Sodium‐ion batteries (SIBs) are a viable alternative to meet the requirements of future large‐scale energy storage systems due to the uniform distribution and abundant sodium resources. Among the ...various cathode materials for SIBs, phosphate‐based polyanionic compounds exhibit excellent sodium‐storage properties, such as high operation voltage, remarkable structural stability, and superior safety. However, their undesirable electronic conductivities and specific capacities limit their application in large‐scale energy storage systems. Herein, the development history and recent progress of phosphate‐based polyanionic cathodes are first overviewed. Subsequently, the effective modification strategies of phosphate‐based polyanionic cathodes are summarized toward high‐performance SIBs, including surface coating, morphological control, ion doping, and electrolyte optimization. Besides, the electrochemical performance, cost, and industrialization analysis of phosphate‐based polyanionic cathodes for SIBs are discussed for accelerating commercialization development. Finally, the future directions of phosphate‐based polyanionic cathodes are comprehensively concluded. It is believed that this review can provide instructive insight into developing practical phosphate‐based polyanionic cathodes for SIBs.
Recently, sodium‐ion batteries have attracted extensive attention due to the high abundance of sodium resources and low cost. In this review, the development history, recent progress, optimization strategies, and commercialization degree of phosphate‐based polyanionic cathodes for high‐performance sodium‐ion batteries are comprehensively summarized.
Forming an ideal bulk heterojunction (BHJ) morphology is a critical issue governing the photon to electron process in organic solar cells (OSCs). Complementary to the widely‐used blend casting (BC) ...method for BHJ construction, sequential casting (SC) can also enable similar or even better morphology and device performance for OSCs. Here, BC and SC methods on three representative donor:acceptor (D:A) blends are utilized, that is, PM6:PC71BM, PM6:IT‐4F and PM6:L8‐BO. Higher power conversion efficiencies (PCEs) in all cases by taking advantage of beneficial morphology from SC processing are achieved, and a champion PCE of 18.86% (certified as 18.44%) based on the PM6:L8‐BO blend is reached, representing the record value among binary OSCs. The observations on phase separation and vertical distribution inspire the proposal of the swelling–intercalation phase‐separation model to interpret the morphology evolution during SC processing. Further, the vertical phase segregation is found to deliver an improvement of device performance via affecting the charge transport and collection processes, as evidenced by the D:A‐ratio‐dependent photovoltaic properties. Besides, OSCs based on SC processing show advantages on device photostability and upscale fabrication. This work demonstrates the versatility and efficacy of the SC method for BHJ‐based OSCs.
Sequential casting (SC) processing is practical and universal for device performance improvement in both fullerene‐ and nonfullerene‐based systems of organic solar cells (OSCs). A swelling–intercalation phase‐separation model is proposed to interpret the morphology evolution during SC processing. Notably, a champion efficiency of 18.86% (certified as 18.44%) is reached from SC processing, representing the highest value among binary OSCs.
With the continuous breakthrough of the efficiency of organic photovoltaics (OPVs), their practical applications are on the agenda. However, the thickness tolerance and upscaling in recently reported ...high‐efficiency devices remains challenging. In this work, the multiphase morphology and desired carrier behaviors are realized by utilizing a quaternary strategy. Notably, the exciton separation, carrier mobility, and carrier lifetime are enhanced significantly, the carrier recombination and the energy loss (Eloss) are reduced, thus beneficial for a higher short‐circuit density (JSC), fill factor (FF), and open‐circuit voltage (VOC) of the quaternary system. Moreover, the intermixing‐phase size is optimized, which is favorable for constructing the thick‐film and large‐area devices. Finally, the device with a 110 nm‐thick active layer shows an outstanding power conversion efficiency (PCE) of 19.32% (certified 19.35%). Furthermore, the large‐area (1.05 and 72.25 cm2) devices with 110 nm thickness present PCEs of 18.25% and 12.20%, and the device with a 305 nm‐thick film (0.0473 cm2) delivers a PCE of 17.55%, which are among the highest values reported. The work demonstrates the potential of the quaternary strategy for large‐area and thick‐film OPVs and promotes the practical application of OPVs in the future.
A quaternary strategy is used to achieve desirable carrier behaviors and optimized multiphase morphology; thus, the device shows an outstanding power conversion efficiency (PCE) of 19.32% (certified 19.35%). Furthermore, the device with ≈300 nm‐thick film shows a high efficiency of 17.55%, and the large‐area devices (1.05 and 72.25 cm2) deliver encouraging PCEs of 18.25% and 12.20%, which are among the highest values reported so far.
Aesthetic and functional design in the molecular structure of oligothiophenes is discussed. These compounds are ideal models for polymer construction and are building blocks for certain ...metal-catalyzed reactions.
Perovskite solar cells (PSCs) longevity is nowadays the bottleneck for their full commercial exploitation. Although lot of research is ongoing, the initial decay of the output power – an effect known ...as “burn‐in” degradation happening in the first 100 h – is still unavoidable, significantly reducing the overall performance (typically of >20%). In this paper, the origin of the “burn‐in” degradation in n‐i‐p type PSCs is demonstrated that is directly related to Li+ ions migration coming from the SnO2 electron transporting layer visualized by time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) measurements. To block the ion movement, a thin cross‐linked 6,6‐phenyl‐C61‐butyric acid methyl ester layer on top of the SnO2 layer is introduced, resulting in Li+ immobilization. This results in the elimination of the “burn‐in” degradation, showing for the first time a zero “burn‐in” loss in the performances while boosting device power conversion efficiency to >22% for triple‐cation‐based PSCs and >24% for formamidinium‐based (FAPbI3) PSCs, proving the general validity of this approach and creating a new framework for the realization of stable PSCs devices.
Li+ ion migration induced “burn‐in” degradation in n‐i‐p type perovskite solar cells is reported. To block the Li+ ion movement, a thin cross‐linked 6,6‐phenyl‐C61‐butyric acid methyl ester layer is introduced on top of the SnO2 layer, resulting in Li+ immobilization. Finally, the efficiency and stability are significantly improved.
Photovoltaic windows with easy installation for the power supply of household appliances have long been a desire of energy researchers. However, due to the lack of top electrodes that offer both high ...transparency and low sheet resistance, the development of high‐transparency photovoltaic windows for indoor lighting scenarios has lagged significantly behind photovoltaic windows where privacy issues are involved. Addressing this issue, this work develops a solution‐processable transparent top electrode using sandwich structure silver nanowires, realizing high transparency in semi‐transparent organic solar cells. The wettability and conducting properties of the electrode are improved by a modified hole‐transport layer named HP. The semi‐transparent solar cell exhibits good see‐through properties at a high average visible transmittance of 50.8%, with power conversion efficiency of 7.34%, and light utilization efficiency of 3.73%, which is the highest without optical modulations. Moreover, flexible devices based on the above‐mentioned architecture also show excellent mechanical tolerance compared with Ag electrode counterparts, which retains 94.5% of their original efficiency after 1500 bending cycles. This work provides a valuable approach for fabricating solution‐processed high transparency organic solar cells, which is essential in future applications in building integrated photovoltaics.
A solution‐processed sandwich structure silver‐nanowires top electrode is designed for semi‐transparent organic photovoltaics (ST‐OPVs) to address conductivity and processibility issues. Compared with traditional evaporated Ag counterpart, ST‐OPV based on the new electrode achieves more excellent optical and electrical properties, including light utilization efficiency, transmittance, reflection rate, viewing angle, and can tolerate harsher mechanical bending on flexible substrates.
The n‐i‐p type perovskite solar cells suffer unpredictable catastrophic failure under operation, which is a barrier for their commercialization. The fluorescence enhancement at Ag electrode edge and ...performance recovery after cutting the Ag electrode edge off prove that the shunting position is mainly located at the edge of device. Surface morphology and elemental analyses prove the corrosion of the Ag electrode and the diffusion of Ag+ ions on the edge for aged cells. Moreover, much condensed and larger Ag clusters are formed on the MoO3 layer. Such a contrast is also observed while comparing the central and the edge of the Ag/Spiro‐OMeTAD film. Hence, the catastrophic failure mechanism can be concluded as photon‐induced decomposition of the perovskite film and release reactive iodide species, which diffuse and react with the loose Ag clusters on the edge of the cell. The corrosion of the Ag electrode and the migration of Ag+ ions into Spiro‐OMeTAD and perovskite films lead to the forming of conducting filament that shunts the cell. The more condensed Ag cluster on the MoO3 surface as well as the blocking of holes within the Spiro‐OMeTAD/MoO3 interface successfully prevent the oxidation of Ag electrode and suppress the catastrophic failure.
The catastrophic failure of n‐i‐p type perovskite solar cells under operation is reported, which is proven by the corrosion of the metal electrode on the edge. After inserting a thin MoO3, the improved Ag thin film morphology as well as better energy alignment suppress the catastrophic failure of perovskite solar cells.
Inkjet printing (IJP) is a roll‐to‐roll (R2R) compatible fabrication method for large‐area organic solar cells (OSCs). Unlike the coating process, the films are formed through droplet leveling and ...merging during IJP, and the pre‐deposited droplets are partly dissolved by the subsequent droplets. Such a process yields undesired printing pattern lines, especially in large‐area printed films. This study reveals that such a temperature‐dependent “drying lines‐related” phase separation morphology has caused component variation in the organic blend films, which leads to an obvious inhomogeneity of photocurrent in the printed OSCs. Such a phenomenon is attributed to the solubility difference between organic donor and acceptor molecules in the main printing solvent. A composite solvent strategy of ortho‐dichlorobenzene (oDCB)/trimethylbenzene (TMB) and tetralin (THN) is developed to solve this problem. The introduction of THN suppresses the formation of printing drying lines during high‐temperature printing due to the preferential miscibility of acceptor in THN, leading to the efficiency improvement to 13.96% and 15.78% for the binary and ternary devices. In addition, the 1 cm2 device with a disruptive pattern gives an efficiency of 12.80% and a certificated efficiency of 12.18%.
High‐performance organic solar cells based on the inkjet‐printed photoactive layer with efficiency approaching 16% are achieved by eliminating the “drying‐line” dependent component inhomogeneity. The device of the disruptive pattern of 1 cm2 gives a certificated efficiency of 12.18%.
Zinc oxide (ZnO) nanoparticles are widely used as electron- transport layer (ETL) materials in organic solar cells and are considered to be the candidate with the most potential for ETLs in ...roll-to-roll (R2R)-printed photovoltaics. However, the tendency of the nanoparticles to aggregate reduces the stability of the metal oxide inks and creates many surface defects, which is a major barrier to its printing application. With the aim of improving the stability of metal oxide nanoparticle dispersions and suppressing the formation of surface defects, we prepared 3-aminopropyltrimethoxysilane (APTMS)-capped ZnO (ZnO@APTMS) nanoparticles through surface ligand exchange. The ZnO@APTMS nanoparticles exhibited excellent dispersibility in ethanol, an environmentally friendly solvent, and remained stable in air for at least one year without any aggregation. The capping of the ZnO nanoparticles with APTMS also reduced the number of surface-adsorbed oxygen defects, improved the charge transfer efficiency, and suppressed the light-soaking effect. The thickness of the ZnO@APTMS ETL could reach 100 nm without an obvious decrease in the performance. Large-area APTMS-modified ZnO films were successfully fabricated through roll-to-roll microgravure printing and exhibited good performance in flexible organic solar cells. This work demonstrated the distinct advantages of this ZnO@APTMS ETL as a potential buffer layer for printed organic electronics.
