Light Soaking Research Articles

Improved Light Soaking and Thermal Stability of Organic Solar Cells by Robust Interfacial Modification

The most widely used material in electron transport layers (ETL) of inverted organic solar cells (iOSCs) is zinc oxide (ZnO). However, the brittleness, inorganic nature, surface defects, and photocatalytic activity of ZnO lead to poor stability in iOSCs. Herein, the light‐soaking and thermal stability of iOSCs are substantially improved by modifying ZnO surface with polyurethane diacrylate (SAR) or urethane acrylate (OCS)‐based ultraviolet (UV) resins. The UV resins significantly reduce the energy barrier, suppress surface defects, and improve interfacial contact between ZnO ETL and the organic photoactive layer. Notably, the SAR and OCS resins mitigate the photocatalytic activity of ZnO, electrical leakage, and interfacial resistance during photoaging of OSCs. As a result, iOSCs based on modified ZnOs retain over 80% of initial efficiency under 1 sun illumination for light soaking 1000 h. Furthermore, SAR and OCS resins on ZnO surfaces form a robust crosslinked network with excellent solvent resistant properties, which result in enhanced thermal stability. These results reveal that this simple and effective approach is a promising procedure to fabricate high‐performance iOSCs.

Multifunctional sulfonium-based treatment for perovskite solar cells with less than 1% efficiency loss over 4,500-h operational stability tests

The stabilization of grain boundaries and surfaces of the perovskite layer is critical to extend the durability of perovskite solar cells. Here we introduced a sulfonium-based molecule, dimethylphenethylsulfonium iodide (DMPESI), for the post-deposition treatment of formamidinium lead iodide perovskite films. The treated films show improved stability upon light soaking and remains in the black α phase after two years ageing under ambient condition without encapsulation. The DMPESI-treated perovskite solar cells show less than 1% performance loss after more than 4,500 h at maximum power point tracking, yielding a theoretical T80 of over nine years under continuous 1-sun illumination. The solar cells also display less than 5% power conversion efficiency drops under various ageing conditions, including 100 thermal cycles between 25 °C and 85 °C and an 1,050-h damp heat test.

Synergetic interfacial conductivity modulation dictating hysteresis evolution in perovskite solar cells under operation.

In this work, the configuration of compact TiO2 coating (c-TiO2) interface as electron transport layer (ETL) in giving rise to loss and gain of fill factor (FF) and therefore modulation of hysteresis behavior in perovskite solar cells (PSCs) is investigated. For this purpose, PSCs based on planar compact TiO2 (c-TiO2) as well as a scaffold-based architecture are studied. In the latter case c-TiO2 coats a hydrothermally grown titania nanorod scaffold. The results demonstrate that when c-TiO2 is used in planar configuration, FF considerably improves with prolonged light soaking which is in sharp contrast to what is observed for scaffold-based PSCs. Moreover, higher thickness of planar c-TiO2 is shown to be beneficial for sustaining FF in forward scan. Finally, through studying the intricate interfacial dynamics utilizing electrochemical impedance spectroscopy (EIS), it was concluded that for a PSC under operation, the cumulative effect of conductivity modulation at the perovskite with transport layer interfaces, for their respective charge carriers, determines the loss and gain in performance depending on scan rate, applied bias and prolonged light soaking. This work points towards multiple factors affecting PSC output, which could work either in confluence or against one another depending on the interfacial configuration of transport layers.

Accelerated Redox Reactions Enable Stable Tin-Lead Mixed Perovskite Solar Cells.

The facile oxidation of Sn2+ to Sn4+ poses an inherent challenge that limits the efficiency and stability of tin-lead mixed (Sn-Pb) perovskite solar cells (PSCs) and all-perovskite tandem devices. In this work, we discover the sustainable redox reactions enabling self-healing Sn-Pb perovskites, where their intractable oxidation degradation can be recovered to their original state under light soaking. Quantitative and operando spectroscopies are used to investigate the redox chemistry, revealing that metallic Pb0 from the photolysis of perovskite reacts with Sn4+ to regenerate Pb2+ and Sn2+ spontaneously. Given the sluggish redox reaction kinetics, V3+ /V2+ ionic pair is designed as an effective redox shuttle to accelerate the recovery of Sn-Pb perovskites from oxidation. The target Sn-Pb PSCs enabled by V3+ /V2+ ionic pair deliver an improved power conversion efficiency (PCE) of 21.22 % and excellent device lifespan, retaining nearly 90 % of its initial PCE after maximum power point tracking under light for 1,000 hours.

Accelerated Redox Reactions Enable Stable Tin‐Lead Mixed Perovskite Solar Cells

AbstractThe facile oxidation of Sn2+ to Sn4+ poses an inherent challenge that limits the efficiency and stability of tin‐lead mixed (Sn−Pb) perovskite solar cells (PSCs) and all‐perovskite tandem devices. In this work, we discover the sustainable redox reactions enabling self‐healing Sn−Pb perovskites, where their intractable oxidation degradation can be recovered to their original state under light soaking. Quantitative and operando spectroscopies are used to investigate the redox chemistry, revealing that metallic Pb0 from the photolysis of perovskite reacts with Sn4+ to regenerate Pb2+ and Sn2+ spontaneously. Given the sluggish redox reaction kinetics, V3+/V2+ ionic pair is designed as an effective redox shuttle to accelerate the recovery of Sn−Pb perovskites from oxidation. The target Sn−Pb PSCs enabled by V3+/V2+ ionic pair deliver an improved power conversion efficiency (PCE) of 21.22 % and excellent device lifespan, retaining nearly 90 % of its initial PCE after maximum power point tracking under light for 1,000 hours.

Metastable defect curing by alkaline earth metal in chalcogenide thin-film solar cells

This study investigates the use of an alkaline earth metal precursor (MgF2) to enhance the performance of chalcogenide-based Cu(In,Ga)Se2 (CIGS) solar cells with a chemically bath deposited-Zn(O,S) (CBD-Zn(O,S)) buffer layer via post-deposited treatment (PDT). The optimal substrate temperature and layer thickness are 570 °C and 5 nm, and the light soaking (LS) treatment does not be required in this condition. The morphological properties and chemical reaction at the p-n junction of CIGS/CBD-Zn(O,S) are examined as a function of MgF2 PDT layer thickness. As the MgF2 PDT layer thickness increases, the CIGS surface becomes rough with vigorously agglomerated Cu clusters owing to the substantially high substrate temperature, which increases the incorporation of In-Se bonds and the oxygenation rate of MgF2. Density functional theory (DFT) clarifies the improved cell efficiency without the need for LS treatment (MgF2 PDT, 5 nm) by calculating the defect-related electronic behavior. The MgF2 phase effectively passivates metastable defect Cu-Se vacancy defects (VCu-Se), related to the LS effect without the additional formation of deep-level defect states into the CIGS bandgap. Moreover, VCu-Se states exert the most influence on the LS effect, and the control of defect states in the CIGS layer (not the buffer layer) is crucial for cell efficiency.

Optical properties and stability of Coumarin 7 luminescent down shifting layers in different host polymers

In this work, pristine Coumarin 7 (C7) layers and mixtures of C7 with Poly(methyl methacrylate) (PMMA), Polycarbonate (PC) and Polyurethane (PU) were produced by drop casting and characterized by UV-vis absorption and Photoluminescence spectroscopy, aiming at investigating the effect of the different host polymers on the optical properties of the luminescent material. The optical properties of the luminescent down shifting LDS layers are adjusted by using the different polymers, different solvents and by changing the relative concentration of the host, resulting in Photoluminescence Quantum Yield (PLQY) values of 98, 92 and 96% for C7:PMMA, C7:PC and C7:PU layers, respectively. The overall enhancement in emission is about 5 times when compared to pristine C7 layers (PLQY = 19% in DMSO solvent). The effect of the different LDS layers in a simulated Perovskite Solar Cell (PSC) was assessed using Rothemundś model. The External Quantum Efficiency (EQE) curve of the simulated device was obtained using SCAPS-1D software and calculations with Rothemund's model show enhancements of about 11, 15 and 17% in the short-circuit current density when C7:PC, C7:PU and C7:PMMA LDS layers are used, respectively. The stability of the layers under different stressing conditions was examined with Differential Scanning Calorimetry DSC measurements and optical characterizations. There is no dramatic effect of the temperature on the optical properties of the layers, however, upon interaction with light, PLQY values are significantly reduced during the first hours of light soaking. C7:PMMA layers were the more stable combination after the light-soaking stability tests, indicating that PMMA is the most suitable option as host matrix for organic LDS dyes, with potential applications in photovoltaic devices. Our work highlights the importance of choosing the host polymer and evaluate its stability for the successful application of organic LDS layers in solar cells.

Light Induced Degradation Quantification by Monitoring the VOC Output of Silicon Solar Cell Using Low-Cost Real-Time Virtual Instrumentation

Silicon-based solar cells suffer from different types of light-induced efficiency losses (can cause up to 10% loss), known as light-induced degradation (LID). Impurities, such as boron, iron, and oxygen, are common at different concentrations in these solar cells. They form active recombination defects in boron-doped mono-crystalline (Cz-Si) and multi-crystalline (mc-Si) solar cells during illumination. For the solar industry, this will lead to serious financial loss, hence the importance of inspecting and controlling the LID level accurately. Seeking to minimize the human factor and the inaccuracy that comes with it, we have proposed in this research a low-cost virtual instrumentation solution to provide a new real-time instrumentation technique for solar cell characteristics such as open circuit voltage (VOC). The virtual data acquisition system (VDAS) design is based on a low-cost Arduino board associated with MATLAB/Simulink software. Moreover, this system can collect in real time the values of solar cell outputs under prolonged illumination and under different temperatures of the LID test. Further, kinetic modeling of the solar cell output VOC variation as a function of light soak duration; shows the predominance of one type metastable defect over the LID test of c-Si solar cells. Additionally, degradation mechanism in mc-Si solar cells involve more than one metastable defect and are more complexes due to the mc-Si substrate elaboration technique compared to c-Si substrate. Furthermore, the temperature dependence of the concentrations (NVoc) and the thermal activation energies of the defects have been extracted from the experimental VOC measurements obtained using the VDAS. Finally, the system minimizes the test period and errors for solar cell characterization compared to traditional approaches.

Mismatch of Quasi–Fermi Level Splitting and Voc in Perovskite Solar Cells

AbstractPerovskite solar cells have demonstrated low non‐radiative voltage losses and open‐circuit voltages (VOCs) that often match the internal voltage in the perovskite layer, i.e. the quasi‐Femi level splitting (QFLS). However, in many cases, the VOC differs remarkably from the internal voltage, for example in devices without perfect energy alignment. In terms of recombination losses, this loss often outweighs all non‐radiative recombination losses observed in photoluminescence quantum efficiency measurements by many orders of magnitude. As such, understanding this phenomenon is of great importance for further perovskite solar cell development and tackling stability issues. The classical theory developed for Si solar cells explains the QFLS‐VOC mismatch by considering the partial resistances/conductivities for majority and minority carriers. Here, the authors demonstrate that this generic theory applies to a variety of physical mechanisms that give rise to such a mismatch. Additionally, it is found that mobile ions can contribute to a QFLS‐VOC mismatch in realistic perovskite cells, and it is demonstrated that this can explain various key observations about light soaking and aging‐induced VOC losses. The findings in this paper shine a light on well‐debated topics in the community, identify a new degradation loss, and highlight important design principles to maximize the VOC for improved perovskite solar cells.

Light soaking effect on defect states distribution of Hydrogenated amorphous silicon investigated By means of constant photocurrent technique

In the present paper we have investigated, by using the constant photocurrent method in dc-mode (dc-CPM), the effect of the light soaking (LS) on the deep defect density (Nd) and the slope of the Urbach tail (E0) of a slightly phosphorus-doped hydrogenated amorphous silicon (a-Si:H) film prepared by Plasma-Enhanced Chemical Vapour Deposition (PECVD). By applying the derivative method, we have converted the measured data into a density of states (DOS) distribution in the lower part of the energy gap. The evolution of the sub-band-gap absorption coefficient and the CPMdetermined density of gap-states distribution within the gap versus the illumination time leads to: (i) an increase in the deep defect absorption without any significant changes in the Urbach tail (exponential part), (ii) a presence of more charged than neutral defects as predicted by the defect pool model, and (iii) a saturation point of the degradation of both optical absorption coefficient and density of deep states of slightly P-doped sample measured by dc-CPM. The constant photocurrent technique in dc-mode as a spectroscopy method for the defect distribution determination is, therefore, most reliable to study the light soaking effect on the stability of hydrogenated amorphous silicon layers used in solar cells manufacturing.

Surface Cleaning and Passivation Strategy for Durable Inverted Formamidinium–Cesium Triiodide Perovskite Solar Cells

AbstractFormamidinium‐cesium triiodide (FAxCs1‐xPbI3) perovskite exhibits excellent phase stability, making it the most promising candidate for commercial perovskite solar cell (PSC) applications, particularly those with inverted structures present a promising contribution to the field of perovskite production. However, this composition often forms small grain sizes and has a large number of defects and PbI2 residues on its surface, which can damage device performance. In this study, a post‐surface engineering strategy called the “clean‐passivation” method is proposed to address the interfacial problem between the perovskite and the electron transport layer (ETL). This method significantly reduces surface and grain boundary defects and eliminates unreacted PbI2, resulting in suppressed iodine decomposition and ion migration during operation. As a result, an excellent power conversion efficiency of 24.27% with superior stability is achieved, as the unencapsulated device maintains 97.12% of its initial efficiency after 1500 h of continuous light soaking. Furthermore, this new surface clean‐passivate strategy can be universally applied to other typical perovskite compositions.

Electronic and Photochemical Passivation by a Classic Sunscreen Material Leading to Reduced Voc Losses and Enhanced Stability in Organic Solar Cells.

Organic solar cells (OSCs) have been a popular topic of research for a long time. As a well-known electron transport layer (ETL) material for inverted device architecture, sol-gel-derived zinc oxide (ZnO) displays certain defective surfaces that cause excessive charge recombination and lower device performance. While ultraviolet (UV)-light soaking is sometimes necessary for the ZnO layer to function properly, the latter can also cause the photodegradation of conjugated organic semiconductors. The photostability of OSCs has always been a hot research topic, as the radiation of UV light may cause changes in the material's properties, and that, in turn, may cause rapid attenuation of the devices. Herein, ZnO is modified by inserting the commonly used sunscreen ingredient benzophenone-3 (BP-3) between the photoactive layer, consisting of a PM6:Y6 blend, and ZnO to reduce the impact of UV radiation on the photosensitive layer. The addition of BP-3 successfully enhances the photovoltaic parameters, and a remarkable open-circuit voltage (Voc) value of 0.887 V is obtained for PM6:Y6-based inverted solar cells, corresponding to a Voc loss as small as 0.547 V. Finally, the application of this strategy increases the device's power conversion efficiency from 12.44 to 13.71% and provides improved UV stability.

High‐Efficiency Layer‐by‐Layer All‐Polymer Solar Cell Enabled by Bottom‐Layer Optimization

All‐polymer solar cells (all‐PSCs) have attracted extensive attention for their advantages in long‐term thermal‐ and photostability. However, the power conversion efficiencies (PCEs) of all‐PSCs still lag behind organic solar cells based on small‐molecular acceptors. The long‐chain entanglement between polymers brings complex morphological problems, which contribute to lower fill factor (FF). Herein, an effective approach is proposed to build the ideal morphology and pseudo‐p–i–n vertical component distribution in all‐polymer active layer by independently casting donor and acceptor films with different solvents. Through the solvent engineering, the layer‐by‐layer device with o‐xylene and carbon disulfide (O‐XY:CS2)‐processed D18 donor layer achieves a PCE of 17.53%, much higher than commonly used solvents (chloroform and chlorobenzene) processed donor layers with PCEs of 16.49 and 16.04%, respectively. In‐depth investigation reveals that outstanding performance of O‐XY:CS2‐processed donor layer device is attributed to mitigated bimolecular recombination, more balanced mobility, and reduced trap density of states, which contribute to the enhancement of short‐current density and FF. Moreover, favorable morphology network also brings prolonged lifetime under continuous light soaking. This work presents a simple and effective way to obtain ideal active layer morphology and construct favorable vertical component distribution through optimizing donor morphology in all‐PSCs.

Photoluminescence Mapping over Laser Pulse Fluence and Repetition Rate as a Fingerprint of Charge and Defect Dynamics in Perovskites

AbstractDefects in metal halide perovskites (MHP) are photosensitive, making the observer effect unavoidable when laser spectroscopy methods are applied. Photoluminescence (PL) bleaching and enhancement under light soaking and recovery in dark are examples of the transient phenomena that are consequent to the creation and healing of defects. Depending on the initial sample composition, environment, and other factors, the defect nature and evolution can strongly vary, making spectroscopic data analysis prone to misinterpretations. Herein, the use of an automatically acquired dependence of PL quantum yield (PLQY) on the laser pulse repetition rate and pulse fluence as a unique fingerprint of both charge carrier dynamics and defect evolution is demonstrated. A simple visual comparison of such fingerprints allows for assessment of similarities and differences between MHP samples. The study illustrates this by examining methylammonium lead triiodide (MAPbI3) films with altered stoichiometry that just after preparation showed very pronounced defect dynamics at time scale from milliseconds to seconds, clearly distorting the PLQY fingerprint. Upon weeks of storage, the sample fingerprints evolve toward the standard stoichiometric MAPbI3 in terms of both charge carrier dynamics and defect stability. Automatic PLQY mapping can be used as a universal method for assessment of perovskite sample quality.

Suppressing the Light‐Soaking Effect of CsPbI2Br‐Based p–i–n Perovskite Solar Cells

The light‐soaking (LS) effect has been reported to limit the accuracy and stability of device power output of perovskite solar cells (PSCs) and it is significant to develop effective approaches and strategies to eliminate the LS effect in PSCs. There are very few reports on suppressing the LS effect in CsPbI2Br‐based all‐inorganic PSCs. Herein, a method to eliminate the LS effect by synchronous passivation of anionic and cationic defects in CsPbI2Br perovskite film is demonstrated. The 4‐(chlorosulfonyl)benzoic acid (CSBA) is added into perovskite precursor and the in situ generation of I3 − effectively passivates the anionic halogen vacancy defects in CsPbI2Br. In the meantime, the Lewis base groups on CSBA coordinate with Cs+ and Pb2+ to passivate the cationic defects. This zwitterionic passivation effect of CSBA remarkably cuts off the path of defect‐induced charge recombination and thus eliminates the LS effect. This work offers a deep opinion for future researchers to modulate the LS effect of all‐inorganic PSCs.

Improving the light stability of perovskite solar cell with new hole transport material based on spiro[fluorene-9,9′-xanthene

Development of suitable hole transport materials is vital for perovskite solar cells (PSCs) to diminish the energy barrier and minimize the potential loss. Here, a low-cost hole transport molecule named SFX-POCCF3 (23.72 $/g) is designed with a spiro[fluorene-9,9'-xanthene] (SFX) core and terminated by trifluoroethoxy units. Benefiting from the suitable energy level, high hole mobility, and better charge extraction and transport, the PSCs based on SFX-POCCF3 exhibit improved open-circuit voltage by 0.02 V, therefore, the PSC device based on SFX-POCCF3 exhibits a champion PCE of 21.48%, which is comparable with the control device of Spiro-OMeTAD (21.39%). More importantly, the SFX-POCCF3 based PSC possesses outstanding light stability, which retains 95% of the initial efficiency after about 1,000 h continuous light soaking, which is in accordance with the result continuous output at maximum power point. Whereas, Spiro-OMeTAD witnesses a rapid decrease to 80% of its original efficiency after 100 h light soaking. This work demonstrated that an efficient alignment of energy levels between HTL and perovskite will lead to significant highly efficient PSCs with remarkably enhanced light stability.

UV Light-Induced Degradation of Industrial Silicon HJT Solar Cells: Degradation Mechanism and Recovery Strategies

Abstract: The demand for Silicon heterojunction solar cells (HJT) has significantly grown recently. These solar cells have gained recognition for their remarkable performance, which can be attributed to the exceptional passivation properties of bilayers consisting of intrinsic and doped hydrogenated amorphous silicon. This study investigates alternative recovery methods and looks into the deterioration caused by UV radiation in commercial Silicon HJT solar cells. The carrier lifetimes of the samples were measured before and after the HJT solar cells were exposed to ultraviolet radiation. The findings revealed a decrease in carrier lifetime, iVoc, and iFF, indicating the creation of defects in the bulk of a-Si:H and the interface between c-Si and a-Si:H. It was assessed how SiOx performed as a passivation layer. It has been discovered that SiOx can passivate dangling bonds, increase carrier lifetime and reduce trap density. In addition, recovery techniques like current injection, infrared, light soaking, and annealing were applied. The current injection, infrared, and light soaking treatments were discovered to be able to partially restore the efficiency of the solar cells without the combination of temperature, while annealing was found to be more effective. Additionally, the effects of both short and prolonged exposure to UV are investigated. The HJT solar cells exposed to prolonged UV radiation for an extended period of time could not fully regain their efficiency and displayed irreparable flaws. Overall, this study demonstrates the potential of recovery treatments and passivation techniques in increasing the efficiency of Si HJT solar cells and illuminates the processes underlying ultraviolet-induced deterioration. Overall, this study sheds light on ultraviolet-induced degradation mechanisms and highlights the potential of recovery treatments and passivation techniques in enhancing the efficiency of Si HJT solar cells.

Synergistic co-sensitization of environment-friendly chlorophyll and anthocyanin-based natural dye-sensitized solar cells: An effective approach towards enhanced efficiency and stability

This study reports on the preparation of TiO2 nanorods (TNRs) and their application in dye-sensitized solar cells (DSSCs) to enable the production of efficient sources of energy for use in ambient indoor circumstances. The aim of the study is to enhance the efficiency and stability of DSSCs while also making them more affordable and eco-friendly. To achieve this, a novel approach was taken through the synergistic co-sensitization of environment-friendly natural dyes based on Spinacia Oleracea Leaves (SOL: chlorophyll) and Ixora Coccinea Flowers (ICF: anthocyanin). The combination of these dyes improved light absorption and charge separation, leading to enhanced power conversion efficiency. Various physicochemical characterizations of TNRs and dyes were performed and the co-sensitized dyes exhibited greatly enhanced visible-light photo-electrochemical performance which were later evaluated by J-V and electrochemical impedance spectroscopy (EIS) studies. Additionally, the role of various economical and environment-friendly counter electrodes was investigated. Using this co-sensitization technique, FTO/c-TiO2/TNRs/dyes/electrolyte/(C, Ninp, Nip) structured DSSCs were designed for the production of power under ambient light conditions. The optimal PCE of 2.39% is achieved under the artificial irradiation of ∼ 996 Wm−2 which is 2.3 and 4.2- times greater efficiency compared to single natural SOL and ICF-dyes-based DSSCs, respectively. Moreover, the synergistically co-sensitized DSSCs showed improved stability under prolonged light soaking (∼450 h) and storage conditions (at 27 °C). This study highlights the potential of PV technologies in enabling buildings and movable gadgets to become more independent and smarter while also providing an efficient source of energy for use in ambient indoor circumstances.

Short Wavelength Photons Destroying Si–H Bonds and Its Influence on High‐Efficiency Silicon Solar Cells and Modules

Photons of varying wavelengths exert substantial effects on silicon heterojunction (SHJ) solar cells. Collaborative research previously establishes that light soaking with long‐wavelength photons can activate boron doping in hydrogenated amorphous silicon (a‐Si:H), thereby augmenting cell efficiency (Eff). Herein, this investigation is extended, exploring the effects of short‐wavelength photons on a‐Si:H layers, SHJ solar cells, and modules. The ultraviolet A (UVA) light with the wavelengths peak of 365 nm can disrupt Si–H bonds, resulting in a notable reduction in hydrogen content within both intrinsic and doped a‐Si:H films, and the deterioration of deteriorated interface passivation. Following exposure to 60 kWh m−2 of UVA light, both Eff and module power output decrease significantly, primarily attributable to the degradation of open‐circuit voltage and fill factor. As a feasible solution, the application of a light‐soaking process or the implementation of UV band cutoff module encapsulants can effectively mitigate the loss induced by UV irradiation, thereby ensuring the long‐term operation of SHJ solar cells and modules. Herein, a deeper understanding of UV‐induced performance changes in a‐Si:H film and its degradation mechanism for SHJ solar cells are contributed to in this research and also a viable strategy is provided to counter UV‐induced degradation.

Lead-chelating hole-transport layers for efficient and stable perovskite minimodules

The defective bottom interfaces of perovskites and hole-transport layers (HTLs) limit the performance of p-i-n structure perovskite solar cells. We report that the addition of lead chelation molecules into HTLs can strongly interact with lead(II) ion (Pb2+), resulting in a reduced amorphous region in perovskites near HTLs and a passivated perovskite bottom surface. The minimodule with an aperture area of 26.9 square centimeters has a power conversion efficiency (PCE) of 21.8% (stabilized at 21.1%) that is certified by the National Renewable Energy Laboratory (NREL), which corresponds to a minimal small-cell efficiency of 24.6% (stabilized 24.1%) throughout the module area. Small-area cells and large-area minimodules with lead chelation molecules in HTLs had a light soaking stability of 3010 and 2130 hours, respectively, at an efficiency loss of 10% from the initial value under 1-sun illumination and open-circuit voltage conditions.