Thermal annealing improves the crystallinity of perovskite films and boosts their power conversion efficiencies (PCEs) in solar cells but also induces surface iodine loss and local lattice degradation. We demonstrate a molecular press annealing (MPA) strategy in which a 2-pyridylethylamine film is thermally and pressure-bonded to the perovskite surface. Real-time healing of iodine vacancies occurred during annealing and the lead-iodine framework was stabilized through optimized ligand engineering, resulting in enhanced structural integrity and long-term stability of perovskite films. This strategy enabled n-i-p perovskite solar cells to achieve a PCE of 26.6% (certified 26.5%). Notably, the devices retain 98.6 and 97.2% of their initial PCEs after 1617 hours of continuous operation under maximum power point tracking [ISOS-L-3 protocol, 85°C, 60% relative humidity (RH)] and 5280 hours of ambient storage (ISOS-D-1 protocol, room temperature, 10% RH).

High-performance inverted perovskite solar cells (PSCs) rely critically on high-quality interfaces and efficient bulk defect passivation. However, achieving simultaneous optimization of charge extraction and lattice stabilization through functional molecular modifiers remains a persistent challenge in the field. Herein, we demonstrate a multidentate molecular anchoring strategy leveraging tripodal phosphonic acid molecules to regulate the co-deposition dynamics of the perovskite absorber and hole transport layer. The trifurcated phosphonic acid moieties enable robust multidentate chemisorption onto the glass substrate, yielding an interface with face-on pi-stacking orientation that facilitates optimal band alignment and suppresses interfacial charge recombination. Concurrently, these molecules segregate preferentially to perovskite grain boundaries, where they engage in coordinative passivation of undercoordinated Pb2 + defects. This dual-functional design constructs a coherent charge-transport network that synergistically enhances interfacial hole extraction while mitigating ion migration and bulk defect formation. The resulting PSCs deliver a certified power conversion efficiency of 26.35%, accompanied by exceptional operational stability: retaining 82% of their initial performance after 1000 h of thermal stability test (85 degrees C) and 86% after 1000 h of maximum power point tracking. This work establishes critical insights into molecular-mediated interface stabilization, providing a generalized framework for the rational design of functional molecules for optoelectronic devices.

Although self-assembled molecules (SAMs) have shown great potential in simplifying the fabrication of perovskite solar cells (PSCs) as the co-deposited hole-selective layers (HSLs), only a few SAMs have demonstrated high device performance up to date. In this work, a series of novel SAMs with a phosphonic acid group directly anchored onto the carbazole skeleton is designed. This linking mode can prevent the aggregation of SAMs in the solution state while enhancing their photostability. By further incorporating oligoether side chains, the target SAMs EGCPA and 3EGCPA can form homogeneous and dense HSL during the co-deposition process and assist the growth of high-quality perovskite film. Particularly, 3EGCPA featuring multiple oligoether chains possesses a high dielectric constant, which enables more efficient interfacial hole extraction and transfer, thereby reducing the charge recombination. Consequently, the 3EGCPA-based co-deposited PSCs delivered a champion efficiency of 24.64% along with good ISOS-D-1 stability, which is among the highest performances for co-deposited PSCs. Furthermore, acoustic resonance can be effectively utilized to test the power conversion efficiency (PCE) of PSCs. This work provides a creative molecular design strategy for exploring efficient hole-selective molecules with a high dielectric constant applied in PSCs.

Charge selective contacts are critical in perovskite solar cells (PSCs) for charge dissociation, collection and transport. However, these layers can cause interfacial incompatibility and complicate the manufacturing process. To address these challenges, simplifying the PSC structure has become a key strategy. Although efforts have been made to develop hole transport layer (HTL)-free inverted PSCs, their photovoltaic performance has not yet matched that of conventional PSCs, and the mechanisms of interfacial charge dynamics in these simplified devices remain poorly understood. In this work, we propose a powerful strategy of rational molecular doping to optimize the interfacial energy-level alignment and carrier dynamics in PSCs. We demonstrate that the electron affinity of p-type organic molecules is pivotal in controlling perovskite crystallization and improving the quality of perovskite films, which in turn enhances interfacial charge collection and reduces carrier recombination losses. By doping with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), we significantly enhance the conductivity of perovskite films and strengthen the electronic contact with the conductive substrate. As a result, F4TCNQ-based HTL-free inverted PSCs achieve an impressive power conversion efficiency of 18.07%, surpassing the 9.75% of control devices. This study introduces an effective method for fabricating reliable HTL-free PSCs through rational molecular doping, laying the groundwork for further improvements in device performance.

Self-assembled monolayers (SAMs) have displayed unpredictable potential in efficient perovskite solar cells (PSCs). Yet most of SAMs are largely suitable for pure Pb-based devices, precisely developing promising hole-selective contacts (HSCs) for Sn-based PSCs and exploring the underlying general mechanism are fundamentally desired. Here, based on the prototypical donor-acceptor SAM MPA-BT-BA (BT), oligoether side chains with different length (i.e., methoxy, 2-methoxyethoxy, 2-(2-methoxyethoxy)ethoxy group) were custom-introduced on the benzothiadiazole unit to produce the target SAMs with acronyms MPA-MBT-BA (MBT), MPA-EBT-BA (EBT), and MPA-MEBT-BA (MEBT), respectively, and acting as HSCs for efficient Sn-Pb PSCs and all-perovskite tandems. The introduction of oligoether side chains enables HSCs effectively accelerate hole extraction, regulate the crystal growth and passivate surface defects of Sn-Pb perovskites. In particular, benefiting from the enhanced Sn-Pb perovskite film quality and the suppressed interfacial non-radiative recombination losses, EBT-tailored LBG devices yield a champion efficiency of 23.54%, enabling 28.61% efficient monolithic all-perovskite tandems with an impressive VOC of 2.155 V and excellent operational stability as well as 28.22%-efficiency 4-T tandems. The development of hole-selective contacts for Sn-based perovskite solar cells is highly desirable. Here, the authors report self-assembled monolayers with oligoether side chains on the benzothiadiazole unit and achieve an efficiency of 28.61% for operationally stable all-perovskite tandems.

High-efficiency n-i-p perovskite solar cells (PSCs) inherently rely on doped 2,2 ',7,7 '-Tetrakis[N,N-di(4-methox-yphenyl)amino]-9,9-spirobifluorene (Spiro-OMeTAD) as hole transport layers (HTLs). Yet, dopants (tert-butylpyridine [tBP] and lithium bis(trifluoromethanesulfonyl)imide [LiTFSI]) instigate energy-level disorder and morphological degradation in HTLs, hampering technological advancement. Herein, we propose a redoxmediated nanoscale solid-state doping strategy using multifunctional CuInS2/ZnS quantum dots (CISQDs) to enhance the performance and operational stability of HTLs. The Cu2+/Cu+ redox-active centers in CISQD promote Spiro-OMeTAD & sdot;+ cation formation, facilitating efficient charge collection. Additionally, uncoordinated sulfur sites on the ZnS shell act as ionic traps, effectively immobilizing Li+ ions to further fortify the structural stability of HTLs. Based on this non-volatile solid-state doping strategy, tBP-free devices have achieved a record certified power conversion efficiency of 26.34% and demonstrate unprecedented operational reliability. The devices retain over 90% of initial performance after 2,000 h of continuous 1-sun illumination. This study presents a universal approach for reliable doping of organic materials in optoelectronic devices.

To elevate the performance and durability of perovskite solar cells, a holistic approach to mitigating defects throughout the device is essential. While advancements in refining top interfaces have been significant, the potential of stabilizing buried interfaces and grain boundaries has not been fully tapped. The research underscores the transformative impact of guanidine phosphate (GP), a chemical agent that converts surplus PbI2 into a low-dimensional perovskite, thus reinforcing the stability of both buried interfaces and grain boundaries. Employing GP on quantum dot tin dioxide (QD-SnO2) surfaces revealed an exceptional grain wrapping effect at these critical junctures, as revealed by high-resolution transmission electron microscopy. This novel low-dimensional perovskite enveloping strategy not only passivates the grain boundaries but also delays the cooling of hot carriers, thereby diminishing charge carrier recombination. This strategy exhibits an enhanced power conversion efficiency, rising from 23.16% to 24.55%. Moreover, the modified device sustains over 90% of their initial efficiency after 1000 h of maximum power point tracking under one sun illumination and maintain 90% efficiency after 1400 h in moderate humidity, all achieved without the encapsulation. This breakthrough points to a robust method for augmenting perovskite solar cell, promising a more durable, and efficient solar energy. The research utilizing guanidine phosphate in perovskite films creates a low-dimensional perovskite enveloping layer at the buried interface and grain boundaries, enhancing exciton dissociation, and reducing recombination while improving moisture resistance. This approach results in an improved power conversion efficiency and a T90 lifetime of 1000 h under MPPT tests, marking an advancement in perovskite solar energy technology. image

High efficiency and long-term stability are the prerequisites for the commercialization of perovskite solar cells (PSCs). However, inadequate and non-uniform doping of hole transport layers (HTLs) still limits the efficiency improvements, while the intrinsic instability of HTLs caused by ion migration and accumulation is difficult to be addressed by external encapsulation. Here it is shown that the addition of a conjugated phosphonic acid (CPA) to the Spiro-OMeTAD benchmark HTL can greatly enhance the device efficiency and intrinsic stability. Featuring an optimal diprotic-acid structure, indolo(3,2-b)carbazole-5,11-diylbis(butane-4,1-diyl) bis(phosphonic acid) (BCZ) is developed to promote morphological uniformity and mitigate ion migration across both perovskite/HTL and HTL/Ag interfaces, leading to superior charge conductivity, reinforced ion immobilization, and remarkable film stability. The dramatically improved interfacial charge collection endows BCZ-based n-i-p PSCs with a champion power conversion efficiency of 24.51%. More encouragingly, the BCZ-based devices demonstrate remarkable stability under harsh environmental conditions by retaining 90% of initial efficiency after 3000 h in air storage. This work paves the way for further developing robust organic HTLs for optoelectronic devices.

A self-assembled monolayer of DCB-BPA hole-selective layer facilitates the improved buried-interface quality, leading to a certified V OC of 1.339 V of 1.77 eV wide-bandgap perovskite solar cells.

All-perovskite tandem solar cells (TSCs) have exhibited higher efficiencies than single-junction perovskite solar cells (PSCs) but still suffer from the unsatisfactory performance of low-bandgap (LBG) tin-lead (Sn-Pb) subcells. The inherent properties of PEDOT:PSS are crucial to high-performance Sn-Pb perovskite films and devices; however, the underlying mechanism has not been fully explored and revealed. Here, we report a facile oxalic acid treatment of PEDOT:PSS (OA-PEDOT:PSS) to precisely regulate its work function and surface morphology. OA-PEDOT:PSS shows a larger work function and an ordered reorientation and fiber-shaped film morphology with efficient hole transport pathways, leading to the formation of more ideal hole-selective contact with Sn-Pb perovskite for suppressing interfacial nonradiative recombination losses. Moreover, OA-PEDOT:PSS induces (100) preferred orientation growth of perovskite for higher-quality Sn-Pb films. Last, the OA-PEDOT:PSS–tailored LBG PSC yields an impressive efficiency of up to 22.56% (certified 21.88%), enabling 27.81% efficient all-perovskite TSC with enhanced operational stability.

Naphthalene diimides (NDI) are widely serving as the skeleton to construct electron transport materials (ETMs) for optoelectronic devices. However, most of the reported NDI-based ETMs suffer from poor interfaces with the perovskite which deteriorates the carrier extraction and device stability. Here, a representative design concept for editing the peripheral groups of NDI molecules to achieve multifunctional properties is introduced. The resulting molecule 2,7-bis(2,2,3,3,4,4,4-heptafluorobutyl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone (NDI-C4F) incorporated with hydrophobic fluorine units contributes to the prevention of excessive molecular aggregation, the improvement of surface wettability and the formation of strong chemical coordination with perovskite precursors. All these features favor retarding the perovskite crystallization and achieving superior buried interfaces, which subsequently promote charge collection and improve the structural compatibility between perovskite and ETMs. The corresponding PSCs based on low-temperature processed NDI-C4F yield a record efficiency of 23.21%, which is the highest reported value for organic ETMs in n-i-p PSCs. More encouragingly, the unencapsulated devices with NDI-C4F demonstrate extraordinary stability by retaining over 90% of their initial PCEs after 2600 h in air. This work provides an alternative molecular strategy to engineer the buried interfaces and can trigger further development of organic ETMs toward reliable PSCs.

The heat pipe cooled microreactor (HPMR) has become increasingly popular in the realm of research, largely due to its clean, efficient, and safe properties. This paper presents the development of Myrmecia, a simulation software built on the MOOSE framework. Myrmecia integrates the thermodynamic model and failure analysis model of a heat pipe, facilitating the assessment of the failure probability of a given heat pipe based on its thermodynamic parameters and design parameters. The verification of both models has been conducted. The findings demonstrate that increasing the wall thickness of the heat pipe leads to a reduction in its heat transfer capacity, while significantly decreasing the failure probability. Furthermore, appropriately elevating the initial temperature contributes to a decreased likelihood of a break event occurring in the heat pipe. Under the assumption of a fixed heat source/sink temperature, enlarging the inner diameter of the heat pipe exerts negligible influence on the failure probability, yet substantially enhances its heat transfer capability. In summary, various parameters of the heat pipe exert considerable influence on both its safety performance and heat transfer performance. Consequently, the trade-off between these two aspects represents a critical consideration for heat pipe designers.

The wastewater generated by nuclear power plants contains a large number of radioactive substances, including 134Cs and 137Cs, which pose significant threats to human health and the environment. It is crucial to remove these radioactive substances from the nuclear waste. A significant challenge we encounter is the effective and selective extraction of cesium ions from wastewater. The wastewater is typically rich in competition ions and spans a wide pH range. In this report, we report a novel manganese silicate/MoS2 composite material with high adsorption capacity for selectively removing Cs+ from aqueous solutions with competition ions. Adsorption behaviors of cesium ions were investigated for composite ratio, adsorbent dosage, contact time, pH and competitive cations. Optimal conditions for the adsorption of cesium ions from aqueous solutions were achieved using a composite ratio of manganese silicate to MoS2 at 9:1, an adsorbent concentration of 1.0 g L-1, and a pH of 8 for a duration of 1 h. While the impact of K+ and Na+ is minimal at lower concentrations, it becomes more pronounced with increasing concentrations. The composite material demonstrates effective performance over the pH range of 2.0-12.0. Experimental data fitted with the pseudo-second-order kinetics and the Langmuir isotherm model suggests a single-layer chemical adsorption process, resulting in a remarkable adsorption capacity of 78.99 mg g-1. Microscopic analysis reveals the synergistic effect of manganese silicate and MoS2. The manganese silicate provides efficient active sites for selective Cs+ adsorption, while MoS2 allows the highly dispersed surface for manganese silicate. This work reveals new insights into the design and synthesis of high-performance Cs+ adsorption materials for application in the treatment of nuclear wastewater.

Poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) represents the state-of-the-art hole transport material (HTM) in inverted perovskite solar cells (PSCs). However, unsatisfied surface properties of PTAA and high energy disorder in the bulk film hinder the further enhancement of device performance. Herein, a simple small molecule 10-(4-(3,6-dimethoxy-9H-carbazol-9-yl)phenyl)-3,7-bis(4-vinylphenyl)-10H-phenoxazine (MCz-VPOZ) is strategically developed for in situ fabrication of polymer hole conductor (CL-MCz) via a facile and low-temperature cross-linking technology. The resulting polymer CL-MCz offers high energy ordering and improved electrical conductivity, as well as appropriate energy-level alignment, enabling efficient charge carrier collection in the devices. Meanwhile, CL-MCz synchronously provides satisfied surface wettability and interfacial functionalization, facilitating the formation of high-quality perovskite films with fewer bulk iodine vacancies and suppressed carrier recombination. Significantly, the device with CL-MCz yields a champion efficiency of 23.9% along with an extremely low energy loss down to 0.41 eV, which represents the highest reported efficiency for non-PTAA-based polymer HTMs in inverted PSCs. Furthermore, the corresponding unencapsulated devices exhibit competitive shelf-life stability under various operational stressors up to 2500 h, reflecting high promises of CL-MCz in the scalable PSC application. This work underscores the promising potential of the cross-linking approach in preparing low-cost, stable, and efficient polymer HTMs toward reliable PSCs.

Interfaces between functional layers in perovskite solar cells (PSCs) are of paramount importance in determining their efficiency and stability, but the interaction and stability of metal-hole conductor (HC) interfaces have received less attention. Here, we discover an intriguing transient behavior in devices which induces a profound efficiency fluctuation from 9 to 20% during the initial performance testing. Air exposure (e.g., oxygen and moisture) can significantly accelerate this nonequilibrium process and simultaneously enhance the device maximal efficiency. Structural analysis reveals that the chemical reaction between Ag and HC occurred during the metal deposition by thermal evaporation, leading to the formation of an insulating barrier layer at their interfaces, which results in a high charge-transport barrier and poor device performance. Accordingly, we propose a metal diffusion-associated barrier evolution mechanism to understand the metal/HC interfaces. To mitigate these detrimental effects, we strategically develop an interlayer strategy by introducing an ultrathin layer of molybdenum oxide (MoO3) between Ag and HC, which is found to effectively suppress the interfacial reaction, yielding highly reliable PSCs with instant high efficiency. This work provides new insights into understanding the metal-organic interfaces, and the developed interlayer strategy can be generally applicable to engineer other interfaces in realizing efficient and stable contacts.

All-inorganic semiconductor CsBi3I10 (CBI) has recently been recognized as promising alternatives to lead-based light harvesting materials. However, poor film quality and high defects greatly limit its photovoltaic performance in solar cell applications. Here, a simple and effective multifunctional additive of lead thiocyanate (Pb(SCN)2) is doped into CBI for tailoring film morphology and optoelectronic properties. Synergistic effects of Pb2+ and pseudohalide SCN- enable fine regulation of CBI crystallization as well as defects passivation, resulting in the formation of high-quality thin film with desirable uniformity, negligible pinholes, high electrical conductivity and remarkable moisture tolerance. The additive Pb(SCN)2 can efficiently alleviate moisture-induced degrada-tion mechanism by inhibiting the phase transition from CBI to Cs3Bi2I9. In addition, the resulting solar cells exhibit significantly enhanced carrier lifetime, reduced charge recombination and increased charge collection yield, leading to a record efficiency of 1.13 % for planar CBI-based thin film solar cells. This work suggests additive engineering is efficient to modulate film properties and solar cell performance, which could be generally applicable to fabricate other Bi-based thin film and optoelectronic devices.

Investigation and optimization of the buried interfaces are crucial for further improving the efficiency and stability of perovskite solar cells (PSCs). In this work, a general route to modify the interfaces of electron conductor is strategically developed via introducing a well‐designed core@dual–shell structure based on SnO2 nanoparticles grafted by potassium thiocyanate (KSCN) and polyethylene oxide (PEO). This graded bimolecular strategy is desired as it efficiently decouples the processes of defect healing and crystallization engineering. Synergistic effects of KSCN and PEO lead to superior structural uniformity at the buried interfaces, enhanced charge collection, as well as the suppressed carrier recombination. Consequently, a significant increase of efficiency from 20.0% to 23.01% is achieved, accompanied by a remarkable open‐circuit voltage of 1.19 V and extremely low energy losses down to 0.4 eV. Moreover, this interfacial configuration enables the unencapsulated devices to have greatly improved performance longevity by retaining 87% of initial power after 5112 h storage in air, as well as strong mechanical endurance by maintaining over 80% of initial efficiency after 4700 bending cycles at a curvature radius of 5 mm for flexible devices. This work offers an effective and generally applicable approach for engineering the nanostructured interface to realize stable and efficient PSCs.

Perovskites solar cells (PSCs) have been recognized as one of the most prospective photovoltaic technologies for their combined properties of simple fabrication process, low material cost, and remarkable power conversion efficiencies of over 25%. However, the instability and poor reliability of PSCs remain the major obstacles to their practical applications. Specifically, light-soaking effect (LSE), which refers to the fluctuations of photovoltaic parameters under light exposure, represents a critical factor limiting the accuracy and stability of device power output. However, great challenges still remain in understanding and modulating the LSE in PSCs. In this review, we discuss different transient behaviors associated with LSE, and summarize various physical mechanisms (such as light-induced ions migration, trap defect passivation, lattice expansion, and charge carrier accumulation) behind the LSE together with their impacts to the device performance. Moreover, we systematically review the recent advances in developing effective approaches and strategies to mitigate or eliminate the LSE in PSCs, including interfacial modification, material doping, and surface passivation. Finally, a perspective and outlook toward LSE-free PSCs are further provided. This review offers a deeper opinion of the LSE physics with further guidance on ways to optimize the photostability of PSCs.

The bottom hole transport layers (HTLs) are of paramount importance in determining both the efficiency and stability of inverted perovskite solar cells (PSCs), however, their surface nature and properties strongly interfere with the upper perovskite crystallization kinetics and also influence interfacial carrier dynamics. In this work, we strategically develop a simple, facile and spontaneous fabrication method of the HTL at the perovskite/electrode interface by dynamic self-assembly (DSA) of small molecules during perovskite crystallization. Different from the traditional layer-by-layer approach, this DSA strategy involves a bilateral movement of self-assembled molecules (SAMs) from perovskite solution, realizing simultaneous fabrication of the HTL and perovskite surface passivation. We design a multifunctional molecule, (4-(7H-benzo[c]carbazol-7-yl)butyl)phosphonic acid (BCB-C4PA), for the DSA process, to optimize both self-assembly ability and interfacial energy alignment. Benefitting from this unconventional DSA approach and BCB-C4PA, a champion PCE of 22.2% is achieved along with remarkable long-term environmental stability for over 2750 h, which is among the highest reported efficiencies for SAM-based PSCs. This investigation provides a creative, unique and effective molecular approach for preparing reliable charge transport layers, opening up new avenues for the further development of efficient interfacial contacts for PSCs.