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Phenazine‐based small molecular acceptors (SMAs), which benefit from the reduced energy loss (Eloss), have emerged as promising candidates for achieving high‐efficiency organic solar cells (OSCs). Nevertheless, the potential advancements of phenazine‐based photovoltaic devices are hindered by the constrained short‐circuit current (Jsc). Though the incorporation of selenium (Se) atoms has been proven effective in enhancing Jsc, it simultaneously introduces molecular disorder stacking and charge recombination. Based on the desire to harness the full potential of phenazine structure and the benefits of Se substitution, a series of Se‐substituted phenazine‐based SMAs, namely PzIC‐SSe‐4F and PzIC‐SeSe‐4F are meticulously synthesized. Due to the increased photon harvesting capabilities, the photovoltaic device using PzIC‐SeSe‐4F demonstrated a significantly increased Jsc of 27.73 mA cm−2. Remarkably, the PzIC‐SeSe‐4F‐based device displayed an astonishing open circuit voltage (Voc) of 0.873 V, representing the highest Voc recorded among all reported symmetric Se‐substituted Y‐series SMAs‐based photovoltaic devices. Thanks to the synergistic effect of phenazine central cores and Se substitution, the PM6:PzIC‐SeSe‐4F‐based device achieves a power conversion efficiency (PCE) of 17.69%. The findings serve as a pivotal reference for further development of high‐efficiency Se‐substituted photovoltaic devices. [ABSTRACT FROM AUTHOR]

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 Eg 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. [ABSTRACT FROM AUTHOR]

Organic ternary solar cells as a more simple, more powerful, more stability photovoltaic technology has been attracting more and more attention, and recently the power conversion efficiency has exceeded 18%. In order to promote the commercialization of organic photovoltaics, work mechanisms and the improvement origin should be researched more deeply. In addition, eco-compatible solvents and large-scale fabricating methods should be adopted along with the improvement of efficiency and stability. [Display omitted] • The mechanisms of organic ternary solar cells are discussed. • Various roles of the third component in the active layer are discussed. • The challenges and perspective of organic ternary solar cells are discussed. The record of power conversion efficiency (PCE) of organic solar cells (OSCs) is updating every day, and the value has exceeded 19% already, but it still lags behind those of commercialized inorganic solar cells. The addition of a third component not only can reduce energy loss for achieving a higher open circuit voltage (V OC), but also can enlarge the light harvesting range as well as optimize morphology for getting a higher short circuit current (J SC) and fill factor (FF). For further promoting the development of organic photovoltaic technology, this article first presents general principles of organic ternary solar cells (OTSCs), and then summarizes the recent developments of OTSCs in terms of the roles of third component. In the end, the challenges and perspectives for OTSCs are discussed. This review may provide guidance for preparing highly efficient organic ternary solar cells. [ABSTRACT FROM AUTHOR]

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 (VOC) 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 VOC 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 (JSC) of 25.87 mA cm−2, fill factor (FF) of 76.92% and VOC of 0.900 V in comparison with those of D18-Cl : Y6 binary OPVs. The JSC 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. [ABSTRACT FROM AUTHOR]

A power conversion efficiency (PCE) of 16.2% is achieved in PM6:BTP‐4F‐12 based organic photovoltaics (OPVs). On the basis of efficient binary OPVs, a series of ternary OPVs are constructed by incorporating MeIC as the third component. The open circuit voltages (VOCs) of ternary OPVs can be gradually increased along with the incorporation of MeIC, suggesting the formation of an alloy state between BTP‐4F‐12 and MeIC with good compatibility. The energy loss (Eloss) of ternary OPVs can be decreased compared with that of two binary OPVs, contributing to the VOC improvement of ternary OPVs. The short circuit current density (JSC) and fill factor (FF) of ternary OPVs can also be simultaneously enhanced with MeIC content up to 10 wt% in acceptors, leading to 17.4% PCE of the optimized ternary OPVs. The JSC and FF improvement of ternary OPVs is thought to result from the optimized ternary active layers with more efficient photon harvesting, exciton dissociation and charge transport. The 17.4% PCE and 79.2% FF is among the top values of ternary OPVs. This work indicates that a ternary strategy is an emerging method to simultaneously minimize Eloss and optimize photon harvesting as well as improve the morphology of active layers for realizing performance improvement for OPVs. [ABSTRACT FROM AUTHOR]

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/cm2, 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. [ABSTRACT FROM AUTHOR]

Abstract: Nonfullerene polymer solar cells (PSCs) are fabricated by using one wide bandgap donor PBDB‐T and one ultranarrow bandgap acceptor IEICO‐4F as the active layers. One medium bandgap donor PTB7‐Th is selected as the third component due to the similar highest occupied molecular orbital level compared to that of PBDB‐T and their complementary absorption spectra. The champion power conversion efficiency (PCE) of PSCs is increased from 10.25% to 11.62% via incorporating 20 wt% PTB7‐Th in donors, with enhanced short‐circuit current (JSC) of 24.14 mA cm−2 and fill factor (FF) of 65.03%. The 11.62% PCE should be the highest value for ternary nonfullerene PSCs. The main contribution of PTB7‐Th can be summarized as the improved photon harvesting and enhanced exciton utilization of PBDB‐T due to the efficient energy transfer from PBDB‐T to PTB7‐Th. Meanwhile, PTB7‐Th can also act as a regulator to adjust PBDB‐T molecular arrangement for optimizing charge transport, resulting in the enhanced FF of ternary PSCs. This experimental result may provide new insight for developing high‐performance ternary nonfullerene PSCs by selecting two well‐compatible donors with different bandgap and one ultranarrow bandgap acceptor. [ABSTRACT FROM AUTHOR]

Nowadays, non-fullerene electron transport material for the fabrication of organic photovoltaic devices has become one of extensive issue of research. But unfortunately, it has been observed that the replacements of the fullerene acceptors with non-fullerene acceptor materials typically led down the device efficiency. In this article, improvement in photovoltaic response of bilayer solar cells based on small molecular Zinc Phthalocyanine (ZnPc) and non-fullerene acceptor material (Perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA)) is reported via their geometrical rearrangement. The structural and optical property of ZnPc and PTCDA thin films were investigated using SEM, AFM, XRD and UV–vis absorption spectroscopy and their role on device performance is discussed in detail. It has been observed that the photovoltaic performance of the devices in PTCDA/ZnPc layer sequence exhibits 8 times higher value ofJSCwith almost doubleVOCthat collectively shows 15 times higher value of the device efficiency as compared to the devices with ZnPc/PTCDA layer sequence. The results show that ZnPc and PTCDA exhibit complimentary absorption spectra but it would be efficient only if the materials are deposited in right sequence. [ABSTRACT FROM PUBLISHER]

An optimal PCE of 17.81% is achieved in LbL type OPVs by employing solvent additives for the layered optimization, which should be among the top level for all the LbL type binary OPVs. The performance improvement should be benefited from simultaneously improved J SC and FF due to the individually optimized photon harvesting and molecular arrangement, as well as suppressed charge recombination. [Display omitted] • A PCE of 17.81% is achieved in the optimal LBL type OPVs. • The additives can act as photon harvesting reinforcer and morphology regulator. • The increased crystallize with additive can facilitate more swell matrix for exciton diffusion. In this work, layer-by-layer (LbL) type OPVs are constructed with wide bandgap polymer PNTB6-Cl as donor and nonfullerene material BTP-4F-12 as acceptor. The layered optimization strategy is employed via separately incorporating the diphenyl ether (DPE) and 1,8-diiodooctane (DIO) into PNTB6-Cl chlorobenzene solution and BTP-4F-12 chloroform solution. A power conversion efficiency (PCE) of 17.81% was achieved from the optimal LbL type OPVs with two solvent additives, which should be among the top level for LBL type binary OPVs. The incorporation of DPE and DIO can separately induce more ordered PNTB6-Cl and BTP-4F-12 orientation, which should contribute to charge transport with suppressed charge recombination in active layers. Meanwhile, BTP-4F-12 crystallization is strongly increased with the incorporation of DIO, which should facilitate more swell matrix for exciton diffusion in active layers. Over 13% PCE improvement can be realized in LbL type OPVs by incorporating two additives, benefiting from simultaneously improved short circuit current density (J SC) of 26.89 mA cm−2 and fill factor (FF) of 75.79%. Meanwhile, the PCE of optimized LbL type OPVs is higher than that of 17.33% for the optimized OPVs with bulk-heterojunction (BHJ) configuration, which reveals that layered optimization strategy should be a promising approach to achieve highly efficient LbL type OPVs. [ABSTRACT FROM AUTHOR]

Propagating optical eigenmodes are found in densely packed monolayers of plasmonic nanoparticles on a metal mirror. FDTD numerical calculations show that these 2D waves carry strongly confined and amplified light energy directly in the layer of nanoparticles or in the gap between the nanoparticles and the mirror. The extreme amplification of light intensity and localization at the nanoscale offer a high potential of these waves for photon emission, light harvesting, and waveguiding applications. [ABSTRACT FROM AUTHOR]

Abstract: Herein we present a methodology for improving the power conversion efficiency of organic solar cells made by photoactive layers of poly(3-hexylthiophene) (P3HT) and phenyl-C61 butyric acid methyl ester (PCBM) of non-optimized microstructure. In our study we achieve a 47% improvement in the power conversion efficiency (PCE) of the device by utilizing a thiophene-based quinoid (QBT) moiety as the third component in the P3HT:PCBM:QBT photoactive layers. Based on a set of independent characterization experiments we address the QBT composition dependent photophysical, electrical, thermal, structural and morphology-related properties of the ternary photovoltaic P3HT:PCBM:QBT system for elucidating the origin of the PCE improvement. In small amounts (0.3–0.6wt%), QBT serves as a nucleation agent, it enlarges the size of the P3HT crystallites by 15% and it increases the fraction of well-ordered P3HT chains in the P3HT:PCBM:QBT layer. The improved microstructure of the photoactive layer in combination with the QBT-assisted photo-induced hole transfer step from PCBM to P3HT, lead to an increase of the charge photogeneration yield in the P3HT:PCBM:QBT triple bulk heterojunction. The relatively small optical gap of QBT facilitates a resonant energy transfer step from the photoexcited PCBM to the QBT followed by a charge transfer process between QBT and the P3HT matrix. Based on these findings we propose general guidelines for the design of next generation functional additives to be used in organic photovoltaics. [Copyright &y& Elsevier]

Abstract: Two series of P3HT-based polymer solar cell (PSCs) only with different electron acceptors PC70BM or PC60BM were investigated under the same conditions. The PSCs with PC70BM as the electron acceptor exhibit a relatively strong and broad absorption in the visible range and high external quantum efficiency, which results in a relatively high open circuit voltage (V oc ) of 0.62V, short circuit current density (J sc ) of 11.85mA/cm2 and power conversion efficiency (PCE) of 3.52%. The PSCs with PC60BM as the electron acceptor have a relatively low V oc of 0.58V, J sc of 10.68mA/cm2 and PCE of 3.02% due to the weak absorption of PC60BM in the visible light range. The function of PC70BM instead of PC60BM as electron acceptor could be summarized as follows: i) the strong absorption PC70BM in the visible range results in much more photon harvesting; ii) the relatively low electron mobility and relatively big size of PC70BM molecule influences the charge transporting and phase separation. The ultimate performances of PSCs are codetermined by the photon harvesting, exciton dissociation, charge carrier transport and collection. [Copyright &y& Elsevier]

Abstract: Organic semiconductors usually show high absorption coefficients only over a limited spectral range. This has to be taken into account when designing organic solar cells with low-energy gap absorbers, as it is likely that these cells will have reduced harvesting abilities for photons of higher energy. We will present two routes to tackle this problem via luminescence and energy transfer and outline three novel concepts of how to integrate these mechanisms. We use an efficient low-energy gap organic solar cell based on zinc-phthalocyanine and fullerene C60 as a model system. [Copyright &y& Elsevier]