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Mixed‐halide perovskites are emerging as excellent photovoltaic candidates because of their tunable bandgaps for semitransparent and tandem perovskite solar cells. However, the notorious film quality originated from the rapidly downward crystallization process susceptibly propagates enormous detrimental defects, which deteriorate the photovoltaic performance and accelerate halide segregation. To address this issue, herein, a multilayer alkalis‐intercalated‐vermiculite is employed as pre‐buried interface modifier to regulate the perovskite lattice property. The matchable lattice structure between perovskite and vermiculite by forming Pb─O bond not only releases the interfacial strain during the film growth but also the embedded alkalis ions can gradually diffuse into perovskite lattice to form a favorable vertical gradient owing to the weak interlamellar van der Waals interaction, playing bis‐roles of atomical lubricant and ion‐reservoir to eliminate detrimental defects. As a result, the film quality and lattice stability is significantly improved with suppressed phase segregation for mixed‐halide perovskites, accompanying a champion efficiency of 11.42% for carbon‐based CsPbIBr2 device, 15.25% for carbon‐based CsPbI2Br device and 23.17% for p‐i‐n inverted (Cs0.05MA0.05FA0.9)Pb(I0.93Br0.07)3 cell. This work provides a new strategy on buried interface engineering for making high‐efficiency and stable perovskite platforms. [ABSTRACT FROM AUTHOR]

Active oxygen highly affects the efficiency and stability of perovskite solar cells (PSCs) owing to the capacity to either passivate defects or decompose perovskite lattice. To better understand the in‐depth interaction, we demonstrate for the first time that photooxidation mechanism in all‐inorganic perovskite film dominates the phase deterioration kinetics by forming superoxide species in the presence of light and oxygen, which is significantly different from that in organic‒inorganic hybrid and even tin‐based perovskites. In all‐inorganic perovskites, the superoxide species prefer to oxidize longer and weaker Pb‒I bond to PbO and I2, leaving the much stable CsPbBr3 phase. From this chemical proof‐of‐concept, we employ an organic bioactive factor, Tanshinone IIA, as a superoxide sweeper to enhance the environmental tolerance of inorganic perovskite, serving as a "skincare" agent for anti‐aging organisms. Combined with another key point on healing defective lattice, the best carbon‐based all‐inorganic CsPbI2Br solar cell delivers an efficiency as high as 15.12% and superior stability against oxygen, light, humidity, and heat attacks. This method is also applicable to enhance the efficiency of p‒i‒n inverted (Cs0.05MA0.05FA0.9)Pb(I0.93Br0.07)3 cell to 23.46%. These findings not only help us understand the perovskite decomposition mechanisms in depth but also provide a potential strategy for advanced PSC platforms. [ABSTRACT FROM AUTHOR]

Suppressing nonradiative recombination and releasing residual strain are prerequisites to improving the efficiency and stability of perovskite solar cells (PSCs). Here, long‐chain polyacrylic acid (PAA) is used to reinforce SnO2 film and passivate SnO2 defects, forming a structure similar to "reinforced concrete" with high tensile strength and fewer microcracks. Simultaneously, PAA is also introduced to the SnO2/perovskite interface as a "buffer spring" to release residual strain, which also acts as a "dual‐side passivation interlayer" to passivate the oxygen vacancies of SnO2 and Pb dangling bonds in halide perovskites. As a result, the best inorganic CsPbBr3 PSC achieves a champion power conversion efficiency of 10.83% with an ultrahigh open‐circuit voltage of 1.674 V. The unencapsulated PSC shows excellent stability under 80% relative humidity and 80°C over 120 days. [ABSTRACT FROM AUTHOR]

Alkylamines with different chain lengths including n-butylamine, n-hexylamine, and n-octylamine, are applied to regulate the CsPbIBr2 perovskite film quality by strain engineering. The status of residual strains is controllably modulated, resulting in improved efficiency and stability of carbon-based hole-transport-material free CsPbIBr2 perovskite solar cells. [ABSTRACT FROM AUTHOR]

Wide‐bandgap (WBG) perovskite solar cells (PSCs) are acknowledged as promising candidates for tandem solar cells and building photovoltaics. It is well known that cesium‐based all‐inorganic halide WBG perovskites possess the comparable optoelectronic properties as the organic–inorganic counterparts, but exhibit superior thermal stability. Among them, CsPbIBr2 is considered a feasible material for tandem solar cells after balancing the bandgap and stability of the inorganic perovskite. However, CsPbIBr2 PSCs are often subjected to drastic interfacial charge recombination especially in carbon‐based device structure derived from the chemical bonding defects (i.e., uncoordinated Pb2+) naked on CsPbIBr2 soft lattice, which dramatically limits overall efficiency of CsPbIBr2 WBG PSCs. Herein, a trimethyl ammonium salt hexyltrimethylammonium bromide is presented for CsPbIBr2/carbon interfacial modification. Benefiting from the −N+(CH3)3 passivation effect and −C6H13 hydrophobic alkyl chain, the optimal device with highly smooth morphology and sufficient charge extraction exhibits a champion power conversion efficiency of 11.24% and improved long‐term stability with 99.7% and 79.7% efficiency retention under dry air atmosphere and continuous 85 °C thermal stress, indicating the valuable potential application of the lattice solidified CsPbIBr2 WBG PSCs. [ABSTRACT FROM AUTHOR]

Heat accumulation within in‐service perovskite solar cells (PSCs) under light irradiation is one imminent threat in deteriorating the persistent power output and long‐term durability. Herein, a novel strategy is reported to remove dissipated heat by improving the thermal conductivity and thermal diffusivity of perovskite film with multi‐walled carbon nanotubes (MWCNTs) as additives. Benefiting from the interaction between perovskite and MWCNTs as well as the accelerated heat transfer kinetics mediated by MWCNTs, this method produces a high‐quality perovskite film with high crystallinity and reduced defects. Meanwhile, the incorporation of MWCNTs self‐cools the operational temperature of final PSC from 42.5 to 38.5 °C to compensate the high temperature‐induced performance reduction. Consequently, a significantly improved efficiency of 11.78% for carbon‐based CsPbIBr2 cell, 15.14% for carbon‐based CsPbI2Br cell, 22.13% and 23.05% for regular and inverted (FA0.83MA0.17)0.95Cs0.05Pb(I0.9Br0.1)3 cells, respectively, is achieved. Apart from the larger power conversion efficiency conservation rate > 94% over 2800 h in air without encapsulation, the optimal device demonstrates significant stability improvement by nearly 1.5‐times after thermal aging at 85 °C for 1300 h and 40‐fold after persistent operation for 350 h, providing a new path for high‐efficiency and stable perovskite platforms. [ABSTRACT FROM AUTHOR]

Bandgap‐tunable mixed‐halide perovskite materials have attracted considerable interest because of their indispensability as top counterparts in tandem solar cells. However, the soft and disordered lattice always suffers from severe phase segregation under illumination, which is particularly susceptible to residual lattice strain. Herein, we report a strain regulation strategy by using alkenamides terminated Ti3C2Tx MXenes as an additive into perovskite precursor. Apart from the role of a template for grain growth to obtain high‐quality films, the stretchable alkyl chain promotes lattice shrinkage or expansion to form an elastic grain boundary to eliminate the spatially distributed stain and shut down ion migration channels. As a result, the all‐inorganic perovskite solar cells based on CsPbIBr2 and CsPbI2Br halides achieve prolonged device stability under harsh conditions and the best power conversion efficiencies up to 11.06% and 14.30%, respectively. [ABSTRACT FROM AUTHOR]

Severe nonradiative recombination and energy level mismatch in perovskite solar cells (PSCs) are key factors affecting efficiency. Here, we report an effective strategy for surface passivation and interfacial dipole engineering of perovskite films. By precisely introducing electron-withdrawing and electron-donating groups on 7-azaindole, we have effectively controlled the passivation ability of N atoms and the polarity of the interfacial dipole, thereby regulating the perovskite surface's work function and obtaining the optimal energy level matching. This strategy yields an impressive efficiency of 10.76% for the CsPbBr3 PSC and exceptional stability. [ABSTRACT FROM AUTHOR]

All-inorganic CsPbBr3 perovskite solar cells (PSCs) without hole-transport materials (HTMs) have attracted widespread attention because of their significant environmental stability. However, the poor quality of perovskite film and the energetics mismatch between CsPbBr3 and charge-transport layers limit the further improvement of the CsPbBr3 PSC performance. To solve this issue, the synergistic effect of alkali metal doping and thiocyanate passivation in NaSCN and KSCN dopants is utilized to improve the properties of the CsPbBr3 film. The Na+ and K+ with smaller ionic radii are doped at the A-site of CsPbBr3 to cause a lattice contraction, which contributes to the formation of CsPbBr3 film with enhanced grain size and crystallinity. The SCN− exerts the function of passivating the uncoordinated Pb2+ defects of CsPbBr3 film, leading to a reduction of trap state density. The incorporation of NaSCN and KSCN dopants also adjusts the band structure of CsPbBr3 film to improve the interfacial energetics match of the device. As a result, the charge recombination is suppressed, and the charge transfer and extraction are effectively promoted, delivering a highly enhanced power conversion efficiency of 10.38% for the champion KSCN doped CsPbBr3 PSCs without HTMs compared to 6.72% efficiency for the original device. Moreover, the stability of the unencapsulated PSCs under ambient conditions with high humidity (85% RH, 25 °C) is distinctly improved, retaining 91.1% of the initial efficiency after 30 days of aging. [ABSTRACT FROM AUTHOR]

All-inorganic CsPbBr3 perovskite solar cells have received growing attention in the photovoltaic field due to their high stability, low cost, and simple preparation processes. However, the high-density defects in perovskite films and the large energy differences at interfaces have been the main challenges for achieving high power conversion efficiency and good stability. In this work, nickel oxide (NiOx) decorated graphene oxide (GO) is used as a hole collector at the perovskite/carbon interface for a carbon-based CsPbBr3 perovskite solar cell. The crystallinity of the CsPbBr3 perovskite layer and the hole extraction ability are markedly enhanced because of the p-type charge transfer doping of GO from oxygenic groups to NiOx. Finally, the all-inorganic CsPbBr3 perovskite solar cell achieves a power conversion efficiency of 8.59%. More importantly, the best solar cell free of encapsulation retains 94.2% of its initial efficiency in an air environment over 21 days. [ABSTRACT FROM AUTHOR]

A photovoltaic–hydrovoltaic-coupled carbon-based, all-inorganic Cs0.91Rb0.09PbBr3 perovskite solar cell achieved a peak power conversion efficiency of 9.40% under one sun illumination and a maximum voltage of 0.39 V and current of 1.40 μA in a flowing vapor atmosphere. [ABSTRACT FROM AUTHOR]

A perovskite layer functionalized to be an outermost screen can strongly affect the capacity of the underlying device to avoid becoming decomposed under external stimuli, and subsequently affect the photovoltaic performance as well. Herein, we report an interface-stabilization strategy for an all-inorganic CsPbIBr2 film involving forming in situ an inorganic ZrO2 layer to solidify the soft perovskite lattice. As a result of defect passivation and self-encapsulation, the best device achieved an enhanced efficiency of up to 10.12%, which was much higher than the 7.47% efficiency for the reference device tested, with prolonged stability under conditions of persistent light irradiation and exposure to air. [ABSTRACT FROM AUTHOR]

One of the key problems to improving the performance of a typical perovskite solar cell (PSC) is to minimize the defect‐determined nonradiative recombination. So far, the cutting‐edge strategies mainly focus on the film‐scale defect manipulation at grain boundaries and surfaces by trial‐and‐error, but the intrinsic passivation mechanism and fundamental guideline in the perspective of crystal lattices are still unclear. Herein, a much lower defect formation energy of PbBr antisite defect at (110) plane than that at (h00) planes is demonstrated by theoretically studying the crystal plane‐dependent defect density in an inorganic CsPbBr3 film, and then the authors precisely control the plane growth by selectively anchoring (pseudo‐) halide anions from ionic liquids to (110) plane. Because of the different adsorption energies on various planes, the growth of defective (110) plane is suppressed, leading to the formation of (h00) plane‐oriented film. Finally, the all‐inorganic CsPbBr3 PSC passivated by ionic liquid EMImCl delivers the best efficiency of 10.71% with an open‐circuit voltage up to 1.650 V. This work provides an in‐depth insight into defect formation and passivation mechanism to stabilize perovskite photovoltaics. [ABSTRACT FROM AUTHOR]

All‐inorganic CsPbIBr2 perovskite solar cells (PSCs) recently demonstrated great superiority for application in tandem and semitransparent photovoltaics because of their excellent phase stability. However, compared to state‐of‐the‐art PSCs, the inferior film quality is harmful for the photovoltaic performance improvement. Herein, a novel ionic additive, tetrabutylammonium hexafluorophosphate (TBAPF6), is employed to improve the all‐inorganic CsPbIBr2 perovskite film quality and passivate detrimental defects. By assembly into carbon–electrode‐based solar cells, a champion efficiency as high as 10.57% is achieved, which is much higher than that of a control device with 8.30% efficiency, mainly attributed to the suppressed non‐radiative recombination. More importantly, the presence of alkyl chains and fluorine atoms in TBAPF6 significantly increases the hydrophobicity of perovskite films and therefore improves the long‐term stability under harsh conditions without encapsulation. [ABSTRACT FROM AUTHOR]

The crystal distortion such as lattice strain and defect located at the surfaces and grain boundaries induced by soft perovskite lattice highly determines the charge extraction‐transfer dynamics and recombination to cause an inferior efficiency of perovskite solar cells (PSCs). Herein, the authors propose a strategy to significantly reduce the superficial lattice tensile strain by means of incorporating an inorganic 2D Cl‐terminated Ti3C2 (Ti3C2Clx) MXene into the bulk and surface of CsPbBr3 film. Arising from the strong interaction between Cl atoms in Ti3C2Clx and the under‐coordinated Pb2+ in CsPbBr3 lattice, the expanded perovskite lattice is compressed and confined to act as a lattice "tape", in which the PbCl bond plays a role of "glue" and the 2D Ti3C2 immobilizes the lattice. Finally, the defective surface is healed and a champion efficiency as high as 11.08% with an ultrahigh open‐circuit voltage up to 1.702 V is achieved on the best all‐inorganic CsPbBr3 PSC, which is so far the highest efficiency record for this kind of PSCs. Furthermore, the unencapsulated device demonstrates nearly unchanged performance under 80% relative humidity over 100 days and 85 °C over 30 days. [ABSTRACT FROM AUTHOR]

We present the fabrication of electron-rich Pt3M alloy-tailored carbon electrodes to maximize hole extraction. Through optimizing the doses and alloy species systematically, the best all-inorganic CsPbBr3 perovskite solar cell achieved a power conversion efficiency of 9.08% and showed excellent long-term stability at 80% RH over 20 days. [ABSTRACT FROM AUTHOR]

The passivation of defects at perovskite films, surfaces and the promotion of charge extraction across perovskite/carbon back interface are of vital importance to develop the power conversion efficiency (PCE) and stability of carbon‐based perovskite solar cells (PSCs) free of hole‐transporting layers (HTLs). Herein, an electron donor material with polyamino groups, hexamethylenetetramine (HMTA), is used as an efficient surface modifier for tribrominated all‐inorganic perovskite films. The modification with HMTA not only eliminates the defects by forming a bond between N atoms and positively charged ions but also optimizes the energy level structure of the perovskite film and back interface contact. Therefore, CsPbBr3 films with decreased trap states, extended carrier lifetimes, and enhanced hole mobility are gained, which significantly restrains charge recombination and energy loss as well as facilitates charge extraction and transfer at the perovskite/carbon interface. Finally, an improvement of PCE from 6.75% to 10.08% is obtained for carbon‐based HTL‐free CsPbBr3 PSCs without and with HMTA modification, respectively. Furthermore, the HMTA‐modified device without encapsulation presents an enhanced long‐term moisture and heat stability after being stored in the atmospheric environment with 80% relative humidity (RH) at 25 °C and 20% RH at 85 °C, respectively, due to the reduced defects and the improved hydrophobicity of perovskite film. [ABSTRACT FROM AUTHOR]

The precise regulation of interfacial charge distribution highly determines the power conversion efficiency of perovskite solar cells (PSCs). Herein, inorganic (NiCo)1−yFeyOx nanoparticle decorated graphene oxide (GO) is successfully demonstrated as a hole booster for all‐inorganic CsPbIBr2 PSC free of precious metal electrode. Arising from the spontaneous electron transfer induced p‐type doping of GO from edged oxygen‐containing functional groups to (NiCo)1−yFeyOx, the best all‐inorganic CsPbIBr2 PSC achieves an efficiency of 10.95 % under one standard sun owing to the eliminated paradox between charge extraction and charge localization in GO surface. Furthermore, the champion device exhibits an excellent long‐term stability at 10 % relative humidity without encapsulation over 70 days because of the suppressed ions migration. [ABSTRACT FROM AUTHOR]

High‐quality perovskite films with low imperfections, high hole mobility, and matching energy levels play a crucial role in enhancing performance of perovskite solar cells (PSCs) without hole‐transporting materials (HTMs). Herein, it is demonstrated that the incorporation of a stable tetra‐bisphenol A (TBBPA) with diphenyl ring, polybromides, and hydroxyl groups additive into a perovskite film can simultaneously manipulate the crystal growth and passivate the defects through coordination interaction between the functional group (OH, Br) and the unsaturated halogen and metal ions (Br−, Cs+, and Pb2+), resulting in a reduced grain boundary as well as imperfection and increased hole mobility of the CsPbBr3 perovskite film. In addition, the valence band of a perovskite film with TBBPA additive is shifted upward to approach the work function of the carbon electrode, thereby improving the energy level alignment. Consequently, a significantly boosted charge extraction and reduced charge recombination of the carbon‐based HTM‐free CsPbBr3 PSCs is obtained after incorporating the TBBPA additive, yielding a maximum power conversion efficiency of up to 9.82% of the optimized device. Furthermore, the champion PSC without encapsulation displays a remarkable thermal and moisture stability after being kept in ambient air for 720 h at 85 °C and 85% relative humidity, respectively. [ABSTRACT FROM AUTHOR]

All‐inorganic CsPbBr3 perovskite solar cells (PSCs) have attracted tremendous attention, owing to their excellent stability and rising power conversion efficiency. However, the mechanical flexibility of these solar cells has ground to a standstill because of the high‐temperature requirement for ideal CsPbBr3 perovskite films. In this study, a flexible CsPbBr3 PSC with an efficiency of 5.71 % has been made by means of fabricating a heat‐resistant conductive muscovite substrate, which demonstrates very high mechanical flexibility with nearly unchanged resistance even after 4000 bending cycles (12000 cycles of concave and convex bending for PSCs), owing to the weak van der Waals force and layered structure. Implementation of the muscovite substrate enables the fabrication of flexible PSCs under high‐temperature conditions, providing a new path to increase the efficiency without lowering the crystallization temperature of state‐of‐the‐art electron‐transporting materials and perovskite films in the future. [ABSTRACT FROM AUTHOR]

Perovskite lattice distortion induced by residual tensile strain from the thermal expansion mismatch between the electron‐transporting layer (ETL) and perovskite film causes a sluggish charge extraction and transfer dynamics in all‐inorganic CsPbBr3 perovskite solar cells (PSCs) because of their higher crystallization temperatures and thermal expansion coefficients. Herein, the interfacial strain is released by fabricating a WS2/CsPbBr3 van der Waals heterostructure owing to their matched crystal lattice structure and the atomically smooth dangling bond‐free surface to act as a lubricant between ETL and CsPbBr3 perovskite. Arising from the strain‐released interface and condensed perovskite lattice, the best device achieves an efficiency of 10.65 % with an ultrahigh open‐circuit voltage of 1.70 V and significantly improved stability under persistent light irradiation and humidity (80 %) attack over 120 days. [ABSTRACT FROM AUTHOR]

Carbon‐based CsPbBr3 perovskite solar cells (PSCs) without hole‐transporting layers (HTLs) have aroused extensive attention due to their low manufacturing cost and prominent ambient stability. However, the defects of perovskite film and the poor charge extraction within PSCs result in severe charge recombination, which restricts the further enhancement of device efficiency. In view of this critical point, a compositional engineering of CsPbBr3 perovskite via doping with Cl− ions is presented herein to decrease the trap states and enhance the charge extraction. It is revealed that the doping of Cl− ions not only enlarges the grain size and thereby reduces the trap‐state density, but also optimizes the energy‐level alignment and improves the hole mobility of the perovskite film, leading to an evidently suppressed charge recombination and improved charge extraction and transportation. As a result, a champion power conversion efficiency (PCE) of 9.73% is achieved for carbon‐based HTL‐free CsPbBr2.98Cl0.02 PSC, yielding a marked enhancement in comparison with 6.69% efficiency for the control. Meanwhile, the thermal and moisture stabilities of unencapsulated CsPbBr2.98Cl0.02 PSC are improved, maintaining 93% and 95% of the initial PCE after expose to air atmosphere with 80% relative humidity (RH) and at 80 °C over 60 days, respectively. [ABSTRACT FROM AUTHOR]

The preparation of high‐quality perovskite films with low grain boundaries and defect states is a prerequisite for achieving high‐efficiency perovskite solar cells (PSCs) with good environmental stability. An effective additive engineering strategy has been developed for simultaneous defect passivation and crystal growth of CsPbBr3 perovskite films by introducing 1,3,5‐triazine‐2,4,6‐triamine (melamine) into the PbBr2 precursor solution. The resultant melamine–PbBr2 film has a loose, large‐grained structure and decreased crystallinity, which has a positive effect on the crystallization process of the perovskite as it retards the crystallization rate as a result of the interaction between melamine and lead ions. Additionally, the passivation by melamine gives a high‐quality CsPbBr3 perovskite film with fewer grain boundaries, lower defect densities, and better energy level matching is achieved by multistep liquid‐phase spin‐coating, which greatly suppresses the nonradiative recombination resulting from the defects and promotes charge extraction at the interface. A champion power conversion efficiency as high as 9.65 % with a promising open‐circuit voltage of 1.584 V is achieved for PSCs with an architecture of fluorine‐doped tin oxide/c‐TiO2/m‐TiO2/melamine‐added CsPbBr3/carbon‐based hole‐transporting layer. Furthermore, the unencapsulated melamine‐added CsPbBr3 PSC shows superior thermal and humidity stability in ambient air at 85 °C or 85 % relative humidity over 720 h. [ABSTRACT FROM AUTHOR]

Improved charge extraction and wide spectral absorption promote power conversion efficiency of perovskite solar cells (PSCs). The state‐of‐the‐art carbon‐based CsPbBr3 PSCs have an inferior power output capacity because of the large optical band gap of the perovskite film and the high energy barrier at perovskite/carbon interface. Herein, we use alkyl‐chain regulated quantum dots as hole‐conductors to reduce charge recombination. By precisely controlling alkyl‐chain length of ligands, a balance between the surface dipole induced charge coulomb repulsive force and quantum tunneling distance is achieved to maximize charge extraction. A fluorescent carbon electrode is used as a cathode to harvest the unabsorbed incident light and to emit fluorescent light at 516 nm for re‐absorption by the perovskite film. The optimized PSC free of encapsulation achieves a maximum power conversion efficiency up to 10.85 % with nearly unchanged photovoltaic performances under 80 %RH, 80 °C, or light irradiation in air. [ABSTRACT FROM AUTHOR]

The all‐inorganic CsPbBr3 perovskite solar cell (PSC) is a promising solution to balance the high efficiency and poor stability of state‐of‐the‐art organic–inorganic PSCs. Setting inorganic hole‐transporting layers at the perovskite/electrode interface decreases charge carrier recombination without sacrificing superiority in air. Now, M‐substituted, p‐type inorganic Cu(Cr,M)O2 (M=Ba2+, Ca2+, or Ni2+) nanocrystals with enhanced hole‐transporting characteristics by increasing interstitial oxygen effectively extract holes from perovskite. The all‐inorganic CsPbBr3 PSC with a device structure of FTO/c‐TiO2/m‐TiO2/CsPbBr3/Cu(Cr,M)O2/carbon achieves an efficiency up to 10.18 % and it increases to 10.79 % by doping Sm3+ ions into perovskite halide, which is much higher than 7.39 % for the hole‐free device. The unencapsulated Cu(Cr,Ba)O2‐based PSC presents a remarkable stability in air in either 80 % humidity over 60 days or 80 °C conditions over 40 days or light illumination for 7 days. [ABSTRACT FROM AUTHOR]

We present here the construction of all-inorganic bifacial CsPbBr3 perovskite solar cells to harvest solar energy from both sides. The quantum dot modified bifacial device achieves front and rear efficiencies of 7.55% and 7.44% under one sun illumination, respectively. The solar cell without encapsulation retains around 95% of the initial efficiency at 60% RH over a period of 1000 h. [ABSTRACT FROM AUTHOR]

Abstract: Moisture is the worst enemy for state‐of‐the‐art perovskite solar cells (PSCs). However, the flowing water vapor within nanoporous carbonaceous materials can create potentials. Therefore, it is a challenge to integrate water vapor and solar energies into a single PSC device. We demonstrate herein all‐inorganic cesium lead bromide (CsPbBr3) solar cells tailored with carbon electrodes to simultaneously harvest solar and water‐vapor energy. Upon interfacial modification and plasma treatment, the bifunctional PSCs yield a maximum power conversion efficiency up to 9.43 % under one sun irradiation according to photoelectric conversion principle and a power output of 0.158 μW with voltage of 0.35 V and current of 0.45 μA in 80 % relative humidity through the flowing potentials at the carbon/water interface. The initial efficiency is only reduced by 2 % on exposing the inorganic PSC with 80 % humidity over 40 days. The successful realization of physical proof‐of‐concept multi‐energy integrated solar cells provides new opportunities of maximizing overall power output. [ABSTRACT FROM AUTHOR]

Abstract: All‐inorganic CsPbX3 (X=I, Br) perovskite solar cells are regarded as cost‐effective and stable alternatives for next‐generation photovoltaics. However, sluggish charge extraction at CsPbX3/charge‐transporting material interfaces, which arises from large interfacial energy differences, have markedly limited the further enhancement of solar cell performance. In this work, the work function (WF) of the back electrode is tuned by doping alloyed PtNi nanowires in carbon ink to promote hole extraction from CsPbBr3 halides, while an intermediate energy by setting carbon quantum dots (CQDs) at TiO2/CsPbBr3 interface bridges electron transportation. The preliminary results demonstrate that the matching WFs and intermediate energy level markedly reduce charge recombination. A power conversion efficiency of 7.17 % is achieved for the WF‐tuned all‐inorganic perovskite solar cell, in comparison with 6.10 % for the pristine device, and this is further increased to 7.86 % by simultaneously modifying with CQDs. The high efficiency and improved stability make WF‐controlled all‐inorganic perovskite solar cells promising to develop advanced photovoltaic platforms. [ABSTRACT FROM AUTHOR]

Abstract: All‐inorganic perovskite solar cells with high efficiency and improved stability are promising for commercialization. A multistep solution‐processing method was developed to fabricate high‐purity inorganic CsPbBr3 perovskite films for use in efficient solar cells. By tuning the number of deposition cycles (n) of a CsBr solution, the phase conversion from CsPb2Br5 (n ≤3), to CsPbBr3 (n=4), and Cs4PbBr6 (n≥5) was optimized to achieve vertical‐ and monolayer‐aligned grains. Upon interfacial modification with graphene quantum dots, the all‐inorganic perovskite solar cell (without a hole‐transporting layer) achieved a power conversion efficiency (PCE) as high as 9.72 % under standard solar illumination conditions. Under challenging conditions, such as 90 % relative humidity (RH) at 25 °C or 80 °C at zero humidity, the optimized device retained 87 % PCE over 130 days or 95 % over 40 days, compared to the initial efficiency. [ABSTRACT FROM AUTHOR]

Application-specific requirements for future perovskite solar cells include lightweight, mechanical resilience, and deformability for multi-purpose utilizations ranging from electronic skin and implant in the body to wearable textiles. Here we demonstrate the experimental realization of intrinsically bendable, stretchable, twistable, and compressible perovskite solar cells made by adsorbing hole-transporting polyaniline, solvothermal-processed halide (5-AVA) y (CH 3 NH 3 ) 1−y PbI 3 or (5-AVA) y (CH 3 NH 3 ) 1−y PbI 3−x Cl x precursor as well as electron-transporting [6,6]-phenyl-C61-butyric acid methyl with three-dimensional amphiphilic gel matrix. The multi-deformable perovskite solar cell with CH 3 NH 3 PbI 3 crystals yields a power conversion efficiency of 3.62% at undeformed state and AM1.5 G sunlight irradiation, while the efficiency can increase to 4.51% at a bending angle of 140°, to 4.46% at an elongation of 220%, to 5.10% at a twist angle of 360°, and to 5.57% at a compression ratio of 80%. After hundreds of arbitrary deformations, the solar cell still remains ~130% efficiency. Owing to an amphiphilic surface, the solar cell is relatively stable for 7 days when exposed in 78%-humidity ambient air. This work represents a significant step forward, as it realizes the solvothermal synthesis of halide CH 3 NH 3 PbX 3 (X=I, Cl) precursors and low-temperature fabrication, arbitrary deformations without sacrificing power conversion efficiency along with promising humidity-resistance in ambient atmosphere for perovskite solar cells. [ABSTRACT FROM AUTHOR]

Enhancement of light harvesting has been a persistent objective for elevating dye excitation and therefore power conversion efficiency of dye-sensitized solar cells (DSSCs). Here we launch a strategy of markedly enhancing light harvesting by caging TiO 2 nanoparticles with curved silica microsheets. The results show that the strategy is versatile in suppressing the recombination reaction of electrons with I 3 − species in liquid electrolyte. Due to the superior reflective behaviors of curved silica microsheets, an optimal efficiency of 9.22% is recorded under simulated air mass 1.5 global sunlight on the DSSC in comparison with 6.51% and 7.51% from pristine TiO 2 and planar silicate microsheet incorporated TiO 2 photoanode based solar cells, respectively. This strategy is also believed to be applicable to other solar cells such as perovskite solar cells and quantum dot-sensitized solar cells. [ABSTRACT FROM AUTHOR]

The power conversion efficiency (PCE) of state‐of‐the‐art perovskite solar cells (PSCs) with mesoscopic titanium dioxide (TiO2) has rushed to 23.7% in recent years. However, photodegradation of perovskites under illumination (including ultraviolet light), assisted by TiO2, significantly reduces the long‐term stability of the corresponding device, which in turn limits the commercialization of PSCs. Owing to the advantages of high electron mobility, wide bandgap, high transparency, and good photostability, nanostructured tin oxide (SnO2) is demonstrated to be a more promising electron‐transporting material for planar PSCs. Herein, low‐temperature solution‐processed SnO2 quantum dots (QDs) are employed as the electron transport layer (ETL) for all‐inorganic cesium lead bromide (CsPbBr3) PSC applications. Through optimizing the aging time of SnO2 QDs and adding a hole transport layer (HTL) of CsMBr3 (M = Sn, Bi, Cu) QDs between the CsPbBr3 layer and carbon electrode, the all‐inorganic PSC with a structure of FTO/SnO2/CsPbBr3/CsMBr3/carbon achieves a good PCE of 10.60% with an ultrahigh open‐circuit voltage up to 1.610 V. These optimized devices, free of encapsulation, present excellent stability in 80% humidity or temperature of 80 °C. The maximized PCE report to date and improved environmental‐tolerance for all‐inorganic CsPbBr3 solar cells provide new opportunities to dramatically promote the commercialization of PSC platforms. SnO2 QDs and CsMBr3 (M = Sn, Bi, Cu) QDs are applied as ETMs and HTMs for all‐inorganic CsPbBr3 PSCs, respectively. Arising from high optical transmittance and electron mobility of SnO2 QDs ETL as well as hole extraction of CsMBr3 QD HTL, the device achieves a good PCE of 10.60% and improved stability. [ABSTRACT FROM AUTHOR]

All‐inorganic cesium lead bromide (CsPbBr3) perovskite solar cells have attracted enormous attention owing to their outstanding stability in comparison with organic–inorganic hybrid devices. The greatest weakness for inorganic CsPbBr3 solar cells is their lower power conversion efficiencies, mainly arising from inferior light‐absorbance range and serious charge recombination at interfaces or within perovskite films. To address this issue, the lattice doping of lanthanide ions (Ln3+ = La3+, Ce3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Ho3+, Er3+, Yb3+, and Lu3+) into CsPbBr3 films for all‐inorganic solar cells free of hole‐transporting materials and precious metal electrodes is presented. Arising from the enlarged grain size and prolonged carrier lifetimes upon incorporating Ln3+ ions into perovskite lattice, the performances of these inorganic CsPbBr3 solar cell devices are significantly enhanced, achieving a champion efficiency as high as 10.14% and an ultrahigh open‐circuit voltage of 1.594 V under one sun illumination. Meanwhile, the nearly unchanged efficiency upon persistent attack by 80% RH in air atmosphere over 110 d and enhanced thermal stability at 80 °C over 60 d provide new opportunities of promoting commercialization of all‐inorganic CsPbBr3 perovskite solar cells. Lanthanide ions are doped into CsPbBr3 films to modulate crystal lattice for high‐performance all‐inorganic perovskite solar cells. Arising from the improved grain size and carrier lifetime, the solar cell achieves a champion power conversion efficiency of 10.14%, an ultrahigh Voc of 1.594 V, and excellent stability. [ABSTRACT FROM AUTHOR]

By converting the traditional solid–solid contact to solid–liquid contact, the buried interface of perovskite film is healed to release tensile strain and suppress halide segregation, which universally improves the efficiency and stability of a PSC. [Display omitted] • A universal liquid buried interface is fabricated to replace traditional solid–solid interface. • The weak van der Waals interaction releases the tensile strain. • A champion efficiency of 11.13 % and 14.05 % is achieved for CsPbIBr 2 and CsPbI 2 Br PSCs. • Suppressed halide segregation significantly improves the photostability of PSC. The residual tensile strain, which is induced by lattice and thermal expansion coefficient difference between upper perovskite film and underlying charge transporting layer, significantly deteriorates the power conversion efficiency (PCE) and stability of a halide perovskite solar cell (PSC). To overcome this technical bottleneck, herein, we propose a universal liquid buried interface (LBI) by introducing a low melting-point small molecule to replace traditional solid–solid interface. Arising from the movability upon solid-to-liquid phase conversion, LBI plays a role of "lubricant" to effectively free the soft perovskite lattice shrinkage or expansion rather than anchoring onto the substrate, leading to the reduced defects due to the healing of strained lattice. Finally, the inorganic CsPbIBr 2 PSC and CsPbI 2 Br cell achieve the best PCEs of 11.13 % and 14.05 %, respectively, and the photo-stability is improved by 33.3-fold because of the suppressed halide segregation. This work provides new insights on the LBI for making high-efficiency and stable PSC platforms. [ABSTRACT FROM AUTHOR]

Arising from the multiple light scattering sites, the regulation on perovskite film growth, Type-II band alignment and matched lattice spacing of 3D round-comb Fe 2 O 3 @SnO 2 composites, the light harvesting and charge extraction are significantly improved, which helps the CsPbBr 3 PSCs achieve a champion PCE of 10.23 % and excellent moisture tolerance. [Display omitted] The precise design of an electron transport layer (ETL) to improve the light-harvesting and quality of perovskite (PVK) film plays a crucial role in the photovoltaic performance of n-i-p perovskite solar cells (PSCs). In this work, a novel three-dimensional (3D) round-comb Fe 2 O 3 @SnO 2 heterostructure composites with high conductivity and electron mobility induced by its Type-II band alignment and matched lattice spacing is prepared and employed as an efficient mesoporous ETL for all-inorganic CsPbBr 3 PSCs. Arising from the multiple light scattering sites provided by the 3D round-comb structure, the diffuse reflectance of Fe 2 O 3 @SnO 2 composites is increased to improve the light absorption of the deposited PVK film. Besides, the mesoporous Fe 2 O 3 @SnO 2 ETL affords not only more active surface for sufficient exposure to the CsPbBr 3 precursor solution but also a wettable surface to reduce the barrier for heterogeneous nucleation, which realizes the regulated growth of a high-quality PVK film with less undesired defect. Hence, both the light-harvesting capability, the photoelectrons transport and extraction are improved, and the charge recombination is restrained, delivering an optimized power conversion efficiency (PCE) of 10.23 % with a high short-circuit current density of 7.88 mA cm−2 for the c -TiO 2 /Fe 2 O 3 @SnO 2 ETL based all-inorganic CsPbBr 3 PSCs. Moreover, under lasting erosion at 25 °C and 85 % RH for 30 days and light-soaking (AM 1.5G) for 480 h in air atmosphere, the unencapsulated-device shows superiorly persistent durability. [ABSTRACT FROM AUTHOR]

The integration of SWCNT and WO 3 passivates the defects of perovskite film and simultaneously improves carrier transport, interfacial energy level alignment and hole extraction, which helps the carbon-based all-inorganic CsPbBr 3 PSCs achieve a champion PCE up to 10.47% and excellent humidity-heat stability. [Display omitted] • The SWCNT with oxygen-containing edge groups heals the defects of perovskite film. • The incorporation of SWCNT improves the interfacial carriers transport and contact. • The integration of WO 3 with SWCNT lowers energy barrier for enhanced hole extraction. • The unsealed PSCs achieve a champion PCE of 10.47% and high humidity-heat stability. The construction of efficient interfacial charge transfer and extraction plays an essential role in improving the photovoltaic performance of perovskite solar cells (PSCs). Herein, the single-walled carbon nanotube (SWCNT) and WO 3 are integrated as a robust hole extractor for all-inorganic CsPbBr 3 PSCs. The introduction of SWCNT with high carrier transport behavior and numerous oxygen-containing edge groups not only promotes the hole transport from CsPbBr 3 film to carbon back electrode, but also passivates the metal ion defect states within the CsPbBr 3 film. The further integration of WO 3 hole transport materials compensates for the energy level gap between the perovskite film and the carbon electrode to decrease interfacial energy loss and boosts hole extraction. Benefiting from the collaborative promotion of charge transport and extraction by SWCNT and WO 3 , the tailored CsPbBr 3 PSCs without encapsulation achieve a champion power conversion efficiency of 10.47 % and a long-term stability with 91.3 % retention of the initial efficiency under high temperature and humidity conditions for 800 h. [ABSTRACT FROM AUTHOR]

[Display omitted] A perovskite nanocrystal-molecular hybrid is fabricated to heal the defective perovskite surface. Arising from the role of perovskite nanocrystals as electron and ion reservoirs simultaneously, the soft perovskite lattice is well solidified, significantly improving the efficiency and stability of all-inorganic CsPbI x Br 3-x perovskite solar cells. • An organic molecule bound CsPbBr 3 nanocrystal is fabricated to passivate the perovskite surface. • The passivation ability is enhanced owing to the energy transfer between nanocrystal and organic molecule. • A champion efficiency up to 11.60% for all-inorganic CsPbIBr 2 cell and 14.44% for CsPbI 2 Br cell is achieved. • The unencapsulated device shows excellent tolerance under harsh conditions. Electron cloud density around the functional group of Lewis-base molecule (passivator) highly determines the interaction strength with undercoordinated Pb2+ in perovskite film. With the aim to maximize this scenario, herein, we fabricate a thermally-activated delayed fluorescence molecule (3,4,5,6-tetrakis(3,6-diphenylcarbazol-9-yl)-1,2-dicyanobenzene, 4CzPN-Ph) bound CsPbBr 3 nanocrystal (NC) to heal the defective perovskite surface. Because of the suitable energy alignment, there is a Förster or Dexter triplet energy transfer process from CsPbBr 3 NC donor to 4CzPN-Ph acceptor under light irradiation, leading to the increased electron density within 4CzPN-Ph molecule and thus the enhanced passivation ability. Together with the formation of compositional gradient layer owing to the halide exchange reaction with CsPbBr 3 NCs, the stable perovskite film with reduced defect is obtained, consequently promoting the efficiency up to 11.60 % for CsPbIBr 2 and 14.44 % for CsPbI 2 Br carbon-based devices, with excellent durability under harsh conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Low edge defects of CQDs induced by MBA functionalization improve carrier transport. • The MBA/CQDs with high healing effect holistically passivate the defects of PVK film. • The deeper HOMO of MBA/CQDs reduces energy barrier for increased hole extraction. • The unsealed device achieves a best PCE of 10.40% and high humidity-heat stability. The effective improvement of interfacial charge extraction and inhibition of charge recombination are crucial for promoting the performance of perovskite (PVK) solar cells (PSCs). Here, the N,N'-methylenebisacrylamide-functionalized carbon quantum dots (MBA/CQDs) with defects passivation effect and appropriate energy levels are proposed as a back interface modifier for carbon-based CsPbBr 3 PSCs. The functionalization of MBA molecules not only increases the content of sp 2 hybrid carbon in CQDs, but also expands the passivation effect of CQDs on surface defects of PVK films by introducing carbonyl and amino groups, which improves the carrier transport and reduces the carrier nonradiative recombination. Additionally, the modification of MBA/CQDs provides an intermediate energy level at the PVK/carbon back interface, which boosts hole extraction and lowers energy loss. Finally, a leading-edge power conversion efficiency of 10.40 % is derived for the MBA/CQDs modified champion device, which is significantly improved compared to the 7.02 % efficiency for the original CsPbBr 3 PSCs. Furthermore, the unpackaged CsPbBr 3 PSCs with MBA/CQDs have an excellent stability, maintaining an initial efficiency of 92 % after 30 days of storage at high humidity (85 % relative humidity) and temperature (85 °C) in air. [ABSTRACT FROM AUTHOR]

The high-quality electron-transport layer (ETL) plays a vital role in boosting the power conversion efficient (PCE) of perovskite solar cells (PSCs). Herein, the lanthanide neodymium (Nd) is used as a dopant to incorporate into the lattice of TiO 2 to reduce the trap states and form a n-doping effect, resulting in an increase in electron mobility and conductivity of TiO 2 , an energy level of TiO 2 matching well with that of the perovskite layer. Moreover, the improved wettability of the Nd-TiO 2 film enables a fabrication of perovskite light-absorbing layer with high-quality. As a result, the all-inorganic CsPbBr 3 PSCs based on Nd-TiO 2 ETL achieve a champion PCE of 10.06% owing to the promotion of charge extraction and the inhibition of charge recombination, which is a significantly improved efficiency in comparison with the 6.57% value of the reference cell. Additionally, the target device without encapsulation displays an effectively enhanced stability with over 90% and 80% retention of the original efficiency after aging in ambient air with high humidity (80% RH, 25 °C) for 30 days and under AM 1.5 G illumination at 85 °C for 100 h, respectively. • The doping of Nd reduces the trap states of TiO 2 to improve electron extraction. • The E C upshift of Nd-TiO 2 lowers interface energy barrier to boost carrier transfer. • A high-quality perovskite film with fewer defects is formed on the Nd-TiO 2 ETL. • The unencapsulated CsPbBr 3 PSCs achieve a best PCE of 10.06% and excellent stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Residual strain is released via in-situ compensation by phase transformation strain. • The addition of DMSO optimizes PbBr 2 crystallization kinetics and film morphology. • CsPbBr 3 film quality is improved with 2.91 μm-grain size and reduced defect density. • The unsealed device achieves a best PCE of 10.11% and high moisture-heat stability. The presence of defects and residual tensile strain in perovskites has a significant and deleterious impact on the efficiency and stability of all-inorganic perovskite solar cells (PSCs). Here, dimethyl sulfoxide (DMSO) with strong polarity and high boiling point is introduced into the PbBr 2 precursor to delay the crystallization of PbBr 2 , leading to the formation of high-quality PbBr 2 films by delaying the solution reaching supersaturation. The formation of PbBr 2 (DMSO) adduct facilitates the complete reaction of PbBr 2 with CsBr via intramolecular exchange, thus preventing the formation of impurity phases such as CsPb 2 Br 5. As a result, the defect density of CsPbBr 3 films decreased by 33% due to the improved phase purity, thicker films, larger grain sizes, and reduced grain boundaries. The small porosity of PbBr 2 film combined with a more complete phase-conversion process results in an expanded perovskite film that experiences compressive strain, effectively compensating for the tensile strain generated during annealing and thereby achieving the goal of strain relaxation. The optimized DMSO-based device, which exhibits compressive strain and minimal defects, achieves a remarkable efficiency of 10.11% with an open-circuit voltage of up to 1.611 V. Additionally, the unencapsulated PSC demonstrates excellent stability under 80% relative humidity and 80 °C over 30 days. [ABSTRACT FROM AUTHOR]

Abstract Interfacial charge recombination seriously drags efficiency enhancement of all-inorganic perovskite solar cells (PSCs) because of large energy-level differences. Although CsPbBr 3-x I x light-harvesters markedly reduce interfacial charge recombination, the long-term stability of solar cell devices is still unsatisfactory to meet practical requirements. Here we present the improved charge extraction by setting an intermediated energy-level at CsPbBr 3 /carbon interface with colorful CsSnBr 3-x I x quantum dots (QDs). The charge extraction is maximized by tuning Br:I ratio, yielding a power conversion efficiency as high as 9.13% for CsSnBr 2 I QDs-tailored CsPbBr 3 solar cell. Moreover, all the devices show high stability in 80%RH or 80 °C over 720 h. The interfacial decoration of all-inorganic perovskite solar cells by lead-free perovskite QDs provides new opportunities of enhancing solar cell efficiency and reducing environmental impacts. Highlights • PQDs with tunable bandgaps are synthesized to modify CsPbBr 3 /carbon interface. • An intermediate energy level is set at CsPbBr 3 /carbon interface to extract holes. • The electron-hole recommendation is markedly restricted. • A maximized PCE of 9.13% is achieved for the PQDs tailored inorganic PSC. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Development of high-performance light harvesters is a persistent goal for mesoscopic solar cells. In the current work, lead-free CH 3 NH 3 SnBr 3-x I x (x = 0–3) perovskite quantum dots (QDs) are made by integrating Br − ions into host crystal structure. Through tuning Br/I ratio, these perovskite-structured QDs are highlighted with tunable optical bandgaps. When applied as light harvesters for mesoscopic solar cell applications, the devices yield reasonable power conversion efficiency and rapid start-up behaviors. An efficiency of 8.79% is achieved for CH 3 NH 3 SnBr 3-x I x QDs and N719 co-sensitized mesoscopic solar cells. [ABSTRACT FROM AUTHOR]

Photovoltaics are regarded as the promising solution to resolve energy and environmental problems owing to their high power conversion efficiency and zero emissions. However, the narrow-spectra absorption range and serious recombination reactions at electrode/electrolyte interfaces are two major drawbacks for high-performance solar cells. Herein, a new way of synthesizing organic-inorganic hybrid CH 3 NH 3 PbX 3 (X = Cl, Br or I) perovskite quantum dots (PQDs) is demonstrated by dropping perovskite precursor solution into anhydrous toluene. After a systematic study, the results demonstrate that the energy levels of PQDs can be tuned through optimizing the stoichiometric ratio of halide ions, showing good optical properties for photovoltaic applications. A quasi-solid-state sensitized solar cell with configuration of FTO/ m -TiO 2 /PQDs/dye/long persistence phosphor/gel electrolyte/Pt/FTO is fabricated, yielding an impressive power conversion efficiency as high as 7.91%, which is higher than 7.26% for referenced device free of PQDs. The improved performances are mainly attributed to the increased light absorption as well as reduced recombination upon the incorporation of PQDs and long persistence phosphor into devices. [ABSTRACT FROM AUTHOR]

Perovskite-structured CsPbBr 3 halide is an emerging light-harvester for all-inorganic solar cells due to its superior stability against moisture and heat. However, the wide bandgap of CsPbBr 3 (2.3 eV) calls for serious charge recombination and low efficiency in its photovoltaics. We present here all-inorganic CsPbBr 3 perovskite solar cells (PSCs) by modifying TiO 2 /CsPbBr 3 and CsPbBr 3 /carbon interfaces with carbon quantum dots (CQDs) and phosphorus quantum dots (PQDs), respectively. The electron and hole extractions are markedly enhanced by setting intermediate energy levels, and the optimized PSC achieves a power conversion efficiency of 7.93% in comparison with 6.05% for the device free of CQDs and PQDs. Moreover, the unsealed PSCs are highlighted by long-term stability in high humidity over 1400 h. This work may provide new opportunities of promoting charge extraction at CsPbBr 3 /charge-transporting material interfaces. [ABSTRACT FROM AUTHOR]

[Display omitted] • The PAMPS/NQDs with higher hole mobility and conductivity improves hole transport. • Modifying PAMPS/NQDs induced lower interfacial energy barrier boosts hole extraction. • The PAMPS/NQDs heals the defects of CsPbBr 3 film and enhances the hydrophobicity. • The unsealed device achieves a best PCE of 10.21% and excellent long-term stability. The regulation of the interface energetics and the simultaneous passivation of the surface defects of perovskite (PVK) film play an important role in improving the efficiency and stability of perovskite solar cells (PSCs). Here, a composite modification of poly(2-acrylamide-2-methylpropanesulfonic acid) (PAMPS)/NiFe 2 O 4 quantum dots (NQDs) that is formed by the light-triggered polymerization of AMPS monomer in homogeneous AMPS/NQDs is launched at the interface of PVK/carbon in all-inorganic CsPbBr 3 PSCs. Due to the higher hole mobility and conductivity of PAMPS/NQDs and its interface modification induced better energy level alignment and interfacial contact, the hole transport and extraction are significantly promoted. Combined with the simultaneous passivation of cations and anions (Cs+, Pb2+ and Br-) defects on CsPbBr 3 PVK surface by the S O, C O, N H and O H groups in PAMPS, the non-radiative recombination is effectively restrained, rendering a champion power conversion efficiency of 10.21 % with excellent high humidity and temperature (85 % RH, 85 °C) and light soaking tolerances for PAMPS/NQDs composite modified carbon-based CsPbBr 3 PSCs without encapsulation in air, which is markedly higher than the 6.81 % efficiency of the control device. [ABSTRACT FROM AUTHOR]

Through passivating interfacial defects and improving energy level alignment and perovskite quality, ASF as interface modifier helps all-inorganic CsPbBr 3 PSCs achieve a champion PCE of 10.08% and excellent moisture and heat tolerance. [Display omitted] • The interface modification of ASF passivates the defects of TiO 2 and perovskite. • The energy level alignment at TiO 2 /CsPbBr 3 interface is improved by modifying ASF. • A large-grained perovskite film is formed on the ASF-modified TiO 2 ETLs. • The ASF-modified CsPbBr 3 PSCs achieve a best PCE of 10.08% and excellent stability. The interfacial modification has been considered as an effective strategy to build high-efficient and stable perovskite solar cells (PSCs) by reducing the loss of charge recombination and energy at electron transport layers (ETLs)/perovskite interface. Here, a multifunctional inorganic salt of ammonium silicofluoride (ASF) is utilized as an interfacial modifier to incorporate at TiO 2 ETLs/CsPbBr 3 perovskite interface, which decreases the surface oxygen vacancy defects of TiO 2 by its bonding with silicofluoride anion and adjusts the energy level of TiO 2 by dipole effect to minimize interfacial band difference, resulting in a promotion of electrons extraction and a reduction of energy loss. Simultaneously, the ASF modification affords a more hydrophobic TiO 2 substrate for the constitution of perovskite film with larger crystal and passivates anion defects of CsPbBr 3 film via the formation of hydrogen bonds between the H atom in ammonium cations and Br atom in perovskite, which dramatically inhibits the recombination of carriers. Finally, the all-inorganic CsPbBr 3 PSCs based on the ASF-modified TiO 2 ETL achieves a remarkable higher power conversion efficiency of 10.08%, compared to 6.84% efficiency of the control device. In addition, the long-term tolerance of the device without encapsulation towards high humidity and high temperature is significantly enhanced after interface modifying with ASF. [ABSTRACT FROM AUTHOR]

By balancing the multidentate coordination sites and structure-steric hindrance of organic passivator, the bipyridine molecule enables an enhanced efficiency up to 11.04% with voltage of 1.301 V for all-inorganic CsPbIBr 2 perovskite solar cell, demonstrating the steric-charge-dependence of conjugated passivators on π-Pb2+ bond strength. [Display omitted] • Various π-conjugated pyridine derivatives are employed to passivate perovskite film. • The effect of steric-charge-dependence of passivators on films is revealed. • A high efficiency of 11.04% has been realized for carbon-electrode based CsPbIBr 2 PSC. • The stability is significantly enhanced under persistent irradiation and storage. Intramolecular structure of interfacial passivator highly determines the bond strength with detrimental defects located at perovskite surfaces and grain boundaries. Herein, we investigate the steric-charge-dependence of various π-conjugated pyridine derivatives on electron-donating ability to passivate inorganic CsPbIBr 2 perovskite film. The primary results demonstrate that the photovoltaic performances tightly correlate with the multidentate coordination sites and structure-steric hindrance because of their synergistic regulation on intramolecular electron-cloudy density and charge extraction. Comparing to pyridine and terpyridine treated devices, the bipyridine passivated device delivers an increased efficiency of 11.04% with a high open-circuit voltage of 1.301 V and improved stability after persistent irradiation over 20 h and storage for 60 days, which is one of the highest efficiencies for carbon-based all-inorganic CsPbIBr 2 solar cells. This work provides a direction to choose ideal passivator for high-efficiency perovskite optoelectronics. [ABSTRACT FROM AUTHOR]

The soft lattice induced defective nanostructured surface of perovskite film is effectively healed and solidified by organic S-benzylisothiourea hydrochloride, significantly improving the efficiency and stability of inorganic CsPbIBr 2 perovskite solar cells. [Display omitted] • An organic molecule is employed to heal the defective surface of perovskite film. • The regulated surface energetics boosts the charge transfer. • An efficiency of 10.56% has been achieved for HTM-free CsPbIBr 2 PSC. • The long-term stability is significantly improved under air condition. Interfacial regulation to heal the soft lattice induced defective nanostructured surfaces of perovskite films plays a crucial role in determining the stability and efficiency of perovskite solar cells (PSCs). Herein, we report a facile method to strengthen and passivate the inorganic PbI 2 -excess CsPbIBr 2 surface with a multifunctional S-benzylisothiourea hydrochloride (SBTCl), which not only significantly reduces the detrimental defects through interaction between electron-donating groups and defects (as well as Cl doping as lattice "glue") but also enables straightway unobstructed hole extraction and transfer arising from the reduced work function. Consequently, a higher efficiency of 10.56% with an open-circuit voltage of 1.327 V than control device with 7.72%-efficiency is obtained for inorganic CsPbIBr 2 PSC free of hole transporting material, which is one cutting-edge value in this kind of PSC. In addition, the high hydrophobicity of SBTCl passivator hinders the permeation of moisture into perovskite film, resulting in improved long-term air-stability after storage in 5% relative humidity (RH) without encapsulation over 110 days and persistent light irradiation over 16 h in 50% RH condition. [ABSTRACT FROM AUTHOR]

Through passivating defects, improving contact and energy level alignment by interface engineering of hydrophobic DCC, the HTMs-free carbon-based CsPbBr 3 PSCs achieve a champion PCE as high as 10.16% and excellent moisture-heat stability. [Display omitted] • DCC interface engineering reduces defects and improves contact and band alignment. • The low charge recombination and E loss and enhanced charge extraction are realized. • A champion PCE of 10.16% is achieved for HTMs-free carbon-based CsPbBr 3 PSCs. • The unencapsulated PSCs exhibits excellent long-term moisture-heat tolerance. The back interface issues including numerous defects and imperfect contact, mismatched energy level are regarded as the key detrimental factors causing serious charge recombination and energy loss (E loss) and inferior charge extraction to achieve high efficiency Hole transport materials-free (HTMs-free) carbon-based Perovskite solar cells (PSCs). To address this drawback, an effective interface engineering via depositing N, N'-Dicyclohexylcarbodiimide (DCC) at PVSK/Carbon back interface is creatively implemented to passivate CsPbBr 3 surface defects through forming interaction between N atoms with lone pair electrons and uncoordinated ions (eg Pb2+ and Cs+ ions) to suppress the defect states induced non-radiative recombination and E loss. Concurrently, the smoothness and valence band of PVSK film with DCC modification are increased to improve the contact and band alignment at back interface, respectively, remarkably accelerating hole extraction and transportation and also reducing E loss as well as charge recombination. As a result, the comprehensive performance of DCC interface modified HTMs-free carbon-based CsPbBr 3 PSCs is significantly enhanced, especially the champion efficiency boosts to 10.16% from 6.60% of the control PSC. Furthermore, owing to the enhanced hydrophobicity and decreased imperfections of PVSK film with DCC modification, the optimized device without any encapsulation displays an excellent long-term stability under 85% RH air condition at 85 °C over 1200 h. [ABSTRACT FROM AUTHOR]

The unencapsulated all-inorganic CsPbBr 3 PSC achieves a maximized PCE of 10.10% with an excellent stability through passivation, grain size and hole mobility enhancement of perovskite film as well as boosting interfacial hole extraction by additive and interface engineering of Br-GO. [Display omitted] • Adding Br-GO maximizes the grain size and hole mobility of perovskite film. • The defects and charge recombination are evidently decreased by introducing Br-GO. • Using Br-GO as HTM helps the CsPbBr 3 + Br-GO PSCs achieve a best PCE up to 10.10%. • The unencapsulated device shows excellent tolerance to moisture and illumination. The perovskite film with large grain size and high charge mobility is critical for the improvement of the power conversion efficiency (PCE) and the operational stability of perovskite solar cells (PSCs). Herein, multifunctional brominated graphene oxide (Br-GO) is prepared and innovatively used as an effective additive to incorporate into CsPbBr 3 to form a large-grained high-quality perovskite film and to passivate defects at grain boundaries, which remarkably reduces the trap state density and carrier non-radiative recombination. Meanwhile, the hole mobility of the homogeneous CsPbBr 3 + Br-GO photoactive layer is obviously increased due to the hole acceptor properties and high carrier mobility of Br-GO, resulting in an enhanced charge separation as well as transfer and suppressed carrier radiative recombination. Moreover, the Br-GO with a downshift valence band is employed as a hole-transporting material setting at perovskite/Carbon interface to further compensate energy levels and promote hole extraction. As a consequence, a champion PCE of 10.10% with an open-circuit voltage up to 1.602 V for the optimized PSCs with a configuration of FTO/c-TiO 2 /m-TiO 2 /CsPbBr 3 + Br-GO/Br-GO/Carbon is obtained, which is much higher than 6.28% efficiency for the reference device. The unencapsulated solar cells also exhibit a remarkable tolerance toward 85% RH and long-term AM 1.5G illumination in air. [ABSTRACT FROM AUTHOR]