Printable micro-supercapacitors (MSCs) with remarkable versatility, customizability, high power density and long cycling lifespan, are regarded as a promising class of miniaturized power source for wearable and portable microelectronics. Herein, we demonstrate a novel Fe-based zeolitic imidazolate framework (Fe-ZIF)/graphene (FZG) heterostructure with high speci fic surface area and outstanding electrical conductivity for planar MSCs (FZG-MSCs) worked in a high -voltage ionic liquid gel electrolyte via a spray-printed strategy. The fully printed FZG-MSCs deliver a high areal energy density of 9.5 lWh/cm 2 , extraordinary cyclability, and tailored voltage/capacitance output. Furthermore, using a fully printed FZG-MSC, we seamlessly integrate a monolithically planar all - flexible selfsustained sensor system with a mounted solar cell and a printable NH 3 gas sensor on the same side of single flexible substrate. The self-sustained sensor system exhibits high-sensitivity NH 3 detection with a good response of 18.3% at 20 ppm and linear sensibility exposed to 2 -20 ppm. Such a fully integrated system can utilize the converted solar energy stored in the MSC, and offer ef ficient electricity to power microelectronics whenever needed. Therefore, this contribution of printable planar device and integrated system paves a new avenue for constructing flexible microelectronics.

Printable micro-supercapacitors (MSCs) with remarkable versatility, customizability, high power density and long cycling lifespan, are regarded as a promising class of miniaturized power source for wearable and portable microelectronics. Herein, we demonstrate a novel Fe-based zeolitic imidazolate framework (Fe-ZIF)/graphene (FZG) heterostructure with high specific surface area and outstanding electrical conductivity for planar MSCs (FZG-MSCs) worked in a high-voltage ionic liquid gel electrolyte via a spray-printed strategy. The fully printed FZG-MSCs deliver a high areal energy density of 9.5 μWh/cm2, extraordinary cyclability, and tailored voltage/capacitance output. Furthermore, using a fully printed FZG-MSC, we seamlessly integrate a monolithically planar all-flexible self-sustained sensor system with a mounted solar cell and a printable NH3 gas sensor on the same side of single flexible substrate. The self-sustained sensor system exhibits high-sensitivity NH3 detection with a good response of 18.3% at 20 ppm and linear sensibility exposed to 2–20 ppm. Such a fully integrated system can utilize the converted solar energy stored in the MSC, and offer efficient electricity to power microelectronics whenever needed. Therefore, this contribution of printable planar device and integrated system paves a new avenue for constructing flexible microelectronics.

Flexible perovskite solar cells have attracted much attention in the scientific community due to their lightweight nature, high flexibility, and superior power-to-mass ratio. One of the most effective strategies for enhancing the power conversion efficiency of these cells involves addressing grain boundary defects within the perovskite films and interfacial defects between the perovskite films and charge transport layers. In this work, we optimize the performance of inverted flexible perovskite solar cell by using octadecylamine hydrochloride (OACl) as both an additive and a surface passivating agent to achieve synergistic passivation to the bulk phase and surface. The incorporation of OACl in the perovskite precursor solution results in the enlarging of the perovskite crystal grains, enhancing crystallinity, and passivating of grain boundary defects within the perovskite film. This optimization leads the open-circuit voltage to increase from 1.07 to 1.12 V, fill factor from 70.86% to 75.04%, and power conversion efficiency from 18.08% to 20.12%. In addition, the OACl solution is used to passivate the surface of perovskite film, resulting in a smoother perovskite surface, fill the grain boundaries, and reduce the defect density on the perovskite surface. As a result, the optimized device exhibits an open-circuit voltage of 1.15 V, fill factor of 76.15%, and ultimately achieves a power conversion efficiency of 20.80% for flexible perovskite solar cells. The synergistic passivation strategy based on OACl used in this work provides an effective approach for fabricating efficient flexible perovskite solar cells.

Perovskite solar cells (PSCs), have exhibited potential value for revolutionizing photovoltaic technology for space applications, and they have passed a series of tests in a simulated space environment. Nevertheless, the simulated space environment on land is definitely distinguished from the real‐space conditions, and the results cannot completely represent the real operating state of PSCs in space. Herein, PSCs mounted on a high‐altitude balloon are launched into near‐space and the current–voltage characteristics are measured in situ throughout the 19‐h flight, during which the PSCs are exposed directly to near‐space and experience wide temperature variation, vacuum, and strong irradiation. Thus, the diurnal performance evolution of PSCs is obtained for the first time and a possible variation mechanism is identified. The PSCs present expected stability and a champion power density of ≈12 mW cm −2 at noon, which is demonstrated as the highest result achieved in near‐space for PSCs. Additionally, despite a complex degradation process, the PSCs still deliver a high energy density comparable to that of silicon solar cells. Finally, the challenges facing the space application of PSCs are discussed. This work highlights the feasibility of PSCs in near space and provides direction for further exploration.

Printing large-area perovskite thin films is a major challenge for improving the performance and scaling up of perovskite solar modules (PSMs). Surfactants are considered effective chemicals to improve the quality of printed films. Here, we conducted cationic surfactant engineering for PSMs and attained the influencing mechanism. This work not only demonstrates the practical value of cationic provides guidance for future surfactant molecular design for perovskites.

The applications of wide‐bandgap (WBG) perovskite solar cells (PSCs) are limited by their subpar efficiency and stability due to their high density of defects, especially those at interfaces. Theoretical analyses suggest a monolayer of molecules, which is of minimum thickness and, hence, minimum resistance across the interface, possessing multifunctional groups and a permanent dipole, should effectively passivate the defects and minimize energy losses at interfaces. Herein, a self‐assembled monolayer (SAM) composed of amphiphilic molecules is designed and assembled as the interface layer to reduce the energy loss and enhance interface coupling between the perovskite and hole transport layer. It is found that the SAM also builds a back surface field through a p‐type doping effect, which promotes hole extraction and suppress the carrier recombination. Consequently, a remarkable power conversion efficiency (PCE) of 20.4% in parallel with a high open‐circuit voltage up to 1.25 V is attained. Additionally, an indoor PCE of 38.7% is realized. Both are among the best in their respective categories. Moreover, an all‐perovskite tandem solar cell is configured, presenting a decent PCE of 23.2%. This work emphasizes the significance of WBG PSCs for optoelectronic applications and indicates the eminent effects of SAMs for optimization of WBG PSCs.

Metal‐halide perovskite has emerged as an effective photovoltaic material for its high power conversion efficiency (PCE), low cost and straightforward fabrication techniques. Unfortunately, its long‐term operational durability, mainly affected by halide ion migration and undercoordinated Pb 2+ is still the bottleneck for its large‐scale commercialization. In this work, an ionic liquid (IL) is designed to effectively cap the grain surface for improved stability and reduced trap density. More specifically, the Br − in the IL passivates the undercoordinated Pb 2+ by chemically bonding to it, resulting in a thin layer of ionic‐liquid‐perovskite formed on the surface, leading to improved photovoltaic performance and better stability. Specifically, the solar cell exhibits an open‐circuit voltage of 1.192 V and PCE of 24.33% under one‐sun illumination with negligible hysteresis, and a large area (10.75 cm 2 ) integrated module achieves PCE of 20.33%. Moreover, the bare device maintains over 90% of its initial efficiency after 700 h of aging at 65 °C. It also shows outstanding stability with only about 10% degradation after being exposed to the ambient environment for 1000 h. The superior efficiency and stability demonstrate that the present IL passivating strategy is a promising approach for high‐performance large area perovskite solar cell applications.

It is arduous to prepare thin charge transport layers (CTLs) of only a few nanometers in thickness for meter-sized products, particularly for commonly used solution processes. Thus, it is desirable to take advantages of both solution-processed perovskites and vacuum -deposited CTLs. Herein, a surface redox engineering (SRE) is proposed for vacuum-deposited NiOx to make it match with the slot-die-coated perovskite films. Not only does it eliminate the de-wetting problem of perovskite ink, but it also imparts enhanced electronic properties at buried interfaces. Consequently, high-per-formance PSCs are achieved with amazing stability and outstanding power conversion efficiencies of 23.4% and 21.3% for rigid and flex-ible devices, respectively. Furthermore, perovskite submodules of area 156 3 156 mm(2) are successfully assembled with a remarkable PCE of 18.6% along with excellent stability. The SRE provides a strategy to use the advantages of both vacuum-fabricated CTLs with wet-processed perovskites for the development of large-area perovskite modules.

In article number 2100746, Shengzhong (Frank) Liu, Zhong-Shuai Wu and co-workers report an aqueous MXene/PH1000 hybrid ink for inkjet printing of planar micro-supercapacitors, which can serve as a flexible energy storage unit for Si film solar cells and can supply power for printable temperature sensors. Such printable inks are expected to allow for scalable and customizable fabrication of power sources for next-generation, self-sustaining, wearable, and implantable microelectronics.

An in-vacuum low-temperature annealing process is developed to make high-density formamidine-based perovskite films. When the temperature is optimized, the efficiency increases to 21.32%, the highest value for a PSC fabricated with vacuum deposition.

The future of mankind holds great promise for things like the Internet of Things, personal health monitoring systems, and smart cities. To achieve this ambitious goal, it is imperative for electronics to be wearable, environmentally sustainable, and safe. However, large‐scale manufacture of self‐sufficient electronic systems by exploiting multifunctional materials still faces significant hurdles. Herein, multitasking aqueous printable MXene inks are reported as an additive‐free high‐capacitance electrode, sensitive pressure‐sensing material, highly conducting current collector, metal‐free interconnector, and conductive binder. By directly screen printing MXene inks, MXene‐based micro‐supercapacitors (MSCs) and lithium‐ion microbatteries (LIMBs) are delicately fabricated on various substrates. The as‐prepared MSCs exhibit ultrahigh areal capacitance of 1.1 F cm−2 and the serially connected MSCs offer a record voltage of 60 V. The quasi‐solid‐state LIMBs deliver a robust areal energy density of 154 μWh cm−2. Furthermore, an all‐flexible self‐powered integrated system on a single substrate based on the multitasking MXene inks is demonstrated through seamless integration of a tandem solar cell, the LIMB, and an MXene hydrogel pressure sensor. Notably, this integrated system is exceptionally sensitive to body movements with a fast response time of 35 ms. Therefore, this multipurpose MXene ink opens a new avenue for powering future smart appliances.

Given that thermal stability is of considerable importance in the field of photovoltaics, inorganic perovskites have attracted numerous attempts to overcome instability caused by volatile cations in organic–inorganic hybrid perovskites. As always, crystallization optimization is a paramount strategy to enhance the performance of inorganic perovskite‐based solar cells. Recently, nanoconfined crystallization is regarded as a novel and effective strategy due to the absence of chemical reactions. Herein, 1D ordered mesoporous silica is introduced into inorganic perovskite precursors to facilely induce the nanoconfined crystallization. Both theoretical and experimental analyses verify that the nanoconfined crystallization is successfully triggered by the ordered mesoporous silica, fostering the formation of 1D perovskite monocrystal. In addition, the crystallization and morphology of inorganic perovskite are effectively facilitated. As a result, the nonradiative recombination is suppressed along with the distinctly reduced trap‐state density and remarkably enhanced charge transport in perovskite. Finally, the power conversion efficiencies of CsPbIBr 2 ‐ and CsPbI 3 ‐based solar cells are boosted from 8.67% to 10.04% and from 14.10% to 14.69%, respectively. Meanwhile, stability tests of solar cells also show enhancement using the nanoconfined crystallization. This work provides a facile, effective, and flexible crystallization modulating strategy for fabricating efficient and stable inorganic perovskite solar cells.

Despite intense development of inkjet printing for scalable and customizable fabrication of power sources, one major shortcoming is the lack of eco‐friendly aqueous inks free of additives (e.g., toxic solvents, surfactants). Here, an aqueous printable MXene/poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonic acid) (MP) hybrid ink is demonstrated that has an adjustable viscosity to directly inkjet‐print micro‐supercapacitors (MP‐MSCs) with excellent performance, seamless integration, and desirable customization, which is crucial for scalable industrialization of self‐powered integrated systems. The MP‐MSCs deliver an unprecedented volumetric capacitance of 754 F cm −3 and a remarkable energy density of 9.4 mWh cm −3 , superior to previously reported inkjet‐printed MSCs. Such outstanding performance is partly attributed to highly conductive PH1000 that prevents restacking of MXene nanosheets, enabling fast electron and ion diffusion throughout the microelectrodes. Moreover, MP‐MSCs present exceptional miniaturization and superior modularization featuring high voltage output up to 36 V from 60 serially connected cells and impressive areal voltage of 5.4 V cm −2 connected in tandem. Further, a printable temperature sensor integrated with the MP‐MSC and a flexible solar cell exhibits an exceptional response of 2% and mechanical flexibility without any bias voltage input. Therefore, the MXene inks are expected to create various opportunities for miniaturization and innovative construction of flexible, self‐sustaining, energy harvesting–storing–consuming microsystems for printable electronics.

Amorphous silicon (a-Si) has been extensively used to fabricate solar cells for efficient light-to-electricity conversion due to its outstanding light-harvesting properties and its facile and low-cost preparation method. However, photoelectrodes based on single-junction-structured a-Si have not been demonstrated for overall water splitting due to their insufficient photovoltage. Herein, we report the fabrication of single-junction a-Si-based photocathodes and photoanodes and further construct dual-photoelectrode devices for unassisted photoelectrochemical (PEC) water splitting. The p/i/n and n/i/p junction a-Si are used as photoabsorbers and the sputtered Pt nanoparticles and Co3O4 film as cocatalysts for photocathodes and photoanodes, respectively. The photocathode yields a photocurrent density up to 12.03 mA cm(-2) at 0 V versus reversible hydrogen electrode (RHE), which outperforms all previous results of a-Si-based photocathodes for PEC hydrogen evolution reactions. Additionally, the Co3O4/nip photoanode generated a photocurrent density of 7.3 mA cm(-2) at 1.23 V vs RHE. The maximum applied bias photo-to-current efficiencies are 3.3% for the photocathode and 0.93% for the photoanode in alkaline solution. The as-fabricated biphotoelectrode system is able to yield a solar-to-hydrogen efficiency of 0.61%, which presents an example enabling single-junction-structured a-Si for unassisted overall water splitting.

Perovskite solar cells (PSCs) have emerged as a promising class of photovoltaic devices since they combine the benefits of high efficiency beyond 20%, low material cost, as well as easy and scalable processing. The appropriate choice of the electron transport layer (ETL) in these devices is one crucial aspect for achieving high efficient PSCs. The conventional ETL TiO2 is not the best choice due to its relatively low conductivity and problematic photocatalytic activity. Therefore, novel ETLs have attained increasing attention and are making rapid progress and with it the further development and optimization of planar PSCs has been promoted. In this review, we start by introducing the essential functions of ETLs in planar PSCs. Next, we give an extensive description of novel ETL materials, looking at both crystalline and amorphous systems. Their emergence, development, and accompanying optimization strategies will be discussed. Additionally, we provide a brief discussion about the correlation between materials, fabrication methods, and interface related issues. In the end, we propose some prospective research subjects that will be relevant for the further development of novel ETLs.

Slot-die coating holds advantages over other large-scale technologies thanks to its potential for well-controlled, high-throughput, continuous roll-to-roll fabrication. Unfortunately, it is challenging to control thin.film uniformity over a large area while maintaining crystallization quality. Herein, by using a high-pressure nitrogen-extraction (HPNE) strategy to assist crystallization, a wide processing window in the well-controlled printing process for preparing high-quality perovskites is achieved. The yellow-phase perovskite generated by the HPNE acts as a crucial intermediate phase to produce large-area high-quality perovskite film. Furthermore, an ionic liquid is developed to passivate the perovskite surface to reduce surface defect density and to suppress carrier recombination, resulting in significantly increased efficiency to 22.7%, the highest for large-area fabrication. The strategies are successfully extended to large-area device fabrication, making it possible to produce a 40 × 40 mm2 module with stabilized PCE as high as 19.4%, the highest-efficiency for a large-area module to date.

Flexible solar cells could be applied in fields such as satellites, airships, drones, individual soldier equipment, building integrated photovoltaics (BIPV), and wearable smart devices, which indicates great prospects. This paper introduces cell structures, fabrication methods and current statuses of four types of flexible solar cells respectively, including the flexible silicon thin film solar cell, the flexible CdTe solar cell, the flexible CIGS solar cell, and the flexible perovskite solar cell. This paper also analyses the key issue of efficiency improvement and the main problems in the industrialization of the flexible solar cells. Ultimately, the paper proposes suggestions from aspects of substrate development, efficiency improvement and industrial fabrication.

Herein, hydrogenated amorphous Si (a-Si:H) covered with a thin layer of CoOx is applied as photoanode for PEC water splitting. The thin layer of CoOx effectively protects a-Si:H from the corrosive electrolyte and quantitative oxidation of water to oxygen was observed. A high applied bias photon-to-current efficiency of 2.34 % was achieved using an intrinsic absorber and an additional p-type layer. This work shows that a-Si:H with a sandwich-like structure, in which each layer has its own functionality, can be applied as an efficient and stable photoanode for PEC water oxidation.