Printable Perovskite Solar Cells Research Articles

Super-Droplet-Repellent Carbon-Based Printable Perovskite Solar Cells.

Despite attractive cost-effectiveness, scalability, and superior stability, carbon-based printable perovskite solar cells (CPSCs) still face moisture-induced degradation that limits their lifespan and commercial potential. Here, the moisture-preventing mechanisms of thin nanostructured super-repellent coating (advancing contact angle >167° and contact angle hysteresis 7°) integrated into CPSCs are investigated for different moisture forms (falling water droplets vs water vapor vs condensed water droplets). It is shown that unencapsulated super-repellent CPSCs have superior performance under continuous droplet impact for 12h (rain falling experiments) compared to unencapsulated pristine (uncoated) CPSCs that degrade within seconds. Contrary to falling water droplets, where super-repellent coating serves as a shield, water vapor is found to physisorb through porous super-repellent coating (room temperature and relative humidity, RH 65% and 85%) that increase the CPSCs performance for 21% during ≈43 d similarly to pristine CPSCs. It is further shown that water condensation forms within or below the super-repellent coating (40 °C and RH 85%), followed by chemisorption and degradation of CPSCs. Because different forms of water have distinct effects on CPSC, it is suggested that future standard tests for repellent CPSCs should include rain falling and condensate formation tests. The findings will thus inspire the development of super-repellent coatings for moisture prevention.

The impact of carbon nanoparticles derived from sucrose, glucose, and fructose precursors on the performance of fully printed perovskite solar cells

Carbon nanoparticles (CNPs) have emerged as promising biomaterials with applications in energy harvesting devices such as nanogenerators, photovoltaic devices, and electrochemical energy storage. Fully printed perovskite solar cells (PSCs) are gaining attention in solar cell technology. However, the use of CNPs, specifically those synthesized from different carbohydrate precursors (monosaccharide and disaccharide), in fully printed PSCs is not well-explored. This study investigates the impact of CNPs derived from sucrose, glucose, and fructose precursors on the photovoltaic performance of fully printed PSCs with FTO/TiO2/ZrO2/CNPs/Carbon structure. Incorporating CNPs into fully printed PSCs resulted in a notable increase in power conversion efficiency (PCE) compared to cells without CNPs. PSCs with CNPs derived from fructose achieved an impressive PCE of 9.67%, surpassing the 7.91% PCE observed in PSCs without the inclusion of CNPs. Electrochemical impedance spectroscopy (EIS) was employed to assess charge transfer at contact interfaces. The synthesized CNPs underwent comprehensive characterization through various techniques such as transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), photoluminescence spectroscopy (PL), and cyclic voltammetry (CV).

Fully Screen‐Printed Perovskite Solar Cells with 17% Efficiency via Tailoring Confined Perovskite Crystallization within Mesoporous Layer

AbstractUsing a screen‐printing techniques is thought to be a good candidate for simplified, cost‐effective, reliable, and scalable fabrication of fully printed perovskite solar cells (PSCs) for industrialization. Nevertheless, the screen‐printing of perovskite film has not been realized until recently. This group finished the work using ionic liquid methylamine acetate (MAAc) as pure solvent. However, the space‐confining effect during the perovskite crystallization in mesoporous impeded the escape of bottom MAAc molecules, which leads to the poor crystalline quality of the screen‐printed film. In this work, ionic liquid methylamine propionate (MAPa) with stronger coordination is introduced as a co‐solvent to promote the escape of MAAc molecules by forming the solvent volatilization channels in a confined mesoporous structure, which results in the complete MAAc volatilization and high filling degree of perovskite crystals inside the mesoporous structure. Also, MAPa promotes the vertical growth of perovskite crystals and coordinates with unbonded Pb2+ on the perovskite surface, leading to efficient charge transport and interfacial band alignment of the screen‐printed film. Finally, fully screen‐printed PSCs yields a champion power conversion efficiency (PCE) of ≈17%, which is the record value for fully screen‐printed PSCs. Moreover, the unencapsulated device shows robust operational stability that maintains >85.3% of initial PCE (25%RH and 25 °C) under continuous illumination at the maximum power point after 250 h.

Two-in-one additive engineering strategy induced high-quality CsPbBr3 film in printable mesoscopic perovskite solar cells

The use of all-inorganic cesium lead tribromide (CsPbBr3) in photovoltaics has gained significant attention due to its outstanding environmental stability and low cost of preparation. Printable perovskite solar cells (PSCs) based on CsPbBr3 have demonstrated a more straightforward fabrication procedure and remarkable stability, indicating great development potential. However, the preparation of the CsPbBr3 film can be challenging, as it requires depositing a high-quality PbBr2 film in a triple-layer porous scaffold and avoiding the incomplete conversion of PbBr2 in the subsequent step. Herein, we propose a two-in-one additive engineering strategy using 4-tert-Butylpyridine (TBP) into the PbBr2 solution and dimethyl sulfoxide (DMSO) to the CsBr precursor. The improved perovskite layer with better infiltration in scaffold, low carrier recombination rate and high absorption ability results in the boosting performance of PSCs. When the TBP is coupled with DMSO to fabricate printable mesoscopic CsPbBr3 PSCs, the device achieves a power conversion efficiency as high as 8.36 %. Furthemore, the modified CsPbBr3 PSC without any encapsulation retains above 97 % of its initial efficiency after 1600 h of storage in ambient air, indicating outstanding stability.

Enhanced Performance and Stability of Fully Printed Perovskite Solar Cells and Modules by Ternary Additives under High Humidity

To scale up from perovskite solar cells (PSCs) to perovskite solar modules (PSMs), a printing technique with an economical, uncomplicated fabrication process is required to meet the industrial market requirements. Equally important are the high photovoltaic (PV) performance and long-term device stability needed for successful commercialization of the technology. In this study, the effect of ternary additives consisting of guanidinium thiocyanate (GT), thiourea (TU), and urea (U) in MAPbI3 films on power conversion efficiency (PCE) as well as device stability was investigated for the first time based on the experimental results. GT helped influence perovskite crystal grain enlargement, while TU facilitated the perovskite crystal growth, leading to an increase in the current density. Moreover, the use of U was found to reduce the loss in open-circuit voltage as well as the hysteresis of PSC devices. An optimal composition of the ternary additives (1:1:2 molar ratio of GT, TU, and U) resulted in the outstanding performance of fully printed PSCs, showing a PCE of 16.40%, which was significantly higher than that of the pristine device (8.01%). In addition, the unencapsulated device prepared using the ternary additives showed great stability over 1000 h with a PCE retention of 100%, while the PCE of the unencapsulated pristine device decreased by 41.79%. For the large-scale PSM, the ternary additives yielded a significant enhancement of 11.60% PCE, which was over 3 times higher than that for the PSM without additives, as well as 100% retention after 2000 h of both desiccator and ambient storage.

Performance Evaluation of Carbon‐Based Printed Perovskite Solar Cells under Low‐Light Intensity Conditions

Performance Evaluation of Carbon‐Based Printed Perovskite Solar Cells under Low‐Light Intensity Conditions

Solution-Processed SnO2 Quantum Dots for the Electron Transport Layer of Flexible and Printed Perovskite Solar Cells.

Flexible and printed perovskite solar cells (PSCs) fabricated on lightweight plastic substrates have many excellent potential applications in emerging new technologies including wearable and portable electronics, the internet of things, smart buildings, etc. To fabricate flexible and printed PSCs, all of the functional layers of devices should be processed at low temperatures. Tin oxide is one of the best metal oxide materials to employ as the electron transport layer (ETL) in PSCs. Herein, the synthesis and application of SnO2 quantum dots (QDs) to prepare the ETL of flexible and printed PSCs are demonstrated. SnO2 QDs are synthesized via a solvothermal method and processed to obtain aqueous and printable ETL ink solutions with different QD concentrations. PSCs are fabricated using a slot-die coating method on flexible plastic substrates. The solar cell performance and spectral response of the obtained devices are characterized using a solar simulator and an external quantum efficiency measurement system. The ETLs prepared using 2 wt% SnO2 QD inks are found to produce devices with a high average power conversion efficiency (PCE) along with a 10% PCE for a champion device. The results obtained in this work provide the research community with a method to prepare fully solution-processed SnO2 QD-based inks that are suitable for the deposition of SnO2 ETLs for flexible and printed PSCs.

3D Network‐Assisted Crystallization for Fully Printed Perovskite Solar Cells with Superior Irradiation Stability

AbstractMeniscus‐coating as a high‐throughput preparation process has significant advantages in the manufacture of large‐area perovskite solar cells (PSCs). However, the gradient crystallization during printing significantly affects the vertical uniformity of perovskite films, which greatly affects the carrier transport of perovskite films and the stability of PSCs. Here, a perovskite ink compatible with printing technology is reported to realize uniform printing of perovskite film on a 3D scale. The siloxane 3D network hinders the solute migration caused by capillary force and acts as a skeleton to promote the uniform crystallization of perovskite films. Consequently, the corresponding fully printed PSCs have reduced efficiency loss (from 37.4% to 17.0%). In addition, based on the improvement of crystal quality and reduction of defects in perovskite films, the siloxane‐optimized PSCs achieved a championship efficiency of 22.0%, which is one of the highest performance for fully printed devices. The optimized device retains 80% of the initial PCE after 800 h AM 1.5G one‐sun illumination, and only decreases 20% after 160 h of ultraviolet light (365 nm, 20 mW cm−2) irradiation.

Performance Evaluation of Carbon‐Based Printed Perovskite Solar Cells under Low‐Light Intensity Conditions

The use of photovoltaics (PVs) to harvest energy inside modern building environments has great potential for energizing a wide range of futuristic self‐powered electronic devices, Internet of Things (IoT), and sensors using available ambient light. Among the various PV technologies, hole‐conductor‐free carbon‐based printable perovskite solar cells (CPSCs) have attracted significant interest, owing to their impressive PV performance under standard full sunlight conditions, robust stability, and printable fabrication methods. Nevertheless, their ability to harvest indoor light has been rarely explored. Here we report PV performance characterization of these printable CPSCs, and a systematic comparison of their PV performance under commonly available fluorescent (FL) and light‐emitting diode (LED)‐based lamps at various low lux light intensities that replicate standard indoor environmental conditions. To consolidate the proven stability of these CPSCs, the results of one stability test standardized as ISOS‐D‐1, which supports the motivation of their possible deployment under mild indoor lighting conditions are presented. The effective functioning of these CPSCs is also demonstrated for energizing an electrical node as evidence of their potential to be used as an alternative light‐harvesting solution for the targeted futuristic IoT‐based ecosystem. These results greatly support the goal of developing all printed and sustainable IoT devices with robust performance stability.

Synergistic Effect of Anti‐Solvent and Component Engineering for Effective Passivation to Attain Highly Stable Perovskite Solar Cells

Defect passivation is a crucial process for achieving high‐performance perovskite solar cells (PSCs). Herein, the synergistic effect of anti‐solvent and component engineering for effective passivation to attain highly stable PSCs is demonstrated, specifically, for ethyl acetate as the anti‐solvent and CsBr as the additive in the MAPbI3 precursor solution. It is found that the rapid solvent evaporation results in fast nucleation, and the CsBr assists the perovskite grain growth. The synergistic effect of anti‐solvent and additive engineering leads to increased perovskite grain size, reduced defect density, improved quality of the perovskite thin film, and finally, enhanced efficiency and stability of the indium tin oxide/SnO2/perovskite/carbon device. The influence of this synergistic effect on the morphology and photovoltaic performance is systematically investigated. Printable PSCs with hole‐transport‐layer‐free carbon electrodes are designed and constructed, which achieve a champion photoelectric conversion efficiency of 16.45%, fill factor of 72.63%, short circuit current of 19.90 mA cm−2, and open circuit voltage of 1.14 V. Herein, a facile and low‐cost approach is demonstrated to obtain highly stable C‐PSCs and a promising strategy for future commercial application is provided.

Recent Development and Directions in Printed Perovskite Solar Cells

Just over a decade ago, perovskite solar cells (PSCs) established themselves as the next generation of photovoltaic technology due to their comparably higher power conversion efficiency (PCE) (25.6%), cheaper and simpler manufacturing processes to that of Silicon solar cells. Based on the potential, several methods and processes have been developed to produce high‐quality perovskite films for commercialization of PSCs. It has recently been found that printing technology is very effective in controlling film formation, resulting in a high PCE of over 21%. This review summarizes the intense research that has been done on newer printing techniques to enlarge perovskite films and other layers such as the hole transport layer (HTL), the electron transport layer (ETL), and electrodes for PSCs. At the end, the review article describes the future scope of research to address the challenges of commercializing PSCs.

Application of Lead Acetate Additive for Printable Perovskite Solar Cell

Application of Lead Acetate Additive for Printable Perovskite Solar Cell

Two-dimensional BiTeI as a novel perovskite additive for printable perovskite solar cells.

Hybrid organic-inorganic perovskite solar cells (PSCs) are attractive printable, flexible, and cost-effective optoelectronic devices constituting an alternative technology to conventional Si-based ones. The incorporation of low-dimensional materials, such as two-dimensional (2D) materials, into the PSC structure is a promising route for interfacial and bulk perovskite engineering, paving the way for improved power conversion efficiency (PCE) and long-term stability. In this work, we investigate the incorporation of 2D bismuth telluride iodide (BiTeI) flakes as additives in the perovskite active layer, demonstrating their role in tuning the interfacial energy-level alignment for optimum device performance. By varying the concentration of BiTeI flakes in the perovskite precursor solution between 0.008 mg mL-1 and 0.1 mg mL-1, a downward shift in the energy levels of the perovskite results in an optimal alignment of the energy levels of the materials across the cell structure, as supported by device simulations. Thus, the cell fill factor (FF) increases with additive concentration, reaching values greater than 82%, although the suppression of open circuit voltage (V oc) is reported beyond an additive concentration threshold of 0.03 mg mL-1. The most performant devices delivered a PCE of 18.3%, with an average PCE showing a +8% increase compared to the reference devices. This work demonstrates the potential of 2D-material-based additives for the engineering of PSCs via energy level optimization at perovskite/charge transporting layer interfaces.

Mechanism of the Dimethylammonium Cation in Hybrid Perovskites for Enhanced Performance and Stability of Printable Perovskite Solar Cells

Upscaling efficient and stable perovskite materials is vital for metal halide perovskite solar cells (PSCs) and additive engineering contributes a lot to making high‐quality PSCs. While the recent examples involved mixing dimethylammonium (DMA) cation has been employed for the fabrication of all‐inorganic perovskites with improved efficiency and stability, the role of DMA cation in hybrid perovskite (formamidinium lead triiodide, denoted as FAPbI3) remains inconclusive. Herein, DMA cations are substituted for FA sites of Cs0.12FA0.88PbI3 for printable triple mesoscopic PSCs and shed lights on the roles and mechanism of DMA in the perovskite. It is found that a small amount of DMA is doped into the perovskite lattices, meanwhile, an intermediate compound DMAPbI3 is formed and exists at grain boundaries, which improves the crystallinity of perovskite films and reduces nonradiative recombination through a passivation role. With these benefits, the best‐performing printable PSC attained a power conversion efficiency of 17.46%. Unencapsulated devices maintained over 96% of the initial efficiencies in ambient condition for 960 h and 95% of the initial efficiencies after 360 h under continuous thermal aging at 85 °C in N2 atmosphere.

Microfluidic Processing of Ligand‐Engineered NiO Nanoparticles for Low‐Temperature Hole‐Transporting Layers in Perovskite Solar Cells

Nickel oxide (NiO) is used as a hole‐transporting layer (HTL) in perovskite solar cells (PSCs) because of its high optical transmittance, intrinsic p‐type doping, and suitable valence band energy level. However, fabricating high‐quality NiO films typically requires high‐temperature annealing, which limits their applicability for low‐temperature, printable PSCs. Herein, the need for such postprocessing steps is circumvented by coupling 4‐hydroxybenzoic acid (HBA) or trimethyloxonium tetrafluoroborate (Me3OBF4) ligand‐modified NiO nanoparticles (NPs) with a Tesla‐valve microfluidic mixer to deposit high‐quality NiO films at a temperature <150 °C. The NP dispersions and the resulting thin films are thoroughly characterized using a combination of optical, structural, thermal, chemical, and electrical methods. While the optical and structural properties of the ligand‐exchanged NiO NPs remain comparable with those possessing the native long‐chained aliphatic ligands, the ligand‐modified NiO thin films exhibit dramatic reductions in surface energy and an increase in hole mobilities. These are correlated with concomitant and significant enhancements in performance and stability factors of PSCs when the ligand‐modified NiO NPs are used as HTL layers within p−i−n device architectures.

A data fusion approach to optimize compositional stability of halide perovskites

Summary Search for resource-efficient materials in vast compositional spaces is an outstanding challenge in creating environmentally stable perovskite semiconductors. We demonstrate a physics-constrained sequential learning framework to subsequently identify the most stable alloyed organic-inorganic perovskites. We fuse data from high-throughput degradation tests and first-principle calculations of phase thermodynamics into an end-to-end Bayesian optimization algorithm using probabilistic constraints. By sampling just 1.8% of the discretized CsxMAyFA1−x−yPbI3 (MA, methylammonium; FA, formamidinium) compositional space, perovskites centered at Cs0.17MA0.03FA0.80PbI3 show minimal optical change under increased temperature, moisture, and illumination with >17-fold stability improvement over MAPbI3. The thin films have 3-fold improved stability compared with state-of-the-art multi-halide Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3, translating into enhanced solar cell stability without compromising conversion efficiency. Synchrotron-based X-ray scattering validates the suppression of chemical decomposition and minority phase formation achieved using fewer elements and a maximum of 8% MA. We anticipate that this data fusion approach can be extended to guide materials discovery for a wide range of multinary systems.

Chlorine management of a carbon counter electrode for high performance printable perovskite solar cells

The schematic of the effects of chlorinated graphite (C–Cl) on the interface of carbon and perovskite and the energy level alignment.

Efficient fully blade-coated perovskite solar cells in air with nanometer-thick bathocuproine buffer layer

Fully printed perovskite solar cells (PSCs) were fabricated in air with all constituent layers, except for electrodes, deposited by the blade coating technique. The PSCs incorporated, for the first time, a nanometer-thick printed bathocuproine (BCP) hole blocking buffer using blade coating and deposited at relative humidity up to 50%. The PSCs with a p-i-n structure (glass/indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/CH3NH3PbI3/[6,6]-phenyl-C61-butyric acid methyl ester (PCBM)/BCP/Ag) delivered a maximum power conversion efficiency (PCE) of 14.9% on an active area of 0.5 cm2 when measured under standard test conditions. The PSCs with a blade coated BCP delivered performance of 10% and 63% higher (in relative terms) than those incorporating a spin coated BCP or without any BCP film, respectively. The atomic force microscopy (AFM) showed that blade coated films were more homogeneous and acted also as a surface planarizer leading to a reduction of roughness which improved BCP/Ag interface lowering charge recombination. The demonstration of 15% efficient devices with all constituent layers, including nanometer-thick BCP (∼ 10 nm), deposited by blade coating in air, demonstrates a route for industrialization of this technology.

Effects of HI Additive on the Crystallization of Perovskite in Printed Mesoscopic Scaffolds

Carbon-based fully printable perovskite solar cells (CFP-PSCs) are attracting interests of many researchers, because of their easy large-scale fabrication and their high stability. In order to improve the photovoltaic conversion efficiency (PCE) of PSCs, it is necessary to optimize the crystallization processes of perovskite films. Hydrogen iodide (HI) additive enhances the solubility of PbI2 or PbCl2 and retards the growth of perovskite crystals, resulting in round-shaped crystals and high photovoltaic efficiency. In this paper, the effects of HI additive on the PCE and stability of the CFP-PSCs are tested. It is found that PCE enhancement was achieved by mixing much smaller concentration of HI additive into the precursor solution as compared to the concentrations in other reports. The mesoscopic scaffolds might suppress the evaporation of HI additive, thereby enhancing the effects of HI additive. Adding 50 mg% HI into perovskite precursor solution, the many characteristics such as the penetrability of the precursor into the mesoscopic scaffolds, the crystallization of perovskite and charge transfer were improved, whereas charge recombination was reduced. Accordingly, the PCE of the devices with 50 mg% HI additive are improved from 10.12% (the device without HI additive) to 11.27%, corresponding 10% higher efficiency. The morphologies of perovskite crystals could be different between the inside and the surface of the mesoscopic scaffold due to the difference of the evaporation rates of HI additive. This result suggests that the removal dynamics of additive changes the effects of additive on the perovskite crystallization.

Crystalline D-π-D porphyrin molecules as a hole-transporting material for printable perovskite solar cells

Crystalline, electrically conductive molecules that transport charge carriers efficiently are candidates for next–generation printable optoelectronic devices. Here, we have designed a series of D-π-D porphyrin molecular systems as either a free-base or with coordinated metals (Cu and Zn) via high yield, low-temperature synthetic procedures. The D-π-D porphyrin molecular systems (coded as HPPHT, CPPHT and ZPPHT) were comprehensively investigated employing electrical and electrochemical methods, optical absorption spectroscopy, XRD, and XPS to identify their energy levels, optical, electrical and structural properties. The studies revealed that the D-π-D porphyrin molecular systems were crystalline, with desirable energy levels and superior electrical properties compared to the benchmark Spiro-OMeTAD under similar conditions. Among these molecular systems, CPPHT exhibited an activation energy of 0.13 eV and a higher charge carrier density (Nd ~ 4.84 × 1013 cm−3), when compared to the HPPHT (4.20 × 1011 cm−3, 0.13 eV) and ZPPHT (1.92 × 1012 cm−3, 0.17 eV) systems. These molecular systems were introduced as hole transport materials into pre-made perovskite solar cells (without a HTM) by a simple infiltration process via the front contact layer. Among the three systems studied, CPPHT solar cells showed the highest photo-current density (Jsc) of 20.44 mA·cm−2 and power conversion efficiency (PCE) of 11.76% when compared with the H/ZPPHT devices under AM 1.5G (100 mW·cm−2) illumination; signifying lower recombination at the interface of the CPPHT/perovskite (MAPbI3). Incorporation of Li-TFSI/t-BP additives on the device surface improved the HTM-MAPbI3 interface, and increased the Jsc to 21.35 mA·cm−2 with a PCE of 12.88% for CPPHT devices. These D-π-D porphyrin molecular systems under ambient conditions demonstrated excellent short-term and operational stability in the presence of moisture. The modified device architecture opens up a novel configuration for designing high–performance optoelectronic devices.