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Enhanced photovoltaic efficiency and persisted photoresponse switchability in LaVO3/Pb(Zr0.2Ti0.8)O3 perovskite heterostructures
摘要： For the ferroelectric photovoltaics, it is challenging to enhance the power conversion efficiency (PCE) without sacrificing the photoresponse switchability. Here, we demonstrate that enhanced PCE and good photoresponse switchability can be simultaneously achieved in perovskite heterostructures comprising narrow-gap semiconductor LaVO3 (LVO) and ferroelectric Pb(Zr0.2Ti0.8)O3 (PZT). The LVO(24 nm)/PZT(120 nm) based device exhibits a ~5-fold enhancement in PCE compared with the PZT-only based device, which is attributed to the enhanced absorption from the LVO layer and the built-in field at the LVO/PZT interface facilitating the separation of photo-generated e-h pairs. In addition, the switched photovoltage of the LVO/PZT based device is above 1 V, which is as large as that of the PZT-only based device. This persisted photoresponse switchability is obtained because the polarization can be fully switched in the LVO/PZT based devices when the LVO thickness is less than 24 nm. Our finding therefore provides a promising route for the development of the high-efficiency and highly switchable ferroelectric photovoltaic devices.
关键词： perovskite heterostructures,ferroelectric photovoltaics,LaVO3,photoresponse switchability,power conversion efficiency,Pb(Zr0.2Ti0.8)O3
更新于2025-09-11 14:15:04
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Anomalous Stokes shift of colloidal quantum dots and their influence on solar cell performance
摘要： We report an anomalous Stokes shift effect observed in colloidal solutions containing down-shifting Carbon quantum dots (CQDs) of different sizes that is expected to have a positive in?uence on the power conversion ef?ciency of photovoltaic structures. Speci?cally, with an excitation wavelength of 390 nm, individual colloidal solutions of CQDs whose diameter was determined by the applied current during synthesis, exhibited photoluminescent (PL) emission wavelength peaks centered at 420 nm. However, the colloidal solution comprising the mixture of all the previously synthesized CQDs of different diameters was observed to have an anomalous PL Stokes shift centered at 515 nm. Furthermore, the afore-mentioned anomalous SSE was also observed in CdTe QDs when added to the CQD mixed-solution (CMS). Thus, whereas a mixture of CdTe QDs of different sizes, exhibited a down-shifted photoluminescence centered at 555 nm, the peak was observed to have an anomalous Stokes shift centered at 580 nm when combined with the CMS. Quantum dot characterization included crystal structure analysis as well as photon absorption and photoluminescence wavelengths. Subsequently, the synthesized QDs were dispersed in a polymeric layer of PMMA and incorporated on functional and previously characterized solar cells, to quantify their in?uence in the electrical performance of the photovoltaic devices. The observations indicate an improvement in the PCE of 4.6% when incorporating Carbon QDs, 2.9% with CdTe QDs and 4.8% when employing both C and CdTe QDs.
关键词： solar cell performance,photoluminescence,Carbon quantum dots,Anomalous Stokes shift,colloidal quantum dots,CdTe quantum dots,power conversion efficiency
更新于2025-09-11 14:15:04
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New small molecule electrolytes based on tosylate anion for organic solar cells
摘要： Reduction of a Schottky barrier between the active layer and electrodes can play an important role enhancing the power conversion efficiency (PCE) of organic solar cells (OSCs), which originated from a favorable interface dipole at the cathode interface. Herein, two new small molecules (SM) electrolytes based on tosylate anions, named 2,2’-(ethane-1,2-diylbis(oxy))bis(N,N,N-trimethylethananminium) benzenesulfonate (TEG-M-OTs) and 1,1’-bis(1-dodecyl)-4,40-bipyridine-1,10-diium benzenesulfonate (V-C12-OTs), were synthesized to induce the reduction of a Schottky barrier in OSCs. The PCE of devices based on ZnO with TEG-M-OTs or V-C12-OTs as the cathode buffer layer (CBL) was enhanced from 7.48% to 7.74% and 7.88%. In case of ZnO-free devices, the PCE of TEG-M-OTs or V-C12-OTs was achieved up to 4.22% and 6.95%, respectively. The Kelvin probe microscopy was performed by measuring the work function (WF) of SM electrolytes with or without ZnO on the ITO surface. It showed that the WFs of SM electrolytes coated ITO are closer to - 4.02 eV, the lowest unoccupied molecular orbitals (LUMO) of the acceptor, than the WF of MeOH treated ITO with ZnO (- 4.37 eV).
关键词： Schottky barrier,organic solar cells,tosylate anion,power conversion efficiency,small molecule electrolytes
更新于2025-09-11 14:15:04
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Utilization of 2D gahnite nanosheets as highly conductive, transparent and light trapping front contact for silicon solar cells
摘要： The current scenario illustrates distinct interest in developing renewable energy sources for power generation. In this regard, several researches are performed in enhancing the power conversion efficiency of solar cells. The present work focuses on utilizing ZnAl2O4 (gahnite) spinel as antireflection coating material to improve the power conversion efficiency of silicon solar cells. Gahnite was synthesized using two precursors namely zinc nitrate hexahydrate and aluminum nitrate nonahydrate through sol–gel technique. The thickness of the prepared gahnite sheets measured through atomic force microscopy was around 50?nm. Single to quintuple layers of gahnite was deposited on silicon solar substrate using spin coating technique. The influence of gahnite coating on the structural, optical, electrical properties and cell temperature of silicon solar cells are analyzed. The synthesized gahnite bears spinel crystal structure in the form of two dimensional nanosheet. Increment in layer thickness proves the deposition of single to quintuple layer on silicon substrate. A maximum of 93% transmittance and 20.72% power conversion efficiency at a low cell temperature (39.4?°C) has been achieved for triple layer deposition proving diffusion of more photons on the substrate. The obtained results prove gahnite as suitable anti-reflection coating material for enhancing the power conversion efficiency of silicon solar cells.
关键词： Anti-reflection coating,Silicon solar cell,Gahnite,Power conversion efficiency,Sol–gel
更新于2025-09-11 14:15:04
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Ultrafast laser-annealing of perovskite films for efficient perovskite solar cells
摘要： Perovskite solar cells have attracted much attention recently for their high efficiency, ease of preparation and low cost. Here, we report a novel laser-annealing method for perovskite films at a low substrate temperature by scanning laser spots on the film surfaces. An ultrafast crystallization process within a few seconds is realized under a laser with a high intensity and a fast scanning speed. Because the crystalline perovskite phase has a stronger light absorption than the amorphous phase, the fast laser annealing can induce a higher temperature in the former and lead to the selective growth of large perovskite grains. Under optimum conditions, perovskite films with high crystallinity are successfully fabricated, resulting in perovskite solar cells with high power conversion efficiency and good stability. Moreover, a faster laser-annealing process of perovskite films is achieved by using a linear laser beam, which is expected to be a promising technique for the mass production of large-scale perovskite solar cells.
关键词： Perovskite solar cells,ultrafast crystallization,laser-annealing,large-scale production,power conversion efficiency
更新于2025-09-11 14:15:04
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Spontaneous Enhancement of the Stable Power Conversion Efficiency in Perovskite Solar Cells
摘要： The power conversion efficiency (PCE) of lead-halide perovskite solar cells (PSCs) is reported to increase over a period of days after their fabrication while they are stored in dark. Thus far, effects underlying this spontaneous enhancement are not understood. This work investigates the phenomenon for a variety of multi-cation-halide PSCs with different perovskite compositions and architectures. The observations reveal that spontaneous enhancement is not restricted to specific charge-transport layers or perovskite compositions. The highest PCE observed in this study is the enhanced stable PCE of 19% (increased by 4% absolute). An increased open-circuit voltage is the primary contributor to the improved efficiency. Using time-resolved photoluminescence measurements, initially-present low-energy states are identified that disappear over a storage period of a few days. Furthermore, trap states probed by thermally stimulated current technique exist in pristine PSCs and strikingly decrease for stored devices. In addition, ideality factor approaches unity and X-ray diffraction analyses show a lattice strain relaxation over the same period of time. These observations indicate that spontaneous enhancement of the PSCs is based on a reduction in trap-assisted non-radiative recombination possibly due to strain relaxation. Considering the demonstrated generality of spontaneous enhancement for different compositions of multi-cation-halide PSCs, our results highlight the importance of determining absolute PCE increase initiated by spontaneous enhancement for developing high-efficiency PSCs.
关键词： spontaneous enhancement,perovskite solar cells,power conversion efficiency,trap states,strain relaxation
更新于2025-09-11 14:15:04
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Boosting the ultra-stable unencapsulated perovskite solar cells by using montmorillonite/CH <sub/>3</sub> NH <sub/>3</sub> PbI <sub/>3</sub> nanocomposite as photoactive layer
摘要： Lead halide perovskites, such as methylammonium lead iodide (MAPbI3) can reach near 100% internal quantum e?ciency in single solar cells, but they still encounter significant thermodynamic losses in photon energy to o?set device photovoltage and performance. Herein, a novel prismatic perovskite solar cell with light trapping configuration, namely, Prim PVSC, is designed to mitigate such losses in devices, through modulating the pathway of light inside series cells, wherein incident high-to-low energy photons are separately captured by four horizontally aligned MAPbIxBr3?x subcells with varied bandgaps. This newly designed PVSC has remarkably led to a record open circuit voltage of 5.3 V in four series devices and power conversion e?ciency of 21.3%, which could provide a new way to break the performance bottleneck of perovskites. Practically, this type of device architecture could also be applied in flexible modules for large-area application.
关键词： perovskite solar cells,light trapping,photovoltage,thermodynamic losses,power conversion efficiency
更新于2025-09-11 14:15:04
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Improving the efficiency and stability of inverted perovskite solar cells by CuSCN-doped PEDOT:PSS
摘要： Hole transport layer (HTL) is important in inverted perovskite solar cells (PSCs) to facilitate the hole extraction and suppress the charge recombination for high device performance. Based on the widely used HTL material of poly(ethylenedioxythiophene) (PEDOT):poly(styrenesulfonate) (PSS), we proposed a new HTL modification method using the widely available copper(I) thiocyanate (CuSCN); the doping of CuSCN NH3 [aq] in PEDOT:PSS followed by low-temperature annealing results in reduced energy barrier, improved charge extraction efficiency and increased the mean size of perovskite crystal of the PEDOT:PSS-CuSCN HTL-based inverted PSCs. Significantly improved device performance was observed with open current voltage over 1.0 V and power conversion efficiency (PCE) up to 15.3%, which is 16% higher in PCE than that of the PEDOT:PSS-based PSCs. More impressively, with a lower acidity than PEDOT:PSS, the PEDOT:PSS-CuSCN HTL enables excellent long-term stability of the inverted PSCs, exhibiting almost doubly improved device stability at the same storage condition. Thus, the successful application of CuSCN doping in PEDOT:PSS HTLs should provide a novel approach for the development of high-performance HTLs for highly efficient and stable PSCs.
关键词： Perovskite solar cells,Power conversion efficiency,CuSCN,Hole transport layer,Stability
更新于2025-09-11 14:15:04
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High-yield production of stable antimonene quantum sheets for highly efficient organic photovoltaics
摘要： High-performance organic photovoltaics (OPVs) are of great scientific and technological importance due to their potential large-scale industrial applications. Introducing semiconductor quantum dots has been proven to be an effective way to improve the power conversion efficiency (PCE) of OPVs. In this paper, we report a novel approach to fabricate atomically thin antimonene quantum sheets (AMQSs) possessing a uniform size (～2.2 nm) via imidazolium ionic liquid-assisted exfoliation. In this method, the yield of AMQSs (1.1 mg mL?1) has been increased by nearly two orders of magnitude compared with that of previously reported methods. Furthermore, upon adding AMQSs into the light absorber in OPVs, the optimal device with 1.0 mg mL?1 AMQSs shows the highest PCE of 9.75%, resulting in over 25% enhancement in PCE compared to that of the reference device. It also leads to a noticeable enhancement in the short-circuit current density (Jsc) of 16.7% and the fill factor (FF) of 8.4%. The increased PCE is mainly due to the two-dimensional electronic structure of AMQSs that can enhance the light absorption, assist exciton dissociation and reduce charge recombination of OPVs. This work provides a new avenue toward mass production of two-dimensional quantum sheets and points to a new strategy for highly efficient OPVs.
关键词： antimonene quantum sheets,organic photovoltaics,power conversion efficiency,ionic liquid-assisted exfoliation,two-dimensional materials
更新于2025-09-11 14:15:04
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Self-doping small molecular conjugated electrolytes enabled by n-type side chains for highly efficient non-fullerene polymer solar cells
摘要： We developed a series of novel small molecular conjugated electrolytes (SMCEs) via side chain engineering. The introduced n-type 1,3,4-thiadiazole/1,3,4-oxadiazole side chains featured the related SMCEs with self-doping nature and high electron conductive property. On using as cathode interlayers in non-fullerene-polymer solar cells, a high power conversion efficiency (PCE) of up to 13.21% was achieved with an excellent thickness-insensitive property.
关键词： thickness-insensitive property,side chain engineering,power conversion efficiency,non-fullerene polymer solar cells,small molecular conjugated electrolytes
更新于2025-09-11 14:15:04