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The emergence of polymerized small molecule acceptors (PSMAs) has significantly improved the performance of all‐polymer solar cells (all‐PSCs). However, the pace of device engineering lacks behind that of materials development, so that a majority of the PSMAs have not fulfilled their potentials. Furthermore, most high‐performance all‐PSCs rely on the use of chloroform as the processing solvent. For instance, the recent high‐performance PSMA, named PJ1‐γ, with high LUMO, and HOMO levels, could only achieve a PCE of 16.1% with a high‐energy‐level donor (JD40) using chloroform. Herein, we present a methodology combining sequential processing (SqP) with the addition of 0.5%wt PC71BM as a solid additive (SA) to achieve an impressive efficiency of 18.0% for all‐PSCs processed from toluene, an aromatic hydrocarbon solvent. Compared to the conventional blend‐casting (BC) method whose best efficiency (16.7%) could only be achieved using chloroform, the SqP method significantly boosted the device efficiency using toluene as the processing solvent. In addition, the donor we employ is the classic PM6 that has deeper energy levels than JD40, which provides low energy loss for the device. We compare the results with another PSMA (PYF‐T‐o) with the same method. Finally, an improved photostability of the SqP devices with the incorporation of SA is demonstrated. [ABSTRACT FROM AUTHOR]

The two-step layer-by-layer (LBL) deposition of donor and acceptor films enables desired vertical phase separation and high performance in organic solar cells (OSCs), which becomes a promising technology for large-scale printing devices. However, limitations including the use of toxic solvents and unpredictable infiltration between donor and acceptor still hinder the commercial production of LBL OSCs. Herein, we developed a water-based nanoparticle (NP) ink containing donor polymer to construct a mesoscale structure that could be infiltrated with an acceptor solution. Using non-halogen o-xylene for acceptor deposition, the LBL strategy with a mesoscale structure delivered outstanding efficiencies of 18.5% for binary PM6:L8-BObased LBL OSCs. Enhanced charge carrier mobility and restricted trap states were observed in the meso-LBL devices with optimized vertical morphology. It is believed that the findings in this work will bring about more research interest and effort on eco-friendly processing in preparation for the industrial production of OSCs. [ABSTRACT FROM AUTHOR]

All‐polymer solar cells (all‐PSCs) have promising potential for industrial production due to their superior stability. Recently, the widespread application of the polymerized small molecule acceptor (PSMA) has led to a surge in the efficiency of all‐PSCs. However, the high efficiencies of these devices generally rely on the use of the highly volatile solvent, chloroform (CF). Furthermore, the molecular weights of PSMA are lower than polymer donors, yet their crystallinity is weaker than typical small molecules, making most PSMA‐based all‐PSCs suffer from low electron mobility. To improve device performance and facilitate large scale production of all‐PSCs, it is necessary to enhance electron mobility and avoid the use of CF. This paper investigates the use of sequential processing (SqP) for active layer preparation using toluene as the solvent to address these issues. This work reports 18.1% efficient all‐PSC devices, which is the highest efficiency of all‐PSCs prepared using non‐halogen solvents. This work systematically compares the conventional blend‐casting method with the SqP method using PM6 as the donor and PY‐V‐γ and PJ1‐γ as the acceptors, and compares the performance of binary and ternary blends in both methods. Finally, this work measures the device stability and finds that SqP can significantly improve the photostability of the device. [ABSTRACT FROM AUTHOR]

Organic solar cells (OSCs) have gained increasing attention. Among the various directions in OSCs, all-polymer solar cells (all-PSCs) have emerged as a highly promising and currently active research area due to their excellent film formation properties, mechanical properties, and thermal stabilities. However, most of the high-efficiency all-PSCs are processed from chloroform with an active layer thickness of ~100 nm. In order to meet the requirements for industrialization, a thicker active layer processed from low-vapor pressure solvents (preferentially a hydrocarbon solvent) is strongly desired. Herein, we employ toluene (a hydrocarbon solvent with a much higher boiling point than chloroform) and a method known as sequential processing (SqP) to mitigate the rapid decline in efficiency with increasing film thickness. We show that SqP enables a more favorable vertical phase segregation that leads to less trap-assisted recombination and enhanced charge extraction and lifetime than blend-cast devices at higher film thicknesses. [ABSTRACT FROM AUTHOR]

The electron transport layer (ETL) with excellent charge extraction and transport ability is one of the key components of high-performance perovskite solar cells (PSCs). SnO2 has been considered as a more promising ETL for the future commercialization of PSCs due to its excellent photoelectric properties and easy processing. Herein, we propose a facile and effective ETL modification strategy based on the incorporation of methylenediammonium dichloride (MDACl2) into the SnO2 precursor colloidal solution. The effects of MDACl2 incorporation on charge transport, defect passivation, perovskite crystallization, and PSC performance are systematically investigated. First, the surface defects of the SnO2 film are effectively passivated, resulting in the increased conductivity of the SnO2 film, which is conducive to electron extraction and transport. Second, the MDACl2 modification contributes to the formation of high-quality perovskite films with improved crystallinity and reduced defect density. Furthermore, a more suitable energy level alignment is achieved at the ETL/perovskite interface, which facilitates the charge transport due to the lower energy barrier. Consequently, the MDACl2-modified PSCs exhibit a champion efficiency of 22.30% compared with 19.62% of the control device, and the device stability is also significantly improved. [ABSTRACT FROM AUTHOR]

Water processing is an ideal strategy for the ecofriendly fabrication of organic photovoltaics (OPVs) and exhibits a strong market−driven demand. Here, we report a state−of−the−art active material, namely PM6:BTP−eC9, for the synthesis of water−borne nanoparticle (NP) dispersion towards ecofriendly OPV fabrication. The surfactant−stripping technique, combined with a poloxamer, facilitates purification and eliminates excess surfactant in water−dispersed organic semiconducting NPs. The introduction of 1,8−diiodooctane (DIO) for the synthesis of surfactant−stripped NP (ssNP) further promotes a percolated microstructure of the polymer and NFA in each ssNP, yielding water−processed OPVs with a record efficiency of over 11%. The use of an additive during water−borne ssNP synthesis is a promising strategy for morphology optimization in NP OPVs. It is believed that the findings in this work will engender more research interest and effort relating to water−processing in preparation of the industrial production of OPVs. [ABSTRACT FROM AUTHOR]

All-polymer solar cells (all-PSCs) are organic solar cells in which both the electron donor and the acceptor are polymers and are considered more promising in large-scale production. Thanks to the polymerizing small molecule acceptor strategy, the power conversion efficiency of all-PSCs has ushered in a leap in recent years. However, due to the electrical properties of polymerized small-molecule acceptors (PSMAs), the FF of the devices is generally not high. The typical electron transport material widely used in these devices is PNDIT-F3N, and it is a common strategy to improve the device fill factor (FF) through interface engineering. This work improves the efficiency of all-polymer solar cells through interfacial layer engineering. Using PDINN as the electron transport layer, we boost the FF of the devices from 69.21% to 72.05% and the power conversion efficiency (PCE) from 15.47% to 16.41%. This is the highest efficiency for a PY-IT-based binary all-polymer solar cell. This improvement is demonstrated in different all-polymer material systems. [ABSTRACT FROM AUTHOR]

All-polymer solar cells (All-PSCs), whose electron donor and acceptors are both polymeric materials, have attracted great research attention in the past few years. However, most all-PSC devices with top-of-the-line efficiencies are processed from chloroform. In this work, we apply the sequential processing (SqP) method to fabricate All-PSCs from an aromatic hydrocarbon solvent, toluene, and obtain efficiencies up to 17.0%. By conducting a series of characterizations on our films and devices, we demonstrate that the preparation of SqP devices using toluene can effectively reduce carrier recombination, enhance carrier mobility and promote the fill factor of the device. [ABSTRACT FROM AUTHOR]

In this work, we apply the sequential processing (SqP) method to address the relatively low electron mobility in recent all-polymer solar cells (all-PSCs) based on the polymerized small-molecule acceptor (PSMA). Compared to the blend-casting (BC) method, all-PSCs composed of PM6/PY-IT via the SqP method show boosted electron mobility and a more balanced charge carrier transport, which increases the FF of the SqP device and compensates for the short-circuit current loss, rendering comparable overall performance with the BC device. Through film-depth-dependent light absorption spectroscopy, we analyze the sub-layer absorption and exciton generation rate in the vertical direction of the device, and discuss the effect of the increased electron mobility on device performance, accordingly. [ABSTRACT FROM AUTHOR]

Ferrimagnetic insulators (FMIs) have abundant advantages for the application in spintronic devices, which have attracted intensive studies. However, in most previous studies on heavy metal (HM)/FMI bilayers, the FMI layers are deposited by pulsed laser deposition (PLD), and the HM layers are deposited by magnetron sputtering. This will cause the interfacial contamination due to the inevitable vacuum breaking, and then significantly affect the spin‐orbit torque (SOT) generation and the Dzyaloshinskii–Moriya interaction (DMI) in the HM/FMI bilayers. In this work, the SOT and DMI in the HM/FMI bilayers deposited by magnetron sputtering without vacuum breaking are studied. The successful fabrication of the Tm3Fe5O12 (TmIG) layer, a typical FMI, with good crystallinity and perpendicular magnetic anisotropy (PMA) by magnetron sputtering is first demonstrated. Then by systematically varying the TmIG thickness, the SOT and DMI in the Pt/TmIG bilayers are studied. It is shown that the effective spin Hall angle in the Pt/TmIG bilayers is much larger than most previously reported values. It is further demonstrated that the DMI constant scales linearly with the inverse of the TmIG thickness, indicating the interfacial origin of the DMI. The study provides a piece of information for the basic understandings of the SOT and DMI in the HM/FMI bilayers. [ABSTRACT FROM AUTHOR]

Spin–orbit torques (SOTs) in compensated ferrimagnets (FMs) have been widely studied due to their abundant advantages for the application in spintronic devices. Recently, the SOT in FM metals near compensation tuned by composition and temperature has been reported. However, the SOT in FM insulators (FMIs) near compensation still remains elusive. In this work, we report the study of the SOT in FMI near compensation tuned by the temperature. First, Pt/Gd3Fe5O12 (GdIG) bilayer films with high crystallinity and perpendicular magnetic anisotropy were fabricated by magnetron sputtering. Then, the SOT was measured by varying the temperature. It is found that the SOT generation is drastically enhanced close to the compensation temperature, which is verified to be caused by the decrease in the net magnetization. The effective spin Hall angle in Pt/GdIG bilayer films is estimated to be ∼0.0073, which is almost independent of the temperature. Our study provides a potential approach in emerging FMIs for spintronic devices with low-energy consumption. [ABSTRACT FROM AUTHOR]

An optically addressed spatial light modulator (OASLM) works by using the intensity of a 'write' light to modulate the phase of a 'read' light. OASLM using ZnO nanoparticles (NPs) as a photoconductor is important to holographic displays because of its record-high spatial resolution. However, its response time to the write light is long and the switch-off time (τoff) can take tens of seconds due to the trap states in the ZnO NP layer. This results in residual images and poses limitations to its application in dynamic holographic displays. In this work, a ZnO NP photoconductor was replaced by a solution-processed ZnO NP/PEDOT:PSS heterojunction photodiode and the τoff of OASLM was significantly reduced to about 0.6 s. Electrical and optical properties of the heterojunction were characterized and a barrier height of 0.604 eV was determined by CV measurement. The heterojunction-based OASLM was then fabricated and its light modulating performance was investigated by using a diffractive phase grating. Finally, impedance spectroscopy was used to analysis the device equivalent circuit and optimize the operation of the OASLM. [ABSTRACT FROM AUTHOR]

We report the first demonstration of current-induced magnetization switching in a perpendicularly magnetized A1 CoPt single layer. We show that good perpendicular magnetic anisotropy can be obtained over a wide composition range of A1 Co1−xPtx single layers, which allows the fabrication of a perpendicularly magnetized CoPt single layer with a composition gradient that breaks the inversion symmetry of the structure. By fabricating a CoPt single layer with a gradient, we were able to evaluate spin-orbit torque (SOT) efficiency and successfully realize SOT-induced magnetization switching. Our study provides an approach for realizing current-induced magnetization in ferromagnetic single layers without attaching SOT source materials. [ABSTRACT FROM AUTHOR]

We present a low-cost fabrication process to deposit patterned inorganic nanoparticle films with submicrometer thickness and in turn to build higher dimensional structures through sequential multilayer deposition. Oxide nanoparticle films including semiconductors, dielectrics, and conductors have been patterned by moulding or imprinting from their solvent–suspension/paste using polydimethylsiloxane stamps. The easily controlled film thickness and good duplication fidelity with high resolution allows one to fabricate various layered structures, such as double layer and multilayer structures with minimized residual materials between them to finally define quasi-3D structures. Our experiment shows that colloidal suspension of materials can readily be patterned by stamping techniques with similar quality as compared to well-developed thermal or UV imprinting using solvent-free molecule-based materials. The usability of the fabricated structure is further demonstrated by integration of a 2-D grating on dye sensitized solar cell for improved power conversion efficiency. [ABSTRACT FROM PUBLISHER]

Self‐assembled monolayers (SAMs) have significantly improved the device performance of inverted perovskite solar cells (PSCs). However, the inadequate chemical bonding affinity between SAMs and the substrate as well as the uneven SAM distribution can lead to the decrease in device performance. Herein, the study reports a bilayer NiOx hole transport layer (HTL), consisting of ultrathin NiOx buffer film prepared through atomic layer deposition (ALD‐NiOx) and spin‐coated NiOx film (Spin‐NiOx). The work function difference between the two NiOx films will facilitate the hole transfer from the ALD‐NiOx to the Spin‐NiOx in the ALD‐NiOx/Spin‐NiOx bilayer structure. These holes will undergo surface hydroxylation reactions with water molecules on the Spin‐NiOx film surface, generating additional hydroxyl groups covalently bonded to the Spin‐NiOx film, which can provide more anchoring sites for SAM molecules. Stable covalent bonds can be formed between the Spin‐NiOx film and the subsequently coated SAM film. As a result, SAM films with better coverage and molecular arrangement can be obtained. The ALD‐NiOx/Spin‐NiOx/SAM composite HTL also demonstrates superior charge transport capability and thermal stability. For small area PSCs (0.06 cm2) prepared by using the composite HTL, a champion power conversion efficiency (PCE) of 25.25% is achieved, and the device stabilities are also significantly improved. [ABSTRACT FROM AUTHOR]