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Improving efficiency and stability of colorful perovskite solar cells with two-dimensional photonic crystals
摘要： Colorful solar cells have been much sought after because they can generate electricity and concurrently satisfy ornamentation purposes. Owing to their outstanding power conversion efficiency and flexibility in processing, perovskite solar cells (PSCs) have the great potential to become both efficient and aesthetically appealing. Here, we specially devise and fabricate two novel electron transport layers (ETLs) for PSCs with two-dimensional (2D) photonic crystal structures, namely the 2D inverse opal (IO) structured SnO2 (IOS) and SnO2-TiO2 composite (IOST), using the template-assisted spin-coating method. The synergistic structure and material modifications to the ETLs lead to a number of unique features, including the remarkable electron transfer ability, vivid colors and good protection to the infiltrated perovskite films. Furthermore, the IOS and IOST ETLs are effectively incorporated into the CH3NH3PbI3-based PSC devices that deliver the best efficiency of 16.8% with structural colors.
关键词： structural colors,two-dimensional photonic crystals,SnO2,electron transport layers,TiO2,perovskite solar cells
更新于2025-09-23 15:21:01
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Cathode Interface Engineering Approach for a Comprehensive Study of the Indoor Performance Enhancement in Organic Photovoltaic
摘要： Organic photovoltaic (OPV) has a prospective future as a reliable energy harvesting to drive low power consumption devices for indoor applications. In this article, the outdoor (1 sun) and indoor (LED 2700K) performance of PTB7-Th:PC70BM inverted OPV with three different solution-processed electron transport layers (ETL = PFN, TiOx, and ZnO) were compared. The morphology, optical, and electrical measurements indicate the strong dependency of the OPV performance with the illumination conditions. The sample with PFN-ETL that shows the highest outdoor performance with power conversion efficiency (PCE) of 10.55% and the best-reported fill factor (FF) of 75.00% among PTB7-Th:PC70BM-based OPV, surprisingly exhibits the lowest performance when illuminated under 250–2000 lux LED 2700K. Meanwhile, the lowest outdoor performance performed by ZnO with PCE of 10.03% displays the best indoor performance with the PCE of 13.94% under 1000 lux and a PCE of up to 16.49% under 1750 lux LED lamp, respectively. The changes in the FF values can be estimated by incorporating the parasitic resistance effect due to the type ETL used. Besides, using impedance spectroscopy, we observed that indoor performance agreed well with the trend of charge collection efficiency.
关键词： impedance spectroscopy,Organic photovoltaic,electron transport layers,PTB7-Th:PC70BM,indoor performance
更新于2025-09-23 15:21:01
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Composite Interlayer Consisting of Alcohol-Soluble Polyfluorene and Carbon Nanotubes for Efficient Polymer Solar Cells
摘要： We report the synthesis of composite interlayers using alcohol-soluble polyfluorene (ASP)-wrapped single-walled carbon nanotubes (SWNTs) and their application as electron transport layers for efficient organic solar cells. The ASP enables the individual dispersion of SWNTs in solution. The ASP-wrapped SWNT solutions are stable for 54 days without any aggregation or precipitation, indicating their very high dispersion stability. Using the ASP-wrapped SWNTs as a cathode interlayer on zinc oxide nanoparticles (ZnO NPs), a power conversion efficiency of 9.45% is obtained in PTB7-th:PC71BM-based organic solar cells, which is mainly attributed to the improvement in the short circuit current. Performance enhancements of 18% and 17% are achieved compared to those of pure ZnO NPs and ASP on ZnO NPs, respectively. In addition, the composite interlayer is applied to non-fullerene-based photovoltaics with PM6:Y6, resulting in the PCE up to 14.37%. The type of SWNT (e.g., in terms of diameter range and length) is not critical to the improvement in the charge-transport properties. A low density of SWNTs in the film (~1 SWNTs/μm2 for ASP-wrapped SWNTs) has a significant influence on the charge transport in solar cells. The improvement in the performance of the solar cell is attributed to the increased internal quantum efficiency, balanced mobility between electrons and holes, and minimized charge recombination.
关键词： interfacial layers,alcohol-soluble polyfluorene,interlayers,organic solar cells,conjugated polyelectrolytes,Carbon nanotubes,electron transport layers,composites
更新于2025-09-23 15:19:57
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Thin Film of TiO <sub/>2</sub> a??ZnO Binary Mixed Nanoparticles as Electron Transport Layers in Low-Temperature Processed Perovskite Solar Cells
摘要： Organic–inorganic hybrid perovskite solar cells have become one of the highly promising candidates for photovoltaic technologies because of their low processing cost, rapid-growing power conversion efficiency and easy preparation process. Electron transfer layer (ETL) plays an important role in exciton separation and charge transport for perovskite devices. A TiO2–ZnO binary mixed nanoparticle (NP) ETL, which can be prepared in low-temperature hydrothermal method, was proposed. By analyzing the XRD and SEM, the incorporation of mixed NPs thin film improved the interfacial stability of ZnO/perovskite and prevented the perovskite layer from being decomposed as compared to the pure ZnO NPs thin film. Furthermore, UV spectrum and EIS results show that TiO2–ZnO mixed NP ETL has high transmittance and maintains good electrical properties of pure ZnO NPs basically. Finally, the efficiency of perovskite device based on TiO2–ZnO mixed NP ETL was improved to 15%. Our research provides a simple way for the application of ZnO in PCSs.
关键词： Perovskite solar cells,electron transport layers,ZnO,TiO2,low temperature
更新于2025-09-23 15:19:57
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Functionalization of fullerene by polyethylene glycol toward promoted electron transport in inverted polymer solar cells
摘要： A novel polyethylene glycol-functionalized fullerene derivative (C60-PEGA) was synthesized by a facile one-step nucleophilic addition reaction. C60-PEGA possessed good solubility in methanol and was estimated as C60-( C8H18N)13H13O with average PEG moiety of 13 by 1H NMR, FT-IR and X-ray photoelectron spectroscopy (XPS) spectra. C60-PEGA was applied as an ETL to construct inverted bulk heterojunction polymer solar cells (inverted BHJ-PSCs) based on photoactive layers of poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene-co-3-fluorothieno[3,4-b]thiophene-2-carboxylate]: [6,6]-phenyl-C71-butyric acid methyl ester (PTB7-Th: PC71BM), which achieve the best PCE of 9.25%, surpassing that of reference device based on the ZnO ETL (8.61%). The higher ETL performance of C60-PEGA ETL in BHJ-iPSC device relative to that of the ZnO ETL was attributed to the increase of electron mobility and effective electron transport from the active layer to the ITO cathode because that the reduced work function (WF) of ITO via the modification of C60-PEGA leads to the increase of short-circuit current density (Jsc) and consequent PCE.
关键词： polyethylene glycol (PEG),electron transport layers (ETLs),inverted polymer solar cells,work function,fullerene derivative
更新于2025-09-19 17:13:59
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Cesium carbonate modified electron transport layer for improving the photoelectric conversion efficiency of planar perovskite solar cells
摘要： TiO2 is a commonly used material in the electron transport layers (ETLs) of perovskite solar cells (PSCs) but its defects restrict the development of PSCs. In this study, cesium carbonate (Cs2CO3) was used to modify the TiO2 ETLs because of its excellent electron injection ability. The new structure of the PSC was FTO/TiO2/Cs2CO3/perovskite (MAPbI3)/sprio-OMETAD/back electrode. As expected, adding Cs2CO3 increased the champion photoelectric conversion efficiency (PCE) from 9.2% to 12.8% in comparison with unmodified solar cells, and the device maintained 78% of the original efficiency after 250 h. Moreover, the reduction of defects in the TiO2 ETLs reduced the coincidence probability of carriers after modification with Cs2CO3. Due to the excellent electron injection ability of Cs2CO3, the modified ETLs yielded lower work functions and smaller energy level barriers, which makes the energy levels between the TiO2 ETL and the MAPbI3 layer well-matched, and reduced the carrier coincidence probability.
关键词： Cs2CO3,Perovskite solar cells,Electron transport layers,Interface modification
更新于2025-09-19 17:13:59
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Record Photocurrent Density over 26a??mAa??cm <sup>a??2</sup> in Planar Perovskite Solar Cells Enabled by Antireflective Cascaded Electron Transport Layer
摘要： Here an antireflective cascaded SnO2/TiO2-Cl electron transport layer (ETL) is devised to enhance the performance of planar perovskite solar cells (PSCs). The primary optical reflection of planar PSCs at the front side can be dramatically reduced by using cascaded ETL. Based on this strategy, we achieved a record-high short-circuit current density of 26.1 mA cm-2 and a high PCE of 22.9% in FAPbI3-based planar PSCs.
关键词： planar perovskite solar cells,cascaded electron transport layers,anti-reflection,bilayer,short-circuit current density
更新于2025-09-19 17:13:59
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The improved performance and mechanism of solution-processed blue PhOLEDs based on double electron transport layers
摘要： Performance improved solution-processed blue phosphorescent organic light emitting diodes (PhOLEDs) are demonstrated by adopting a double electron transport layer (ETL) strategy, which consists of TPBi and an additional Alq3 ETL. With the help of Alq3 ETL, the performance of the optimal device with a double ETL is significantly enhanced. The maximum luminance of OLEDs is improved from 6787 cd m?2 to 13 054 cd m?2, and the maximum current efficiency is increased from 3.9 cd A?1 to 11.4 cd A?1. Furthermore, the difference of carrier injection in the two types of PhOLEDs is explored by using the transient electroluminescence measurement method. The results imply that double ETL can help to balance electron injection and carrier transport, reduce the interface charge accumulation, leading to a high efficiency. The PL decay of the emission layer with different ETL is detected to analyze the effect of the introduced second ETL layer and the interface on the exciton decay of the emission layer. The results show that the introduced interface in devices with a double ETL has an adverse effect on the exciton emission, which contributes to the serious efficiency roll-off of devices with a double ETL.
关键词： blue PhOLEDs,performance improvement,solution-processed,double electron transport layers,transient electroluminescence measurement
更新于2025-09-19 17:13:59
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Interface Engineering of Aira??Stable na??Doping Fullerenea??Modified TiO <sub/>2</sub> Electron Transport Layer for Highly Efficient and Stable Perovskite Solar Cells
摘要： As one common electron transport material for planar n-i-p perovskite solar cell, titanium dioxide (TiO2) compact layer has several challenging issues, such as surface hydroxyl groups, high defect density, and unmatched energy levels, causing severe energy loss and poor stability at contact. To solve these problems, the authors introduce a thin [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) interlayer doped with an air stable n-type dopant, 3-dimethyl-2-phenyl-2,3- dihydro-1H-benzoimidazole (DMBI) to modify the TiO2 surface. The state-of-the-art characterizations demonstrate such modification significantly improves charge transfer at MAPbI3/TiO2 interface together with smaller energy level offset, leading to suppressed charge recombination. High-quality perovskite film with larger crystal grain size grows on the n-doped PCBM/TiO2 attributed to the better surface affinity. As a result, the average power conversion efficiency of perovskite solar cell exhibits a prominent improvement from 17.46% to 20.14%, with an enhancement in all device photovoltaic parameters. In addition, the stability of the device with n-doped PCBM/TiO2 is much better than that of the control device with the bare TiO2 due to hydrophobicity nature of PCBM and low defect densities in the perovskite film and at the interface. This work indicates that many further device performance improvements should be conceivable by focusing on the perovskite interface.
关键词： stability,interfaces,perovskite solar cells,n-type doping,efficiency,electron transport layers
更新于2025-09-16 10:30:52
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Synergistic Interface Energy Band Alignment Optimization and Defect Passivation toward Efficient and Simplea??Structured Perovskite Solar Cell
摘要： Efficient electron transport layer–free perovskite solar cells (ETL-free PSCs) with cost-effective and simplified design can greatly promote the large area flexible application of PSCs. However, the absence of ETL usually leads to the mismatched indium tin oxide (ITO)/perovskite interface energy levels, which limits charge transfer and collection, and results in severe energy loss and poor device performance. To address this, a polar nonconjugated small-molecule modifier is introduced to lower the work function of ITO and optimize interface energy level alignment by virtue of an inherent dipole, as verified by photoemission spectroscopy and Kelvin probe force microscopy measurements. The resultant barrier-free ITO/perovskite contact favors efficient charge transfer and suppresses nonradiative recombination, endowing the device with enhanced open circuit voltage, short circuit current density, and fill factor, simultaneously. Accordingly, power conversion efficiency increases greatly from 12.81% to a record breaking 20.55%, comparable to state-of-the-art PSCs with a sophisticated ETL. Also, the stability is enhanced with decreased hysteresis effect due to interface defect passivation and inhibited interface charge accumulation. This work facilitates the further development of highly efficient, flexible, and recyclable ETL-free PSCs with simplified design and low cost by interface electronic structure engineering through facile electrode modification.
关键词： perovskite solar cells,energy level alignment,work function,nonconjugated small molecules,electron transport layers
更新于2025-09-16 10:30:52