Power Conversion Efficiency Of Device Research Articles

Monolithic Perovskite-Silicon Tandem Solar Cells: From the Lab to Fab?

This review focuses on monolithic 2-terminal perovskite-silicon tandem solar cells and discusses key scientific and technological challenges to address in view of an industrial implementation of this technology. The authors start by examining the different crystalline silicon (c-Si) technologies suitable for pairing with perovskites, followed by reviewing recent developments in the field of monolithic 2-terminal perovskite-silicon tandems. Factors limiting the power conversion efficiency of these tandem devices are then evaluated, before discussing pathways to achieve an efficiency of >32%, a value that small-scale devices will likely need to achieve to make tandems competitive. Aspects related to the upscaling of these device active areas to industry-relevant ones are reviewed, followed by a short discussion on module integration aspects. The review then focuses on stability issues, likely the most challenging task that will eventually determine the economic viability of this technology. The final part of this review discusses alternative monolithic perovskite-silicon tandem designs. Finally, key areas of research that should be addressed to bring this technology from the lab to the fab are highlighted.

Machine learning with knowledge constraints for process optimization of open-air perovskite solar cell manufacturing

Machine learning with knowledge constraints for process optimization of open-air perovskite solar cell manufacturing

Inside Front Cover: Volume 1 Issue 2

Interdisciplinary MaterialsVolume 1, Issue 2 p. ii-ii COVER IMAGEOpen Access Inside Front Cover: Volume 1 Issue 2 First published: 30 April 2022 https://doi.org/10.1002/idm2.12029AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Graphical Abstract Inside Front Cover: Tin oxide is known as an efficient electron transport layer in perovskite solar cells (PSCs) due to its high transmittance, wide bandgap, and high electron mobility. In article number idm212021, Fuzhi Huang and co-workers develop high-quality tin oxide films via a nitrogen-doping strategy, the power conversion efficiency (PCE) and stability of devices have been improved significantly owing to the optimized interface of doped SnO2/perovskite. This simple scalable strategy has shown great promise toward highly efficient and stable PSCs. Volume1, Issue2April 2022Pages ii-ii RelatedInformation

Chlorobenzenesulfonic Potassium Salts as the Efficient Multifunctional Passivator for the Buried Interface in Regular Perovskite Solar Cells

AbstractThe interfacial properties for the buried junctions of the perovskite solar cells (PSCs) play a crucial role for the further enhancement of the power conversion efficiency (PCE) and stability of devices. Delicate manipulation of the interface properties such as the defect density, energy alignment, perovskite film quality, etc., guarantees efficient extraction and transport of photogenerated carriers. Herein, chlorobenzenesulfonic potassium salts are presented as a novel multifunctional agent to modify the buried tin oxide (SnO2)/perovskite interface for regular PSCs. The increasing number of carbon‐chlorine bonds (CCl) in 2,4,5‐trichlorobenzenesulfonic potassium (3Cl‐BSAK) exhibit efficient interaction with uncoordinated Sn, effectively filling oxygen vacancies in the SnO2 surface. Importantly, synergistic effects of the functional group‐rich organic anions and the potassium ion are achieved for reduced defect density, carrier recombination, and hysteresis. A champion PCE of 24.27% and the open‐circuit voltage (VOC) up to 1.191 V for modified devices are obtained. The unencapsulated devices maintain 80% of their initial PCE after aging at 80 °C for 800 h in the atmosphere and 95% after aging for 100 d. With 3Cl‐BSAK decoration, a high efficiency semitransparent PSC with a PCE of 12.83% and an average visible light transmittance (AVT) over 27% is also obtained.

Modeling and numerical simulation of high efficiency perovskite solar cell with three active layers

Recently, organic–inorganic metal halide perovskites, due to their promising optical properties, are widely used in solar cell applications yielding power conversion efficiencies (PCE) above 21%. In this study, using solar cell capacitance one-dimensional tool (SCAPS-1D), we have numerically simulated a novel solar cell consisting of three perovskite absorbers (MASnI3, MAPbI3 and FAMASnGeI3) as the active layer and achieved power conversion efficiency of 30.77%. We have also compared the performance of the proposed triple active layer perovskite solar cell (PSC) with single (MAPbI3) and double (MASnI3, MAPbI3) active layer PSCs and observed that the triple active layer PSC outperforms the single and double layer structures. Moreover, changing hole transport layer (HTL), it is found that inorganic Cu2O can be a suitable substitute for expensive prevalent organic Spiro-OMeTAD as HTL of our PSC and enhances the device PCE to 31.04%. In addition, by increasing the first absorber layer’s (MASnI3) thickness, while maintaining the total active layer thickness constant, a high PCE of 31.44% for triple active layer PSC is achieved. Furthermore, it is shown that materials with work functions more than 4.4 eV are not appropriate to be used as front contact of this structure. Finally, our simulations indicate that increase of defect density in absorber layers and working temperature of the cell monotonically degrade the efficiency of the device. We believe that the proposed triple active layer PSC can open a new route for realization of highly efficient PSCs.

Manipulating Ion Migration and Interfacial Carrier Dynamics via Amino Acid Treatment in Planar Perovskite Solar Cells.

Instability caused by the migrating ions is one of the major obstacles toward the large-scale application of metal halide perovskite optoelectronics. Inactivating mobile ions/defects via chemical passivation, e.g., amino acid treatment, is a widely accepted approach to solve that problem. To investigate the detailed interplay, L-phenylalanine (PAA), a typical amino acid, is used to modify the SnO2/MAPbI3 interface. The champion device with PAA treatment maintains 80% of its initial power conversion efficiency (PCE) when stored after 528 h in an ambient condition with the relative humidity exceeding 70%. By employing a wide-field photoluminescence imaging microscope to visualize the ion movement and calculate ionic mobility quantitatively, we propose a model for enhanced stability in perspective of suppressed ion migration. Besides, we reveal that the PAA dipole layer facilitates charge transfer at the interface, enhancing the PCE of devices. Our work may provide an in-depth understanding toward high-efficiency and stable perovskite optoelectronic devices.

Para-halogenated triphenyltriazine induced surface passivation toward efficient and stable perovskite solar cells

Surface passivation is a practical approach to improve the efficiency and stability of perovskite solar cells (PSCs). In this paper, we introduce para-halogenated triphenyltriazine (TRZ-X, X = F, Br, I) to modify the perovskite absorbers. As the core of TRZ-X, 1,3,5-Triazine has abundant C = N bonds, which can produce intermolecular interactions with uncoordinated Pb2+. The halogen atoms as peripheral unit of TRZ-X with strong electronegativity can not only generate ionic bonds with Pb2+ in the perovskite but also form a stable rigid plane with the TRZ group. Under the synergy effect of C = N bonds and halogen atoms, the defect density of perovskite films is effectively decreased, contributing to the power conversion efficiency (PCE) and stability of devices. Moreover, the presence of TRZ-X hydrophobic passivation layer could prevent moisture penetration, which is beneficial to long-term stability of PSCs. Due to the strong electronegativity, TRZ-F modified device presents the best PCE of 19.81% compared with that (18.32%) of control device. In addition, TRZ-F passivated and unencapsulated device retains 81% of the initial PCE after 1200 h storage under ambient condition with a relative humidity of 70%, whereas the pristine device decays to 59% of the initial PCE under the same conditions.

Passivation of iodine vacancies of perovskite films by reducing iodine to triiodide anions for high-performance photovoltaics

Inverted perovskite solar cells (PSCs) exhibit great potential in large-scale fabrication due to the low-temperature manufacturing process and low cost compared to normal PSCs. However, defects at the surface and grain boundaries (GBs) of perovskite films, such as iodine vacancies, lead to low efficiency and poor stability. Herein, we report a strategy to passivate the defects in situ with tetrabutylammonium chloride (TABCl). Both the surface defects and GB defects are passivated after perovskite film growth. Moreover, TABCl modifies iodine vacancies by reducing I2 to iodide ions, leading to a decrease in charge recombination in the films and enhanced device performance. The power conversion efficiency (PCE) of devices increases from 18.52% to 20.36 % by TBACl modification, and TBACl also reduces the Voc loss in the PSCs. Meanwhile, TBACl enhances the UV light stability of devices tested by continuous UV light irradiation due to the decreased defects by TBACl. The PSCs could maintain over 90% PCE under continuous UV light irradiation for 450 min. This work not only presents a method to effectively passivate the defects in situ including the surface defects and GB defects but also demonstrates a novel strategy to modify the iodine vacancies by the reducibility of TBACl. In addition, the reducibility of TBACl suppresses the degradation of perovskite films, leading to improved stability.

Utilizing Sulfonated Reduced Graphene Oxide as a Dopant to Enhance Perovskite Grain Sizes

Out of the perovskite material used in Perovskite Solar Cells, methylammonium lead triiodide (MAPbI3) is the most studied, proving to yield a device with high power conversion efficiency. However, this perovskite material has a high tendency to degrade, especially when exposed to high humidity and ambient atmosphere. The degradation issue has led to its poor morphology, which eventually affects the device's power conversion efficiency based on this perovskite material. Therefore, this study aims to enhance the morphological property of the perovskite thin film by incorporating sulfonated reduced graphene oxide (srGO) as a dopant. The reduced graphene oxide is synthesized through modified Hummer's method and further sulfonated before being incorporated into the perovskite thin film deposited under relative humidity above 80% in ambient conditions. The srGO has successfully assisted the nucleation growth of MAPbI3 with the increment of grain size is approaching micron-sized. In this work, the optimized weight percentage of srGO in methylammonium iodide (MAI) precursor is found to be 20% resulting in grain size in the diameter range of 300 to 1000 nm. Hence, this perovskite doped srGO would be incorporated as the active layer for further application, especially in inverted planar perovskite solar cells.

Measured power conversion efficiencies of bifacial luminescent solar concentrator photovoltaic devices of the mosaic series

AbstractThe optical and electrical performances of varied configurations of visually attractive mosaic cubical luminescent solar concentrator photovoltaic (LSC PV) devices have been measured. These new designs of LSC PV devices consist of four cubical lightguides containing commercially available fluorophores with edge‐ and bottom‐mounted silicon solar cells. The 1 cm3 cubical component LSC PVs are made of poly (methyl methacrylate) (PMMA) doped by dyes from 10 to 150 ppm. The lightguides are covered with bifacial silicon solar cells at their edges and/or bottom and connected in series or parallel, depending on the device configuration. In total, 19 different configurations of mosaic LSC PV devices have been experimentally evaluated in this study.

Interface Engineering in Solution-Processed Thin-Film Solar Cells

ConspectusAlong with the rapid industrialization of human society over the past century, incessant energy consumption and endless damage to the environment have aroused growing attention for seeking clean and renewable energy sources. Photovoltaics (PV) that can directly harvest and transform sunlight into electricity have shown great potential in achieving this goal. Especially for solution-processed thin-film solar cells, their extremely cost-effective and facile processing methods compatible with different substrates at large scales exhibit unique advantages over conventional PVs based on crystalline silicon. Various types of solution-processed thin-film PVs have been achieving or already exceeded 15% power conversion efficiency (PCE) through the numerous efforts of researchers. Organic solar cells (OSCs) and organic–inorganic hybrid perovskite solar cells (PVSCs) are the most well-known emerging solution-processed thin-film solar cells that have attracted great interest recently (the PCE of PVSCs soared form 3.8% to over 25% in the past decade). Usually, photogenerated excitons will form as a response to illumination in the active layer, then dissociate into charge carriers, travel in between layers, and finally get collected by electrodes of the device. Besides the broad exploration of active layer materials, suitably matched charge-transporting layers and electrodes also play a vital role in achieving high PCE and stability in PV devices. Furthermore, interfaces between different functional layers created during solution processing need to be carefully addressed to ensure efficient charge transport and prevent degradation. The utilization of proper interfacial materials to modify the chemical and electrical properties at interfaces has become an effective strategy to enhance the performance of PV. Therefore, it is important to develop a comprehensive understanding into the correlation between interfacial properties and charge carrier dynamics and establish molecular design principles for interfacial materials to realize commercialization of emerging PVs.In this Account, we first introduce the fundamental roles of interfaces in PVs, including the modulation of film formation, together with management of charge transport and recombination. Detailed analysis of interfaces and related surface science are also discussed to provide better understanding. Then, we highlight our research on interfacial materials with different functionalities including self-assembled monolayers, dopants, functional molecules for post-treatment, and composite materials. Combining with the fundamental mechanisms and design criteria of interfacial materials, new materials and interface engineering strategies can be integrated into other PV systems to achieve high PCE and stability. In the end, the main challenges and future perspectives toward the commercialization of solution-processed thin-film PVs are discussed to inspire more novel material designs and interface engineering.

Insight the difference of free charge generation in two small molecular accepter organic solar cells

Totally understanding the excitons dissociation in nonfullerene organic solar cells (OSCs) is the first priority for the minimum of the device energy loss and so that it can get the highest power conversion efficiency (PCE). The free charges harvesting is complicated though it has already published some evident examples to investigate this issue by small driving force between donors (D) and accepters (A). Here, a robust minus highest occupied molecular orbital (HOMO) level offset D-A couple unveiled this phenomena in greater depth by a time-resolved photo physical processes. The OSCs D-A heterojunction interfacial doping resonant coupling relaxation effect was observed and found some clues with device open-circuit voltage (Voc) energy loss. It undoubtedly demonstrated the device PCE up to 2.37% by a −0.12 eV HOMO offsets value. It was also found that the donor polymer aggregation behavior was greatly affected by the small molecular acceptor. These results will be beneficial to promote the OSCs comprehensive properties in future.

Stable Metal–Halide Perovskite Colloids in Protic Ionic Liquid

Stable Metal–Halide Perovskite Colloids in Protic Ionic Liquid

Selection of the ultimate perovskite solar cell materials and fabrication processes towards its industrialization: A review

AbstractHybrid organic–inorganic perovskite materials have become one of the most studied classes of light‐harvesting materials due to their exceptional properties such as high light absorption, long carrier diffusion lengths, bandgap tuning and defect tolerance. Since 2009 that the scientific community has been working on improving the power conversion efficiency (PCE) of perovskite solar cell devices, reaching now an impressive value of 25.5%. Moreover, efficiencies over 18% are often reported by several authors. Since the efficiency goal is almost fulfilled, the scientific community is currently addressing five challenges, with the ultimate objective to make this technology competitive and turn it commercial; these challenges are cost, stability, upscaling, safety and environmental impact. Given the astonishing progresses reached during the past decade and the numerous research groups working to the same goal, it is a matter of time until commercial perovskite solar devices become a reality. In this review work, the most recent achievements regarding this purpose are put together and compared, so as to suggest the most suitable perovskite solar fabrication processes and materials to produce commercial devices.

Effect of poly (ethylene glycol) gel polymer electrolyte consist of novel heteroleptic cobalt redox shuttle and pyridine based organic additive on performance of dye sensitized solar cells

A newly designed heteroleptic cobalt I/II [2,6-bis (1-(naphthalen-2-ylmethyl)-1H-benzo[d] imidazole-2-yl)pyridine) (2,6-bis (1-(4-(tert-butyl)benzyl)-1H-benzo [d] imidazole-2-yl)pyridine)] redox shuttle (Co2+/3+[(bnbip) (b(tbb)bip)]) and pyridine based organic additive 2, 6-bis(pyridin-2-ylthio)pyridine (BPTP) was introduced first time into the Poly(ethylene glycol) (PEG) gel polymer electrolyte to improvise power conversion efficiency (PCE) of Dye sensitized solar cells (DSSCs). Interestingly gel electrolytes (PEG/Co2+/3+[(bnbip) (b(tbb)bip)]/BPTP) attained an improved conductivity of 11.54 × 10−4 S cm−1higher than the gel polymer electrolyte without additive BPTP. Mainly, the redox potential (Emed = 0.64 V Vs NHE) of cobalt redox pair sustains the gel polymer electrolyte to conquer a higher open circuit voltage of devices. The PCE of device with PEG/Co2+/3+[(bnbip) (b(tbb)bip)]/BPTP gel electrolyte achieved up to 5.12% under 1 sun (100 mW/cm2) condition which was superior than the device with PEG gel polymer electrolyte without BPTP. This enhancement of PCE was confirmed via certain consequences such as longer electron life time (1.3 ms), lower charge transfer resistance (217 Ω), lower charge transfer kinetics (0.77 ms−1), higher Chemical capacitance (5.99 × 10−3 F), high diffusion coefficient (2.59 × 10−5 cm2 s−1) and a shift in Quasi Fermi level of TiO2. The newly integrated Co2+/3+[(bnbip) (b(tbb)bip)] redox and BPTP additive in PEG gel polymer electrolytes readily suppress the recombination reaction between TiO2 and Co3+ species of Cobalt redox pair. An opening of PEG gel electrolytes with new organic additive and Cobalt redox pair paved a way to replacement of liquid electrolytes with usual Iodine/Iodide redox pair, homoleptic cobalt redox pair and commercial costly additive in DSSCs.

Combating open circuit voltage loss in Sb2Se3 solar cell with an application of SnS as a back surface field layer

Recently, Sb2Se3 based solar cells have shown severe open-circuit voltage (VOC) loss that results in low device efficiency. In the present work, a model of Sb2Se3 solar cell with tin sulfide (SnS) as a back surface field layer (BSF) layer was designed and investigated via a solar cell capacitance simulator (SCAPS)-1D simulation software. The influence of the ultrathin BSF layer was investigated as a function of Sb2Se3 absorber thickness, and the corresponding device performance was analyzed. Apart from this, the effect of high BSF layer thickness, doping concentration, interface defect density, and resistance were also examined. Applying the BSF layer decreased the valence band offset value, which eases the hole transport at the back interface. At the same time, the high electric field region generated at the back interface creates a barrier for the minority carriers. Synergistically, in the presence of the BSF layer, the carrier recombination current densities were found to be almost negligible. As a result, the introduction of the 10 nm thin BSF layer significantly improved the device's VOC and power conversion efficiency (PCE) from 0.416 to 0.603 V and 9.61 to 17.75%, respectively for the absorber layer thickness of 700 nm. The present simulation study performed with the full earth-abundant element-based low-cost materials may assist the photovoltaic community in combating the VOC loss and further improving the PCE of Sb2Se3 based solar cells.

Fabricating stable and efficient perovskite solar cells in air ambient via lattice anchoring strategy

The stability issue is becoming more and more important in the development of halide perovskite solar cells (PSCs). Various strategies have been adopted to explore the stability of perovskite films and devices. Nevertheless, most perovskite films are prepared in inert atmosphere, limiting the practical application of PSCs. Herein, lattice anchoring strategy was employed to prepare stable perovskite films in air ambient. The adopted bidentate anchor cations (BACs) could effectively inhibit the invasion by moisture and restrain organic component escaping from perovskite structure during preparation process. The steric and coulomb effects of embedded BACs have dual influence on the crystal growth process and morphology of perovskite films. The BACs are pinned on the crystal lattices and the surface of perovskite film without forming 2D perovskite, which would enhance the crystal intrinsic stability and moisture resistance. The modified CH3NH3PbI3 device power conversion efficiency (PCE) raises to 20.33%, and remains over 85% of the initial PCE during exposure to ambient air (humidity＞70 RH, temperature＞30 °C) for over 90 days. The lattice anchoring strategy provides a convenient method to improve the quality of perovskite films in air ambient.

Multi-cation hybrid stannic oxide electron transport layer for high-efficiency perovskite solar cells

The performance of perovskite solar cells (PSCs) can be improved by optimizing the perovskite film quality and electron transfer layers (ETLs). In this study, high-efficient PSCs with multi-cation hybrid electron transport layer (SnO2@Na:Cs ETL) were fabricated using continuous spin-coating. Compared to the pristine SnO2, the power conversion efficiency (PCE) of device based on SnO2@Na:Cs ETL have reached 22.06% (with an open circuit voltage of 1.13 V), up approximately 21%. The photovoltaic performance of the device is enhanced due to the increase in the transmission rate, electrical conductivity, electron mobility and surface state owing to the multi-cation hybrid. In addition, because SnO2@Na:Cs ETL can significantly improve interface contact with the perovskite film and improve its crystallinity, the transport defect state and carrier transport efficiency are significantly improved at the ETL/Perovskite interface. Therefore, the open circuit voltage (Voc) and fill factor (FF) of PSCs was significantly increased. The application of SnO2@Na:Cs ETL provides a simple and efficient method to obtain highly-efficient PSCs.

Analytical models of electron leakage currents in gallium nitride-based laser diodes and light-emitting diodes.

The electrical-to-optical power conversion efficiencies of the light-emitting devices based on gallium nitride (GaN) are seriously limited by electron leakage currents due to the relatively low mobility and activation ratio of holes. However, there have been few theoretical models on the behavior of the leakage current with an increasing total current. We develop an Ohmic-law-like method to describe the transport behaviors of the systems with electron and hole currents simultaneously. Based on reasonable assumptions, the ratio of the leakage current to the total current is related to the differential resistances of the devices. Through the method, we develop analytical models of the leakage currents in GaN-based laser diodes (LDs) and light-emitting diodes (LEDs). The ratios of the leakage currents with total currents in LDs and LEDs are shown to increase, which explains the sublinear behaviors of the luminescence-current (LI) curves of the devices. The theory agrees well with the numerical simulation and experimental results in larger current ranges in comparison to the traditional ABC model. The above analytical model can be used to fast evaluate the leakage currents in GaN-based LDs and LEDs.

Achieving Enhanced Thermoelectric Performance in Multiphase Materials

ConspectusThermoelectric (TE) devices enable direct solid-state energy conversion from heat to electricity and vice versa, thereby showing great potential in warranting the supply of sustainable energy and mitigating the potentially catastrophic effects of climate change. Therefore, as a clean-energy-generation technology, TE materials have received tremendous research efforts in both industrial and academic communities for applications in the recovery of ubiquitous low-grade waste heat. Achieving high efficiency in TE materials is an ongoing pursuit of the TE research community, considering approximately 90% of all waste heat in the USA comes from medium-temperature (e.g., from 573 to 873 K) heat sources. Hence, synergistic enhancements in the figures-of-merit (ZT) are still highly desired and remain a key task for improving commercial applications of TE materials.Over the past decades, by navigating the interplay between heat and electronic transport, different advanced paradigms in current state-of-the-art TE materials, as well as emerging TE materials, have been adopted to obtain high ZT values, especially for the average ZT (ZTavg), as the power conversion efficiency (PCE) of a TE device depends on the ZTavg over a wide temperature range. Yet, now there are few reviews or perspective reports on methods to synergistically boost both the peak ZT (ZTpeak) and ZTavg, Herein, our recently developed strategies for optimizing and designing high-performance TE materials through advanced multiphase nanocomposite paradigms and material design are presented. Multiphase composites with distributed nanostructures (e.g., nanoplates and/or nanoparticles) provide effective phonon scattering through the nanoscale secondary phases. On the basis of the physical mechanism (the charge carrier transfer, phonon transfer/scattering, phonon-charge carrier interaction, and interface phenomenon), one can derive the optimum direction for the improvement of ZTpeak and ZTavg of TE semiconductors.In this Account, we summarize and discuss the recent advances and insights from our work in designing TE materials with both high ZTpeak and ZTavg by combining precisely engineered doping and nanostructuring. This Account is organized as follows: First, we summarize the advances of representative state-of-the-art TE materials in chronological order, including the advancement of performance-improving mechanisms. Second, we highlight the application of our effective multiphase material design strategies to leading Pb-based (PbTe, PbSe, and PbS) TE materials, with an emphasis on ZTavg and SnSe-based TE materials. Third, we introduce Sb2Si2Te6, which possesses an ultralow thermal lattice conductivity, as a promising new TE material, which was enhanced through a cellular nanostructure strategy. Finally, we outline an entropy-driven paradigm to optimize current SnSe-based and MnTe-based materials, thereby improving their TE performances.