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Inversion symmetry in the 1T-phase of pristine dichalcogenide monolayer MX2 (M = Ge, Sn; X = S, Se) is broken in their Janus structures, MXY (M = Ge, Sn; X ≠ Y = S, Se), which induces an in-plane piezoelectric coefficient, d22 = 4.09 (2.15) pm V-1 and a shear piezoelectric coefficient, d15 = 7.90 (13.68) pm V-1 in the GeSSe (SnSSe) monolayer. High flexibility arising from the small Young's modulus (60-70 N m-1) found in these Group-IV(A) Janus monolayers makes them suitable for large-scale strain engineering. Application of 7% uniaxial tensile strain increases d22 and d15 colossally to 267.07 pm V-1 and 702.34 pm V-1, respectively, thereby reaching the level of bulk piezoelectric perovskite materials. When the Janus GeSSe monolayers are stacked to form a van der Waals (vdW) homo-bilayer, d22 lies between 19.87 and 73.26 pm V-1, while d15 falls into the range between 83.01 and 604.34 pm V-1, depending on the stacking order. The chalcogen exchange energies and overall stabilities of the monolayers and bilayers confirm the feasibility of their experimental synthesis. Moreover, hole mobility in the GeSSe monolayer is greater than the electron mobility along its zigzag directions (μe = 883 cm2 V-1 s-1 and μh = 1134 cm2 V-1 s-1). Therefore, the semiconducting, flexible, and piezoelectric Janus GeSSe monolayer and bilayers are immensely promising for futuristic applications in energy harvesting, nanopiezotronic field-effect transistors, atomically thin sensors, shear/torsion actuators, transducers, self-powered circuits in nanorobotics, and electromechanical memory devices, and biomedical and other nanoelectronic applications.

Two-dimensional (2D) cadmium chalcogenide nanoplatelets (NPLs) have been grown as an emerging material for optoelectronic applications because of their unique properties. Here, we investigate the c...

The simultaneous occurrence of gigantic piezoelectricity and Rashba effect in two-dimensional materials are unusually scarce. Inversion symmetry occurring in MX3 (M= Ti, Zr, Hf; X= S, Se) monolayer...

Using first-principles calculations, we demonstrate a combination of two emergent fields, type II van der Waals heterostructures and Janus structures, for the purpose of optimizing the harvesting o...

A stable ultrathin 2D van der Waals (vdW) heterobilayer, based on the recently synthesized boron monophosphide (BP) and the widely studied molybdenum disulfide (MoS2), has been systematically explored for the conversion of waste heat, solar energy, and nanomechanical energy into electricity. It shows a gigantic figure of merit (ZT) > 12 (4) for p (n)-type doping at 800 K, which is the highest ever reported till date. At room temperature (300 K), ZT reaches 1.1 (0.3) for p (n)-type doping, which is comparable to experimentally measured ZT = 1.1 on the PbTe-PbSnS2 nanocomposite at 300 K, while it outweighs the Cu2Se-CuInSe2 nanocomposite (ZT = 2.6 at 850 K) and the theoretically calculated ZT = 7 at 600 K on silver halides. Lattice thermal conductivity (κl ≈ 49 W m-1 K-1) calculated at room temperature is lesser than those of black phosphorene (78 W m-1 K-1) and arsenene (61 W m-1 K-1). The nearly matched lattice constants in the commensurate lattices of the constituent monolayers help to preserve the direct band gap at the K point in the type II vdW heterobilayer of MoS2/BP, where BP and MoS2 serve as donor and acceptor materials, respectively. An ultrahigh carrier mobility of ∼20 × 103 cm2 V-1 s-1 is found, which exceeds those of previously reported transition metal dichalcogenide-based vdW heterostructures. The exciton binding energy (0.5 eV) is close to those of MoS2 (0.54 eV) and C3N4 (0.33 eV) single layers. The calculated power conversion efficiency (PCE) in the monolayer MoS2/BP heterobilayer exceeds 20%. It surpasses the efficiency in MoS2/p-Si heterojunction solar cells (5.23%) and competes with the theoretically calculated ones, as listed in the manuscript. Furthermore, a high optical absorbance (∼105 cm-1) of visible light and a small conduction band offset (0.13 eV) make MoS2/BP very promising in 2D excitonic solar cells. The out-of-plane piezoelectric strain coefficient, d33 ≈ 3.16 pm/V, is found to be enhanced 4-fold (∼14.3 pm/V) upon applying 7% vertical compressive strain on the heterobilayer, which corresponds to ∼1 kbar of hydrostatic pressure. Such a high out-of-plane piezoelectric coefficient, which can tune top-gating effects in ultrathin 2D nanopiezotronics, is a relatively new finding. As BP has been synthesized recently, experimental realization of the multifunctional, versatile MoS2/BP heterostructure would be highly feasible.

Type II van der Waals (vdW) heterobilayers of six group III chalcogenide monolayers (MX; M = Ga, In; X = S, Se, Te) have been systematically investigated and compared with the pristine monolayers v...

A stable 2D van der Waals (vdW) heterobilayer, constituted by boron monophosphide (BP) and Gallium Nitride (GaN) monolayers, has been explored for different kinds of energy conversion and nanoelectronics. The nearly matched lattice constants of GaN and BP are commensurate with each other in their lattice structures. The out-of-plane inversion asymmetry coupled with the large difference in atomic charges between the GaN and BP monolayers induces in the heterobilayer a giant out-of-plane piezoelectric coefficient (|d33|max ≈ 40 pm V-1), which is the highest ever reported in 2D materials of a finite thickness. It is much higher than the out-of-plane piezoelectric coefficient reported earlier in multilayered Janus transition metal dichalcogenide MXY (M = Mo, W; X, Y = S, Se, Te) (|d33|max = 10.57 pm V-1). Such a high out-of-plane piezoelectricity found in a BP/GaN heterobilayer can bring about gigantic strain-tunable top gating effects in nanopiezotronic devices based on the same. Moreover, electron mobility (∼104 cm2 V-1 s-1) is much higher than that of transition metal dichalcogenides and conventional semiconductors. The origin of low lattice thermal conductivity (κL ∼ 25.25 W m-1 K-1) in BP/GaN at room temperature, which is lower than that of black phosphorene (78 W m-1 K-1), buckled arsenene (61 W m-1 K-1), BCN (90 W m-1 K-1), MoS2 (34.5 W m-1 K-1) and WS2 (32 W m-1 K-1) monolayers, has been systematically investigated via phonon dispersion, lattice thermal conductivity, phonon lifetime and mode Grüneisen parameters. The valence band maximum (VBM) and conduction band minimum (CBM) arising from GaN and BP monolayers respectively result in a type II vdW heterobilayer, which is found to be thermodynamically favorable for photocatalytic water splitting in both acidic and neutral media. The exciton binding energies are comparable to those of MoS2 and C3N4 single layers, while the absorbance reaches as high as ∼105 cm-1 in the visible wavelength region. The emergence of high piezoelectricity, high carrier mobility, low lattice thermal conductivity and photocatalytic water splitting abilities in the proposed vdW heterobilayer signifies enormous potential for its versatile applications in nanoscale energy harvesting, e.g., nano-sensors in medical devices, future nanopiezotronics, 2D thermoelectrics and solar energy conversion.

Phonons in crystalline solids are of utmost importance in governing its lattice thermal conductivity (k L). In this work, k L in hafnium (Hf) dichalcogenide monolayers has been investigated based on ab initio DFT coupled to linearized Boltzmann transport equation together with single-mode relaxation-time approximation. Ultra-low k L found in HfS2 (2.19 W m-1 K-1), HfSe2 (1.23 W m-1 K-1) and HfSSe (1.78 W m-1 K-1) monolayers at 300 K, is comparable to that of the state-of-art bulk thermoelectric materials, such as, Bi2Te3 (1.6 W m-1 K-1), PbTe (2.2 W m-1 K-1) and SnSe (2.6 W m-1 K-1). Gigantic longitudinal-transverse optical (LO-TO) splitting of up to 147.7 cm-1 is noticed at the Brillouin zone-centre (Γ-point), which is much higher than that in MoS2 single layer (∼2 cm-1). It is driven by the colossal phonon-electric field coupling arising from the domination of ionic character in the interatomic bonds and Born effective or dynamical charges as high as 7.4e on the Hf ions, which is seven times that on Mo in MoS2 single layer. Enhancement in k L occurs in HfS2 (2.19 to 4.1 W m-1 K-1), HfSe2 (1.23 to 1.7 W m-1 K-1) and HfSSe (1.78 to 2.2 W m-1 K-1) upon the incorporation of the non-analytic correction term. Furthermore, the mode Gruneisen parameter is calculated to be as high as ∼2.0, at room temperature, indicating a strong anharmonicity. Moreover, the contribution of optical phonons to k L is found to be ∼12%, which is significantly high than that in single-layer MoS2. Large atomic mass of Hf (178.5 u), small phonon group velocities (4-5 km s-1), low Debye temperature (∼166 K), low bond and elastic stiffness (Young's modulus ∼75 N m-1), small phonon lifetimes (∼6 ps), low specific heat capacity (∼17 J K-1 mol-1) and strong anharmonicity are collectively found to be the factors responsible for such a low k L. These findings would be immensely helpful in designing thermoelectric interconnects at the nanoscale and 2D material-based energy harvesters.

Piezoelectric nanomaterials have been emerging as flagship materials for harvesting nanoelectromechanical energy. Pristine, semiconducting 1T-MX2 (M = Zr and Hf; X = S, Se, and Te) monolayers are intrinsically centrosymmetric, and hence non-piezoelectric. This inversion symmetry is broken in their Janus monolayer (non-centrosymmetric) structures, leading to the emergence of a high degree of piezoelectricity in them. This brings along a new dimension in nanoscale piezoelectricity, as the origin of this piezoelectricity is predominantly ionic in nature, in contrast to the 1H-MoS2 monolayer, where it is of electronic character. DFT calculations reveal the piezoelectric coefficient (d22 = 4.68–14.58 pm V−1) in these Janus monolayers to be much higher than that in single layer 1H-MoS2 (d11 = 2.99 pm V−1). 9% uniaxial tensile strain applied along the arm-chair direction is found to raise d22 in HfSSe Janus monolayers to 123.04 pm V−1, which reaches the level of piezoelectric coefficients in the state-of-the-art perovskites. The major contribution of the ionic component to the piezoelectric coefficient is attributable to the predominance of ionic character in the interatomic bonds in these monolayers, which arises from the decoupled band edges, i.e., no hybridization between the band edge states (chalcogen-p and metal-d). Contrarily, 1H-MX2 (M = Mo and W; X = S, Se, and Te) monolayers with coupled band edges are held together mainly by covalent bonds, resulting in the dominance of electronic contribution to piezoelectricity. The nature of band edges causes a lower deformation potential for electrons in 1T Hf and Zr based dichalcogenide monolayers and their Janus structures with respect to 1H-MX2 (M = Mo and W; X = S, Se, and Te) monolayers. This induces a much higher electron mobility in the former than in 1H-MX2 (M = Mo and W; X = S, Se, and Te) monolayers. The carrier mobility calculated using Lang et al.'s formalism [Phys. Rev. B, 2016, 94, 235306] agrees well with the experimentally measured electron mobility. Our predictive findings underscore the imminent need to synthesize these 1T-MX2 semiconducting Janus structures to induce a high level of piezoelectricity together with robust electron mobility.

2D semiconducting transition-metal-dichalcogenides (TMDCs) have drawn a surge of research interests in ultra-thin nanoelectronics and optoelectronics, owing to their moderate charge carrier mobility. Due to a large variation in reported data on charge carrier mobilities of these free-standing monolayers, a more accurate determination of carrier mobilities is a must. This article highlights room temperature carrier mobilities calculated in group-VI B TMDC (i.e., MX2 (M = Mo, W; X = S, Se, Te)) monolayers via a systematic comparison of reliable models used within the framework of density functional theory. Additionally, piezoelectric effects on carrier mobility have been incorporated. The robust formulation by Lang et al. [Phys. Rev. B, 2016, 94, 235306] gives the most accurate estimation, where the carrier (i.e. electron or hole) mobility and the ratio of hole to electron mobility reach closest to the experimentally measured value. The higher mobility of holes with respect to electrons is attributed to the smaller deformation potential of the holes, while smaller carrier effective masses and larger elastic moduli cause larger carrier mobility in WX2 relative to MoX2. Carrier mobility is found to drop from S to Te and also from W to Mo in MX2 on account of the decrease in the elastic moduli, which is consistent with the increase in the macroscopic static dielectric constant. Erroneously high electron mobility (>1000 cm2 V−1 s−1), which is two orders of magnitude higher than the experimental ones, has been disputably reported earlier for MoTe2 and WS2 monolayers. It owes its origin to the ultrasmall deformation potential found therein. High (∼1.4–2.3) hole to electron mobility ratio in MX2 monolayers is found to occur in our work as MoSe2 > WS2 > MoS2 > WSe2 > WTe2 > MoTe2. This large carrier mobility ratio will facilitate an efficient separation of electron–hole pairs, which is particularly useful in optoelectronic applications, e.g., photovoltaics, photocatalysis and artificial photosynthesis. In all terms including optical absorbance, a WS2 monolayer is found to be most suitable for photophysical processes. Using the Nernst formulation, water splitting and CO2 photoreduction on WS2 are found to be favorable over a wide range of pH.

This work sheds light on the intrinsic properties of HfN2 monolayer and its synergistic combination with MoTe2 for diverse applications in thermoelectricity, photovoltaics, piezotronics and digital/analog electronics using the state of art density functional theory. Using Boltzmann transport theory, a low lattice thermal conductivity of 0.49 W m - 1 K - 1 at 300 K along with high waste heat to electricity conversion efficiency (i.e., thermoelectric figure of merit, ZT = 2.28) is predicted for monolayer HfN2. On the other hand, a type-II van der Waals heterostructure (vdWH) is formed with 1H-MoTe2 monolayer, where low conduction band offset and direct band gap leads to high power conversion efficiency (PCE) of 21.44% in HfN2/MoTe2 excitonic solar cell. Moreover, it can be employed in designing multifunctional next-generation excitonic solar cells where electricity can be simultaneously generated from solar energy and the waste heat thrown out by the solar cell. The tunable electronic properties under perpendicular electric field highlights its application in both analog and digital electronics. The built-in electric field at the interface together with broken inversion symmetry along z-direction induces out-of-plane piezoelectricity (d33), which is in excellent agreement with experimental evidence (ACS Appl. Nano Mater. 2020, 3, 11979–11986). d33 further increases 3.5 times under vertical compressive strain.

High photovoltaic efficiency with a staggered type II band alignment has been found in the heterobilayers of relatively less explored dialkali metal oxides and chalcogenides, using DFT-D3 and HSE06 functional. Out of all the type II van der Waals (vdW) heterostructures which are possible through a combination of any two individual monolayers stacked on top of one another, K2O/Cs2O, K2S/Cs2S, and K2Se/Cs2S heterobilayers are found to exhibit a high-power conversion efficiency (PCE) of 21.56%, 19.31%, and 16.43% respectively along with high carrier mobility (>104 cm2/V.s) and high visible light absorption coefficient (α ~ 105 cm−1). Therefore, these heterobilayers will be highly useful in photovoltaic applications. The PCE in the tandem solar cells comprising of the wider band gap, Na2Te/K2Se, in the top cell, and the narrower bandgap, K2O/Cs2O, in the bottom cell, is observed to reach close to 30%. The binding energies in K2O/Cs2O, K2S/Cs2S, and K2Se/Cs2S heterobilayers are found to be −36.38, −28.99, and −29.52 meV/A2 at the interlayer layer distance of 3.30 A, 2.75 A, and 4.0 A respectively, at equilibrium. The large magnitude of negative binding energy indicates the exothermicity and experimental feasibility in the process of formation of these vdW heterostructures.

Elastic-mechanical deformations are found to dramatically alter the electronic properties of monolayer (ML) $\mathrm{Mo}{\mathrm{S}}_{2}$; particularly, the low-energy Bloch bands are responsive to a directional strain. In this study, in-plane uniaxial deformation is found to drift the low-energy electron/hole valleys of strained $\mathrm{ML}\text{\ensuremath{-}}\mathrm{Mo}{\mathrm{S}}_{2}$ far away from $K/K'$ points in the Brillouin zone (BZ). The amount of drift differs notably from hole to electron bands, where the conduction band minimum (CBM) drifts nearly 2 times more than the valence band maximum (VBM) in response to a progressively increasing strain field (0--10%). The resulting strain-induced valley asymmetry/decoherence can lift the momentum degeneracy of valley carriers at the $K$ point, thereby affecting the low-energy valley excitations ($K$-valley polarization) in a strained $\mathrm{ML}\text{\ensuremath{-}}\mathrm{Mo}{\mathrm{S}}_{2}$ lattice. The quantum origin of this decoherent valley arises from the differences in the Bloch orbital wave functions of electron and hole states at the exciton band edges and their deformation under strain. A higher drift (g1.5 times) is noticed when strain is along the zigzag (ZZ) axis relative to the armchair (AC) axis, which is attributed to a faster decline in Young's modulus and Poisson's ratio (PR) along the ZZ direction. A similar valley drift only in the VBM of uniaxially strained $\mathrm{ML}\text{\ensuremath{-}}\mathrm{Mo}{\mathrm{S}}_{2}$ was reported in an earlier local density approximation (LDA) based density functional theory (DFT) study [Q. Zhang et al., Phys. Rev. B 88, 245447 (2013)], where a massive valley drift occurring at the CBM was fully overlooked. Moreover, the giant VBM drift reported therein is 6 times the drift observed in our DFT studies based on spin-orbit coupling (SOC) and Perdew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA) functionals. The physical origin of valley drift has been ascertained in our thorough investigations. The robustness of our approach is substantiated as follows. With progressive increase in strain magnitude (0--10%), the band gap remains direct up to 2% uniaxial tensile strain, under SOC, which accurately reproduces the experimental strain-induced direct-to-indirect band gap transitions occurring at \ensuremath{\sim}2% strain. Based on LDA-DFT [Q. Zhang et al., Phys. Rev. B 88, 245447 (2013)], this crossover in band gap has been incorrectly reported to occur at a higher value of uniaxial strain of 4%. Moreover, the direct SOC band gap shows a linear redshift at a rate of 51--53 meV/(% of strain), under uniaxial tensile strain, which is in excellent quantitative agreement with experimentally observed rates in the redshift of direct excitonic transitions measured in several optical absorption and photoluminescence (PL) spectroscopy experiments. In addition, the Berry curvature \textohm{}($k$) of electron/hole bands gets significantly modulated in strained $\mathrm{ML}\text{\ensuremath{-}}\mathrm{Mo}{\mathrm{S}}_{2}$, where the intensity of the flux profile increases as a function of the magnitude of strain with an opposite drift around $K/K'$, when strained along the ZZ/AC direction. A strong strain-valley coupling leads to an enhancement in the strength of spin-orbit induced spin splitting of bands at VBM/CBM, which is sizably enhanced (\ensuremath{\sim}7 meV) simply by the strain-controlled orbital motions. Our findings are of prime importance in the valley physics of $\mathrm{Mo}{\mathrm{S}}_{2}$. Besides, the important theoretical insights emerging from this work will trigger further experimental investigations on $\mathrm{ML}\text{\ensuremath{-}}\mathrm{Mo}{\mathrm{S}}_{2}$ to realize its novel technological potential in nanoelectronics, spintronics, and valleytronics.

Recent synthesis of thin films of boron monophosphide (BP) motivates us to report herewith the lattice thermal conductivity calculated in nanoscale boron pnictides. The lattice thermal conductivity in BX (X = P, As, Sb) monolayers are calculated to be 51.3, 20.7 and 5.4 Wm−1K−1 respectively at 300 K. The ultra-low lattice thermal conductivity in BSb, which is comparable to that in SnSe, is attributed to low elastic and bond stiffness, low Debye temperature, small group velocity and large mode Gruneisen parameter near zone center. Phonon group velocities in BSb are comparable to that in SnSe and Bi2Te3. Up to 50% reduction in lattice thermal conductivity is noticed at 300 K upon shortening the phonon mean free path, which is realizable, e.g., in 1D nanoribbons, or via defects, vacancies, nanoengineering, etc. A comparative study based on different models to compute the lattice thermal conductivity will provide useful insights into the experimentally measured ones. The widest ever phononic gap (436 & 438 cm−1) is found in BAs and BSb monolayers, where the transverse and longitudinal optical phonons meet the criterion for the prevention of Klemens decay and hence, they can be gainfully exploited in hot-carrier solar cells. BX (X = P, As, Sb) monolayers show a direct bandgap and piezoelectricity. Nanoscale boron pnictides are promising materials in futuristic thermoelectrics, bolometers, third-generation solar cells and nanopiezotronics.

Although CdX (X = S, Se) has been mostly studied in the field of photocatalysis, photovoltaics, their intrinsic properties, such as, mechanical, piezoelectric, electron and phonon transport properties have been completely overlooked in buckled CdX monolayers. Ultra-low lattice thermal conductivity [1.08 W m-1 K-1 (0.75 W m-1 K-1)] and high p-type Seebeck coefficient [1300 μV K-1 (850 μV K-1)] in CdS (CdSe) monolayers have been found in this work based on first-principles DFT coupled to semi-classical Boltzmann transport equations, combining both the electronic and phononic transport. The dimensionless thermoelectric figure of merit is calculated to be 0.78 (0.5) in CdS (CdSe) monolayers at room temperature, which is comparable to that of two-dimensional (2D) tellurene (0.8), arsenene and antimonene (0.8), indicating its great potential for applications in 2D thermoelectrics. Such a low lattice thermal conductivity arise from the participation of both acoustic [91.98% (89.22%)] and optical modes [8.02% (10.78%)] together with low Debye temperature [254 K (187 K)], low group velocity [4 km s-1 (3 km s-1)] in CdS (CdSe) monolayers, high anharmonicity and short phonon lifetime. Substantial cohesive energy (∼4-5 eV), dynamical and mechanical stability of the monolayers substantiate the feasibility in synthesizing the single layers in experiments. The inversion symmetry broken along the z direction causes out-of-plane piezoelectricity. |d 33| ∼ 21.6 pm V-1, calculated in CdS monolayer is found to be the highest amongst structures having atomic-layer thickness. Superlow Young's modulus ∼41 N m-1 (31 N m-1) in CdS (CdSe) monolayers, which is comparable to that of planar CdS (29 N m-1) and TcTe2 (34 N m-1), is an indicator of its superhigh flexibility. Direct semiconducting band gap, high carrier mobility (∼500 cm2 V-1 s-1) and superhigh flexibility in CdX monolayers signify its gigantic potential for applications in ultrathin, stretchable and flexible nanoelectronics. The all-round properties can be synergistically combined together in futuristic applications in nano-piezotronics as well.

Excellent photovoltaic abilities in a 2D excitonic solar cell based on staggered type-II van der Waals (vdW) hetero-bilayers comprising of semiconducting ZrS3 monolayer and monolayers of MS2 & MXY (M Mo, W; X, Y S, Se, Te; X ≠ Y) are reported herewith, using DFT-D2 and HSE06 functional. Studies on vdW hetero-bilayers of MX3/MX2 and MX3/M'Y2 have so far been conveniently avoided on account of their large lattice mismatch. The present work is the first attempt to address such hetero-bilayers constituted by monolayers of transition metal dichalcogenides and trichalcogenides. The nature of the band edges in ZrS3 and MS2 monolayers induces high electron and hole mobility in these individual monolayers, respectively, which has been combined synergistically in the hetero-bilayers consisting of them. The Power Conversion Efficiency (PCE) in ZrS3/MoS2, ZrS3/WS2, ZrS3/MoSeTe, ZrS3/WSTe, and ZrS3/WSeTe hetero-bilayers, calculated within the Anderson-limit, are found to reach as high as ~12%, 8%, 16%, 14%, and 14% respectively. The PCE of the hetero-bilayers reported herewith are much higher than the efficiency in MoS2/p-Si heterojunction solar cells (5.23%) and comparable to that of the theoretically proposed PCBM fullerene/BCN system (10–20%) and g-SiC2-based systems (12–20%) and the recently predicted TiNF/TiNBr (18%), TiNCl/TiNBr (19%), TiNF/TiNCl (22%) bilayer solar cell systems.

In spite of iron being an abundant element present in soil, often crops show iron deficiency, because it is not present in phyto-available forms. External application is also not successful, because of soil carbonate/bicarbonate ions assisted conversion into unavailable oxy hydroxyl forms. Here the chitosan coating on iron powder loaded mesoporous silica have been found to control the above undesired soil reaction. The coating acts as gate, which close the pores in the presence of carbonate ions to keeps the iron in phyto-available forms, whereas open the pores in the presence of the uptake proton signal from the roots. This phenomenon of excellent control in the nutrient supply to plant is a complementary effect of the pH responsive chitosan and the mesoporous channel. Because in the absence of either of the component, the performance is reduced. In the tomato plant experiment, the ferric chelate reductase activity, an iron deficiency parameter, is reduced by ~20% in plants treated with FeSO4@MS@CH compared to the one treated with FeSO4@MS.