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Passivating the interfaces between the perovskite and charge transport layers is crucial for enhancing the power conversion efficiency (PCE) and stability in perovskite solar cells (PSCs). Here we report a dual‐interface engineering approach to improving the performance of FA0.85MA0.15Pb(I0.95Br0.05)3‐based PSCs by incorporating Ti3C2Clx Nano‐MXene and o‐TB‐GDY nanographdiyne (NanoGDY) into the electron transport layer (ETL)/perovskite and perovskite/ hole transport layer (HTL) interfaces, respectively. The dual‐interface passivation simultaneously suppresses non‐radiative recombination and promotes carrier extraction by forming the Pb−Cl chemical bond and strong coordination of π‐electron conjugation with undercoordinated Pb defects. The resulting perovskite film has an ultralong carrier lifetime exceeding 10 μs and an enlarged crystal size exceeding 2.5 μm. A maximum PCE of 24.86 % is realized, with an open‐circuit voltage of 1.20 V. Unencapsulated cells retain 92 % of their initial efficiency after 1464 hours in ambient air and 80 % after 1002 hours of thermal stability test at 85 °C. [ABSTRACT FROM AUTHOR]

The multiple quantum wells (QWs) distribution in low‐dimensional perovskite films hinders charge transport due to the fundamental difficulty of controlling crystal growth from precursor solutions, yielding poorly homogeneous low‐dimensional perovskite solar cells (PSCs), especially in upscaling fabrication. Here, efficient low‐dimensional PSCs are realized by modulating the colloidal assembly behavior in the precursor solution to induce intermediate structures. In combination with in situ liquid time‐of‐flight secondary ion mass spectrometry, the assembly behavior of organic cations involved lead iodide‐dominated colloidal soft framework is visualized by investigating the precursor species differences under hydrogen bonding interactions. Subsequently, solid‐state reactions emerge and the formamidine (FA)‐based perovskite films exhibit significantly suppressed multiple QWs distribution. Encouragingly, the FA device (n=9, by meniscus‐assisted coating) achieves a power conversion efficiency (PCE) of 20.28 % for a size of 0.04 cm2 and a PCE of 15.35 % for a mini‐module of 16.94 cm2 with superior stability. [ABSTRACT FROM AUTHOR]

Although outstanding power conversion efficiency (PCE) has been achieved in flexible perovskite solar cells, unsatisfactory operational stability and toxicity caused by the moisture transmittance of polymer packaging are still the bottleneck challenges that limit their applications. Herein, inspired by the non‐selective permeability of inactivated cell membrane, the diphosphatidyl‐glycerol (Di‐g) is tactfully introduced as a self‐shield interface upon the perovskite layer. 96% of lead leakage is suppressed because the amphipathic Di‐g can simultaneously bind tightly to the divalent lead ion and afford an interfacial water‐resistance. More importantly, the gradient distribution of lattice residual stress perpendicular to the substrate are optimized. The resultant flexible devices achieve a PCE of 20.29% and 15.01% at effective areas of 1.01 and 21.82 cm2 respectively, yielding excellent environmental and mechanical stability. This strategy exhibits the feasibility of developing interfacial encapsulation to stabilize scalable PSCs with negligible lead leakage. [ABSTRACT FROM AUTHOR]

Inorganic cesium lead halide perovskites offer a pathway towards thermally stable photovoltaics. However, moisture‐induced phase degradation restricts the application of hole transport layers (HTLs) with hygroscopic dopants. Dopant‐free HTLs fail to realize efficient photovoltaics due to severe electrical loss. Herein, we developed an electrical loss management strategy by manipulating poly(3‐hexylthiophene) with a small molecule, i.e., SMe‐TATPyr. The developed P3HT/SMe‐TATPyr HTL shows a three‐time increase of carrier mobility owing to breaking the long‐range ordering of "edge‐on" P3HT and inducing the formation of "face‐on" clusters, over 50 % decrease of the perovskite surface defect density, and a reduced voltage loss at the perovskite/HTL interface because of favorable energy level alignment. The CsPbI2Br perovskite solar cell demonstrates a record‐high efficiency of 16.93 % for dopant‐free HTL, and superior moisture and thermal stability by maintaining 96 % efficiency at low‐humidity condition (10–25 % R. H.) for 1500 hours and over 95 % efficiency after annealing at 85 °C for 1000 hours. [ABSTRACT FROM AUTHOR]

Regulating the electron transport layer (ETL) has been an effective way to promote the power conversion efficiency (PCE) of perovskite solar cells (PSCs) as well as suppress their hysteresis. Herein, the SnO2 ETL using a cost‐effective modification material rubidium fluoride (RbF) is modified in two methods: 1) adding RbF into SnO2 colloidal dispersion, F and Sn have a strong interaction, confirmed via X‐ray photoelectron spectra and density functional theory results, contributing to the improved electron mobility of SnO2; 2) depositing RbF at the SnO2/perovskite interface, Rb+ cations actively escape into the interstitial sites of the perovskite lattice to inhibit ions migration and reduce non‐radiative recombination, which dedicates to the improved open‐circuit voltage (Voc) for the PSCs with suppressed hysteresis. In addition, double‐sided passivated PSCs, RbF on the SnO2 surface, and p‐methoxyphenethylammonium iodide on the perovskite surface, produces an outstanding PCE of 23.38% with a Voc of 1.213 V, corresponding to an extremely small Voc deficit of 0.347 V. [ABSTRACT FROM AUTHOR]

Suppressing non‐radiative recombination via passivating surface defects of perovskite films has demonstrated an excellent strategy for high‐performance perovskite solar cells (PSCs). However, it is still hard to realize both high open‐circuit voltage (Voc) of >1.2 V and high power conversion efficiency (PCE) of >22%, because the optimized bandgap of perovskite films is less than 1.60 eV for efficient light harvesting and Voc deficit is generally unavoidable due to carriers recombination. Here, the surface of the perovskite film is treated with a series of phenylhydroxylammonium halide salts and it is found that all of them can remarkably prolong the carrier lifetime owing to their excellent capability of surface defects passivation. The best PSC with phenylbutylammonium bromide treatment realizes a PCE of 22.67% with a Voc of 1.216 V, corresponding to a small Voc deficit of ≈344 mV. [ABSTRACT FROM AUTHOR]

2D Dion–Jacobson (DJ) perovskite solar cells (PVSCs) with a high power conversion efficiency (PCE) are currently predominately fabricated via a hot‐casting process. The reason lies in the difficulty in preparing high‐quality perovskite films under mild conditions when the application of divalent ammonium removes the weak interaction from the spacer cation layer. Herein, the morphology of the 2D DJ perovskite film with a rigid piperidinium ring is tuned through a room‐temperature spin‐coating method, with the aid of a methylammonium thiocyanate (MASCN) additive. With the optimized amount of MASCN addition, the perovskite films deposited on the poly[bis(4‐phenyl)(2,4,6‐trimethylphenyl)amine] (PTAA)/poly[(9,9‐bis(30‐(N,N‐dimethylamino)propyl)‐2,7‐uorene)‐alt‐2,7‐(9,9‐dioctylfuorene)] (PFN) substrate exhibit fine crystallinity, preferred orientation, decreased defects, and better energy‐level alignment with the hole transport layer. The device with the inverted planar structure presents a JSC of 17.91 mA cm−2, VOC of 1.19 V, fill factor of 0.76, with a maximum PCE of 16.25%, which is the highest PCE for 2D DJ PVSCs free of hot casting. The unsealed device maintains around 80% of its initial efficiency after 35 days of exposure to air (Hr = 45 ± 5%). A potential route toward high‐performance 2D DJ PVSCs is provided. [ABSTRACT FROM AUTHOR]

The low toxicity, narrow bandgaps, and high charge‐carrier mobilities make tin perovskites the most promising light absorbers for low‐cost perovskite solar cells (PSCs). However, the development of the Sn‐based PSCs is seriously hampered by the critical issues of poor stability and low power conversion efficiency (PCE) due to the facile oxidation of Sn2+ to Sn4+ and poor film formability of the perovskite films. Herein, a synthetic strategy is developed for the fabrication of methylammonium tin iodide (MASnI3) film via ion exchange/insertion reactions between solid‐state SnF2 and gaseous methylammonium iodide. In this way, the nucleation and crystallization of MASnI3 can be well controlled, and a highly uniform pinhole‐free MASnI3 perovskite film is obtained. More importantly, the detrimental oxidation can be effectively suppressed in the resulting MASnI3 film due to the presence of a large amount of remaining SnF2. This high‐quality perovskite film enables the realization of a PCE of 7.78%, which is among the highest values reported for the MASnI3‐based solar cells. Moreover, the MASnI3 solar cells exhibit high reproducibility and good stability. This method provides new opportunities for the fabrication of low‐cost and lead‐free tin‐based halide perovskite solar cells. [ABSTRACT FROM AUTHOR]

The unique properties of metal halide perovskites give them great potential for applications in portable and wearable optoelectronics. However, the intrinsic brittleness of perovskites favors easy crack propagation that deteriorates the optoelectronic performance of the devices. Inspired by nacre, we propose flexible perovskite thin films fabricated by antisolvent-assisted self-encapsulation of polymer and imprinting techniques during crystallization. Such an approach results in synchronous formation of polymer-glued perovskite grains exhibiting nacre-like "brick-and-mortar" structure. The deformable composite architecture bonding hemisphere-shaped grating (HG) and porous photonic crystal (PC) (HG-PC) improves its crystalline quality and light-harvesting capability. An HG-PC photodetector (PD) with high responsivity of 17.31 A/W and detectivity of 5.02 × 1013 Jones is achieved. Our flexible HG-PC PD retains 95% of the initial photocurrent after 1000 bending cycles at 2 mm curvature radius. This solvent-driven self-encapsulation strategy offers an innovative and universal approach for highly efficient flexible optoelectronics. [Display omitted] • The synergistic effect of "brick-and-mortar" structure and deformable photonic architecture endows flexible perovskite photodetector with high mechanical robustness and durability • A perovskite photodetector with high responsivity of 17.31 A/W and detectivity of 5.02 × 1013 Jones is achieved. [ABSTRACT FROM AUTHOR]

Highlights: Poly(propylene glycol) bis(2-aminopropyl ether) (PEA) additive is introduced into the perovskite solar cells to passivate both surface and grain boundary defects, and hence improve the device efficiency and stability. MAPbI3 device with PEA exhibits significantly enhanced efficiency of 18.87%. (FAPbI3)1-x(MAPbBr3)x device with PEA exhibits enhanced efficiency of 21.60%. The unsealed passivated device degrades only by 5% in PCE after being exposed to air (30 ± 5% relative humidity) for 30 days. Perovskite solar cells (PSCs) are regarded as promising candidates for future renewable energy production. High-density defects in the perovskite films, however, lead to unsatisfactory device performances. Here, poly(propylene glycol) bis(2-aminopropyl ether) (PEA) additive is utilized to passivate the trap states in perovskite. The PEA molecules chemically interact with lead ions in perovskite, considerably passivate surface and bulk defects, which is in favor of charge transfer and extraction. Furthermore, the PEA additive can efficiently block moisture and oxygen to prolong the device lifetime. As a result, PEA-treated MAPbI3 (MA: CH3NH3) solar cells show increased power conversion efficiency (PCE) (from 17.18 to 18.87%) and good long-term stability. When PEA is introduced to (FAPbI3)1-x(MAPbBr3)x (FA: HC(NH2)2) solar cells, the PCE is enhanced from 19.66 to 21.60%. For both perovskites, their severe device hysteresis is efficiently relieved by PEA. [ABSTRACT FROM AUTHOR]

Adding a small amount of CsI into mixed cation‐halide perovskite film via a one‐step method has been demonstrated as an excellent strategy for high‐performance perovskite solar cells (PSCs). However, the one‐step method generally relies on an antisolvent washing process, which is hard to control and not suitable for fabricating large‐area devices. Here, CsF is employed and Cs is incorporated into perovskite film via a two‐step method. It is revealed that CsF can effectively diffuse into the PbI2 seed film, and drastically enhances perovskite crystallization, leading to high‐quality Cs‐doped perovskite film with a very long photoluminescence carrier lifetime (1413 ns), remarkable light stability, thermal stability, and humidity stability. The fabricated PSCs show power conversion efficiency (PCE) of over 21%, and they are highly thermally stable: in the aging test at 60 °C for 300 h, 96% of the original PCE remains. The CsF incorporation process provides a new avenue for stable high‐performance PSCs. [ABSTRACT FROM AUTHOR]