In this review, the factors influencing the power conversion efficiency (PCE) of perovskite solar cells (PSCs) is emphasized. The PCE of PSCs has remarkably increased from 3.8% to 23.7%, but on the ...other hand, poor stability is one of the main facets that creates a huge barrier in the commercialization of PSCs. Herein, a concise overview of the current efforts to enhance the stability of PSCs is provided; moreover, the degradation causes and mechanisms are summarized. The strategies to improve device stability are portrayed in terms of structural effects, a photoactive layer, hole‐ and electron‐transporting layers, electrode materials, and device encapsulation. Last but not least, the economic feasibility of PSCs is also vividly discussed.
In parallel with the tremendous progress in the efficiency of perovskite solar cells, research on the issue of instability has attracted enormous attention. In this review, the strategies to enhance the stability from the perspectives of the device structure, the photoactive layer, hole‐ and electron‐transporting layers, electrode materials, and device encapsulation are portrayed.
The field of halide metal perovskite photovoltaics has caught widespread interest in the last decade. This is seen in the rapid rise of power conversion efficiency, which is currently over 23%. It ...has also stimulated a widespread application of halide metal perovskites in other fields, such as light‐emitting diodes, field‐effect transistors, detectors, and lasers. Despite the fascinating characteristics of the halide metal perovskites, the presence of toxic lead (Pb) in their chemical composition is regarded as one of the major limiting factors preventing their commercialization. Addressing the toxicity issues in these compounds by a careful and strategic replacement of Pb2+ with other nontoxic candidate elements represents a promising direction to fabricate lead‐free optoelectronic devices. Such attempts yield a halide double perovskite structure which allows flexibility for various compositional adjustments. Here, the authors present the current progress and setbacks in crystal structures, materials preparation, optoelectronic properties, stability, and photovoltaic applications of lead‐free halide double perovskite compounds. Prospective research directions to improve the optoelectronic properties of existing materials are given that may help in the discovery of new lead‐free halide double perovskites.
Halide double perovskites represent a promising direction to fabricate lead‐free optoelectronic devices. The current progress and setbacks in crystal structures, materials preparation, optoelectronic properties, stability, challenge, and photovoltaic applications of lead‐free halide double perovskite compounds are reviewed in detail.
Interface strains and lattice distortion are inevitable issues during perovskite crystallization. Silane as a coupling agent is a popular connector to enhance the compatibility between inorganic and ...organic materials in semiconductor devices. Herein, a protonated amine silane coupling agent (PASCA‐Br) interlayer between TiO2 and perovskite layers is adopted to directionally grasp both of them by forming the structural component of a lattice unit. The pillowy alkyl ammonium bromide terminals at the upper side of the interlayer provide well‐matched growth sites for the perovskite, leading to mitigated interface strain and ensuing lattice distortion; meanwhile, its superior chemical compatibility presents an ideal effect on healing the under‐coordinated Pb atoms and halogen vacancies of bare perovskite crystals. The PASCA‐Br interlayer also serves as a mechanical buffer layer, inducing less cracked perovskite film when bending. The developed molecular‐level flexible interlayer provides a promising interfacial engineering for perovskite solar cells and their flexible application.
A protonated amino silane coupling agent as an interlayer is exploited on rigid and flexible substrates, which not only sets up well‐matched growth underlay but also serves as a structural component of the lattice units, leading to less‐distorted perovskite films, resulting in an obvious advance in device performance, stability, and mechanical tolerance in the corresponding flexible device.
Energy generation and consumption have always been an important component of social development. Interests in this field are beginning to shift to indoor photovoltaics (IPV) which can serve as power ...sources under low light conditions to meet the energy needs of rapidly growing fields, such as intelligence gathering and information processing which usually operate via the Internet‐of‐things (IoT). Since the power requirements for this purpose continue to decrease, IPV systems under low light may facilitate the realization of self‐powered high‐tech electronic devices connected through the IoT. This review discusses and compares the characteristics of different types of IPV devices such as those based on silicon, dye, III‐V semiconductors, organic compounds, and halide perovskites. Among them, specific attention is paid to perovskite photovoltaics which may potentially become a high performing IPV system due to the fascinating photophysics of the halide perovskite active layer. The limitations of such indoor application as they relate to the toxicity, stability, and electronic structure of halide perovskites are also discussed. Finally, strategies which could produce highly functional, nontoxic, and stable perovskite photovoltaics devices for indoor applications are proposed.
Indoor photovoltaics (IPV) can serve as power sources under low‐light conditions to meet the energy needs of rapidly growing fields, such as intelligence gathering and information processing. Among different types of IPV devices, the eco‐friendly tin‐based perovskite photovotaics may potentially become a high performing IPV system due to the fascinating photo‐physics of the halide perovskite.
The chemical composition engineering of lead halide perovskites via a partial or complete replacement of toxic Pb with tin has been widely reported as a feasible process due to the suitable ionic ...radius of Sn and its possibility of existing in the +2 state. Interestingly, a complete replacement narrows the bandgap while a partial replacement gives an anomalous phenomenon involving a further narrowing of bandgap relative to the pure Pb and Sn halide perovskite compounds. Unfortunately, the merits of this anomalous behavior have not been properly harnessed. Although promising progress has been made to advance the properties and performance of Sn‐based perovskite systems, their photovoltaic (PV) parameters are still significantly inferior to those of the Pb‐based analogs. This review summarizes the current progress and challenges in the preparation, morphological and photophysical properties of Sn‐based halide perovskites, and how these affect their PV performance. Although it can be argued that the Pb halide perovskite systems may remain the most sought after technology in the field of thin film perovskite PV, prospective research directions are suggested to advance the properties of Sn halide perovskite materials for improved device performance.
The replacement of lead with tin in halide perovskites is feasible due to suitable ionic radius and valency. However, easy oxidation, high cost and toxicity concerns in Sn halide perovskite systems may limit the consideration of Sn as a suitable alternative to Pb.
To fine‐tune surface ligands towards high‐performance devices, we developed an in situ passivation process for all‐inorganic cesium lead iodide (CsPbI3) perovskite quantum dots (QDs) by using a ...bifunctional ligand, L‐phenylalanine (L‐PHE). Through the addition of this ligand into the precursor solution during synthesis, the in situ treated CsPbI3 QDs display significantly reduced surface states, increased vacancy formation energy, higher photoluminescence quantum yields, and much improved stability. Consequently, the L‐PHE passivated CsPbI3 QDs enabled the realization of QD solar cells with an optimal efficiency of 14.62 % and red light‐emitting diodes (LEDs) with a highest external quantum efficiency (EQE) of 10.21 %, respectively, demonstrating the great potential of ligand bonding management in improving the optoelectronic properties of solution‐processed perovskite QDs.
A passivation process for all‐inorganic cesium lead iodide (CsPbI3) perovskite quantum dots (QDs) was developed by using a bifunctional ligand, L‐phenylalanine (L‐PHE). The in situ treated CsPbI3 QDs display significantly reduced surface states, increased vacancy formation energy, higher photoluminescence quantum yields, and much improved stability.
Compared to efficient green and near‐infrared light‐emitting diodes (LEDs), less progress has been made on deep‐blue perovskite LEDs. They suffer from inefficient domain various number of PbX6− ...layers (n) control, resulting in a series of unfavorable issues such as unstable color, multipeak profile, and poor fluorescence yield. Here, a strategy involving a delicate spacer modulation for quasi‐2D perovskite films via an introduction of aromatic polyamine molecules into the perovskite precursor is reported. With low‐dimensional component engineering, the n1 domain, which shows nonradiative recombination and retarded exciton transfer, is significantly suppressed. Also, the n3 domain, which represents the population of emission species, is remarkably increased. The optimized quasi‐2D perovskite film presents blue emission from the n3 domain (peak at 465 nm) with a photoluminescence quantum yield (PLQY) as high as 77%. It enables the corresponding perovskite LEDs to deliver stable deep‐blue emission (CIE (0.145, 0.05)) with an external quantum efficiency (EQE) of 2.6%. The findings in this work provide further understanding on the structural and emission properties of quasi‐2D perovskites, which pave a new route to design deep‐blue‐emissive perovskite materials.
A quasi‐two‐dimensional perovskite film with stable domain distribution is prepared based on a new spacer. The film containing pure bromide perovskite exhibits enhanced deep‐blue fluorescence with quantum yield of 77% by low‐dimensional component engineering. As a result, the corresponding light‐emitting diodes deliver stable deep‐blue emission with a peak external quantum efficiency of 2.6%.
A key issue for perovskite solar cells is the stability of perovskite materials due to moisture effects under ambient conditions, although their efficiency is improved constantly. Herein, an improved ...CH3NH3PbI3−xClx perovskite quality is demonstrated with good crystallization and stability by using water as an additive during crystal perovskite growth. Incorporating suitable water additives in N,N‐dimethylformamide (DMF) leads to controllable growth of perovskites due to the lower boiling point and the higher vapor pressure of water compared with DMF. In addition, CH3NH3PbI3−xClx · nH2O hydrated perovskites, which can be resistant to the corrosion by water molecules to some extent, are assumed to be generated during the annealing process. Accordingly, water additive based perovskite solar cells present a high power conversion efficiency of 16.06% and improved cell stability under ambient conditions compared with the references. The findings in this work provide a route to control the growth of crystal perovskites and a clue to improve the stability of organic–inorganic halide perovskites.
Water additive is incorporated into the perovskite precursor solution to control the oriented growth of crystal perovskites and improve the stability of perovskite solar cells. As a result, a power conversion efficiency of 16.06% and an improved cell stability under ambient conditions are achieved.
Since the emergence of inorganic–organic hybrid perovskites a few years ago, there have been many promising achievements in the field of green and red perovskite light‐emitting diodes (PeLEDs). ...Nevertheless, the performance of blue‐light PeLEDs faces challenges. In this work, the unique synergy obtained by introducing two different ligands to successfully form quasi‐2D perovskite films, which can exhibit stable blue‐light emission, is utilized. The fabricated PeLEDs have a maximum external quantum efficiency of 2.62% and a half lifetime (T50) of 8.8 min. Meanwhile, the electroluminescence spectrum with its peak located at 485 nm, demonstrates improved stability by applying different voltage bias. The finding in this work offers a new way to achieve steady blue PeLEDs with high performance.
Utilizing synergistic effects with two different ligands, a stable blue perovskite emitter is successfully fabricated. The corresponding blue perovskite light‐emitting diode shows excellent device performance with a peak external quantum efficiency of 2.62% and a T50 lifetime of 8.8 min, demonstrating remarkable color stability under operation.
In hybrid organic–inorganic lead halide perovskite solar cells, the energy loss is strongly associated with nonradiative recombination in the perovskite layer and at the cell interfaces. Here, a ...simple but effective strategy is developed to improve the cell performance of perovskite solar cells via the combination of internal doping by a ferroelectric polymer and external control by an electric field. A group of polarized ferroelectric (PFE) polymers are doped into the methylammonium lead iodide (MAPbI3) layer and/or inserted between the perovskite and the hole‐transporting layers to enhance the build‐in field (BIF), improve the crystallization of MAPbI3, and regulate the nonradiative recombination in perovskite solar cells. The PFE polymer‐doped MAPbI3 shows an orderly arrangement of MA+ cations, resulting in a preferred growth orientation of polycrystalline perovskite films with reduced trap states. In addition, the BIF is enhanced by the widened depletion region in the device. As an interfacial dipole layer, the PFE polymer plays a critical role in increasing the BIF. This combined effect leads to a substantial reduction in voltage loss of 0.14 V due to the efficient suppression of nonradiative recombination. Consequently, the resulting perovskite solar cells present a power conversion efficiency of 21.38% with a high open‐circuit voltage of 1.14 V.
Perovskite solar cells based on polarized ferroelectric polymers are fabricated by doping the ferroelectric polymer into the perovskite layer with different polarizing electric fields and different doping concentrations, different polarized ferroelectric polymers' interlayers between the perovskite and the hole‐transporting layer, and both doping and interlayer. After these treatments, the fabricated devices show a maximum power conversion efficiency of 21.38%.
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