Direct AFM-based nanoscale mapping and tomography of open-circuit voltages for photovoltaics

• Katherine Atamanuk,
• Justin Luria and
• Bryan D. Huey

Beilstein J. Nanotechnol. 2018, 9, 1802–1808, doi:10.3762/bjnano.9.171

• , local photovoltaic (PV) properties such as the open-circuit voltage, photocurrent, and work function have been demonstrated to vary by an order of magnitude, or more, within tens of nanometers [1][2][3]. Recently, property mapping with high spatial resolution by AFM has been further combined with the

• -circuit current (ISC) can then be directly visualized by simply measuring the photocurrent when there is no potential difference between the sample and the scanning probe. By further sweeping the bias between the sample and the grounded tip, for a single spot or an array of locations, the resulting I–V

• curves can be analyzed to interpret several additional performance metrics, which are widely employed by the PV and solar power communities. The open-circuit voltage (VOC), for example, is the probe bias necessary for the photocurrent to pass from positive to negative values, i.e. when the solar cell

Cr(VI) remediation from aqueous environment through modified-TiO₂-mediated photocatalytic reduction

• Rashmi Acharya,
• Brundabana Naik and
• Kulamani Parida

Beilstein J. Nanotechnol. 2018, 9, 1448–1470, doi:10.3762/bjnano.9.137

• ) curve (Figure 5) obtained from linear sweep voltammetry (LSV) gives the photocurrent generation by an applied bias; the higher the current density, the better the separation of photogenerated charge carriers [97][98]. It has been shown that a more negative open circuit potential (Voc), results in higher

• photoinduced charge carriers and shifts the absorption edge to the visible region by reducing the band gap of TiO2 [162][174]. The highest photoreduction efficiency of Cr(VI) was obtained with WO3/TiO2 NTs containing 1% tungsten (W) as it provides highest photocurrent and creates photogenerated carriers with

• photocurrent. Dozzi et al. synthesized a series of titanium–tungsten mixed oxides through coupling of TiO2 with varying WO3 percentage by a base-catalyzed sol–gel method [175]. WO3 plays a vital role in inhibiting charge recombination for efficient charge transfer to enhance the Cr(VI) reduction. Bi2O3

Semi-automatic spray pyrolysis deposition of thin, transparent, titania films as blocking layers for dye-sensitized and perovskite solar cells

• Hana Krýsová,
• Josef Krýsa and
• Ladislav Kavan

Beilstein J. Nanotechnol. 2018, 9, 1135–1145, doi:10.3762/bjnano.9.105

• . Without post-calcination at 500 °C, the photocurrent density is negligible. The photoresponse was similarly negligible for the deposition temperature of 300 °C (data not shown). Only after calcination at 500 °C will the low-temperature-grown films become photoactive, where the photocurrent onset was

• observed at around −0.35 V (Figure 1a). In the applied potential range of 0.25–1.2 V there is a photocurrent plateau at ≈14 μA/cm2 at the UV illumination intensity applied (7.5 mW/cm2). For the deposition temperature of 450 °C, our titania films are photoactive already in the as-grown state (see Figure 1b

• ). These TiO2 films exhibit the photocurrent onset at around –0.3 V but there is no plateau at larger potentials. Instead, the photocurrent increases monotonically with the applied potential. The effect of post-calcination is opposite compared to the low-temperature films deposited at 150 °C (cf. Figure 1a

Synthesis and characterization of two new TiO₂-containing benzothiazole-based imine composites for organic device applications

• Anna Różycka,
• Agnieszka Iwan,
• Krzysztof Artur Bogdanowicz,
• Michal Filapek,
• Natalia Górska,
• Damian Pociecha,
• Marek Malinowski,
• Patryk Fryń,
• Agnieszka Hreniak,
• Jakub Rysz,
• Paweł Dąbczyński and
• Monika Marzec

Beilstein J. Nanotechnol. 2018, 9, 721–739, doi:10.3762/bjnano.9.67

• , while for DSC studies, the mixture was scratched with a spatula and put into aluminum pans. Assembly and characterization of organic devices Samples for photocurrent measurements were prepared on ITO patterned glass substrates (Osilla S211) to form ITO/TiO2/SP1 (or SP1:P3HT, SP1:TiO2, SP1:PC71BM or P3HT

Facile synthesis of ZnFe₂O₄ photocatalysts for decolourization of organic dyes under solar irradiation

• Arjun Behera,
• Debasmita Kandi,
• Sanjit Manohar Majhi,
• Satyabadi Martha and
• Kulamani Parida

Beilstein J. Nanotechnol. 2018, 9, 436–446, doi:10.3762/bjnano.9.42

• , FESEM, UV–vis DRS, PL, FTIR and photocurrent measurements. The photocatalytic activity of the prepared material is studied with regard to the degradation of rhodamine B (Rh B) and Congo red under solar irradiation. The kinetic study showed that the material exhibits zeroth and first order reaction

• correlates well with the lowest PL intensity, highest photocurrent and lowest particle size. Keywords: Congo red; electrochemical study; phenol; photocatalyst; rhodamine B (Rh B); ZnFe2O4; Introduction Photocatalysis is a “green” technology for the treatment of environmental pollutants with solar energy [1

• –540 cm−1 is due to stretching vibrations of M–O bonds (Zn-O and Fe-O). Electrochemical studies Linear-sweep voltammetry In order to know the photocurrent response of the prepared catalysts, linear-sweep voltammetry was carried out in the range of 0–1.1 V in 0.1 M Na2SO4 at a scan rate of 10 mV·s−1

Enhanced photoelectrochemical water splitting performance using morphology-controlled BiVO₄ with W doping

• Xin Zhao and
• Zhong Chen

Beilstein J. Nanotechnol. 2017, 8, 2640–2647, doi:10.3762/bjnano.8.264

• . By changing the solvent ratio, planar and porous nanostructured W-doped BiVO4 thin films were prepared. The photocurrent of the porous W-doped BiVO4 is ca. 50% higher than that of planar W-doped BiVO4. We have analyzed this improvement quantitatively with regard to contributions from light absorption

• substrate and a worse performance than the other two samples (1-EG, 2-EG). In the following, we attempt to quantify the contributions from light absorption, charge separation, and charge injection across the electrode/electrolyte interface. These three factors contribute to the water oxidation photocurrent

• , which is expressed by Equation 1 [21], where JH2O is the total water splitting photocurrent, J0 is the theoretical solar photocurrent assuming that all solar energy corresponding to the band edge can be fully converted to fuel energy (7.3 mA/cm2 for BiVO4), ηabs is the light absorption efficiency, ηsep

Synthesis and characterization of noble metal–titania core–shell nanostructures with tunable shell thickness

• Bartosz Bartosewicz,
• Marta Michalska-Domańska,
• Malwina Liszewska,
• Dariusz Zasada and
• Bartłomiej J. Jankiewicz

Beilstein J. Nanotechnol. 2017, 8, 2083–2093, doi:10.3762/bjnano.8.208

• electromagnetic fields increased the efficiency of light interaction with sensitizers (dyes). On the other hand, plasmon resonance energy transfer (PRET) and “hot” electron transfer led to an increased e−/h+ pair generation and amplified number of carriers available for photocurrent generation. An increased

Growth and characterization of textured well-faceted ZnO on planar Si(100), planar Si(111), and textured Si(100) substrates for solar cell applications

• Chin-Yi Tsai,
• Jyong-Di Lai,
• Shih-Wei Feng,
• Chien-Jung Huang,
• Chien-Hsun Chen,
• Fann-Wei Yang,
• Hsiang-Chen Wang and
• Li-Wei Tu

Beilstein J. Nanotechnol. 2017, 8, 1939–1945, doi:10.3762/bjnano.8.194

• replacement for the metal contact in semiconductor devices. When applied to solar cells, it can eliminate the optical shading effect induced by the conventional metal contact thereby effectively increasing solar cell photocurrent and efficiency. Granular ZnO thin films grown by low pressure chemical vapor

• optical path and the photon absorption probability of the incident light, thus increasing the photocurrent of the solar cells [3]. As a result, for thin film solar cells, ZnO not only serve as a TCO, but also a light-trapping structure. In addition, the exposed planes in the crystal growth process depend

Three-in-one approach towards efficient organic dye-sensitized solar cells: aggregation suppression, panchromatic absorption and resonance energy transfer

• Jayita Patwari,
• Samim Sardar,
• Bo Liu,
• Peter Lemmens and
• Samir Kumar Pal

Beilstein J. Nanotechnol. 2017, 8, 1705–1713, doi:10.3762/bjnano.8.171

• , using time-resolved fluorescence decay measurements. The electron transfer time scales from the dyes to TiO2 have also been characterized for each dye. The current–voltage (I–V) characteristics and the wavelength-dependent photocurrent measurements of the co-sensitized DSSCs reveal that FRET between the

• two dyes increase the photocurrent as well as the efficiency of the device. From the absorption spectra of the co-sensitized photoanodes, PPIX was observed to be efficiently acting as a co-adsorbent and to reduce the dye aggregation problem of SQ2. It has further been proven by a comparison of the

• device performance with a chenodeoxycholic acid (CDCA) added to a SQ2-sensitized DSSC. Apart from increasing the absorption window, the FRET-induced enhanced photocurrent and the anti-aggregating behavior of PPIX towards SQ2 are crucial points that improve the performance of the co-sensitized DSSC

Two-dimensional carbon-based nanocomposites for photocatalytic energy generation and environmental remediation applications

• Suneel Kumar,
• Ashish Kumar,
• Ashish Bahuguna,
• Vipul Sharma and
• Venkata Krishnan

Beilstein J. Nanotechnol. 2017, 8, 1571–1600, doi:10.3762/bjnano.8.159

Light-induced magnetoresistance in solution-processed planar hybrid devices measured under ambient conditions

• Sreetama Banerjee,
• Daniel Bülz,
• Danny Reuter,
• Karla Hiller,
• Dietrich R. T. Zahn and
• Georgeta Salvan

Beilstein J. Nanotechnol. 2017, 8, 1502–1507, doi:10.3762/bjnano.8.150

• -TIE) having a channel length of ca. 100 nm fabricated in this work and, for comparison, commercially available pre-structured organic field-effect transistor (OFET) substrates with a channel length of 20 µm were used. The magnitude of the photocurrent as well as the magnetoresistance was found to be

• photocurrent. The magnetoresistance effect was found to diminish over time under ambient conditions compared to a freshly prepared sample. We propose that the much faster degradation of the magnetoresistance effect as compared to the photocurrent was due to the incorporation of water molecules in the TIPS

• . Magnetoconductance (MC) is the change in conductivity of a material/device upon application of an external magnetic field. The magnetoresistance effect, however, was found to degrade over time significantly faster than the photocurrent. We suggest that this degradation is due to incorporation of water molecules from

Spin-chemistry concepts for spintronics scientists

• Konstantin L. Ivanov,
• Alexander Wagenpfahl,
• Carsten Deibel and
• Jörg Matysik

Beilstein J. Nanotechnol. 2017, 8, 1427–1445, doi:10.3762/bjnano.8.143

• carriers can be extracted to yield the photocurrent. The role of the spin in several loss mechanisms [30][36][37], which reduce the power conversion efficiency, is only partly understood. For instance, if the delocalization of charge carriers in the CTS is limited, for example, by energetic disorder, CTS

• , which makes an electron back transfer (labeled as ebt in Figure 1) into an intramolecular triplet state of either donor or acceptor possible. The loss in photocurrent due to the electron back transfer is not known quantitatively. It can be minimized by increasing the donor LUMO–acceptor LUMO gap [31

• the sum of the radical radii. MFEs can be studied using different techniques. The concentration of radicals, as well as the radical pair recombination yield can be traced by detecting optical absorption, luminescence, photocurrent, etc. These quantities can be monitored either in steady-state

Synthesis of graphene–transition metal oxide hybrid nanoparticles and their application in various fields

• Arpita Jana,
• Elke Scheer and
• Sebastian Polarz

Beilstein J. Nanotechnol. 2017, 8, 688–714, doi:10.3762/bjnano.8.74

• effective in improving the charge/discharge performance of TiO2 anodes and is responsible for the improved photocurrent response of the hybrid materials [82]. In most cases, for the formation of TiO2–graphene hybrids, TiO2 is prepared by hydrolysis of Ti-containing precursors [83][84][85] as the hydrolysis

Role of oxygen in wetting of copper nanoparticles on silicon surfaces at elevated temperature

• Tapas Ghosh and
• Biswarup Satpati

Beilstein J. Nanotechnol. 2017, 8, 425–433, doi:10.3762/bjnano.8.45

• higher theoretical photocurrent density [23]. The practical conversion efficiency for CuO is low, which may be due to its low carrier concentration [24]. Again, the p-type CuO–n-type Si heterojunction is applicable for solar cells due to their similar electron affinity [25]. The reported open circuit

• voltage for a p-CuO/n-Si heterojunction solar cell is 0.33 V [26] and after improving the crystalline quality and the interface quality between the CuO and the Si, an increased open circuit voltage of 0.509 V and a high photocurrent density of 12 mA/cm2 have been achieved [25]. Therefore, it is important

Tandem polymer solar cells: simulation and optimization through a multiscale scheme

• Fanan Wei,
• Ligang Yao,
• Fei Lan,
• Guangyong Li and
• Lianqing Liu

Beilstein J. Nanotechnol. 2017, 8, 123–133, doi:10.3762/bjnano.8.13

• mimic the photocurrent generation process and subsequently optimize the device structures in tandem polymer solar cells with poly(3-hexylthiophene)/phenyl-C61-butyric acid methyl ester (P3HT/PCBM) and (poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b]dithiophene)-alt-4,7-(2,1,3

• . Multiscale Simulation of Tandem Polymer Solar Cells To simulate the photocurrent generation process and subsequently evaluate the performance indices for tandem photovoltaics, we designed and realized a simulation scheme and denoted it as multiscale simulation. As illustrated in Figure 2, the schematic of

• calculated for configuration A and B, respectively. The weight ratios of P3HT/PCBM and PCPDTBT/PCBM active layers are 1:1 and 1:2. The maximum photocurrent estimated according to the photon absorption efficiency for the two device configurations is displayed in (e) and (f) (e and f share the same color code

Sb₂S₃ grown by ultrasonic spray pyrolysis and its application in a hybrid solar cell

• Erki Kärber,
• Atanas Katerski,
• Ilona Oja Acik,
• Arvo Mere,
• Valdek Mikli and
• Malle Krunks

Beilstein J. Nanotechnol. 2016, 7, 1662–1673, doi:10.3762/bjnano.7.158

• prepared by CBD, as estimated from the photocurrent edge at around 750 nm in the published EQE plots [2][4][6][7][8][9][11][12][15][16][17][40][41][50][51][52][53]. Any Eg larger than 1.7 eV up to 2.6 eV have been attributed to nanocrystalline Sb2S3 [1][44][54], or to amorphous Sb2S3 [6][44][45][53], while

• transmittance of the glass/ITO/TiO2/Sb2S3 stack (Supporting Information File 1, Figure S3). The photocurrent edge at around 1.6 eV (775 nm) corresponds well to the absorption edge of the ITO/TiO2/Sb2S3 stack (Figure 5). The absorption by P3HT has an onset at 1.9 eV (650 nm) [3][8], and it can be seen that there

Nanostructured germanium deposited on heated substrates with enhanced photoelectric properties

• Ionel Stavarache,
• Valentin Adrian Maraloiu,
• Petronela Prepelita and
• Gheorghe Iordache

Beilstein J. Nanotechnol. 2016, 7, 1492–1500, doi:10.3762/bjnano.7.142

• devices individually or with other materials, hence the possibility of fabricating various heterojunctions on Si, glass or flexible substrates for future development of Si-based integrated optoelectronics. Keywords: germanium nanoparticle; photocurrent; photodetectors; response time; transport mechanism

• following equation [40]: where Iph is the measured photocurrent under illumination and Pin is the optical power incident on the active area of the structure (measured with a power-meter LaserStar (Ophir) coupled with a sensor 3A-P-SH-V1). Responsivity shows an increase from approximatively 2 AW−1 to about 7

Photocurrent generation in carbon nanotube/cubic-phase HfO₂ nanoparticle hybrid nanocomposites

• Protima Rauwel,
• Augustinas Galeckas,
• Martin Salumaa,
• Frédérique Ducroquet and
• Erwan Rauwel

Beilstein J. Nanotechnol. 2016, 7, 1075–1085, doi:10.3762/bjnano.7.101

• photoluminescence of the nanocomposites indicates features attributed to combined effects of charge desaturation of HfO2 surface states and charge transfer to the MWCNTs with an overall reduction of radiative recombination. Finally, photocurrent generation under UV–vis illumination suggests that a HfO2 NP/MWCNT

• hybrid system can be used as a flexible nanodevice for light harvesting applications. Keywords: carbon nanotubes; HfO2; nanoparticles; photocurrent; Introduction Nanoparticles (NPs) have emerged as promising candidates for many applications due to their unique electronic, optical and magnetic

• including Hf and O vacancies [21]. The motivation of the present work is different from other well-studied luminescent nanocomposites containing TiO2 and ZnO that are investigated around band gap excitation. Here, contrary to the previous two semiconductors, novel optical properties and photocurrent

Rigid multipodal platforms for metal surfaces

• Michal Valášek,
• Marcin Lindner and
• Marcel Mayor

Beilstein J. Nanotechnol. 2016, 7, 374–405, doi:10.3762/bjnano.7.34

• anchor to stabilize molecules on the surface by photoelectrochemical measurements, where the molecules comprising a tetraphenylmethane anchoring platform show a significantly higher photocurrent density than the same system with a monopodal anchoring group. This can be attributed to a stable arrangement

Synthesis and applications of carbon nanomaterials for energy generation and storage

• Marco Notarianni,
• Jinzhang Liu,
• Kristy Vernon and
• Nunzio Motta

Beilstein J. Nanotechnol. 2016, 7, 149–196, doi:10.3762/bjnano.7.17

• with fullerene derivatives (electron acceptor material) [188]. The generation of a photocurrent due to light incident upon an organic solar cell device consists of three steps (Figure 32) [189][190]: Photon absorption in the conducting polymer (donor material). Creation of an exciton. An exciton is a

Effects of electronic coupling and electrostatic potential on charge transport in carbon-based molecular electronic junctions

• Richard L. McCreery

Beilstein J. Nanotechnol. 2016, 7, 32–46, doi:10.3762/bjnano.7.4

• independent evaluations by ultraviolet photoelectron spectroscopy and photocurrent measurements [31][51][52]. For the G9–AB–G9 model, this offset would be approximated by the difference between the HOMO and H−2 orbitals, or 0.96 eV for the optimized case. The offset varies with dihedral angle, from 0.83 to

Influence of wide band gap oxide substrates on the photoelectrochemical properties and structural disorder of CdS nanoparticles grown by the successive ionic layer adsorption and reaction (SILAR) method

• Mikalai V. Malashchonak,
• Alexander V. Mazanik,
• Olga V. Korolik,
• Еugene А. Streltsov and
• Anatoly I. Kulak

Beilstein J. Nanotechnol. 2015, 6, 2252–2262, doi:10.3762/bjnano.6.231

• optical absorption and photocarrier recombination. The maximal IPCE values for the In2O3/CdS and ZnO/CdS heterostructures are attained at N ≈ 20, whereas for TiO2/CdS, the appropriate N value is an order of magnitude higher. The photocurrent and Raman spectroscopy studies of CdS nanoparticles revealed the

• . Photoelectrochemical study of ZnO/CdS, TiO2/CdS, and In2O3/CdS heterostructures The incident photon-to-current conversion efficiency (IPCE) spectra of the heterostructures are presented in Figure 2. The conduction band level of CdS is located relatively higher than that of the WBGO. Therefore, the photocurrent

• significantly smaller in comparison with the ZnO and In2O3 films. Therefore, the light absorption in sulfide is the main factor limiting the photocurrent for the TiO2/CdS films, thus the increase in the amount of sulfide determines the IPCE growth over a wide range of N. At the same time, as will be shown later

Current–voltage characteristics of manganite–titanite perovskite junctions

• Benedikt Ifland,
• Patrick Peretzki,
• Birte Kressdorf,
• Philipp Saring,
• Andreas Kelling,
• Michael Seibt and
• Christian Jooss

Beilstein J. Nanotechnol. 2015, 6, 1467–1484, doi:10.3762/bjnano.6.152

• , additional charge carriers are generated and are separated in the electric field of the SCR, resulting in a photocurrent. The typical parameters characterizing the photovoltaic effect in solar cells are the short-circuit current density, JSC, and the open circuit voltage, VOC. The analysis of the temperature

• often described by an equivalent circuit. The simplest one is shown in Figure 2 and consists of one diode, which represents the ideal J–V characteristics in terms of the Shockley equation, an external power supply, a current source for the photocurrent and two ohmic resistors. These parasitic

Electronic interaction in composites of a conjugated polymer and carbon nanotubes: first-principles calculation and photophysical approaches

• Florian Massuyeau,
• Jany Wéry,
• Jean-Luc Duvail,
• Serge Lefrant,
• Abu Yaya,
• Chris Ewels and
• Eric Faulques

Beilstein J. Nanotechnol. 2015, 6, 1138–1144, doi:10.3762/bjnano.6.115

• photoexcitation techniques and density functional theory. Charge separation is confirmed experimentally by rapid quenching of PPV photoluminescence and changes in photocurrent starting at relatively low concentrations of SWNT. Calculations predict strong electronic interaction between the polymer and the SWNT

• % (Figure 1d). The photoconductivity measurements show a percolation regime beginning at a low threshold of x = 2% (see Figure 1a). A drastic quenching of PL occurs simultaneously with a substantial rise of the dark current and photocurrent spanning several orders of magnitude. We suggest that the observed

• polymer matrix increases [4][5][6]. Figure 1a and Figure 1b show that the variations of dark current Idark (without illumination) and photocurrent Ipc against SWNT concentration in the composite are exactly matched (Ipc is the difference between the measured photocurrent under illumination and the dark

Experimental determination of the light-trapping-induced absorption enhancement factor in DSSC photoanodes

• Serena Gagliardi and
• Mauro Falconieri

Beilstein J. Nanotechnol. 2015, 6, 886–892, doi:10.3762/bjnano.6.91

• extreme cases of the absence of light trapping and maximum light trapping. Accordingly, the photocurrent was calculated under the assumption of solar irradiation, which defined two useful boundaries. Using the experimentally derived values of the spectral absorption enhancement factor in the photoanode

• , characterization and design of materials with respect to their applications in PVs as an active layer. Under the assumption of unitary injection and collection efficiency, the short-circuit photocurrent JSC can be written as a function of the optical properties of the device as: where the integral is over the

• titania nanospheres was also calculated using a simplified, purely optical model in the two extreme cases of no or maximum light trapping [14]. The corresponding short-circuit photocurrent density under AM1.5 illumination of an ideal DSSC was then calculated for the two limiting cases above and compared