Biological synthesis of nanoparticles (NPs) using alfalfa (<i>Medicago sativa</i> L.) and other plants has several advantages such as lower costs, reduction of pollution, and improvement of the environment and human health. Often, biosynthesis is used to synthesize Ag, Au, and ZnO NPs. Less often are also synthesized Cu and Fe NPs. Synthesis with plant extracts from their parts or callus cultures is a widely used method since extracts contain the most significant number of biomolecules. Synthesis with living plants (<i>in vivo</i>) provides NPs with improved properties for better interactions with plants but is used less often due to the long realization time, the need to control the plants’ growing conditions, and difficulty in controlling the size and shape of the synthesized NPs. Here, we performed a systematic review of various methods for the biological synthesis of different metal NPs with different plants, to highlight advantages and disadvantages of mentioned methods. For discussion, results showed that biosynthesis of NPs allows obtaining NPs with reduced toxicity, and their size and shape depend on the type and number of biomolecules present in plants. Plant biomolecules determine the antibacterial and anticancer properties of NPs, as well as increasing the use of NPs in biomedicine, for better drug transport, therefore medicinal plants or sea plants are mostly used for biosynthesis. NPs which were synthesized in marine plants could be a very effective agent against water bacteria; therefore, if NP biosynthesis takes place in water, biological water purification is possible. Limitations of the study included a great methodological diversity of the synthesis, it is still difficult to systematize the synthesis methods, and it seems that each described study uses a different synthesis protocol; therefore, in future studies, it is necessary to clarify which method can provide the most efficient biosynthesis and develop a unified approach.

Inese Kokina

Ilona Plaksenkova

Lauris Jankovskis

Marija Jermaļonoka

Renata Galek

New Insights on Biosynthesis of Nanoparticles Using Plants Emphasizing the Use of Alfalfa (<i>Medicago sativa</i> L.)

Herein, we report on a fluorine-doped single-walled carbon nanotube (FSWCNT) phenomenon, that yields tunable high-frequency self-sustained acoustoelectric direct current (ADC) oscillations. A tractable analytical method was used in the hypersound domain, to base the calculations on carriers in the lowest miniband. Hypothetically, the energy of interaction between the carriers and the acoustic phonons is less than the energy of the typical carriers. High-order harmonics of the acoustic phonons’ effective field could be disregarded under this supposition. The ADC was observed to exhibit a nonlinearity, that resulted from the carrier distribution function’s distortion as a result of interaction with the acoustic phonons, which had strong nonlinear effects. Theoretically, we demonstrated that the dynamics of space charge instabilities, due to Bragg reflection of Bloch oscillating carriers in the FSWCNT’s miniband, were the only factors which contributed to the creation of radiation in the terahertz (THz) frequency range. The study also investigated the influence of various FSWCNT parameters such as the overlapping integrals (<svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.291101pt" id="M1" height="11.927pt" version="1.1" viewBox="-0.0498162 -8.6359 14.0732 11.927" width="14.0732pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><path id="g113-133" d="M600 0V24L339 665L311 657L43 24V0H600ZM497 50H107L303 539L497 50Z"/></g><g transform="matrix(.0091,0,0,-0.0091,9.958,3.132)"><path id="g50-116" d="M357 391C357 416 325 451 270 451C241 451 179 431 146 400C109 365 97 334 97 307C97 248 143 213 196 180C250 146 261 123 261 101C261 75 237 40 190 40C153 40 110 72 86 109C81 116 68 119 55 112C37 102 24 87 24 66C24 30 85 -12 137 -12C229 -12 331 62 331 140C331 189 304 218 236 260C197 284 164 309 164 346C164 381 194 400 220 400C259 400 282 380 304 350C310 342 321 339 330 344C347 353 357 372 357 391Z"/></g></svg> and <span class="nowrap"><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.382501pt" id="M2" height="12.0184pt" version="1.1" viewBox="-0.0498162 -8.6359 15.2058 12.0184" width="15.2058pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g113-133"/></g><g transform="matrix(.0091,0,0,-0.0091,9.958,3.132)"><path id="g50-123" d="M481 445L456 468C426 437 403 427 388 427C372 427 356 428 302 438C256 447 221 451 187 451C159 451 130 428 105 384C93 363 80 340 65 305L96 290C122 342 149 381 193 381C216 381 267 377 294 374S346 372 365 376L75 105C37 70 24 35 24 16C24 2 30 -5 35 -8C42 -8 46 -6 48 -2C58 14 75 35 90 41C102 46 116 46 147 32C200 8 267 -21 298 -21C347 -21 390 12 448 126L420 151C369 77 338 56 311 56C287 56 249 68 212 81C180 92 149 100 127 98C212 172 353 308 413 372L481 445Z"/></g></svg>),</span> ac-field <span class="nowrap"><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.18147pt" id="M3" height="12.4698pt" version="1.1" viewBox="-0.0498162 -9.28833 22.0486 12.4698" width="22.0486pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><path id="g113-41" d="M300 -147C201 -63 143 98 143 270S200 602 300 686L282 710C136 610 70 450 70 271V270C70 89 136 -72 282 -170L300 -147Z"/></g><g transform="matrix(.013,0,0,-0.013,4.498,0)"><path id="g113-70" d="M593 650H142L136 622C219 616 224 611 209 531L130 120C114 39 108 34 23 28L17 0H501C518 32 557 130 568 158L540 169C519 132 495 93 469 70C439 43 409 35 332 35C272 35 241 37 225 50C211 61 211 89 222 149L253 320H350C441 320 443 312 441 239H471L510 434H481C455 366 448 358 360 358H260L303 572C311 613 312 615 348 615H431C509 615 522 603 532 581C544 555 546 531 545 491L574 493C583 555 592 631 593 650Z"/></g><g transform="matrix(.0091,0,0,-0.0091,12.441,3.132)"><path id="g50-50" d="M389 0V32C297 38 291 46 291 118V635C234 613 175 595 109 583V556L161 554C203 552 207 547 207 497V118C207 46 201 38 110 32V0H389Z"/></g><g transform="matrix(.013,0,0,-0.013,17.387,0)"><path id="g113-42" d="M275 270C275 450 212 609 64 710L45 686C145 604 203 442 203 270S147 -63 45 -147L64 -170C213 -68 275 89 275 270Z"/></g></svg>,</span> and carrier concentration <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.29107pt" id="M4" height="12.5794pt" version="1.1" viewBox="-0.0498162 -9.28833 20.4606 12.5794" width="20.4606pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g113-41"/></g><g transform="matrix(.013,0,0,-0.013,4.498,0)"><path id="g113-111" d="M495 86L479 114C446 82 419 66 409 66C401 66 401 72 406 97C420 166 436 231 453 297C489 435 454 448 428 448C406 448 384 439 354 422C305 394 222 327 161 247H159L183 345C200 415 194 448 173 448C143 448 82 410 23 351L38 325C64 349 95 371 105 371C111 371 116 365 109 336L25 -4L31 -12C50 -4 77 3 107 9C119 69 132 122 145 168C197 254 321 381 370 381C387 381 393 374 378 305L329 95C309 17 320 -12 345 -12C372 -12 430 19 495 86Z"/></g><g transform="matrix(.0091,0,0,-0.0091,10.959,3.132)"><path id="g50-112" d="M452 282C452 397 389 451 302 451C268 451 227 441 188 422C95 377 24 281 24 154C24 65 70 -12 173 -12C240 -12 297 16 342 52C418 113 452 201 452 282ZM359 282C359 163 308 66 247 39C237 35 225 32 212 32C151 32 114 79 114 157C114 301 180 380 223 398C240 405 250 408 265 408C315 408 359 369 359 282Z"/></g><g transform="matrix(.013,0,0,-0.013,15.805,0)"><use xlink:href="#g113-42"/></g></svg>on the behaviour of the ADC. The results showed that the intensity of the ADC oscillation <span class="inline_break"><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" width="24.781pt" style="vertical-align:-4.034909pt" id="M5" height="13.9913pt" version="1.1" viewBox="-0.0498162 -9.95639 24.781 13.9913"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g113-41"/></g><g transform="matrix(.013,0,0,-0.013,4.498,0)"><path id="g113-75" d="M429 650H175L169 622C251 614 259 612 244 532L174 152C163 91 152 37 135 -6C109 -72 67 -101 23 -113L33 -144C45 -143 73 -134 102 -119C186 -76 229 -1 254 133L327 532C341 609 347 613 423 622L429 650Z"/></g><g transform="matrix(.0091,0,0,-0.0091,10.377,-5.741)"><path id="g50-98" d="M490 97L476 124C442 96 405 70 398 70C392 70 390 78 396 114C419 243 448 379 463 432L457 436C446 436 431 439 418 442C393 447 368 451 343 451C281 451 204 418 155 381C74 320 24 206 24 107C24 23 59 -12 88 -12C118 -12 155 5 191 34C236 70 290 122 328 177H330L312 84C296 0 311 -12 331 -12C355 -12 425 24 490 97ZM374 387C371 367 360 299 347 264C323 202 187 53 142 53C128 53 113 73 113 120C113 224 157 332 221 380C241 395 274 403 303 403C330 403 360 395 374 387Z"/></g><g transform="matrix(.0091,0,0,-0.0091,15.056,-5.741)"><path id="g50-102" d="M398 365C398 411 356 451 297 451C250 451 198 430 151 397C65 336 24 230 24 139C24 14 97 -12 148 -12C198 -12 284 7 373 104L355 130C306 84 246 53 198 53C132 53 111 109 111 163V189C209 211 398 261 398 365ZM317 351C317 308 273 262 117 225C134 338 189 383 221 399C230 404 249 407 263 407C295 407 317 389 317 351Z"/></g><g transform="matrix(.0091,0,0,-0.0091,9.529,3.784)"><use xlink:href="#g50-123"/></g><g transform="matrix(.0091,0,0,-0.0091,14.125,3.784)"><use xlink:href="#g50-123"/></g><g transform="matrix(.013,0,0,-0.013,19.425,0)"><path id="g113-48" d="M368 703H309L44 -163H104L368 703Z"/></g></svg><span class="isep"/><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" width="19.611pt" style="vertical-align:-4.034909pt" height="13.9913pt" version="1.1" viewBox="24.736183800000003 -9.95639 19.611 13.9913"><g transform="matrix(.013,0,0,-0.013,24.786,0)"><use xlink:href="#g113-75"/></g><g transform="matrix(.0091,0,0,-0.0091,30.665,-5.741)"><use xlink:href="#g50-98"/></g><g transform="matrix(.0091,0,0,-0.0091,35.344,-5.741)"><use xlink:href="#g50-102"/></g><g transform="matrix(.0091,0,0,-0.0091,29.817,3.784)"><use xlink:href="#g50-112"/></g><g transform="matrix(.013,0,0,-0.013,39.713,0)"><use xlink:href="#g113-42"/></g></svg></span> could be tuned by adjusting <span class="nowrap"><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.291101pt" id="M6" height="11.927pt" version="1.1" viewBox="-0.0498162 -8.6359 14.0732 11.927" width="14.0732pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g113-133"/></g><g transform="matrix(.0091,0,0,-0.0091,9.958,3.132)"><use xlink:href="#g50-116"/></g></svg>,</span> <span class="nowrap"><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.382501pt" id="M7" height="12.0184pt" version="1.1" viewBox="-0.0498162 -8.6359 15.2058 12.0184" width="15.2058pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g113-133"/></g><g transform="matrix(.0091,0,0,-0.0091,9.958,3.132)"><use xlink:href="#g50-123"/></g></svg>,</span> <span class="nowrap"><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.1815pt" id="M8" height="11.8174pt" version="1.1" viewBox="-0.0498162 -8.6359 13.0189 11.8174" width="13.0189pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g113-70"/></g><g transform="matrix(.0091,0,0,-0.0091,7.943,3.132)"><use xlink:href="#g50-50"/></g></svg>,</span> and <span class="nowrap"><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.29111pt" id="M9" height="9.25202pt" version="1.1" viewBox="-0.0498162 -5.96091 11.4308 9.25202" width="11.4308pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><use xlink:href="#g113-111"/></g><g transform="matrix(.0091,0,0,-0.0091,6.461,3.132)"><use xlink:href="#g50-112"/></g></svg>.</span>This tunability suggests that FSWCNTs could be used as an active device operating at very high frequencies, potentially reaching the submillimeter wavelength range. The study also suggests the possibility of domain suppression and acoustic Bloch gain through dynamic ADC stabilisation.

Daniel Sekyi-Arthur

Samuel Yeboah Mensah

Kofi Wi-Adu

Kwadwo Anokye Dompreh

Raymond Edziah

Tunable High-Frequency Acoustoelectric Current Oscillations in Fluorine-Doped Single-Walled Carbon Nanotubes

The presence of emerging contaminants in wastewater like tetracycline poses a significant challenge in water reuse worldwide. The implementation of a p-n heterojunction and dye-sensitized techniques in the enhancement of graphite carbon nitride provides a promising alternative for visible light-driven degradation of emerging contaminants present in wastewater. The present study investigated dye-sensitized and plain composites in degrading tetracycline using natural sunlight in a parabolic trough reactor. The study synthesized four composites of ZnFe<sub>2</sub>O<sub>4</sub>-g-C<sub>3</sub>N<sub>4</sub> at 5, 15, and 25 wt% loading of the ferrite by direct annealing of melamine, followed by thermal and ultrasonic exfoliation of bulk graphite carbon nitride and in situ precipitation with zinc ferrites to yield a composite photocatalyst. The photocatalysts were characterized using X-ray diffraction (XRD) analyses which confirmed that all the spinel ferrite phases of ZnFe<sub>2</sub>O<sub>4</sub> were well bonded with g-C<sub>3</sub>N<sub>4</sub> nanosheets to form a composite. The crystallite sizes were calculated by the Debye–Scherrer equation indicating crystal sizes of between 4.63 and 8.61 nm confirming the nanostructures. The scanning electron microscope-energy dispersive spectroscopy (SEM-EDX) tests verified that the spherical globules of ZnFe<sub>2</sub>O<sub>4</sub> were well attached to the mesoporous layers of g-C<sub>3</sub>N<sub>4</sub> and absence of contaminant phases. The UV-Vis analysis for 25% ZF-GCN revealed a band gap reduction from 2.67 eV to 2.03 eV. The PL intensity for all the composites decreased at excitation of 266 nm and 550 nm which was evidence for suppressed charge recombination. A 25% ferrite loading resulted in the best photocatalytic performance with tetracycline degradation of 93.64% and total organic carbon (TOC) removal of 51.89%. The sensitization of the 25% ZF-GCN composite with Eosin Y further improved its performance for degradation of tetracycline to 94.62% and TOC removal to 68.29%. Therefore, dye sensitization is an efficient way of improving the photocatalytic activity of a multicomponent photocatalyst for the removal of emerging pollutants.

Humphrey Mutuma Samuel

Milton M. M’Arimi

Cleophas Achisa Mecha

Synthesis, Characterization, and Photocatalytic Performance of ZnFe<sub>2</sub>O<sub>4</sub>-g-C<sub>3</sub>N<sub>4</sub> Composites for Tetracycline Removal from Contaminated Water

Cesium lead bromide (CsPbBr<sub>3</sub>) nanocrystals exhibit remarkable optoelectronic properties and exceptional stability. As a result, they have garnered significant interest for their potential applications in various fields, including solar cells, light-emitting devices, photodetectors, and lasers. Despite its resistance to moisture, oxygen, and heat compared to other perovskite materials, CsPbBr<sub>3</sub> still faces challenges maintaining its structural and optical stability over extended periods. This study proposes a robust solution to enhance and improve simultaneously the photoluminescence intensity and stability of CsPbBr<sub>3</sub> nanocrystals. The solution involves doping the perovskite precursor with green-synthesized carbon quantum dots (CQDs) and tri-n-octyl phosphine (TOP). The results indicate that the photoluminescence intensity of the perovskite nanocrystals (NCs) is sensitive to varying CQD ratios. A high photoluminescence intensity enhancement of 45% was achieved at the optimal CQDs ratio. The synthesized perovskite NCs/CQDs also demonstrated improved stability by adding TOP into the mixture. After storage in the air for 45 days, the mixed perovskite NCs maintained their performance, which was almost unchanged. Solar cell devices based on the modified perovskite NCs showed a power conversion of 7.74%. The devices also demonstrated a significant open-circuit voltage (VOC), with the most successful device achieving a VOC of 1.193 V, an Isc of 10.5748 mA cm<sup>−2</sup>, and a fill factor (FF) of 61%. This study introduces a cost-effective method for producing high-quality all-inorganic optoelectronic devices with enhanced performance and stability.

Chiayee Salih Ajaj

Diyar Sadiq

Enhancement of Optical Properties and Stability in CsPbBr<sub>3</sub> Using CQD and TOP Doping for Solar Cell Applications

The dissolution of manganese and its deposition on the anode surface cause poor cycling stability in lithium-ion batteries. To alleviate these issues, this study probes the electrochemical activity of highly crystalline and cation-adjusted lithium manganese oxide (LMO) carbon spinel composite obtained via a modified sol-gel synthesis procedure. The pristine LMO cathode was functionalized with a Fe and Mg alloy and fused with purified multiwalled carbon nanotubes (MWCNTs) to form a catalytically stabilized LiMn<sub>1.98</sub>Fe<sub>0.01</sub>Mg<sub>0.01</sub>O<sub>4</sub>/MWCNT (LMO-FeMg/MWCNT) framework. High-resolution SEM analysis showed well-dispersed particles in the nanometer size range. The electrochemical characteristics of the novel composite materials yielded favourable electrochemical results with diffusion coefficients of 1.91 × 10<sup>−9</sup> cm<sup>2</sup>·s<sup>−1</sup> and 5.83 × 10<sup>−10</sup> cm<sup>2</sup>·s<sup>−1</sup> for LMO-FeMg and LMO-FeMg/MWCNT, respectively. This improvement was supported by impedance studies which showed a considerable <svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg" style="vertical-align:-3.2728pt" id="M1" height="11.9087pt" version="1.1" viewBox="-0.0498162 -8.6359 15.4276 11.9087" width="15.4276pt"><g transform="matrix(.013,0,0,-0.013,0,0)"><path id="g113-83" d="M610 18C585 26 567 34 540 68C517 97 499 128 476 171C452 215 425 276 413 304C496 332 570 394 570 494C570 555 545 595 509 619S419 650 364 650H139L133 622C216 615 219 612 203 527L129 132C112 40 105 36 23 28L17 0H279L285 28C199 34 194 40 211 132L239 284H284C320 284 334 275 351 236C374 182 394 140 420 93C459 23 495 -1 592 -8H600L610 18ZM480 485C480 424 449 372 403 342C374 323 338 316 293 316H245L291 562C296 589 301 601 311 608S337 618 358 618C432 618 480 575 480 485Z"/></g><g transform="matrix(.0091,0,0,-0.0091,8.086,3.132)"><path id="g190-100" d="M390 111C344 68 312 56 269 56C212 56 118 102 118 241C118 346 175 401 241 401C277 401 312 388 342 360C350 352 355 349 361 349C372 349 394 371 394 392C394 403 391 411 378 422C362 436 329 449 288 449H287C250 449 190 432 138 392C71 341 37 274 37 197C37 90 112 -12 238 -12C297 -12 363 32 407 90L390 111Z"/></g><g transform="matrix(.0091,0,0,-0.0091,11.999,3.132)"><path id="g190-117" d="M298 36L289 62C276 55 253 45 228 45C202 45 169 60 169 141V397H276C289 405 292 426 282 437H169V574L155 576L90 509V437H45L17 408L21 397H90V107C90 28 125 -12 188 -12C198 -12 213 -8 230 1L298 36Z"/></g></svg> reduction of 0.27 Ω and 0.71 Ω. The cation stabilized system outperformed the pristine LMO material with specific capacities around 145 mAh·g<sup>−1</sup>, due to an enhancement in electrochemical activity and structural stability.

Natasha Ross

Shane Willenberg

Thando Juqu

Emanuela Carleschi

Bryan P. Doyle

Boosting LiMn<sub>2</sub>O<sub>4</sub> Diffusion Coefficients and Stability via Fe/Mg Doping and MWCNT Synergistically Modulating Microstructure

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<p><em>Journal of Nanotechnology</em> publishes papers related to the science and technology of nanosized and nanostructured materials, with emphasis on their design, characterization, functionality, and preparation for implementation in systems and devices.</p>


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Journal of Nanotechnology - Table of contents 2024

title

Journal of Nanotechnology publishes papers related to the science and technology of nanosized and nanostructured materials, with emphasis on their design, characterization, functionality, and preparation for implementation in systems and devices.

Journal of Nanotechnology