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The sustainable production of energy is a field of interest to which a new requirement is now imposed: the need to be respectful of the environment. New materials and techniques are being developed, but environmental concerns impose the necessity of keeping research active towards the development of green energy. For this reason, we present the study of short polythiophene (PTh) chains (three and five monomers) and their interaction with nickel oxide, looking for properties related to solar photon harvesting in order to produce electricity. The models of the molecules were developed, and the calculations were performed with an M11-L meta-GGA functional, specially developed for electronic structure calculations. The theoretical explorations demonstrated that the geometry of the PTh molecules suffer little distortion when interacting with the NiO molecule. The calculated value of E g lies between 2.500 and 0.412 eV for a three-ring PTh chain and between 1.944 and 0.556 eV for a five-ring PTh chain. The chemical parameters indicated that, depending on the geometry of the system, the chemical potential varies from 81.27 to 102.38 kcal/mol and the highest amount of electronic charge varies from -2.94 to 21.56 a.u. for three-monomer systems. For five-monomer systems, the values lie within similar ranges as those of the three-monomer systems. The Partial Density of States (PDOS) showed that the valence and conduction electronic bands were composed of states in the NiO and PTh rings, except for a system where there was a non-bonding interaction.

A series of ternary organic photovoltaics (OPVs) are fabricated with one wide bandgap polymer D18-Cl as donor, and well compatible Y6 and Y6-1O as acceptor. The open-circuit-voltage ( V OC ) of ternary OPVs is monotonously increased along with the incorporation of Y6-1O, indicating that the alloy state should be formed between Y6 and Y6-1O due to their excellent compatibility. The energy loss can be minimized by incorporating Y6-1O, leading to the V OC improvement of ternary OPVs. By finely adjusting the Y6-1O content, a power conversion efficiency of 17.91% is achieved in the optimal ternary OPVs with 30 wt% Y6-1O in acceptors, resulting from synchronously improved short-circuit-current density ( J SC ) of 25.87 mA cm -2 , fill factor (FF) of 76.92% and V OC of 0.900 V in comparison with those of D18-Cl : Y6 binary OPVs. The J SC and FF improvement of ternary OPVs should be ascribed to comprehensively optimal photon harvesting, exciton dissociation and charge transport in ternary active layers. The more efficient charge separation and transport process in ternary active layers can be confirmed by the magneto-photocurrent and impedance spectroscopy experimental results, respectively. This work provides new insight into constructing highly efficient ternary OPVs with well compatible Y6 and its derivative as acceptor., (© The Author(s) 2021. Published by Oxford University Press on behalf of China Science Publishing & Media Ltd.)

A novel small-molecule (SM) acceptor DTF-IC is designed and synthesized in this work. The power conversion efficiency (PCE) of ternary OSCs increased up to 12.14% from 10.90% by incorporating 10 wt% of DTF-IC as second acceptors into the binary OSCs consisting of PBDB-T as donor and IT-M as acceptor. This was mainly due to the large increase in short-circuit current (J sc ) from 16.18 to 17.95 mA/cm 2 , without any drop in the open-circuit voltage (V oc ) and fill factor (FF). The addition of DTF-IC enabled the donor and acceptor to form a distinct complementary absorption profile in the visible-light region, which boosted the photon harvesting in the range of 730-800 nm and consequently increased the J sc of the ternary system by 11%. Moreover, there was an energy transfer between the two SM acceptors, favorable for enhancing charge separation and transfer as well as reducing charge recombination at PBDB-T:IT-M and PBDB-T:DTF-IC interface. Simultaneously, HOMO and LUMO energy levels of DTF-IC were lower than those of PBDB-T, but still higher than those of IT-M. Thus, DTF-IC is able to provide a cascading energy level with the host donor and acceptor which are beneficial for efficient charge transfer between the acceptors and facilitating exciton dissociation and carrier transport. Meanwhile, the highly crystalline DTF-IC as a third component can improve the crystallization process of the active layer while maintaining proper phase separation. This work proposes a novel idea for non-fullerene acceptors achieved via twin spiro-type structure modifying by indanone and provides a new direction for the selection of ternary solar cell materials., (Copyright © 2019 Science China Press. Published by Elsevier B.V. All rights reserved.)

Nanoplasmonic sensors are heralding exciting advances as clinical diagnostics as they facilitate label-free, real-time, and ultrasensitive monitoring in a small footprint. But in essence, almost all of them still largely rely on expensive and bulky spectroscopy/imaging instrumentation and methodology, which has become the major impediment for point-of-care (POC) testing implantation. In this context, an ultracompact optical sensor is achieved with direct electrical read-out capacity by combining plasmonic sensing resonance and optical-signal-transducing into a unity integrated device. Benefiting from the convergence of high figure-of-merit (∼190) resonance and hot electron enhanced photoelectric conversions on the near-flat Au-Si nanotrench framework, the device is demonstrated to yield a detection limit on the order of 10 -6 RIU in a broadband operating wavelength window (700-1700 nm). Such a compact, silicon process compatible, and ultrasensitive optoelectronic sensing platform holds great potentials for future clinical POC detection and on-chip microspectrometer applications.

Efficiency and stability of polymer solar cells (PSCs) are the two most significant decisive factors for the purpose of actual applications. Here, highly efficient and stable ternary PSCs were fabricated by incorporating two well-compatible polymer donors (poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2- b;4,5- b0]dithiophene-2,6-diyl- alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4- b]thiophene-)-2-carboxylate-2-6-diyl] and poly[[9-(1-octylnonyl)-9 H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl]) with one narrow band gap nonfullerene acceptor (3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone)-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3- d:2',3'- d']- s-indaceno[1,2- b:5,6- b']dithiophene)). It is found that Förster resonance energy transfer acts as an efficient pathway to further strengthen photon harvesting in this ternary system, which results in a significant improvement in current density ( J SC ) without sacrificing the strong absorption of binary blends in the near-infrared region. Meanwhile, both of the inverted and conventional ternary PSCs exhibit better stability compared with the related binary PSCs in air condition because of the interlocked morphology in ternary films. The optimized ternary PSCs exhibit an outstanding power conversion efficiency (PCE) of 9.53% resulting from the synchronous improvements in J SC and fill factor. Moreover, this ternary strategy can be further confirmed by the use of an ultranarrow-band gap nonfullerene acceptor IEICO-4F, and the champion PCE of ternary PSCs reaches to 12.15%.

Superior photon absorption in ordered nanowire arrays has been demonstrated recently. However, systematic studies are still missing to explore the limits of their implementation as functional photonic devices. With emphasis on silicon nanowires, we investigated the effects of nanowire diameter, length, morphology, and pitch on the photon absorption within the visible solar spectrum based on simulations. Our results reveal that these parameters are crucial but disclose a path to improve the absorbance drastically., Pacs: 78.40.Fy; 78.67.Uh; 78.67.-n.

A new benchmark for DSSC performances is set using a novel dye and fabricating a very efficient resonant light-scattering device with a high photocurrent and good stability., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)