All‐inorganic CsPbI3 holds promise for efficient tandem solar cells, but reported fabrication techniques are not transferrable to scalable manufacturing methods. Herein, printable CsPbI3 solar cells are reported, in which the charge transporting layers and photoactive layer are deposited by fast blade‐coating at a low temperature (≤100 °C) in ambient conditions. High‐quality CsPbI3 films are grown via introducing a low concentration of the multifunctional molecular additive Zn(C6F5)2, which reconciles the conflict between air‐flow‐assisted fast drying and low‐quality film including energy misalignment and trap formation. Material analysis reveals a preferential accumulation of the additive close to the perovskite/SnO2 interface and strong chemisorption on the perovskite surface, which leads to the formation of energy gradients and suppressed trap formation within the perovskite film, as well as a 150 meV improvement of the energetic alignment at the perovskite/SnO2 interface. The combined benefits translate into significant enhancement of the power conversion efficiency to 19% for printable solar cells. The devices without encapsulation degrade only by ≈2% after 700 h in air conditions.

All-inorganic halide perovskites hold promise for emerging thin-film photovoltaics due to their excellent thermal stability. Unfortunately, it has been challenging to achieve high-quality thin films over large areas using scalable methods under realistic ambient conditions. Here, we provide important lessons on controlling the solidification and crystallization of CsPbI2Br perovskite inks during ambient scalable fabrication, with results of superior thin-film quality and device performance compared to lab-scale processes.

Perovskite solar cells exhibit not only high efficiency under full AM1.5 sunlight, but also have great potential for applications in low‐light environments, such as indoors, cloudy conditions, early morning, late evening, etc. Unfortunately, their performance still suffers from severe trap‐induced nonradiative recombination, particularly under low‐light conditions. Here, a holistic passivation strategy is developed to reduce traps both on the surface and in the bulk of micrometer‐thick perovskite film, leading to a record efficiency of 40.1% under 301.6 µW cm−2 warm light‐emitting diode (LED) light for low‐light solar‐cell applications. The involvement of guanidinium into the perovskite bulk film and 2‐(4‐methoxyphenyl)ethylamine hydrobromide (CH3O‐PEABr) passivation on the perovskite surface synergistically suppresses the trap states. The charge carrier lifetimes of the perovskite film increase by tenfold and fivefold to 981 ns and 8.02 µs at the crystal surface and in its bulk, respectively. The decreased nonradiative recombination loss translates to a high open‐circuit voltage (Voc) of 1.00 V, a high short‐circuit current (Jsc) of 152.10 µA cm−2, and a fill factor (FF) of 79.52%. Note that this performance also stands as the highest among all photovoltaics measured under indoor light illumination. This work of trap passivation for micrometer‐thick perovskite film paves a way for high‐performance, self‐powered IoT devices.

Two-dimensional (2D) halide perovskites come in several distinct structural classes and exhibit great tunability, stability and high potential for photovoltaic applications. Here, we report a new series of hybrid 2D perovskites in the Dion−Jacobson (DJ) class based on aromatic m-Phenylenediammonium (mPDA) dications. The crystal structures of the DJ perovskite materials (mPDA)MA n-1 Pb n I 3n+1 (n = 1, 2, 3) were solved and refined using single crystal X-ray crystallography. The results indicate a short I•••I interlayer distance of ~4.00 − 4.04 Å for the (mPDA)MA n-1 Pb n I 3n+1 (n = 2 and 3) structures, which is the shortest among DJ perovskites. However, Pb−I−Pb angles are as small as ~158-160º reflecting large distortion of the inorganic framework that results in larger band gaps for these materials compared to other DJ analogues. Density functional theory calculations suggest appreciable dispersion in the stacking direction, unlike the band structures of the Ruddlesden-Popper (RP) phases which exhibit flat bands along the stacking direction. This is a consequence of a short interlayer I•••I distances that can lead to inter-layer electronic coupling across the layers. The solution deposited films (nominal (mPDA)MA n-1 Pb n I 3n+1 compositions of n = 1−6) reveal improved surface coverage with increasing nominal n value with the higher-n films being composed of a mixture of n=1 and bulk 3D MAPbI 3 perovskites. The films made from solutions of these materials behave differently from those of other 2D iodide perovskites and their solar cells have a mixture of n=1 DJ and MAPbI 3 as the light absorbing semiconductors.

PbI 2 -EMIMHSO 4 intermediates, finally enlarged the grain size, decreased the trap density, and relaxed the lattice strain of perovskite. The synergetic effects enable us to fabricate ambient blade-coating high-performance CsPbI 3 solar cells with PCEs as high as 20.01% under 1 sun illumination (100 mW cm −2 ) and 37.24% under indoor light illumination (1000 lux, 365 µW cm −2 ); both are the highest for the printed all-inorganic cells for corresponding applications. More importantly, the PCEs of CsPbI 3 -EMIMHSO 4 -based PSCs without any encapsulation retained 95% of the initial PCE value after 1000 h aging under ambient condition. Considering the simplicity and availability of this approach, our study offers an effective materials strategy to passivate crystal defect and regulate interfacial energy alignment for upscaling high-performance and long-term stable PSCs under ambient conditions.Research data are not shared.

Even though the perovskite solar cell has been so popular for its skyrocketing power conversion efficiency, its further development is still roadblocked by its overall performance, in particular long-term stability, large-area fabrication and stable module efficiency. In essence, the soft component and ionic–electronic nature of metal halide perovskites usually chaperonage large number of anion vacancy defects that act as recombination centers to decrease both the photovoltaic efficiency and operational stability. Herein, we report a one-stone-for-two-birds strategy in which both anion-fixation and associated undercoordinated-Pb passivation are in situ achieved during crystallization by using a single amidino-based ligand, namely 3-amidinopyridine, for metal-halide perovskite to overcome above challenges. The resultant devices attain a power conversion efficiency as high as 25.3% (certified at 24.8%) with substantially improved stability. Moreover, the device without encapsulation retained 92% of its initial efficiency after 5000 h exposure in ambient and the device with encapsulation retained 95% of its initial efficiency after >500 h working at the maximum power point under continuous light irradiation in ambient. It is expected this one-stone-for-two-birds strategy will benefit large-area fabrication that desires for simplicity.

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Monodisperse polystyrene (PS) colloidal spheres were successfully prepared through emulsifier-free emulsion polymerization by controlling the polymerization reaction time, ionic strength of the system, concentration of the ionic copolymer (sodium p-styrenesulfonate) and other factors. The PS colloidal spheres were assembled into colloidal crystals whose structures were mainly face-centered cubic (fcc) close-packed. Then FDTD method was used to calculate the color-rendering characteristics of the colloidal crystals surface. The calculated results were consistent with the experimental results. polystyrene spheres, colloidal crystals, self-assembly, three-dimensional ordered, FDTD method Citation:Fang J F, Xuan Y M, Li Q. Preparation of polystyrene spheres in different particle sizes and assembly of the PS colloidal crystals.