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1.
Organo‐lead halide perovskite solar cells (PSCs) have received great attention because of their optimized optical and electrical properties for solar cell applications. Recently, a dramatic increase in the photovoltaic performance of PSCs with organic hole transport materials (HTMs) has been reported. However, as of now, future commercialization can be hampered because the stability of PSCs with organic HTM has not been guaranteed for long periods under conventional working conditions, including moist conditions. Furthermore, conventional organic HTMs are normally expensive because material synthesis and purification are complicated. It is herein reported, for the first time, octadecylamine‐capped pyrite nanoparticles (ODA‐FeS2 NPs) as a bi‐functional layer (charge extraction layer and moisture‐proof layer) for organo‐lead halide PSCs. FeS2 is a promising candidate for the HTM of PSCs because of its high conductivity and suitable energy levels for hole extraction. A bi‐functional layer based on ODA‐FeS2 NPs shows excellent hole transport ability and moisture‐proof performance. Through this approach, the best‐performing device with ODA‐FeS2 NPs‐based bi‐functional layer shows a power conversion efficiency of 12.6% and maintains stable photovoltaic performance in 50% relative humidity for 1000 h. As a result, this study has the potential to break through the barriers for the commercialization of PSCs.  相似文献   

2.
Perovskite solar cells (PSCs) are highly promising next‐generation photovoltaic devices because of the cheap raw materials, ideal band gap of ≈1.5 eV, broad absorption range, and high absorption coefficient. Although lead‐based inorganic‐organic PSC has achieved the highest power conversion efficiency (PCE) of 25.2%, the toxic nature of lead and poor stability strongly limits the commercialization. Lead‐free inorganic PSCs are potential alternatives to toxic and unstable organic‐inorganic PSCs. Particularly, double‐perovskite Cs2AgBiBr6‐based PSC has received interests for its all inorganic and lead‐free features. However, the PCE is limited by the inherent and extrinsic defects of Cs2AgBiBr6 films. Herein, an effective and facile strategy is reported for improving the PCE and stability by introducing an N719 dye interlayer, which plays multifunctional roles such as broadening the absorption spectrum, suppressing the charge carrier recombination, accelerating the hole extraction, and constructing an appropriate energy level alignment. Consequently, the optimizing cell delivers an outstanding PCE of 2.84%, much improved as compared with other Cs2AgBiBr6‐based PSCs reported so far in the literature. Moreover, the N719 interlayer greatly enhances the stability of PSCs under ambient conditions. This work highlights a useful strategy to boost the PCE and stability of lead‐free Cs2AgBiBr6‐based PSCs simultaneously, accelerating the commercialization of PSC technology.  相似文献   

3.
Rapid extraction of photogenerated charge carriers is essential to achieve high efficiencies with perovskite solar cells (PSCs). Here, a new mesoscopic architecture as electron‐selective contact for PSCs featuring 40 nm sized TiO2 beads endowed with mesopores of a few nanometer diameters is introduced. The bimodal pore distribution inherent to these films produces a very large contact area of 200 m2 g?1 whose access by the perovskite light absorber is facilitated by the interstitial voids between the particles. Modification of the TiO2 surface by CsBr further strengthens its interaction with the perovskite. As a result, photogenerated electrons are extracted rapidly producing a very high fill factor of close to 80% a VOC of 1.14 V and a PCE up to 21% with negligible hysteresis.  相似文献   

4.
Optical effects of the plasmonic structures and the materials effects of the metal nanomaterials have recently been individually studied for enhancing performance of organic solar cells (OSCs). Here, the effects of plasmonically induced carrier generation and enhanced carrier extraction of the carrier transport layer (i.e., plasmonic‐electrical effects) in OSCs are investigated. Enhanced charge extraction in TiO2 as a highly efficient electron transport layer by the incorporation of metal nanoparticles (NPs) is proposed and demonstrated. Efficient device performance is demonstrated by using Au NPs incorporated TiO2 at a plasmonic wavelength (560–600 nm), which is far longer than the originally necessary UV light. By optimizing the concentration ratio of the Au NPs in the NP‐TiO2 composite, the performances of OSCs with various polymer active layers are enhanced and efficiency of 8.74% is reached. An integrated optical and electrical model, which takes into account plasmonic‐induced hot carrier tunneling probability and extraction barrier between TiO2 and the active layer, is introduced. The enhanced charge extraction under plasmonic illumination is attributed to the strong charge injection of plasmonically excited electrons from NPs into TiO2. The mechanism favors trap filling in TiO2, which can lower the effective energy barrier and facilitate carrier transport in OSCs.  相似文献   

5.
The origin of performance enhancements in p‐i‐n perovskite solar cells (PSCs) when incorporating low concentrations of the bulky cation 1‐naphthylmethylamine (NMA) are discussed. A 0.25 vol % addition of NMA increases the open circuit voltage (Voc) of methylammonium lead iodide (MAPbI3) PSCs from 1.06 to 1.16 V and their power conversion efficiency (PCE) from 18.7% to 20.1%. X‐ray photoelectron spectroscopy and low energy ion scattering data show NMA is located at grain surfaces, not the bulk. Scanning electron microscopy shows combining NMA addition with solvent assisted annealing creates large grains that span the active layer. Steady state and transient photoluminescence data show NMA suppresses non‐radiative recombination resulting from charge trapping, consistent with passivation of grain surfaces. Increasing the NMA concentration reduces device short‐circuit current density and PCE, also suppressing photoluminescence quenching at charge transport layers. Both Voc and PCE enhancements are observed when bulky cations (phenyl(ethyl/methyl)ammonium) are incorporated, but not smaller cations (Cs/MA)—indicating size is a key parameter. Finally, it demonstrates that NMA also enhances mixed iodide/bromide wide bandgap PSCs (Voc of 1.22 V with a 1.68 eV bandgap). The results demonstrate a facile approach to maximizing Voc and provide insights into morphological control and charge carrier dynamics induced by bulky cations in PSCs.  相似文献   

6.
Understanding the factors that limit the performance of perovskite solar cells (PSCs) can be enriched by detailed temperature (T)‐dependent studies. Based on p‐i‐n type PSCs with prototype methylammonium lead triiodide (MAPbI3) perovskite absorbers, T‐dependent photovoltaic properties are explored and negative T‐coefficients for the three device parameters (VOC, JSC, and FF) are observed within a wide low T‐range, leading to a maximum power conversion efficiency (PCE) of 21.4% with an impressive fill factor (FF) approaching 82% at 220 K. These T‐behaviors are explained by the enhanced interfacial charge transfer, reduced charge trapping with suppressed nonradiative recombination and narrowed optical bandgap at lower T. By comparing the T‐dependent device behaviors based on MAPbI3 devices containing a PASP passivation layer, enhanced PCE at room temperature is observed but different tendencies showing attenuating T‐dependencies of JSC and FF, which eventually leads to nearly T‐invariable PCEs. These results indicate that charge extraction with the utilized all‐organic charge transporting layers is not a limiting factor for low‐T device operation, meanwhile the trap passivation layer of choice can play a role in the T‐dependent photovoltaic properties and thus needs to be considered for PSCs operating in a temperature‐variable environment.  相似文献   

7.
A graphene oxide (GO) film is functionalized with metal (Au) and metal‐oxide (MoOx) nanoparticles (NPs) as a hole‐extraction layer for high‐performance inverted planar‐heterojunction perovskite solar cells (PSCs). These NPs can increase the work function of GO, which is confirmed with X‐ray photoelectron spectra, Kelvin probe force microscopy, and ultraviolet photoelectron spectra measurements. The down‐shifts of work functions lead to a decreased level of potential energy and hence increased Voc of the PSC devices. Although the GO‐AuNP film shows rapid hole extraction and increased Voc, a Jsc improvement is not observed because of localization of the extracted holes inside the AuNP that leads to rapid charge recombination, which is confirmed with transient photoelectric measurements. The power conversion efficiency (PCE) of the GO‐AuNP device attains 14.6%, which is comparable with that of the GO‐based device (14.4%). In contrast, the rapid hole extraction from perovskite to the GO‐MoOx layer does not cause trapping of holes and delocalization of holes in the GO film accelerates rapid charge transfer to the indium tin oxide substrate; charge recombination in the perovskite/GO‐MoOx interface is hence significantly retarded. The GO‐MoOx device consequently shows significantly enhanced Voc and Jsc, for which its device performance attains PCE of 16.7% with great reproducibility and enduring stability.  相似文献   

8.
Organic–inorganic metal halide perovskite solar cells (PSCs) have attracted much research interest owing to their high power conversion efficiency (PCE), solution processability, and the great potential for commercialization. However, the device performance is closely related to the quality of the perovskite film and the interface properties, which cannot be easily controlled by solution processes. Here, 2D WS2 flakes with defect‐free surfaces are introduced as a template for van der Waals epitaxial growth of mixed perovskite films by solution process for the first time. The mixed perovskite films demonstrate a preferable growth along (001) direction on WS2 surfaces. In addition, the WS2/perovskite heterojunction forms a cascade energy alignment for efficient charge extraction and reduced interfacial recombination. The inverted PSCs with WS2 interlayers show high PCEs up to 21.1%, which is among the highest efficiency of inverted planar PSCs. This work demonstrates that high‐mobility 2D materials can find important applications in PSCs as well as other perovskite‐based optoelectronic devices.  相似文献   

9.
The optoelectronic properties of perovskite films are closely related to the film quality, so depositing dense, uniform, and stable perovskite films is crucial for fabricating high‐performance perovskite solar cells (PSCs). CsPbI2Br perovskite, prized for its superb stability toward light soaking and thermal aging, has received a great deal of attention recently. However, the air instability and poor performance of CsPbI2Br PSCs are hindering its further progress. Here, an approach is reported for depositing high‐quality CsPbI2Br films via the Lewis base adducts PbI2(DMSO) and PbBr2(DMSO) as precursors to slow the crystallization of the perovskite film. This process produces CsPbI2Br films with large‐scale crystalline grains, flat surfaces, low defects, and long carrier lifetimes. More interestingly, PbI2(DMSO) and PbBr2(DMSO) adducts could significantly improve the stability of CsPbI2Br films in air. Using films prepared by this technique, a power conversion efficiency (PCE) of 14.78% is obtained in CsPbI2Br PSCs, which is the highest PCE value reported for CsPbI2Br‐based PSCs to date. In addition, the PSCs based on DMSO adducts show an extended operational lifetime in air. These excellent performances indicate that preparing high‐quality inorganic perovskite films by using DMSO adducts will be a potential method for improving the performance of other inorganic PSCs.  相似文献   

10.
Perovskite solar cells (PSCs) have received great attention due to their outstanding performance and their low processing costs. To boost their performance, one approach is to reinforce the built‐in electric field (BEF) to promote oriented carrier transport. The BEF is maximized by reinforcing the work function difference between cathode and anode (Δμ1) and increasing the work function difference between lower and upper surfaces of perovskite film (Δμ2) via introduction of electric dipole molecules, denoted as PTFCN and CF3BACl. The synergistic reinforcement of BEF improves charge transport and collection, and realizes markedly high photovoltaic performances with the best power conversion efficiency (PCE) up to 21.5%, a growth of 15.6% as compared to the control device, which is higher than the superposition of improvements achieved by either raising Δμ1 or Δμ2. Importantly, dual‐functional CF3BACl not only supplies dipole effect for tuning the surface potential of perovskite but offers hydrophobic trifluoride group toward the long‐term stable unencapsulated PSCs retaining more than 95% PCE after storing 2000 h under ambient conditions. This work demonstrates the synergistic effect of Δμ1 and Δμ2, providing an effective strategy for the further development of PSC in terms of photovoltaic conversion and stability.  相似文献   

11.
《Organic Electronics》2014,15(2):348-355
We report that the power conversion efficiency (PCE) can be enhanced in polymer bulk heterojunction solar cells by inserting an interfacial electron transporting layer consisting of pristine TiO2 or reduced graphene oxide–TiO2 (RGO–TiO2) between the active layer and cathode Al electrode. The enhancement in the PCE has been analyzed through the optical absorption, current–voltage characteristics under illumination and estimation of photo-induced charge carrier generation rate. It was found that either TiO2 or RGO–TiO2 interfacial layers improve the light harvesting, as well as the charge extraction efficiency, acting as a blocking layer for holes, and also reducing charge recombination. The combined enhancement in light harvesting property and charge collection efficiency improves the PCE of the organic solar cell up to 4.18% and 5.33% for TiO2 and RGO–TiO2 interfacial layer, respectively, as compared to a value of 3.26% for the polymer solar cell without interfacial layer.  相似文献   

12.
3D organic–inorganic lead halide perovskites have shown great potential in efficient photovoltaic devices. However, the low stability of the 3D perovskite layer and random arrangement of the perovskite crystals hinder its commercialization road. Herein, a highly oriented 2D@3D ((AVA)2PbI4@MAPbI3) perovskite structure combining the advantages of both 2D and 3D perovskite is fabricated through an in situ route. The highest power conversion efficiency (PCE) of 18.0% is observed from a 2D@3D perovskite solar cell (PSC), and it also shows significantly enhanced device stability under both inert (90% of initial PCE for 32 d) and ambient conditions (72% of initial PCE for 20 d) without encapsulation. The high efficiency of 18.0% and nearly twofold improvement of device stability in ambient compared with pure 3D PSCs confirm that such 2D@3D perovskite structure is an effective strategy for high performance and increasing stability and thus will enable the timely commercialization of PSCs.  相似文献   

13.
Planar perovskite solar cells (PSCs) based on low‐temperature‐processed (LTP) SnO2 have demonstrated excellent photovoltaic properties duo to the high electron mobility, wide bandgap, and suitable band energy alignment of LTP SnO2. However, planar PSCs or mesoporous (mp) PSCs based on high‐temperature‐processed (HTP) SnO2 show much degraded performance. Here, a new strategy with fully HTP Mg‐doped quantum dot SnO2 as blocking layer (bl) and a quite thin SnO2 nanoparticle as mp layer are developed. The performances of both planar and mp PSCs has been greatly improved. The use of Mg‐SnO2 in planar PSCs yields a high‐stabilized power conversion efficiency (PCE) of close to 17%. The champion of mp cells exhibits hysteresis free and stable performance with a high‐stabilized PCE of 19.12%. The inclusion of thin mp SnO2 in PSCs not only plays a role of an energy bridge, facilitating electrons transfer from perovskite to SnO2 bl, but also enhances the contact area of SnO2 with perovskite absorber. Impedance analysis suggests that the thin mp layer is an “active scaffold” selectively collecting electrons from perovskite and can eliminate hysteresis and effectively suppress recombination. This is an inspiring advance toward high‐performance PSCs with HTP mp SnO2.  相似文献   

14.
Organic–inorganic halide perovskite solar cells are one of the most efficient photovoltaic devices, and their power conversion efficiency (PCE) continues to grow rapidly due to the optimization of device architecture and functional materials. The involved optical design has an important impact on performance by affecting the light harvesting capability. Here, demonstrated is a simple and effective strategy to boost device performance from the perspective of light management. A diffraction grating pattern into the TiO2 scaffold and antireflection layer is simultaneously introduced to construct a double grating design for perovskite solar cells. The grating pattern obtained using a commercial compact disk as the hard mold can modulate light transport by enhancing the light transmittance and, thus, light absorption in perovskite solar cells. The grating pattern‐induced light trapping can significantly increase the short‐circuit current density and PCE by 4.8% and 7.9%, respectively, on average. The present work develops a feasible method by tailoring the morphology‐related optical property to further improve the performance of perovskite solar cells. The double grating design can also generate structural color and can provide an alternative solution for fabricating colorful solar cells.  相似文献   

15.
Perovskite solar cell (PSC) has attracted great attention due to its high power conversion efficiency (PCE), low cost and solution processability. The well-designed interface and the modification of electron transport layer (ETL) are critical to the PCE and long-term stability of PSCs. In this article, a fused-ring electron acceptor is employed as the interfacial material between TiO2 and the perovskite in rigid and flexible PSCs. The modification improves the surface of TiO2, which decreases the defects of ETL surface. Moreover, the modified surface has lower hydrophilicity, and thus is beneficial to the growth of perovskite with large grain size and high quality. As a result, the interfacial charge transfer is promoted and the interfacial charge recombination can be suppressed. The highest PCE of 19.61% is achieved for the rigid PSCs after the introduction of ITIC, and the hysteresis effect is significantly reduced. Flexible PSC with ITIC obtains a PCE of 14.87%, and the device stability is greatly improved. This study provides an efficient candidate as the interfacial modifier for PSCs, which is compatible with low-temperature solution process and has a great practical potential for the commercialization of PSCs.  相似文献   

16.
The ternary blend system such as binary donor and an acceptor or binary acceptor and a donor offers a way to improve the power conversion efficiency of the polymer solar cells (PSCs) by enhancing optical properties and electrical properties. In this work, PTB7, PC71BM and Molybdenum disulfide nano-sheet (MoS2NS) ternary blend system were investigated as an active material for OPV. The optimized ternary blend system showed increment of 17% power conversion efficiency (PCE) from 6.98% to 8.18%. The origin of improved PCE mainly arises from the significant increment in JSC and marginal change in VOC and FF. This improved PCE is due to increased light harvesting and improved charge carrier mobility in the active matrix. The marginal enhancement in VOC and FF was correlated with the density of trap states (DOS) obtained from capacitance measurement of the device. The optical absorption and energy transfer mechanism of the ternary blend film is explained by absorption and photoluminescence measurement respectively. Further, the conversion efficiency due to improved charge carrier transport was described by modified SCLC mobility measurements for electron and hole only devices. The obtained result suggests that presence of MoS2NS along with PTB7:PC71BM binary system play dual role like an improved charge transport layer as well as light harvesting.  相似文献   

17.
Organolead halide perovskite solar cells (PSC) are arising as promising candidates for next‐generation renewable energy conversion devices. Currently, inverted PSCs typically employ expensive organic semiconductor as electron transport material and thermally deposited metal as cathode (such as Ag, Au, or Al), which are incompatible with their large‐scale production. Moreover, the use of metal cathode also limits the long‐term device stability under normal operation conditions. Herein, a novel inverted PSC employs a SnO2‐coated carbon nanotube (SnO2@CSCNT) film as cathode in both rigid and flexible substrates (substrate/NiO‐perovskite/Al2O3‐perovskite/SnO2@CSCNT‐perovskite). Inverted PSCs with SnO2@CSCNT cathode exhibit considerable enhancement in photovoltaic performance in comparison with the devices without SnO2 coating owing to the significantly reduced charge recombination. As a result, a power conversion efficiency of 14.3% can be obtained on rigid substrates while the flexible ones achieve 10.5% efficiency. More importantly, SnO2@CSCNT‐based inverted PSCs exhibit significantly improved stability compared to the standard inverted devices made with silver cathode, retaining over 88% of their original efficiencies after 550 h of full light soaking or thermal stress. The results indicate that SnO2@CSCNT is a promising cathode material for long‐term device operation and pave the way toward realistic commercialization of flexible PSCs.  相似文献   

18.
A novel scaffold layer composed of TiO2-ZrO2 composite was fabricated for perovskite solar cell. Compared with pure TiO2 nanoparticles (NPs), the relatively larger ZrO2 NPs could increase film roughness and enhance light-scattering effect in TiO2-ZrO2 composite films. The device exhibited outstanding power conversion efficiency (PCE) of 11.41%. The morphology and aggregation of particles, three-dimensional roughness, as well as the ingredient and micro-structure of FTO/compact TiO2/TiO2-ZrO2 was investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscope (AFM), energy dispersive spectrometer (EDS), and X-ray diffraction (XRD), respectively. Moreover, the optical property of TiO2-ZrO2 films for visible light was characterized by UV–visible absorption spectroscopy (UV–vis), and its influence on quantum yield of the device was further demonstrated by incident photon-to-electron conversion efficiency (IPCE). Owing to the inert oxide, the short-circuit current density of perovskite solar cell using TiO2-ZrO2 composition as scaffold layer increased by 21% compared to the one employing pure TiO2 mesoporous film.  相似文献   

19.
Solution‐processed triple‐cation perovskite solar cells (PSCs) rely on complex compositional engineering or delicate interfacial passivation to balance the trade‐off between cell efficiency and long‐term stability. Herein, the facile fabrication of highly efficient, stable, and hysteresis‐free tin oxide (SnO2)‐based PSCs is demonstrated with a champion cell efficiency of 20.06% using a green, halogen‐free antisolvent. The antisolvent, composed of ethyl acetate (EA) solvent and hexane (Hex) in different proportions, works exquisitely in regulating perovskite crystal growth and passivating grain boundaries, leading to the formation of a crack‐free perovskite film with enlarged grain size. The high quality perovskite film inhibits carrier recombination and substantially improves the cell efficiency, without requiring an additional enhancer/passivation layer. Furthermore, these PSCs also demonstrate remarkable long‐term stability, whereby unencapsulated cells exhibit a power conversion efficiency (PCE) retention of ≈71% after >1500 hours of storage under ambient condition. For encapsulated cells, an astounding PCE retention of >98% is recorded after >3000 hours of storage in air. Overall, this work realizes the fabrication of SnO2‐based PSCs with a performance greater or comparable to the state‐of‐the‐art PSCs produced with halogenated antisolvents. Evidently, EA–Hex antisolvent can be an extraordinary halogen‐free alternative in maximizing the performance of PSCs.  相似文献   

20.
Perovskite solar cells (PSCs) have improved dramatically over the past decade, increasing in efficiency and gradually overcoming hurdles of temperature‐ and humidity‐induced instability. Materials that combine high charge‐carrier lifetimes and mobilities, strong absorption, and good crystallinity of 3D perovskites with the hydrophobic properties of 2D perovskites have become particularly promising candidates for use in solar cells. In order to fully understand the optoelectronic properties of these 2D–3D hybrid systems, the hybrid perovskite BAx(FA0.83Cs0.17)1‐xPb(I0.6Br0.4)3 is investigated across the composition range 0 ≤ x ≤ 0.8. Small amounts of butylammonium (BA) are found that help to improve crystallinity and appear to passivate grain boundaries, thus reducing trap‐mediated charge‐carrier recombination and enhancing charge‐carrier mobilities. Excessive amounts of BA lead to poor crystallinity and inhomogeneous film formation, greatly reducing effective charge‐carrier mobility. For low amounts of BA, the benevolent effects of reduced recombination and enhanced mobilities lead to charge‐carrier diffusion lengths up to 7.7 µm for x = 0.167. These measurements pave the way for highly efficient, highly stable PSCs and other optoelectronic devices based on 2D–3D hybrid materials.  相似文献   

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