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Polymeric hole‐selective materials (P‐HSMs) offer advantages like solution processability, tunable energy levels, and improved mechanical stability, making them suitable for large‐scale and flexible substrates. Poly[bis(4‐phenyl) (2,4,6‐trimethylphenyl) amine] (PTAA) based p–i–n perovskite solar cells exhibit promising power conversion efficiency (PCE), but wettability, dopant, and cost challenges necessitate the development of advanced next‐generation P‐HSMs. To provide a clear understanding of the structural property with photovoltaic performance, this review classifies such newly developed P‐HSMs into five distinct structural categories. Specifically, this review discusses the current status, advancements, challenges, and prospects in structural design and synthetic variations, focusing on enhancing photovoltaic performance, wettability, mitigating surface defects, and stability. Notably, incorporating polar units into P‐HSMs enhances wettability and mitigates ion instabilities and uncoordinated lead defects. Promising structural designs like polymeric self‐assembled monolayers and in situ polymerized hole‐selective materials are examined. Despite performance advancements, emerging, P‐HSMs face significant challenges such as limited thermal stress analysis (55–85 °C) and scalability restricted to small‐scale devices. To bridge this gap, this review emphasizes the urgent need for prioritizing thermal stability testing and large‐scale device fabrication in future research, paving the way for commercial viability of P‐HSMs in p–i–n perovskite photovoltaics. [ABSTRACT FROM AUTHOR]

Potential‐induced degradation (PID) is a prevalent concern in current commercial photovoltaic technologies, impacting their reliability, with the mechanistic basis for PID in perovskite photovoltaic technologies being poorly understood. Here, we investigate the PID mechanism in perovskite minimodules. Our findings reveal nonuniform degradation in the photoluminescence intensity and spectral blue shift. After 60‐h laboratory PID stress tests at −1500 V and 60°C, device efficiency drastically decreases by 96%, and the shunt resistance decreases by 97%, accompanied by a significant quantity of Na+ ions (derived from the soda lime glass) throughout the device structure, leading to a typical PID‐shunting effect. Interestingly, we observed a rapid recovery of device performance during room‐temperature dark storage, in which Na+ ions located close to the glass substrate side rapidly migrated out of the device. Moreover, we also found that the Na+ ions do not appear to diffuse through the grain boundaries but rather their neighboring area and grain interiors, judging by microscopic conductivity mappings. [ABSTRACT FROM AUTHOR]

Hole‐transporting material (HTMs) are crucial for obtaining the stability and high efficiency of perovskite solar cells (PSCs). However, the current state‐of‐the‐art n‐i‐p PSCs relied on the use of 2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene (spiro‐OMeTAD) exhibit inferior intrinsic and ambient stability due to the p‐dopant and hydrophilic Li‐TFSI additive. In this study, a new spiro‐type HTM with a critical quasi‐planar core (Z‐W‐03) is developed to improve both the thermal and ambient stability of PSCs. The results suggest that the planar carbazole structure effectively passivates the trap states compared to the triphenylamine with a propeller‐like conformation in spiro‐OMeTAD. This passivation effect leads to the shallower trap states when the quasi‐planar HTMs interact with the Pb‐dimer. Consequently, the device using Z‐W‐03 achieves a higher Voc of 1.178 V compared to the spiro‐OMeTAD's 1.155 V, resulting in an enhanced efficiency of 24.02 %. In addition, the double‐column π–π stacking of Z‐W‐03 results in high hole mobility (~10−4 cm2 V−1 s−1) even without p‐dopant. Moreover, when the surface interface is modified, the undoped Z‐W‐03 device can achieve an efficiency of nearly 23 %. Compared to the PSCs using spiro‐OMeTAD, those with Z‐W‐03 exhibit enhanced stability under N2 and ambient conditions. This superior performance is attributed to the quasi‐planar core structure and the presence of multiple CH/π and π–π intermolecular stacking in Z‐W‐03. The multiple CH/π and π–π intermolecular contacts of HTMs can improve the hole hopping transport. Therefore, it is imperative to focus on further molecular structure design and optimization of spiro‐type HTMs incorporating quasi‐planar cores and carbazole moieties for the commercialization of PSCs. [ABSTRACT FROM AUTHOR]

The global energy system transforming from fossil fuels to renewable green energy through the adaption of innovative and dynamic green technologies. Energy‐saving buildings (ESBs) are attracting extensive attention as intelligent architectures capable of significantly reducing the energy consumption for heating, air‐conditioning, and lighting. They provide comfortable working and living environment by regulating and harnessing solar energy. Smart photovoltaic windows (SPWs) offer a promising platform for designing ESBs due to their unique feature. They can modulate solar energy based on dynamic color switching behavior under external stimuli and generate electrical power by harvesting solar energy. In this review, the‐state‐of‐art of strategies and technologies are summarized putting SPWs toward high‐efficiency ESBs. The SPWs are systematically categorized according to the working principle and functional component. For each type of SPWs, material and architecture engineering are focused on to optimize operation mode, optical modulation capability, photovoltaic performance and durability for giving ESBs flexible manipulation, extraordinary energy‐saving effect, and high electricity power. In addition, the challenges and opportunities in this cutting‐edge research area are discussed, with the aim of promoting the development of advanced multifunctional SPWs and their application in high efficiency ESBs. [ABSTRACT FROM AUTHOR]

The antisolvent‐assisted spin‐coating still lags behind the thermal evaporation method in fabricating perovskite films atop industrially textured silicon wafers in making monolithic perovskite/silicon solar cells (P/S‐TSCs). The inhomogeneity of hole‐selective self‐assembled monolayers (SAMs) often arises from the insufficient bonding between hygroscopic phosphonic acid anchors and metal oxide. To address this, a mixed‐SAM strategy (Mx‐SAM) is proposed to enhance the adsorption energy of SAMs on the ITO surface, facilitate the formation of dense and humidity‐resistant hole‐selective layer (HSL) on substrates, and improve hole transport capabilities. With the aid of the Mx‐SAM strategy, the optimized wide‐bandgap PSCs achieved an impressive power conversion efficiency (PCE) of 22.63% with an exceptionally high fill factor (FF) of 86.67% using the 1.68 eV perovskite. Moreover, they exhibited enhanced stability under damp‐heat conditions (ISOS‐D‐3, 85% RH, 85 °C) with a T90 of 900 h for encapsulated PSCs, representing one of the best performances for wide‐bandgap PSCs. When further extending the Mx‐SAM strategy to making P/S‐TSCs using silicon wafers from industry, a remarkable efficiency of 28.07% is reached while upholding outstanding reproducibility. This strategy holds significant promise for the feasibility of fabricating industrially‐compatible P/S‐TSCs. [ABSTRACT FROM AUTHOR]

Herein, Cu(II)Pcs and Ni(II)Pcs peripherally tetra‐functionalized with 5‐hexylthiophene (HT), 5‐hexyl‐2,2′‐bithiophene (HBT), and tertbutyl groups (TB) are readily synthesized and employed as hole‐transporting materials (HTMs) in mixed‐ion perovskite ([FAPbI3]0.85[MAPbBr3]0.15) solar cells, achieving power conversion efficiencies (PCEs) up to 20.0%. Remarkably, both the peripheral functionalization and the central metal are found to play a role in the performance. Through a combination of experimental and theoretical techniques, it is found that the simplest HTM, TB‐CuPc, is the best‐performing HTM primarily due to its higher hole mobility and a more appropriate highest‐occupied molecular orbital, whose enables efficient hole extraction without open‐circuit voltage (Voc)losses. This derivative leads to PCEs of 19.96%, which are among the highest values for Pc‐based HTMs. Importantly, devices incorporating these HTMs present significantly higher stability compared to those based on spiro‐OMeTAD. The results here presented pave the way for more realistic, efficient, and inexpensive photovoltaic devices using phthalocyanine derivatives. [ABSTRACT FROM AUTHOR]

As a leading contender to replace lead halide perovskites, tin‐based perovskites have demonstrated ever increasing performance in solar cells and light‐emitting diodes (LEDs). They tend to be processed with dimethyl sulfoxide (DMSO) solvent, which has been identified as a major contributor to the Sn(II) oxidation during film fabrication, posing a challenge to the further improvement of Sn‐based perovskites. Herein, we use NMR spectroscopy to investigate the kinetics of the oxidation of SnI2, revealing that autoamplification takes place, accelerating the oxidation as the reaction progresses. We propose a mechanism consistent with these observations involving water participation and HI generation. Building upon these insights, we have developed low‐temperature Sn‐based perovskite LEDs (PeLEDs) processed at 60 °C, achieving enhanced external quantum efficiencies (EQEs). Our research underscores the substantial potential of low‐temperature DMSO solvent processes and DMSO‐free solvent systems for fabricating oxidation‐free Sn‐based perovskites, shaping the future direction in processing Sn‐containing perovskite materials and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Utilization of small molecules as passivation materials for perovskite solar cells (PSCs) has gained significant attention recently, with hundreds of small molecules demonstrating passivation effects. In this study, a high‐accuracy machine learning model is established to identify the dominant molecular traits influencing passivation and efficiently screen excellent passivation materials among small molecules. To address the challenge of limited available dataset, a novel evaluation method called random‐extracted and recoverable cross‐validation (RE‐RCV) is proposed, which ensures more precise model evaluation with reduced error. Among 31 examined features, dipole moment is identified, hydrogen bond acceptor count, and HOMO‐LUMO gap as significant traits affecting passivation, offering valuable guidance for the selection of passivation molecules. The predictions are experimentally validate with three representative molecules: 4‐aminobenzenesulfonamide, 4‐Chloro‐2‐hydroxy‐5‐sulfamoylbenzoic acid, and Phenolsulfonphthalein, which exhibit capability to increase absolute efficiency values by over 2%, with a champion efficiency of 25.41%. This highlights its potential to expedite advancements in PSCs. [ABSTRACT FROM AUTHOR]

Hole‐transporting materials (HTMs) are indispensable for realizing efficient and stable perovskite solar cells (PSCs). Herein, a novel dibenzo[g,p]chrysene‐based HTM, termed FTPE‐OSMe, is synthesized with peripheral methoxy‐ and methylthio‐groups, which contrasts with most other small molecule HTMs that feature only methoxy‐groups. The presence of methoxy‐ and methylthio‐groups endows FTPE‐OSMe with appropriate energy levels, high‐hole mobility and enhanced interfacial interactions. PSCs employing Li‐TFSI and 4‐tert‐butylpyridine‐doped FTPE‐OSMe demonstrate a remarkable power conversion efficiency (PCE) of 24.94% (certified 24.89%). The larger‐scale PSC (1.0 cm2) and module (29.0 cm2) yield PCEs of 23.57 and 20.22%, respectively. In addition, the dopant‐free FTPE‐OSMe‐based PSCs exhibit a respectable PCE of 22.40% and excellent stability. [ABSTRACT FROM AUTHOR]

Nickel oxide (NiOx)‐based inverted perovskite solar cells stand as promising candidates for advancing perovskite photovoltaics towards commercialization, leveraging their remarkable stability, scalability, and cost‐effectiveness. However, the interfacial redox reaction between high‐valence Ni4+ and perovskite, alongside the facile conversion of iodide in perovskite into I2, significantly deteriorates the performance and reproducibility of NiOx‐based perovskite photovoltaics. Here, potassium borohydride (KBH4) is introduced as a dual‐action reductant, which effectively avoids the Ni4+/perovskite interface reaction and mitigates the iodide‐to‐I2 oxidation within perovskite film. This synergistic redox modulation significantly suppresses nonradiative recombination and increases the carrier lifetime. As a result, an impressive power conversion efficiency of 24.17% for NiOx‐based perovskite solar cells is achieved, and a record efficiency of 20.2% for NiOx‐based perovskite solar modules fabricated under ambient conditions. Notably, when evaluated using the ISOS‐L‐2 standard protocol, the module retains 94% of its initial efficiency after 2000 h of continuous illumination under maximum power point at 65 °C in ambient air. [ABSTRACT FROM AUTHOR]

Hybrid perovskites have attracted enormous attention in the next generation resistive switching (RS) memristor for the artificial synapses, owing to their ambipolar charge transport, long diffusion length, and tunable visible bandgap. However, the variable switch, limited reproducibility, and poor endurance are the obstacles to the practical application of the perovskite memristors. Herein, we reported a multilevel RS nonvolatile memory based on a 3D trigonal HC(NH2)2PbI3 (α‐FAPbI3) perovskite layer modified by 1‐cyanobutyl‐3‐methylimidazolium chloride ([CNBmim]Cl) and sandwiched between ITO and Au electrodes (Au/[CNBmim]Cl/α‐FAPbI3/SnO2/ITO). In contrast to the bare memristor with failure switching from low resistance state (LRS) to high resistance state (HRS), the memristor device based on the α‐FAPbI3 modified with [CNBmim]Cl (Target device) shows the retention time over 104 s with On/Off ratio (>102) and endurance up to 550 cycles. The stable RS cycle benefits from the accelerated electrons de‐trapping from the reduced defects and fast charge separation in the interface of α‐FAPbI3/electrode, leading to the rupture of conductive filaments and transition of LRS to HRS. As a two‐terminal analog synaptic device, the target device can realize random handwritten digit recognition with an impressive accuracy of 89.3% on the condition of low learning phases (500 training cycles). [ABSTRACT FROM AUTHOR]

Dopant‐free hole transporting materials (HTMs) is significant to the stability of perovskite solar cells (PSCs). Here, we developed a novel star‐shape arylamine HTM, termed Py‐DB, with a pyrene core and carbon‐carbon double bonds as the bridge units. Compared to the reference HTM (termed Py‐C), the extension of the planar conjugation backbone endows Py‐DB with typical intermolecular π–π stacking interactions and excellent solubility, resulting in improved hole mobility and film morphology. In addition, the lower HOMO energy level of the Py‐DB HTM provides efficient hole extraction with reduced energy loss at the perovskite/HTM interface. Consequently, an impressive power conversion efficiency (PCE) of 24.33 % was achieved for dopant‐free Py‐DB‐based PSCs, which is the highest PCE for dopant‐free small molecular HTMs in n‐i‐p configured PSCs. The dopant‐free Py‐DB‐based device also exhibits improved long‐term stability, retaining over 90 % of its initial efficiency after 1000 h exposure to 25 % humidity at 60 °C. These findings provide valuable insights and approaches for the further development of dopant‐free HTMs for efficient and reliable PSCs. [ABSTRACT FROM AUTHOR]

Ultraviolet‐induced degradation has emerged as a critical stability concern impeding the widespread adoption of perovskite solar cells (PSCs), particularly in the context of phase‐unstable wide‐band gap perovskite films. This study introduces a novel approach by employing a fully aromatic carbazole‐based self‐assembled monolayer, denoted as (4‐(3,6‐dimethoxy‐9H‐carbazol‐9‐yl)phenyl)phosphonic acid (MeO‐PhPACz), as a hole‐selective layer (HSL) in inverted wide‐band gap PSCs. Incorporating a conjugated linker plays a pivotal role in promoting the formation of a dense and highly ordered HSL on substrates, facilitating subsequent perovskite interfacial interactions, and fostering the growth of uniform perovskite films. The high‐quality film could effectively suppress interfacial non‐radiative recombination, improving hole extraction/transport efficiency. Through these advancements, the optimized wide‐band gap PSCs, featuring a band gap of 1.68 eV, attain an impressive power conversion efficiency (PCE) of 21.10 %. Remarkably, MeO‐PhPACz demonstrates inherent UV resistance and heightened UV absorption capabilities, substantially improving UV resistance for the targeted PSCs. This characteristic holds significance for the feasibility of large‐scale outdoor applications. [ABSTRACT FROM AUTHOR]

Besides further improvement in the power conversion efficiency (PCE) of perovskite solar cells (PSC), their long‐term stability must also be ensured. Additives such as organic cations with halide counter anions are considered promising candidates to address this challenge, conferring both higher performance and increased stability to perovskite‐based devices. Here, a stabilizing additive (N,N‐dimethylmethyleneiminium chloride, [Dmmim]Cl) is identified, and its effect on charge carrier mobility and lifetime under thermal stress in triple cation perovskite (Cs0.05MA0.05FA0.90PbI3) thin films is investigated. To explore the fundamental mechanisms limiting charge carrier mobility, temperature‐dependent microwave conductivity measurements are performed. Different mobility behaviors across two temperature regions are revealed, following the power law Tm, indicating two different dominant scattering mechanisms. The low‐temperature region is assigned to charge carrier scattering with polar optical phonons, while a strong decrease in mobility at high temperatures is due to dynamic disorder. The results obtained rationalize the improved stability of the [Dmmim]Cl‐doped films and devices compared to the undoped reference samples, by limiting temperature‐activated mobile ions and retarding degradation of the perovskite film. [ABSTRACT FROM AUTHOR]

Surface passivation with 2D perovskites is a powerful strategy to achieve improved stability and performance in perovskite solar cells (PSCs). Various large organic cations have been successfully implemented, led by phenylethylammonium (PEA+) and its derivatives. However, systematic studies on large sets of cations to understand the effect of substituent position on 2D perovskite passivation and device performance are lacking. Herein, a collection of halogenated PEA+ iodide salts (x‐XPEAI where x: ortho (o), meta (m), para (p), X: F, Cl, Br) are synthesized by a facile method and deposited on top of 3D perovskite. The 2D perovskite layer formation is confirmed by X‐ray diffraction (XRD) and grazing‐incidence wide‐angle X‐ray scattering analyses for all cations, regardless of the nature and position of the halogen. Density functional theory analysis reveals that lower formation energies and higher interfacial dipoles achieved by m‐substituted cations are responsible for enhanced performance compared to their o‐ and p‐ counterparts. While the m‐BrPEAI‐treated device shows a champion efficiency of 23.42%, (VOC=1.13 V, FF=81.2%), considering average efficiencies, stability, and reproducibility, the treatment with m‐ClPEAI salt yields the best overall performance. This comprehensive study provides guidelines for understanding the influence of large cation modification on performance and stability of 3D/2D PSCs. [ABSTRACT FROM AUTHOR]

Despite recent increases in perovskite solar cell (PSC) efficiencies, long-term stability remains a barrier to manufacturing and marketing. SnO2 electron transport layers enable the low-temperature processing of planer n-i-p structured PSCs. However, ultraviolet radiation damages to the interface between the electron transport layer and the perovskite (PVK), which is a significant issue for n-i-p configuration. Herein, the insertion of a thin CeO2 passivation layer between the SnO2 and PVK is investigated to block the interface degradation. This CeO2 layer improves charge extraction and reduces defects in the PVK/CeO2 interface, resulting in 22.71% power conversion efficiency (PCE) compared to the pristine SnO2 PSC devices, which has a PCE of 20.7%. In addition, after 1700 h of storage at room temperature and 5%-8% RH (dry box), the PCE stability of the reinforced SnO2-CeO2 PSC devices drops from 22% to 19%, whereas that of the pristine SnO2 PSC devices drops from 20% to 16%. [ABSTRACT FROM AUTHOR]

Hole transport materials (HTMs) are a key component of perovskite solar cells (PSCs). The small molecular 2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenyl)‐amine‐9,9′‐spirobifluorene (spiro‐OMeTAD, termed "Spiro") is the most successful HTM used in PSCs, but its versatility is imperfect. To improve its performance, we developed a novel spiro‐type HTM (termed "DP") by substituting four anisole units on Spiro with 4‐methoxybiphenyl moieties. By extending the π‐conjugation of Spiro in this way, the HOMO level of the HTM matches well with the perovskite valence band, enhancing hole mobility and increasing the glass transition temperature. DP‐based PSC achieves high power conversion efficiencies (PCEs) of 25.24 % for small‐area (0.06 cm2) devices and 21.86 % for modules (designated area of 27.56 cm2), along with the certified efficiency of 21.78 % on a designated area of 27.86 cm2. The encapsulated DP‐based devices maintain 95.1 % of the initial performance under ISOS‐L‐1 conditions after 2560 hours and 87 % at the ISOS‐L‐3 conditions over 600 hours. [ABSTRACT FROM AUTHOR]

Although the power conversion efficiency of perovskite solar cells (PSCs) has reached 25.7%, there is still great potential for improvement in their performance and stability. In the past few years, ionic liquids (ILs) have been extensively investigated and demonstrated to enhance the efficiency and stability of devices substantially. Herein, the role of ILs in PSCs as additives, solvents, interface engineering, and charge transport layer is reviewed. Also, this review will guide the researchers in understanding bulk doping and interface engineering for efficient and stable PSCs. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Inverted perovskite solar cells (PSCs) have attracted increasing attention in recent years owing to their low‐temperature fabrication proces s. However, they suffer from a limited number of electron transport materials available with [6,6]‐phenyl C61 butyric acid methyl ester (PCBM) to be the most widely studied based on its appropriate energy levels and high electron mobility. The low relative permittivity and aggregation tendency upon illumination of PCBM, however, compromises the solar cell efficiency whereas its modest hydrophobicity negatively impacts on the device stability. Alternative electron transport materials with desired properties and appropriate degree of hydrophobicity are thus desirable for further developments in inverted PSCs. Herein, we synthesize a triethyleneglycol C60 mono‐adduct derivative (termed as EPF03) and test it as a novel electron transport material to replace PCBM in inverted PSCs based on a quadruple cation (RbCsMAFA) perovskite. We also compare this derivative with two novel fullerenes decorated with two (EPF01) or one dodecyl (EPF02) long side chains. The latter two fail to perform efficiently in inverted PSCs whereas the former enabled a power conversion efficiency of 18.43%, which represents a 9% improvement compared to the reference device using PCBM (17.21%). The enhanced performance mainly stems from improved electron extraction and reduced recombination enabled by the insertion of the large relative permittivity amongst other properties of EPF03. Furthermore, our results indicate that triethylene glycol side chains can also passivate perovskite trap states, suppress ion migration and enhance photostability and long‐term stability of EPF03 based perovskite solar cells. [ABSTRACT FROM AUTHOR]

Hexakis(hexyloxy)triphenylene (HAT6) discotic liquid crystal is employed as a transparent hole‐transporting material (HTM) for perovskite solar cells (PSCs) and a power conversion efficiency (PCE) of 15.7% is obtained, which is the highest using HAT6 type of HTMs. Despite lower PCE than spiro‐OMeTAD‐based devices (20.3%), the PSCs based on HAT6 exhibit much higher ambient and thermal stability. A fused polyaromatic core with six alkyl chains leads to high hydrophobicity, and the π‐stacked molecular columns of the HAT6 shield the bis(trifluoromethane)sulfonamide lithium salt dopant migration into the perovskite absorber. The PSCs (under N2 condition) exhibit superior stability compared to the devices employing spiro‐OMeTAD, retaining nearly 92% of their initial efficiency after 1200 h operation. Under ambient conditions, HAT6‐based hole‐transportation layer devices retain 93% of the initial efficiency for 690 h. Under continuous thermal stress of 85 °C, the devices based on HAT6 retain 95% of the initial PCE. The results demonstrate the time applicability of liquid crystal for stable PSCs fabrication. [ABSTRACT FROM AUTHOR]

In this study, a series of donor–acceptor–donor (D‐A‐D) type small molecules based on the fluorene and diphenylethenyl enamine units, which are distinguished by different acceptors, as holetransporting materials (HTMs) for perovskite solar cells is presented. The incorporation of the malononitrile acceptor units is found to be beneficial for not only carrier transportation but also defects passivation via Pb–N interactions. The highest power conversion efficiency of over 22% is achieved on cells based on V1359, which is higher than that of spiro‐OMeTAD under identical conditions. This st shows that HTMs prepared via simplified synthetic routes are not only a low‐cost alternative to spiro‐OMeTAD but also outperform in efficiency and stability state‐of‐art materials obtained via expensive cross‐coupling methods. [ABSTRACT FROM AUTHOR]

Defect passivation has been recognized as an effective strategy to improve efficiency and stability of perovskite solar cells (PSCs). In this work, in‐depth theoretical calculations and experimental characterizations reveal the dual‐site synergistic passivation of 1H‐benzimidazole (BIZ), and the conjugated structure of the benzene ring tends to increase the interaction between BIZ and perovskite. High‐quality perovskite films are thus achieved, with increased grain size, reduced defect density, and suppressed ion migration. Simultaneously, the reduced work function and optimized band alignment promote carrier transport, reducing nonradiative recombination, and loss of open‐circuit voltages, as well as fill factor. Consequently, the target PSC devices achieve a champion power conversion efficiency (PCE) of 24.59%, and 20.49% for perovskite solar module (a designated area of 27.5 cm2). The unencapsulated PSC maintains 91.49% of original PCE after storing in air with an average relative humidity of 40% for 2400 h. Moreover, the device exhibits remarkable the long‐term operational stability, maintaining 90.47% of initial PCE after continuously operating at the maximum power point for 1000 h. This study not only provides insights into the synergistic passivation of BIZ but also provides a strategy for the application of BIZ derivatives in the photovoltaic field. [ABSTRACT FROM AUTHOR]

Inverted planar perovskite solar cells (PSCs) have intrigued great promise in negative hysteresis, simple fabrication process, and flexible substrate implementation, in which the shared hole transport materiel is NiOx. However, the low‐temperature solution processing of the NiOx film is usually accompanied by defect formation, which deteriorates the perovskite quality and device performance. Meanwhile, the energy‐level offset between the NiOx and perovskite films is relatively large, limiting the interfacial charge transport. To suppress those setbacks, a defect‐free monolayer graphene sheet is transferred onto the NiOx film surface as a template for van der Waals epitaxial growth of perovskite films for the first time, leading to enhancing crystallinity with a large grain size of perovskite layer, 0.20 eV energy level offset drop, and accelerating charge transfer for the devices. Finally, the power conversion efficiency of 19.21% without hysteresis is achieved, exceeding 18.35% of the control device. [ABSTRACT FROM AUTHOR]

The under‐coordinated defects within perovskite and its relevant interfaces always attract and trap the free carriers via the electrostatic force, significantly limiting the charge extraction efficiency and the intrinsic stability of perovskite solar cells (PSCs). Herein, self‐diffusion interfacial doping by using ionic potassium L‐aspartate (PL‐A) is first reported to restrain the carrier trap induced recombination via the reconstruction of energy level structure at SnO2/perovskite interface in conventional n‐i‐p structured PSCs. Experiments and theories are consistent with the PL‐A anions that can remain at the SnO2 surface due to strong chemical adsorption. During the spin‐coating of the perovskite film, the cations gradually diffuse into perovskite and endow an n‐doping effect, which provides higher force and a better energy level alignment for the carrier transport. As a result, they obtained 23.74% power conversion efficiency for the PL‐A modified small‐area devices, with dramatically improved open‐circuit voltage of 1.19 V. The corresponding large‐area devices (1.05 cm2) achieved an efficiency of 22.23%. Furthermore, the modified devices exhibited negligible hysteresis and enhanced ambient air stability exceeding 1500 h. [ABSTRACT FROM AUTHOR]

Metal‐halide perovskites are optoelectronic materials applied to solar cells as a light absorber due to their excellent optoelectronic properties. The power conversion efficiency of perovskite solar cells (PSCs) reaches 25.7% certified, which stands in comparison with Si solar cells. Importantly, compositional engineering of perovskites has been one of the keys to the breakthrough. However, the presence of defects within perovskites is a matter of importance as it can cause nonradiative recombination of charge carriers. In addition, defect migration can degrade the photovoltaic performance and stability of PSCs. Previous studies have commonly addressed that iodide‐related defects such as interstitial iodide and iodide vacancy are problematic due to their low formation energy. Thus, halide engineering is imperative to mitigate the defect‐related dynamics and improve the materials quality of perovskites. In this sense, superhalogen is a promising candidate for defect passivation and stabilization of perovskites based on its higher electronegativity and electron affinity than halides, which are beneficial to the formation of a more robust interaction with adjacent elements in perovskites. This perspective gives an overview of studies regarding the use of superhalogen to develop efficient and stable PSCs and concludes with an outlook of further research directions. [ABSTRACT FROM AUTHOR]

Interface engineering and passivating contacts are key enablers to reach the highest efficiencies in photovoltaic devices. While printed carbon–graphite back electrodes for hole‐transporting material (HTM)‐free perovskite solar cells (PSCs) are appealing for fast commercialization of PSCs due to low processing costs and extraordinary stability, this device architecture so far suffers from severe performance losses at the back electrode interface. Herein, a 2D perovskite passivation layer as an electron blocking layer (EBL) at this interface to substantially reduce interfacial recombination losses is introduced. The formation of the 2D perovskite EBL is confirmed through X‐ray diffraction, photoemission spectroscopy, and an advanced spectrally resolved photoluminescence microscopy mapping technique. Reduced losses that lead to an enhanced fill factor and VOC are quantified by electrochemical impedance spectroscopy and JSC–VOC measurements. This enables reaching one of the highest reported efficiencies of 18.5% for HTM‐free PSCs using 2D perovskite as an EBL with a significantly improved device stability. [ABSTRACT FROM AUTHOR]

New Spiro‐OMeTAD analogues and the simpler "half" structures with the terminated methoxyphenyl and/or carbazolyl chromophores are successfully synthesized under Hartwig–Buchwald amination conditions using commercially available starting materials. New fluorene‐based hole‐transporting materials combined with suitable ionization energies properly align with the valence band of the perovskite absorber. Additionally, these compounds are amorphous, which is an advantage for the formation of homogenous films, as well as eliminate the possibility for films to crystallize during operation of the devices. The most efficient perovskite solar cells devices contain carbazolyl‐terminated Spiro‐OMeTAD analogue V1267 and reach a power conversion efficiency of 18.3%, along with a short‐circuit current density, open‐circuit voltage, and fill factor of 23.41 mA cm−2, 1.06 V, and 74.0%, respectively. Moreover, "half" structures with methoxyphenyl/carbazolyl fragments show excellent long‐term stability and outperform Spiro‐OMeTAD and, therefore, hold a great prospect for practical wide‐scale applications in optoelectronic devices. [ABSTRACT FROM AUTHOR]

Studying the compositional instability of mixed ion perovskites under light illumination is important to understand the mechanisms underlying their efficiency and stability. However, current techniques are limited in resolution and are unable to deconvolute minor ion migration phenomena. Here, a method that enables ion migration to be studied allowing different segregation mechanisms to be elucidated is described. Statistical analysis is applied to cathodoluminescence data to generate compositional distribution histograms. Using these histograms, two different ion migration phenomena, horizontal ion migration (HIM) and vertical ion migration (VIM), are identified in different perovskite films. It is found that most passivating agents inhibit HIM, but not VIM. However, VIM can be reduced by deposition of imidazolium iodide on the perovskite surface. This method can be used to study perovskite‐based devices efficiency and stability by providing molecular level mechanistic understanding of passivation approaches leading to performance improvement of perovskite solar cells via rational design. [ABSTRACT FROM AUTHOR]

While perovskite solar cells (PSCs) have recently experienced a rapid rise in power conversion efficiency (PCE), the prevailing PSCs still contain nondesirable defects in the interior and interface of the perovskite layer, which limits further enhancement in PCE and device stability. Herein, a new D–π–A‐type zinc pyridine porphyrin derivative (ZnPP) is synthesized and used as a passivation molecular via the antisolvent process for modifying the typical perovskite bulk thin film, leading to a new type of PSC with a graded passivation of the perovskite layer. Impressively, it is found that ZnPP treatment significantly improves the quality of perovskite films and reduces charge transport losses through passivating the uncoordinated Pb2+ cations, yielding devices with a high efficiency of 21.08% with fill factor (FF) of 82.91% and demonstrating the promise of integration of perovskite bulk thin films with tailor molecular via graded modification. [ABSTRACT FROM AUTHOR]

Organic hole‐transporting materials (HTMs) based on the Ullazine core yield so far only moderate power conversion efficiencies of up to 13.08% in perovskite solar cells (PSCs). Aiming to fabricate efficient and stable PSCs, novel Ullazine derivatives bearing thiophene units were designed and synthesized, allowing modulation of the electronic states of the HTMs and further providing defect passivation of the perovskite surface. Experimental and theoretical analysis show that thiophene units with ‐N(p‐MeOC6H4)2 groups improve the conductivity of Ullazine HTMs, boosting the efficiency of PSCs to 20.21%. This value is the highest reported to date for Ullazine‐based HTMs, and is close to the performance of Spiro‐OMeTAD. In addition, unencapsulated PSCs based on the champion Ullazine exhibit superior stability with respect to Spiro‐OMeTAD, retaining nearly 90% of the initial efficiency following 1000 h aging, which is ascribed to a combination of higher water repellency and passivation of defects on the perovskite surface. This work demonstrates the high potential of HTMs based on Ullazine core as substitutes to Spiro‐OMeTAD. [ABSTRACT FROM AUTHOR]

Hybrid lead halide perovskite solar cells (PSCs) have emerged as potential competitors to silicon‐based solar cells with an unprecedented increase in power conversion efficiency (PCE), nearing the breakthrough point toward commercialization. However, for hole‐transporting materials, it is generally acknowledged that complex structures often create issues such as increased costs and hazardous substances in the synthetic schemes, when translated from the laboratory to manufacture on a large scale. Here, we present cyclobutane‐based hole‐selective materials synthesized using simple and green‐chemistry inspired protocols in order to reduce costs and adverse environmental impact. A series of novel semiconductors with molecularly engineered side arms were successfully applied in perovskite solar cells. V1366‐based PSCs feature impressive efficiency of 21 %, along with long‐term operational stability under atmospheric environment. Most importantly, we also fabricated perovskite solar modules exhibiting a record efficiency over 19 % with an active area of 30.24 cm2. [ABSTRACT FROM AUTHOR]

Three benzodipyrrole (BDP)‐based organic small molecules with substituted 4‐methoxyphenyl (CB‐1), 3‐fluorophenyl (CB‐2), and 3‐trifluoromethylphenyl (CB‐3) are designed, synthesized, and used as a hole‐transporting material (HTM) for perovskite solar cells (PSCs). The electrochemical, optical, thermal, electronic, and optoelectronic properties of the HTMs are characterized to verify their suitability for PSCs. The terminal functional groups of the HTMs having different heteroatoms mainly target effective defect passivation of perovskites. Photoluminescence studies and molecular dynamic simulations reveal that fluorine atoms within CB‐2 and CB‐3 can contribute to the defect passivation via interaction with Pb of the perovskite. In particular, a highly planar conformation of CB‐2 on the perovskite surface can facilitate more efficient hole transfer at the interface. Thus, the PSCs employing CB‐2 achieve the highest power conversion efficiency (PCE) of 18.23% while the devices using CB‐1 and CB‐3 exhibit a lower PCE of 16.78% and 16.74%, respectively. PSCs with the BDP‐based HTMs demonstrate excellent long‐term storage stability without degradation in their PCEs over 6 months. The highly planar geometry, defect passivation effect, and hydrophobicity of CB‐2 show its great potential as an HTM for efficient and stable PSCs. [ABSTRACT FROM AUTHOR]

The improvement of the long‐term stability of perovskite‐based solar cells (PSCs) toward commercialization is closely linked to the development of cutting‐edge charge‐transporting materials. The progress on the design and the synthesis of new hole‐transporting materials (HTMs) is synergistically attaining both top efficiencies and promising stability. Herein, the synthesis and characterization of two doped‐HTMs based on electron‐rich spiranic cores, namely, 9H‐quinolinophenoxazine (spiro‐POZ) and 9H‐quinolinophenothiazine (spiro‐PTZ), are presented. The novel HTMs exhibit excellent solubility, optimal highest occupied molecular orbital energy, and excellent thermal stability with glass transition temperatures higher than those for spiro‐OMeTAD. [(FAPbI3)0.87(MAPbBr3)0.13]0.92[CsPbI3]0.08‐based solar cells using the new spiro‐type HTMs deliver power conversion efficiencies (PCEs) around 17% for mesoporous cells, and higher than 18% in planar configurations, matching the PCE of spiro‐OMeTAD. Remarkably, doped spiro‐POZ and spiro‐PTZ exhibit excellent long‐term stability in planar devices, retaining over 84% of their initial efficiency after more than 300 days of exposure to ambient conditions. Furthermore, after 1200 h under continuous 1 sun illumination, the PCE of the PSCs based on spiro‐POZ and spiro‐PTZ decreases by only 6%. [ABSTRACT FROM AUTHOR]

The application of low average layer‐number (〈n〉 ≤ 2) 2D perovskites in semitransparent photovoltaics (ST‐PVs) has been hindered by their strong exciton binding energy and high electrical anisotropy. Here, the phase distribution is expanded fully and orderly to enable efficient charge transport in 2D (NMA)2(MA)Pb2I7 (NMA: 1‐naphthylmethylammonium, MA: CH3NH3+) perovskite films by regulating the sedimentation dynamics of organic cation‐based colloids. Ammonium chloride is synergistically introduced to enhance the phase separation further and construct a favorable out‐of‐plane orientation. The wide and graded phase distribution well aligns the energy level to facilitate charge transfer. As a result, the first application of an average 〈n〉 = 2 2D perovskite is implemented in ST‐PVs with visible power conversion efficiency (PCE) of 7.52% and high average visible transmittance (AVT) of 40.5%. This study offers a new candidate and an effective strategy for efficient and stable ST‐PVs and is relevant to other perovskite optoelectronic devices. [ABSTRACT FROM AUTHOR]

Textile electronics embedded in clothing represent an exciting new frontier for modern healthcare and communication systems. Fundamental to the development of these textile electronics is the development of the fibers forming the cloths into electronic devices. An electronic fiber must undergo diverse scrutiny for its selection for a multifunctional textile, viz., from the material selection to the device architecture, from the wearability to mechanical stresses, and from the environmental compatibility to the end‐use management. Herein, the performance requirements of fiber‐shaped electronics are reviewed considering the characteristics of single electronic fibers and their assemblies in smart clothing. Broadly, this article includes i) processing strategies of electronic fibers with required properties from precursor to material, ii) the state‐of‐art of current fiber‐shaped electronics emphasizing light‐emitting devices, solar cells, sensors, nanogenerators, supercapacitors storage, and chromatic devices, iii) mechanisms involved in the operation of the above devices, iv) limitations of the current materials and device manufacturing techniques to achieve the target performance, and v) the knowledge gap that must be minimized prior to their deployment. Lessons learned from this review with regard to the challenges and prospects for developing fiber‐shaped electronic components are presented as directions for future research on wearable electronics. [ABSTRACT FROM AUTHOR]

The emerging CsPbI3 perovskites are highly efficient and thermally stable materials for wide‐band gap perovskite solar cells (PSCs), but the doped hole transport materials (HTMs) accelerate the undesirable phase transition of CsPbI3 in ambient. Herein, a dopant‐free D‐π‐A type HTM named CI‐TTIN‐2F has been developed which overcomes this problem. The suitable optoelectronic properties and energy‐level alignment endow CI‐TTIN‐2F with excellent charge collection properties. Moreover, CI‐TTIN‐2F provides multisite defect‐healing effects on the defective sites of CsPbI3 surface. Inorganic CsPbI3 PSCs with CI‐TTIN‐2F HTM feature high efficiencies up to 15.9 %, along with 86 % efficiency retention after 1000 h under ambient conditions. Inorganic perovskite solar modules were also fabricated that exhibiting an efficiency of 11.0 % with a record area of 27 cm2. This work confirms that using efficient dopant‐free HTMs is an attractive strategy to stabilize inorganic PSCs for their future scale‐up. [ABSTRACT FROM AUTHOR]

The perovskite photovoltaic technology is now transitioning from basic research to the pre‐industrialization phase. In order to achieve reliable and high‐performance commercial perovskite solar modules, high throughput manufacturing technologies must now be adapted to the specific constraints and requirements imposed by the perovskite solar cells unique new chemistries, film deposition methodologies, and encapsulation requirements. Laser technologies will play an important role in the industrialization of these devices, both to achieve high active surface area modules and for the deposition and/or treatment of the critical layers. Industrial lasers will be essential to achieve active areas greater than 95% of the total area to retain the benefits of the very high performances reported for <1 cm2 laboratory cells. The speed of laser processing for the preparation of interconnects is unrivalled by comparison to other structuring methods. Recent reports of the use of lasers in upscaling perovskite solar cells are presented and analyzed here. [ABSTRACT FROM AUTHOR]

Low‐dimensional perovskites (LDP) are nowadays recognized as promising materials for the realization of highly performing photovoltaic cells. However, issues related to film morphology, composition, crystal quality and material homogeneity limit the device performances and reproducibility. In this work, we implement a robust method for the deposition of a LDP mixing methylammonium (MA) and phenylethylammonium (PEA) cations to create the mixed system (PEA)2MA39Pb40I121 by using a two‐step thermal annealing treatment (at 60 and 100 °C). Our approach results in LDP films with high crystal quality and enhanced carrier lifetime, which double the power conversion efficiency of reference devices, reaching up to 15 %. [ABSTRACT FROM AUTHOR]

Hybrid lead halide perovskites typically form polycrystalline films that have multiple grain sizes and surface defects. A key engineering challenge toward commercialization is therefore the production of homogeneous, defect‐free large‐area devices achieving high efficiency. New market opportunities may arise from vacuum‐deposited perovskites if detailed understanding and control of crystal formation are available. Of the many factors that make reproducibility of device performance difficult, two variables are identified that have not yet been considered in detail: deposition speed and underlayer material selection. Herein, it is demonstrated that small changes in the perovskite growth rate (0.18–0.72 Å·s−1) substantially affect the preferred crystal orientation. Further, varying underlayer interfaces greatly influence the composition of the final perovskite and thus its energetic profile. The research aids control in fine‐tuning the perovskite film at the nanometer scale, which enables the reproducible fabrication of vertically aligned and micrometer‐sized grain features, highly demanded for in high‐quality semiconductors. [ABSTRACT FROM AUTHOR]

Recently, polymeric carbon nitride (g‐C3N4) as a proficient photo‐catalyst has been effectively employed in photocatalysis for energy conversion, storage, and pollutants degradation due to its low cost, robustness, and environmentally friendly nature. The critical review summarized the recent development, fundamentals, nanostructures design, advantages, and challenges of g‐C3N4 (CN), as potential future photoactive material. The review also discusses the latest information on the improvement of CN‐based heterojunctions including Type‐II, Z‐scheme, metal/CN Schottky junctions, noble metal@CN, graphene@CN, carbon nanotubes (CNTs)@CN, metal‐organic frameworks (MOFs)/CN, layered double hydroxides (LDH)/CN heterojunctions and CN‐based heterostructures for H2 production from H2O, CO2 conversion and pollutants degradation in detail. The optical absorption, electronic behavior, charge separation and transfer, and bandgap alignment of CN‐based heterojunctions are discussed elaborately. The correlations between CN‐based heterostructures and photocatalytic activities are described excessively. Besides, the prospects of CN‐based heterostructures for energy production, storage, and pollutants degradation are discussed. [ABSTRACT FROM AUTHOR]

Two novel and simple donor‐π‐bridge‐donor (D‐π‐D) hole‐transporting materials (HTMs) containing two units of the p‐methoxytriphenylamine (TPA) electron donor group covalently bridged by means of the 3,4‐dimethoxyselenophene spacer through single and triple bonds are reported. The optoelectronic and thermal properties of the new selenium‐containing HTMs have been determined using standard experimental techniques and theoretical density functional theory (DFT) calculations. The selenium‐based HTMs have been incorporated in mesoporous perovskite solar cells (PSCs) in combination with the triple‐cation perovskite [(FAPbI3)0.87(MAPbBr3)0.13]0.92 [CsPbI3]0.08. Limited values of power conversion efficiencies, up to 13.4 %, in comparison with the archetype spiro‐OMeTAD (17.8 %), were obtained. The reduced efficiencies showed by the new HTMs are attributed to their poor film‐forming ability, which constrains their photovoltaic performance due to the appearance of structural defects (pinholes). [ABSTRACT FROM AUTHOR]

To achieve both high efficiency and long‐term stability of perovskite solar cells (PSCs), it is effective to use a perovskite layer in which a low‐dimensional perovskite layer is stacked on a 3D perovskite layer. However, the guidelines for the effective structure of these perovskite layers remain unclear. Herein, the gradient structured 1D perovskite layer formed on top of a 3D perovskite layer using 4‐tert‐butylpyridinium iodide (TBPI) as a capping layer is introduced. It is demonstrated that the gradient structured 1D perovskite layer on the 3D perovskite improves the conversion efficiency of PSCs despite the lateral orientation of the (PbI3−)n linear chain of the 1D perovskite, which is responsible for electronic conduction. In addition, it is found that the hydrophobic organic unit of TBPI protects the 3D perovskite layer, which enhances its long‐term stability. [ABSTRACT FROM AUTHOR]

Deep learning (DL) is a modern powerful instrument for multiple purposes, including classification. In this study, this technique is applied to the task of perovskites formability. A commonly known perovskite dataset is used to try to make an instrument superior to the 'classic' geometric approach. The authors found that the resulting models allow the finding of inaccuracies in the data and can successfully forecast perovskite formability with an accuracy of over 98% for the best case. [ABSTRACT FROM AUTHOR]

Crystalline, dense, and uniform perovskite thin films are crucial for achieving high‐power conversion efficiency solar cells. Herein, a universal method of fabricating highly crystalline and large‐grain perovskite films via crystal engineering is demonstrated. Anion exchange of Cl− and I−, and annealing perovskite films, in an ultraconfined and uniform temperature enclosed space with saturated MAI (or FAI) vapor using hot‐pressing sublimation technology are conducted. This process ensures a rapid crystal growth rate due to fast exchange between the gas phase and the crystalline film to reduce vertically oriented grain boundaries. The generation of the commonly observed PbI2 phase is also suppressed due to the chemical equilibrium state during the thermal annealing process. Using this approach, pinhole‐free perovskite films with preferred crystal orientation and micrometer‐scale grains are obtained, leading to a high steady‐state efficiency of 22.15% based on mixed‐cation perovskite composition. In addition, devices based on different perovskite compositions all exhibit enhanced photovoltaic performance based on the crystal engineering method. The device (without encapsulation) has an efficiency loss of about only 4% after 2520 h of aging in ambient conditions and retains 87% of its initial efficiency after 1000 h of continuous 1 Sun light soaking, thus demonstrating considerably improved stability. [ABSTRACT FROM AUTHOR]

Passivation approaches of perovskite surface are key to improve the light stability of perovskite solar cells. However, a passivation strategy is still required to enhance the durability of the perovskite layer. Here, a promising passivation concept is demonstrated by applying a fluorinated agent on the perovskite layer for light stability improvement. Such fluorinated passivation agents can prevent the formation of Pb0 at the perovskite surface resulting in suppressing a defect‐induced recombination and improving the durability of the perovskite solar cells. As an additional benefit, the fluorinated passivation agent increases the VOC which improves the photovoltaic performance of the perovskite solar cells. Consequently, with a fluorinated passivation agent, the perovskite maintains a power conversion efficiency of 95% after 300 h of light illumination. It is found that the fluorinated passivation material of 1H,1H,2H,2H‐perfluorooctyltriethoxysilane (PFOTES) can improve the stability of the perovskite solar cells. [ABSTRACT FROM AUTHOR]