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Despite the outstanding role of conjugated polyelectrolytes (CPEs) in organic solar cells, the use of CPEs in perovskite solar cells has rarely been reported due to instability issues of the material itself under operating conditions.

Despite the promise of simple manufacturing via an entirely solution-based process at low temperature (

Correction for ‘Conjugated polyelectrolytes for stable perovskite solar cells based on methylammonium lead triiodide’ by Yong Ryun Kim et al., J. Mater. Chem. A, 2022, 10, 3321–3329, https://doi.org/10.1039/D1TA10185D.

Carbazole-based conjugated small molecule electrolytes (CSEs) containing different numbers of amine groups were synthesized and applied to bulk-heterojunction (BHJ) organic solar cells for the formation of a spontaneous self-assembled electron transporting layer (ETL). The active layer was spin-coated with a mixture solution containing the BHJ materials and a small amount of CSE, and a thin layer of CSE was formed underneath the active layer (CSE/BHJ bi-layer) via spontaneous phase separation, which is confirmed by the depth profile of the time of flight secondary ion mass spectroscopy (ToF-SIMS) spectrum. The amino groups in the CSEs form hydrogen-bonds with the surface of indium tin oxide (ITO), which acts as an ETL in BHJ solar cells. Moreover, the formed CSE layer is capable of changing the effective work function (WF) of ITO. An increasing number of amino groups in the CSEs (from Cz1N to Cz3N) provides more reduction of the effective WF of ITO, which results in a lower internal resistance and a higher power conversion efficiency (PCE). Furthermore, the enhanced hydrogen bonding between the amines and ITO with an increased number of amine groups has been studied by XPS. This result suggests that one-step processing provides a reduction of the manufacturing cost, which can provide an attractive design concept for ETL fabrication.

Recently, the most efficient tandem polymer solar cells (PSCs) have used poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PSS) as a p-type component of recombination layer (RL). However, its undesirable acidic nature, originating from insulating PSS, ofPSS drastically reduces the lifetime of PSCs. Here, we demonstrate the efficient and stable tandem PSCs by introducing acid-free self-doped conducting polymer (SCP), combined with zinc oxide nanoparticles (ZnO NPs), as RL forPSS-free tandem PSCs. Moreover, we introduce an innovative and versatile nanocomposite system containing photoactive and p-type conjugated polyelectrolyte (p-CPE) into the tandem fabrication of an ideal self-organized recombination layer. In our new RL, highly conductive SCP facilitates charge transport and recombination process, and p-CPE helps to achieve nearly loss-free charge collection by increasing effective work function of indium tin oxide (ITO) and SCP. Because of the synergistic effect of extremely low electrical resistance, ohmic contact, and pH neutrality, tandem devices with our novel RL performed well, exhibiting a high power conversion efficiency of 10.2% and a prolonged lifetime. These findings provide a new insight for strategic design of RLs using SCPs to achieve efficient and stable tandem PSCs and enable us to review and extend the usefulness of SCPs in various electronics research fields.

Despite recent reports of high power conversion efficiency (PCE) values of over 20%, the instability of perovskite solar cells (PSCs) has been considered the most serious obstacle toward their commercialization. By rigorously exploring the self-degradation process of planar-type PSCs using typical metal electrodes (Ag or Al), we found that the corrosion of the metal electrodes by inherent ionic defects in the perovskite layers is a major origin of intrinsic device degradation even under inert conditions. In this work, we have developed a new concept of a chemical inhibition in PSCs using amine-mediated metal oxide systems and succeeded in chemically neutralizing mobile ionic defects through mutual ionic interaction. As a consequence, we realized planar-type PSCs with long-term stability that maintain nearly 80% of their initial PCEs even after 1 year (9000 h) of storage under nitrogen and 80% of their initial PCEs after 200 h in ambient conditions without any encapsulation.

Efficient large-area planar heterojunction (PHJ) perovskite solar cells (PSCs) were successfully developed by adapting a scalable doctor blade printing method under ambient condition. To achieve high-quality perovskite films onto poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) layer, the PEDOT:PSS was modified by adding poly(4-styrenesulfonic acid) (PSSH), which uses the electrostatic interaction between the sulfonyl functional groups in PEDOT:PSS and perovskite precursor ions. The resulting perovskite film on the modified PEDOT:PSS (M-PEDOT:PSS) exhibited excellent uniformity and surface coverage with high crystallinity even for large-area (15 mm×40 mm) scale. In addition, the power conversion efficiency (PCE) of the printed PSCs was significantly improved from 6% to 10.15% by introducing our M-PEDOT:PSS layer. This finding provides an important guideline to achieve highly efficient PSCs using scalable printing techniques.

The fabrication of organic photovoltaic modules via printing techniques has been the greatest challenge for their commercial manufacture. Current module architecture, which is based on a monolithic geometry consisting of serially interconnecting stripe-patterned subcells with finite widths, requires highly sophisticated patterning processes that significantly increase the complexity of printing production lines and cause serious reductions in module efficiency due to so-called aperture loss in series connection regions. Herein we demonstrate an innovative module structure that can simultaneously reduce both patterning processes and aperture loss. By using a charge recombination feature that occurs at contacts between electron- and hole-transport layers, we devise a series connection method that facilitates module fabrication without patterning the charge transport layers. With the successive deposition of component layers using slot-die and doctor-blade printing techniques, we achieve a high module efficiency reaching 7.5% with area of 4.15 cm2., The fabrication of organic photovoltaic modules usually relies on patterning techniques which limit their efficiencies. Here, the authors propose a module structure that avoids the patterning steps, and use doctor-blade printing and slot-die coating to fabricate large-area modules reaching 7.5% efficiencies.

We devised an electrochemical patterning process for large-area perovskite photovoltaic modules., Realizing industrial-scale, large-area photovoltaic modules without any considerable performance losses compared with the performance of laboratory-scale, small-area perovskite solar cells (PSCs) has been a challenge for practical applications of PSCs. Highly sophisticated patterning processes for achieving series connections, typically fabricated using printing or laser-scribing techniques, cause unexpected efficiency drops and require complicated manufacturing processes. We successfully fabricated high-efficiency, large-area PSC modules using a new electrochemical patterning process. The intrinsic ion-conducting features of perovskites enabled us to create metal-filamentary nanoelectrodes to facilitate the monolithic serial interconnections of PSC modules. By fabricating planar-type PSC modules through low-temperature annealing and all-solution processing, we demonstrated a notably high module efficiency of 14.0% for a total area of 9.06 cm2 with a high geometric fill factor of 94.1%.

Vanadium suboxide (VOx) layers deposited by an electro-spray (e-spray) printing method were applied to the fabrication of high efficiency patterned polymer solar cell (PSC) modules. By tailoring surface tension and the atomization condition of the e-sprayed sol precursor, e-sprayed VOx layers on top of both hydrophilic and hydrophobic surfaces were successfully obtained, which enabled alternative architectures of conventional/inverted cells in a sub-module. The integrated PSC module that alternatively incorporated patterned metal oxide layer exhibited the high aperture power conversion efficiency (PCE) of 4.93% with a geometric fill factor (GFF) of 87%. Furthermore, we achieved the high aperture PCE of 4.72% on the flexible polyethylene terephthalate (PET) substrate comparable to that on the glass substrate which is applicable to large area roll-to-roll PSC module production.

The importance of interfacial engineering as a new strategy for improving the power conversion efficiencies (PCEs) of planar-heterojunction (PHJ) perovskite solar cells is highlighted in this study. With our optimized interfacial modification, we demonstrated efficient PHJ perovskite solar cells with a high PCE of 12.2% using a sol–gel-processed ZnO ECL modified by [6,6]-phenyl C61 butyric acid methyl ester (PCBM).

A new architecture for manufacturing large-area polymer solar cells that does not produce concomitant aperture and Ohmic losses is presented. By introducing the innovative concept of metal-filamentary nanoelectrodes, which are vertically formed inside the main active layers, loss-free, widely expandable solar cells with the highest relative power conversion efficiency (ca. 90%) in organic photovoltaic systems are demonstrated.

We propose and demonstrate a new series connection method that employs alternating conventional and inverted bulk-heterojunction (BHJ) solar cells. The two adjacent cells in each submodule are connected through top or bottom ‘continuous terminals’ made of aluminum or indium tin oxide (ITO), which are shared by cells with different polarities in either a top-to-top or a bottom-to-bottom manner. In comparison with the conventional series-interconnection method, our new structure offers unique advantages in that both printing methods and efficient coating methods can be applied in the manufacturing of series-connected BHJ photovoltaic modules.

A new fi lm-casting method for polymer electrodes is reported, in which thickness-controlled drop-casting (TCDC), using polyaniline doped with camphorsulfonic acid (PANI:CSA) is used. By combining the advantages of conventional spin-casting and drop-casting methods, and by rigorously controlling the fi lm formation parameters, fl exible polymer electrodes with high conductivity and excellent transmittance can be produced. The PANI:CSA electrodes cast by the TCDC method exhibited constant thickness-independent conductivities of ∼ 600 S cm − 1 down to a fi lm thickness of 0.2 μ m, and a high optical transmittance of about 85% at 550 nm. Furthermore, the new casting method signifi cantly reduced the sheet resistance ( ∼ 90 Ω /square) of the PANI:CSA electrodes compared with the conventional spin-cast fi lms, enhancing the performance of the devices deposited on plastic substrates. The fl exible polymer light-emitting diode produced a brightness of 6000 cd m − 2 , and the fl exible polymer solar cell exhibited a power conversion effi ciency of 2%, both of which were much higher than those of the devices fabricated by the conventional spin-casting method.

Highly efficient P-I-N type perovskite/bulk-heterojunction (BHJ) integrated solar cells (ISCs) with enhanced fill factor (FF) (≈80%) and high near-infrared harvesting (>30%) are demonstrated by optimizing the BHJ morphology with a novel n-type polymer, N2200, and a new solvent-processing additive. This work proves the feasibility of highly efficient ISCs with panchromatic absorption as a new photovoltaic architecture and provides important design rules for optimizing ISCs.

Despite recent breakthroughs in power conversion efficiencies (PCEs), which have resulted in PCEs exceeding 22%, perovskite solar cells (PSCs) still face serious drawbacks in terms of their printability, reliability, and stability. The most efficient PSC architecture, which is based on titanium dioxide as an electron transport layer, requires an extremely high-temperature sintering process (≈500 °C), reveals hysterical discrepancies in the device measurement, and suffers from performance degradation under light illumination. These drawbacks hamper the practical development of PSCs fabricated via a printing process on flexible plastic substrates. Herein, an innovative method to fabricate low-temperature-processed, hysteresis-free, and stable PSCs with a large area up to 1 cm2 is demonstrated using a versatile organic nanocomposite that combines an electron acceptor and a surface modifier. This nanocomposite forms an ideal, self-organized electron transport layer (ETL) via a spontaneous vertical phase separation, which leads to hysteresis-free, planar heterojunction PSCs with stabilized PCEs of over 18%. In addition, the organic nanocomposite concept is successfully applied to the printing process, resulting in a PCE of over 17% in PSCs with printed ETLs.

Despite the recent unprecedented increase in the power conversion efficiencies (PCEs) of small-area devices (≤0.1 cm2 ), the PCEs deteriorate drastically for PSCs of larger areas because of the incomplete film coverage caused by the dewetting of the hydrophilic perovskite precursor solutions on the hydrophobic organic charge-transport layers (CTLs). Here, an innovative method of fabricating scalable PSCs on all types of organic CTLs is reported. By introducing an amphiphilic conjugated polyelectrolyte as an interfacial compatibilizer, fabricating uniform perovskite films on large-area substrates (18.4 cm2 ) and PSCs with the total active area of 6 cm2 (1 cm2 × 6 unit cells) via a single-turn solution process is successfully demonstrated. All of the unit cells exhibit highly uniform PCEs of 16.1 ± 0.9% (best PCE of 17%), which is the highest value for printable PSCs with a total active area larger than 1 cm2 .

We report a new method for developing a low-temperature solution processed vanadium oxide (s-VOx) and poly(4-styrene sulfonic acid) (PSS) composite to act as an efficient hole-transport layer (HTL) in polymer solar cells (PSCs). By compositing the s-VOx and PSS (s-VOx:PSS), the work function values of the s-VOx:PSS changed from 5.0 to 5.3 eV. Therefore, the energy level barrier between the HTL and organic active layer decreased, facilitating charge injection/extraction at the interfaces. In addition, the s-VOx:PSS films were denser and had more pin-hole-free surfaces than pristine s-VOx films, resulting in enhanced PSC performance due to significantly decreased leakage currents and excellent device stability in ambient condition. Because our approach of combining soluble transition metal oxide (TMO) and polymeric acid shows dramatically better performance than pristine TMO, we expect that it can provide useful guidelines for the synthesis and application of TMOs for organic electronics in the future.

G. Kim, H. Kang, H. Back, Prof. K. Lee School of Materials Science and Engineering Gwangju Institute of Science and Technology Gwangju 500–712 , Republic of Korea E-mail: klee@gist.ac.kr G. Kim, Dr. J. Kong, J. Kim, H. Kang, H. Back, Dr. H. Kim, Prof. K. Lee Heeger Center for Advanced Materials Research Institute for Solar and Sustainable Energies Gwangju Institute of Science and Technology Gwangju 500–712 , Republic of Korea E-mail: heejook@gist.ac.kr J. Kim, Prof. K. Lee Department of Nanobio Materials and Electronics Gwangju Institute of Science and Technology Gwangju 500–712 , Republic of Korea

An efficient module cell architecture of a polymer solar cell built upon self-aligned alternating interfacial layers is presented. Alternating conventional and inverted subcells are serially connected on a single compound electrode with self-aligned interfacial layers. A high relative power conversion efficiency of 82% of the large-area module cell (4.24%) to the small-sized laboratory cells (5.19%) could be obtainable.