Engineered PEG–PCL nanoparticles enable sensitive and selective detection of sodium dodecyl sulfate: a qualitative and quantitative analysis

• Soni Prajapati and
• Ranjana Singh

Beilstein J. Nanotechnol. 2025, 16, 385–396, doi:10.3762/bjnano.16.29

• . Polystyrene latex absorption coefficient and refractive index were used to measure synthesized nanoparticles, prefilled in the software with values of 0.01 and 1.59, respectively. All measurements were performed at 25 °C. The surface morphology of PEG–PCL nanoparticles was analyzed using scanning electron

Pulsed laser in liquid grafting of gold nanoparticle–carbon support composites

• Madeleine K. Wilsey,
• Teona Taseska,
• Qishen Lyu,
• Connor P. Cox and
• Astrid M. Müller

Beilstein J. Nanotechnol. 2025, 16, 349–361, doi:10.3762/bjnano.16.26

• nanosecond pulses, graphite has an effective absorption coefficient of 5 µm−1 [26], resulting in an ablation threshold fluence of 0.7 J·cm−2 [27]; thus, our chosen fluence was well below this ablation threshold. The critical melting fluence of graphite has been reported to be 0.13 J·cm−2 [28], suggesting

Tailoring of physical properties of RF-sputtered ZnTe films: role of substrate temperature

• Kafi Devi,
• Usha Rani,
• Arun Kumar,
• Divya Gupta and
• Sanjeev Aggarwal

Beilstein J. Nanotechnol. 2025, 16, 333–348, doi:10.3762/bjnano.16.25

• , 400 °C, 500 °C, and 600 °C, respectively. Figure 5C shows the absorption coefficient as a function of the wavelength for ZnTe/Qz films at different substrate temperatures. From Figure 5C, it is observed that α has very low values at higher wavelengths (≥600 nm). The absorption coefficient increases

• very slowly in this region. In contrast, a sharp increase in α is observed in the lower-wavelength (≤600 nm) region. This type of variation in absorption coefficient points toward the existence of both direct and indirect bandgaps in a material. ZnTe films exhibit both direct and indirect transitions

• [35][36]. Therefore, in this study we have determined both direct and indirect bandgaps. The Tauc relation was used to determine the optical bandgaps (Eg) of ZnTe/Qz films [34] where h represents the Planck constant, ν is the frequency of the incident light, α is the absorption coefficient, and C is

TiO₂ immobilized on 2D mordenite: effect of hydrolysis conditions on structural, textural, and optical characteristics of the nanocomposites

• Marina G. Shelyapina,
• Rosario Isidro Yocupicio-Gaxiola,
• Gleb A. Valkovsky and
• Vitalii Petranovskii

Beilstein J. Nanotechnol. 2025, 16, 128–140, doi:10.3762/bjnano.16.12

• diffuse reflectance spectra. In this method, it is assumed that the energy-dependent absorption coefficient α can be written as where h is the Planck constant, hν is the photon energy, and B is a constant. The factor n depends on the nature of the electron transition, that is, n = 1/2 for direct and n = 2

Heterogeneous reactions in a HFCVD reactor: simulation using a 2D model

• Xochitl Aleyda Morán Martínez,
• José Alberto Luna López,
• Zaira Jocelyn Hernández Simón,
• Gabriel Omar Mendoza Conde,
• José Álvaro David Hernández de Luz and
• Godofredo García Salgado

Beilstein J. Nanotechnol. 2024, 15, 1627–1638, doi:10.3762/bjnano.15.128

• ratio x = [O]/[Si], which is determined by controlling key parameters in the deposition process [2]. This ratio determines optical and electrical properties such as bandgap energy, absorption coefficient, photoluminescence, refractive index, and electrical conductivity [3]. SiOx cannot only be obtained

Quantum-to-classical modeling of monolayer Ge₂Se₂ and its application in photovoltaic devices

• Anup Shrivastava,
• Shivani Saini,
• Dolly Kumari,
• Sanjai Singh and
• Jost Adam

Beilstein J. Nanotechnol. 2024, 15, 1153–1169, doi:10.3762/bjnano.15.94

• successfully synthesized [28][29][30][31]. Its remarkable features, such as low cost, abundance, environmental friendliness, and many interesting physical properties, indicate a broad range of possible applications in sustainable electronics and photonics [32]. Notably, a high absorption coefficient has been

• investigated structure exhibits strongly anisotropic optical properties for which the parametric values depend on the direction of the chosen plane. Dielectric function and absorption coefficient The static dielectric constants (real part of εr at ω = 0), along the in-plane (XX) and out-of-plane (ZZ) direction

• , which further leads to higher transition possibilities. The absorption coefficient elucidates the rate at which light intensity diminishes while entering the material. It primarily depends upon the imaginary part of the refractive index k(λ) = Im{n(λ)} and the wavelength of the incident light λ, as per

Bolometric IR photoresponse based on a 3D micro-nano integrated CNT architecture

• Yasameen Al-Mafrachi,
• Sandeep Yadav,
• Sascha Preu,
• Jörg J. Schneider and
• Oktay Yilmazoglu

Beilstein J. Nanotechnol. 2024, 15, 1030–1040, doi:10.3762/bjnano.15.84

• [8], the effective reflection from the forest decreased very rapidly. MWCNTs have also been used as absorbers in the infrared region (2–20 μm) with an optical absorption coefficient above 90% [10]. Similar values were achieved for different synthesis temperatures (500–700 °C) with different CNT

Controllable physicochemical properties of WO_x thin films grown under glancing angle

• Rupam Mandal,
• Aparajita Mandal,
• Alapan Dutta,
• Rengasamy Sivakumar,
• Sanjeev Kumar Srivastava and
• Tapobrata Som

Beilstein J. Nanotechnol. 2024, 15, 350–359, doi:10.3762/bjnano.15.31

• fascinating optical and electrical properties [1]. WOx is a wide-bandgap oxide semiconductor with a large excitonic binding energy of 0.15 eV and a high optical absorption coefficient (≥104 cm−1 in the UV region) [2]. These, in conjunction with decent carrier mobility (12 cm2·V−1·s−1), make this material an

• -WOx films. The value of Eg is estimated by employing the well-known Tauc’s equation [34]: where hv is the energy of the incident photons (in eV), α is the optical absorption coefficient, k is a constant, and n is a constant whose value depends on the type of transition (n = 2 for direct and n = 1/2

Fluorescent bioinspired albumin/polydopamine nanoparticles and their interactions with Escherichia coli cells

• Eloïse Equy,
• Jordana Hirtzel,
• Sophie Hellé,
• Béatrice Heurtault,
• Eric Mathieu,
• Morgane Rabineau,
• Vincent Ball and
• Lydie Ploux

Beilstein J. Nanotechnol. 2023, 14, 1208–1224, doi:10.3762/bjnano.14.100

• measured by dynamic light scattering (DLS) using a Zetasizer Nano ZS from Malvern Panalytical (Malvern, UK). Measurements were performed while taking into account a refractive index of 1.73 − 0.02i for PDA (the imaginary part corresponds to the absorption coefficient) at a wavelength of 589 nm, that is

Nanoarchitectonics of photothermal materials to enhance the sensitivity of lateral flow assays

• Elangovan Sarathkumar,
• Rajasekharan S. Anjana and
• Ramapurath S. Jayasree

Beilstein J. Nanotechnol. 2023, 14, 988–1003, doi:10.3762/bjnano.14.82

• nanomaterials become larger, they deflect more light than they absorb, resulting in reduced photothermal conversion [53]. This is because the ratio between absorption coefficient (µa) and scattering coefficient (µs) is higher for smaller particles. Compared to the 80 nm gold nanoparticles (µa = 67.88 µm−1), 40

Plasmonic nanotechnology for photothermal applications – an evaluation

• A. R. Indhu,
• L. Keerthana and
• Gnanaprakash Dharmalingam

Beilstein J. Nanotechnol. 2023, 14, 380–419, doi:10.3762/bjnano.14.33

• interaction between inner-core and outer-shell plasmons, PT energy transduction is significantly more effective. The absorption coefficient (Cabs) of the nanomatryushka (NM) can be calculated by varying the volumetric factor of the different layers of the nanostructures and the refractive index of the

Electrical and optical enhancement of ITO/Mo bilayer thin films via laser annealing

• Abdelbaki Hacini,
• Ahmad Hadi Ali,
• Nurul Nadia Adnan and
• Nafarizal Nayan

Beilstein J. Nanotechnol. 2022, 13, 1589–1595, doi:10.3762/bjnano.13.133

• before and after laser annealing. The bandgap energy Eg was determined using the following equation (Tauc relation) [28]: where α is the absorption coefficient, hν is the photon energy; A is a constant, Eg is the bandgap energy, n = 0.5 for a direct bandgap, and n = 2 for an indirect bandgap. The bandgap

Photoelectrochemical water oxidation over TiO₂ nanotubes modified with MoS₂ and g-C₃N₄

• Phuong Hoang Nguyen,
• Thi Minh Cao,
• Tho Truong Nguyen,
• Hien Duy Tong and
• Viet Van Pham

Beilstein J. Nanotechnol. 2022, 13, 1541–1550, doi:10.3762/bjnano.13.127

• spectroscopy (DRS) was carried out to measure the optical bandgap of the semiconductor materials through the Tauc method using the absorption coefficient α of the material, according to Equation 1 [42]: where h, ν, Eg, and B are the Planck constant, the frequency of the photon, the bandgap energy, and a

Facile preparation of Au- and BODIPY-grafted lipid nanoparticles for synergized photothermal therapy

• Yuran Wang,
• Xudong Li,
• Haijun Chen and
• Yu Gao

Beilstein J. Nanotechnol. 2022, 13, 1432–1444, doi:10.3762/bjnano.13.118

• organic PTAs, boron dipyrromethenes (BODIPYs) have attracted increasing attention because of high molar absorption coefficient and photochemical stability [11]. Besides, fabricating BODIPYs with halogenated substituents can improve the photothermal conversion efficiency during PTT [12]. However, BODIPYs

LED-light-activated photocatalytic performance of metal-free carbon-modified hexagonal boron nitride towards degradation of methylene blue and phenol

• Nirmalendu S. Mishra and
• Pichiah Saravanan

Beilstein J. Nanotechnol. 2022, 13, 1380–1392, doi:10.3762/bjnano.13.114

• formation of C–N moieties in the BN framework [16]. where h, α, c, E denote the Planck’s constant, absorption coefficient derived from the Lambert’s equation, speed of light (3 × 108 m s−1), and energy, respectively. The value of n (n = 4 for direct bandgap and n = 1 for indirect bandgap) depends upon the

Rapid fabrication of MgO@g-C₃N₄ heterojunctions for photocatalytic nitric oxide removal

• Minh-Thuan Pham,
• Duyen P. H. Tran,
• Xuan-Thanh Bui and
• Sheng-Jie You

Beilstein J. Nanotechnol. 2022, 13, 1141–1154, doi:10.3762/bjnano.13.96

• equation as described in Equations 5–7 [43]: where E is the photon energy (eV), h is Planck’s constant (4.132·10−15 eV·s), ν is the photon frequency (s−1), c is the velocity of light (nm·s−1), λ is the wavelength (nm), α is the absorption coefficient, B is a constant, and Eg is the bandgap energy (eV), R

Numerical study on all-optical modulation characteristics of quantum cascade lasers

• Biao Wei,
• Haijun Zhou,
• Guangxiang Li and
• Bin Tang

Beilstein J. Nanotechnol. 2022, 13, 1011–1019, doi:10.3762/bjnano.13.88

• /τsp is the spontaneous emission rate of the upper laser subband, α is the cavity absorption coefficient, β is the rate of spontaneous emission getting into the laser modes, nk is the k-th subband population, S is the photon population in the cavity, and the laser upper and lower subbands are denoted

Efficient liquid exfoliation of KP₁₅ nanowires aided by Hansen's empirical theory

• Zhaoxuan Huang,
• Zhikang Jiang,
• Nan Tian,
• Disheng Yao,
• Fei Long,
• Yanhan Yang and
• Danmin Liu

Beilstein J. Nanotechnol. 2022, 13, 788–795, doi:10.3762/bjnano.13.69

• KP15 dispersions. The Lambert–Beer law (Equation 3) was then used to measure the concentration of the KP15 dispersions: where A is the absorbance, K is the absorption coefficient of the material, b is the absorbing layer thickness (which in this work is the width of the cuvette, i.e., 1 cm), and C is

• the concentration of the KP15 dispersions. The absorbance A and the absorption coefficient K are related to the wavelength of the incident light. To determine A and K, it is necessary to choose a specific incident wavelength. The bandgap of bulk KP15 is approx. 1.75 eV [20]. However, according to our

• influence of the surface state, a wavelength (800 nm) which is far away from the bandgap of KP15 bulk and surface state in the KP15 nanowires was chosen. Some dispersions for which we predetermined the concentration were prepared to fit and determine the absorption coefficient K. Solutions of five different

Sodium doping in brookite TiO₂ enhances its photocatalytic activity

• Boxiang Zhuang,
• Honglong Shi,
• Honglei Zhang and
• Zeqian Zhang

Beilstein J. Nanotechnol. 2022, 13, 599–609, doi:10.3762/bjnano.13.52

• understand the photocatalytic behavior of a given material. The bandgap values were determined from the diffuse reflectance spectra using the Tauc plot method [26]: where A in Equation 1 is a proportional constant, α is the absorption coefficient, and n depends on the type of electron transition. The bandgap

Tin dioxide nanomaterial-based photocatalysts for nitrogen oxide oxidation: a review

• Viet Van Pham,
• Hong-Huy Tran,
• Thao Kim Truong and
• Thi Minh Cao

Beilstein J. Nanotechnol. 2022, 13, 96–113, doi:10.3762/bjnano.13.7

• increasing film thickness [45]. Zhou et al. indicated that the direct bandgap transition of SnO2 has an absorption coefficient α and the optical bandgap (Eg) can be determined by the calculation of α(hν)2 ∝ (hν − Eg)1/2/hν, and the plot of α(hν)2 vs photon energy hν, respectively. For example, the bandgap of

First-principles study of the structural, optoelectronic and thermophysical properties of the π-SnSe for thermoelectric applications

• Muhammad Atif Sattar,
• Najwa Al Bouzieh,
• Maamar Benkraouda and
• Noureddine Amrane

Beilstein J. Nanotechnol. 2021, 12, 1101–1114, doi:10.3762/bjnano.12.82

• [73]: where P and ω represent the principal value and angular frequency, respectively. The other optical parameters, such as the absorption coefficient α(ω), energy loss function L(ω), refractive index n(ω), extinction coefficient K(ω), reflectivity R(ω), and conductivity σ(ω) can be easily obtained

• that two important peaks (α and β) are located in the visible region. Beyond the β peak, ε2(ω) shows a decreasing trend at higher energies. The absorption coefficient α(ω) is presented in Figure 11c as a function of photon energy. The absorption coefficient demonstrates all the information of the

• α(ω) π-SnSe is zero until the photon energy is lower as compared to its energy bandgap of 1.41 eV. After this energy, the π-SnSe alloy displays a sharp increase of absorption coefficient α(ω) up to 139.6 104/cm at 6 eV. After this energy value, α(ω) starts to decrease with the increase in photon

Revealing the formation mechanism and band gap tuning of Sb₂S₃ nanoparticles

• Maximilian Joschko,
• Franck Yvan Fotue Wafo,
• Christina Malsi,
• Danilo Kisić,
• Ivana Validžić and
• Christina Graf

Beilstein J. Nanotechnol. 2021, 12, 1021–1033, doi:10.3762/bjnano.12.76

• are several requirements for materials to be eligible for application in the field of photovoltaics, such as high absorption performance, nontoxicity, abundance, efficiency, and low cost. As a semiconductor with a low band gap and a high absorption coefficient, antimony(III) sulfide (Sb2S3) has become

• receive the band gap values of the material [37][38]. As shown in Equation 1, the absorption coefficient α is expressed by the Planck constant h, the photon frequency ν, a constant B, which Davis and Mott described as the magnitude of the optical absorption constant [38], and a transition factor γ: The

• transition factor γ depends on the type of the band gap transition. It equals 1/2 for a direct allowed transition and 2 for an indirect allowed transition. For reflectance data, α is expressed by the Kubelka–Munk function F(R∞) (Equation 2), which is the quotient of the absorption coefficient k and the

9.1% efficient zinc oxide/silicon solar cells on a 50 μm thick Si absorber

• Rafal Pietruszka,
• Bartlomiej S. Witkowski,
• Monika Ozga,
• Katarzyna Gwozdz,
• Ewa Placzek-Popko and
• Marek Godlewski

Beilstein J. Nanotechnol. 2021, 12, 766–774, doi:10.3762/bjnano.12.60

• junction where they are effectively separated or recombined at the rear contact. Generally, in the infrared region absorption coefficient is low for silicon substrates [20]. Moreover, the electron–hole pairs generated deep in a cell are strongly attracted by the rear contact, and these pairs recombine

Impact of GaAs(100) surface preparation on EQE of AZO/Al₂O₃/p-GaAs photovoltaic structures

• Piotr Caban,
• Rafał Pietruszka,
• Jarosław Kaszewski,
• Monika Ożga,
• Bartłomiej S. Witkowski,
• Krzysztof Kopalko,
• Piotr Kuźmiuk,
• Katarzyna Gwóźdź,
• Ewa Płaczek-Popko,
• Krystyna Lawniczak-Jablonska and
• Marek Godlewski

Beilstein J. Nanotechnol. 2021, 12, 578–592, doi:10.3762/bjnano.12.48

• the Kubelka–Munk function, α is the absorption coefficient, s is the scattering factor and R is the reflectance [46]. After a linear extrapolation within the plot of [F(R)·hν]2 as a function of hν of the relevant area of linear increase, an intersection point with the abscissa was determined for each

• ), where α is the energy-dependent absorption coefficient, B is the constant and Eg is the bandgap energy [47]. Within the obtained plot, the relevant area of rapid linear absorbance growth was extrapolated accordingly, pointing the value of 3.23 eV (the crossing point with the abscissa) as the bandgap of

Structural and optical characteristics determined by the sputtering deposition conditions of oxide thin films

• Petronela Prepelita,
• Florin Garoi and
• Valentin Craciun

Beilstein J. Nanotechnol. 2021, 12, 354–365, doi:10.3762/bjnano.12.29

• thickness. The optical constants (i.e., the refractive index n, the extinction coefficient k, and the absorption coefficient α) of the SiO2 and ZnO oxide films were determined from the transmission spectra recorded in the range of 190–2500 nm by using the Swanepoel method, while the energy bandgap was

• ZnO thin films, between the extinction coefficient, k, (Figure 9) and the absorption coefficient, α, there is this following relation: where λ is the wavelength. We determined the optical bandgap, corresponding to the direct optical transitions, by extrapolating the linear portion of the dependency