor-acceptor type organic dye connected with a quinoidal thiophene for dye-sensitized solar cells.

A donor-acceptor type organic dye connected with a quinoidal thiophene as a π-conjugated chain, cyano-[5'-(4''-(N,N-dimethylamino)benzylidene)-5H-thiophen-2'-ylidene]acetic acid, was synthesized and applied to dye-sensitized solar cells (DSSCs). The absorption band of this quinoidal thiophene dye appeared at longer wavelengths than those of dyes with similar π-conjugation length, indicating the effective π-conjugation through the quinoidal structure. Although the excited state of the quinoidal thiophene dye is deactivated within several picoseconds even in solution, the DSSCs using the quinoidal thiophene dye showed incident photon to current conversion efficiency (IPCE) values of more than 90%, demonstrating the fast and efficient electron injection from the excited dye to TiO(2). By optimizing the fabrication conditions, the DSSC using this dye afforded a photoelectric conversion efficiency of 5.2%, without enlarging the molecular size.

Crystal structure of bis-[octa-kis-(di-methyl sulfoxide-κO)-ytterbium(III)] penta-bromido-plumbate(II) tribromide di-methyl sulfoxide monosolvate: a ytterbium-doped lead halide perovskite precursor.

A mixture of PbBr2 and YbBr3·nH2O in a dimethyl sulfoxide (DMSO) solution yielded single crystals of a lead halide perovskite precursor with ytterbium, bis-[octa-kis-(di-methyl sulfoxide)-ytterbium(III)]penta-bromido-plumbate(II) tri-bromide with di-methyl sulfoxide as co-crystallite, [Yb(C2H6OS)8][PbBr5]0.5Br1.5·0.5C2H6OS. The complex ions PbBr5 3- and Yb(DMSO)8 3+ are present in the crystal together with three Br- ions and DMSO mol-ecules. X-ray crystallography revealed that the Br- ions in YbBr3 are replaced by the solvent and bound to a PbII atom or remain free. The presence of PbBr5 3- units, which are mol-ecular ions with a square-pyramidal structure, is also observed. These single crystals react with a caesium chloride solution, exhibiting near-infrared (NIR) luminescence by visible photoexcitation, suggesting the formation of Yb3+-doped lead halide perovskites (CsPbBr3-x Cl x ·Yb3+).

Effect of Chloride Incorporation on the Intermediate Phase and Film Morphology of Methylammonium Lead Halide Perovskites.

The influence of chloride integration on perovskite film deposition, encompassing both the structures of intermediate phases and the properties of the final films, was explored. Our methodology involved the fabrication of perovskite intermediate-phase films with varying concentrations of methylammonium chloride (MACl). Subsequently, we conducted an analysis employing X-ray diffraction and Rietveld refinement, incorporating the March-Dollase correction, to gain insights into how chloride-induced intermediate phases impact film morphology. Remarkably, a distinct preferred orientation was observed in the (020) lattice plane perpendicular to the substrate surface, and this orientation was found to be directly correlated to the MACl concentration. This distinctive arrangement of chloride-induced intermediate-phase complexes facilitated controlled crystallization, leading to highly oriented crystals and an improved film morphology. As a consequence, perovskite solar cell devices incorporating chloride-containing methylammonium lead iodide achieved a power conversion efficiency exceeding 20%. These findings suggest a crucial link between the preferred orientation observed in the final chlorine-derived perovskite films and the intermediate-phase structure formed during the initial stages of perovskite formation. These results suggest a profound impact of intermediate phase compositions and crystal structures on perovskite formation, emphasizing the importance of a comprehensive understanding of these factors to enable precise control over ideal structures and the subsequent transformation into high-quality perovskite films.