Toward Scalable Perovskite Solar Modules Using Blade Coating and Rapid Thermal Processing

Toward scalable manufacturing of perovskite solar panels, high-performance planar p–i–n perovskite solar cells (PVSCs) and modules have been demonstrated with blade coating and rapid thermal processing (RTP). The PVSCs made using RTP for less than 30 s have equivalent photovoltaic performance as devices fabricated from hot-plate annealing for 2 min. The resulting PVSCs show the best average power conversion efficiency (PCE) of over 18.47% from forward and reverse scans. Mini-modules with an active area of over 2.7 cm2 exhibit a champion average PCE of over 17.73% without apparent hysteresis. To the best of our knowledge, these efficiencies are the highest for PVSCs processed by the combination of blade coating and RTP. Furthermore, both the blade coating and RTP were performed in an ambient environment, paving the way for the large-scale production of PVSCs through high-speed roll-to-roll printing

Scalable Deposition of High-Efficiency Perovskite Solar Cells by Spray-Coating

Spray-deposition is a low-cost, roll-to-roll compatible technique that could potentially replace spin-coating for the deposition of highly efficient perovskite solar cells. Here, perovskite active layers were fabricated in air using an ultrasonic spray system and compared with equivalent spin-coated films. A chlorine-containing perovskite ink with a wide processing window coupled with an antisolvent extraction resulted in perovskite films with relatively rougher surfaces than those spin-coated. A power conversion efficiency (PCE) of 17.3% was achieved with an average of 16.3% from 24 devices. Despite observing differences in film roughness and structure, the performance of sprayed perovskite solar cells was comparable to that of the spin-coated cells processed in an inert atmosphere, showing the versatility of perovskite processing

Transparent Conductive Adhesives for Tandem Solar Cells Using Polymer–Particle Composites

Transparent conductive adhesives (TCAs) can enable conductivity between two substrates, which is useful for a wide range of electronic devices. Here, we have developed a TCA composed of a polymer–particle blend with ethylene-vinyl acetate as the transparent adhesive and metal-coated flexible poly­(methyl methacrylate) microspheres as the conductive particles that can provide conductivity and adhesion regardless of the surface texture. This TCA layer was designed to be nearly transparent, conductive in only the out-of-plane direction, and of practical adhesive strength to hold the substrates together. The series resistance was measured at 0.3 and 0.8 Ω cm2 for 8 and 0.2% particle coverage, respectively, while remaining over 92% was transparent in both cases. For applications in photovoltaic devices, such as mechanically stacked multijunction III–V/Si cells, a TCA with 1% particle coverage will have less than 0.5% power loss due to the resistance and less than 1% shading loss to the bottom cell

Direct Deposition of Nonaqueous SnO₂ Dispersion by Blade Coating on Perovskites for the Scalable Fabrication of p–i–n Perovskite Solar Cells

Tin­(IV) oxide materials have been extensively used as electron transport materials in n–i–p perovskite solar cells (PSCs) due to their superior optoelectronic properties, low-temperature processability, and high chemical stability. However, solvent incompatibility and processing temperature have limited the direct deposition of fully solution-processed SnO2 in p–i–n devices. In this study, we overcome this limitation by the functionalization of SnO2 nanoparticles with acetate through ligand exchange, allowing their dispersion in anhydrous ethanol. The SnO2 dispersion was deposited on the perovskite absorber by blade coating without damaging the underlying perovskite layer, as determined by X-ray diffraction and scanning electron microscopy. Photoluminescence spectroscopy confirmed effective electron extraction. The champion device shows 14.1% initial power conversion efficiency (PCE) which is unprecedented for a p–i–n device employing solution-phase SnO2. PSCs stored for 40 days in a nitrogen flow box retained an average of 95.8% of the initial PCE

Stability at Scale: Challenges of Module Interconnects for Perovskite Photovoltaics

Uniting efficiency, scalability, and stability is the next frontier for perovskite solar cells. Stability tests conducted on efficient perovskite solar cell mini-module architectures reveal promising stability yet also the stability challenges of scale up

Improving Low-Bandgap Tin–Lead Perovskite Solar Cells via Contact Engineering and Gas Quench Processing

Low-bandgap Sn/Pb ABX3 perovskites have reached photovoltaic power conversion efficiencies >20%, but they usually have poor stability due to the common use of acidic poly­(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) hole transport layers and A-site cation compositions containing methylammonium (MA). Here, we develop a process to enable high-quality MA-free Sn/Pb perovskite films grown using a gas quenching process instead of the conventional antisolvents, which provides improved control of the film growth and eliminates wrinkling. Using this method in a device structure with poly­[bis­(4-phenyl)­(2,4,6-trimethylphenyl)­amine] (PTAA) instead of PEDOT:PSS as the hole transport layer, devices can reach efficiencies up to 20%mppt at 0.06 cm2 and up to 17.5%mppt at 1 cm2 active area. With these improvements, the devices are characterized for thermal stability and show 80% of the initial power output remaining after 4000 h at 85 °C

Curtailing Perovskite Processing Limitations via Lamination at the Perovskite/Perovskite Interface

Standard layer-by-layer solution processing methods constrain lead–halide perovskite device architectures. The layer below the perovskite must be robust to the strong organic solvents used to form the perovskite while the layer above has a limited thermal budget and must be processed in nonpolar solvents to prevent perovskite degradation. To circumvent these limitations, we developed a procedure where two transparent conductive oxide/transport material/perovskite half stacks are independently fabricated and then laminated together at the perovskite/perovskite interface. Using ultraviolet–visible absorption spectroscopy, external quantum efficiency, X-ray diffraction, and time-resolved photoluminesence spectroscopy, we show that this procedure improves photovoltaic properties of the perovskite layer. Applying this procedure, semitransparent devices employing two high-temperature oxide transport layers were fabricated, which realized an average efficiency of 9.6% (maximum: 10.6%) despite series resistance limitations from the substrate design. Overall, the developed lamination procedure curtails processing constraints, enables new device designs, and affords new opportunities for optimization

Roll-to-Roll Printing of Perovskite Solar Cells

High efficiency combined with transformative roll-to-roll (R2R) printability makes metal halide perovskite-based solar cells the most promising solar technology to address the terawatt challenge of the future energy demand. However, translation from lab-scale deposition solution processing techniques to large-scale R2R methods has typically led to reduced photovoltaic performance. Here, we demonstrate large-scale, highly crystalline, uniaxially oriented, smooth perovskite films printed at room temperature and in the ambient environment. Confirmed with high speed in situ X-ray diffraction measurements, the perovskite films reach 98% of relative crystallinity at room temperature and display high texture within 1 s of the coating. We demonstrate an all-blade-coated metal halide perovskite cell with power conversion efficiency (PCE) up to 19.6%, a slot-die coated cell with a PCE of 17.3%, and a partially R2R slot-die coated flexible glass-based cell efficiency of 14.1%. The developed printing method can be applied to diverse perovskite compositions, enabling a variety of bandgaps to pave the way for the future R2R printing of highly efficient perovskite–perovskite tandem cells

Roll-to-Roll Printing of Perovskite Solar Cells

High efficiency combined with transformative roll-to-roll (R2R) printability makes metal halide perovskite-based solar cells the most promising solar technology to address the terawatt challenge of the future energy demand. However, translation from lab-scale deposition solution processing techniques to large-scale R2R methods has typically led to reduced photovoltaic performance. Here, we demonstrate large-scale, highly crystalline, uniaxially oriented, smooth perovskite films printed at room temperature and in the ambient environment. Confirmed with high speed in situ X-ray diffraction measurements, the perovskite films reach 98% of relative crystallinity at room temperature and display high texture within 1 s of the coating. We demonstrate an all-blade-coated metal halide perovskite cell with power conversion efficiency (PCE) up to 19.6%, a slot-die coated cell with a PCE of 17.3%, and a partially R2R slot-die coated flexible glass-based cell efficiency of 14.1%. The developed printing method can be applied to diverse perovskite compositions, enabling a variety of bandgaps to pave the way for the future R2R printing of highly efficient perovskite–perovskite tandem cells

Roll-to-Roll Printing of Perovskite Solar Cells

High efficiency combined with transformative roll-to-roll (R2R) printability makes metal halide perovskite-based solar cells the most promising solar technology to address the terawatt challenge of the future energy demand. However, translation from lab-scale deposition solution processing techniques to large-scale R2R methods has typically led to reduced photovoltaic performance. Here, we demonstrate large-scale, highly crystalline, uniaxially oriented, smooth perovskite films printed at room temperature and in the ambient environment. Confirmed with high speed in situ X-ray diffraction measurements, the perovskite films reach 98% of relative crystallinity at room temperature and display high texture within 1 s of the coating. We demonstrate an all-blade-coated metal halide perovskite cell with power conversion efficiency (PCE) up to 19.6%, a slot-die coated cell with a PCE of 17.3%, and a partially R2R slot-die coated flexible glass-based cell efficiency of 14.1%. The developed printing method can be applied to diverse perovskite compositions, enabling a variety of bandgaps to pave the way for the future R2R printing of highly efficient perovskite–perovskite tandem cells