A simple route for manufacture of photovoltaic devices based on chalcohalide nanowires (original) (raw)
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Nano Energy, 2018
Antimony sulfoiodide (SbSI) has been demonstrated to act as an effective energy harvester due to its ferroelectric-semiconductor characteristics. This has furthered the advancement of futuristic self-powered optoelectronic devices. We studied the feasibility of designing an SbSI-based piezoelectric nanogenerators (PNGs) with polymer matrix interfaces, such as polydimethylsiloxane (PDMS), polyvinylidene fluoride (PVDF) and polymethyl methacrylate (PMMA). SbSI/PMMA composites exhibit promising states with respect to the potential establishment of SbSI/PMMA piezoelectric nanogenerator (S-PNG). Furthermore, as-fabricated S-PNG is highly stable, with an average peak to peak electrical response of~5 V and 150 nA. The employment of SbSI overcomes the limitations of PNGs made of insulator materials, enabling the generation of dual harvesters. The piezophototronic properties of SbSI/PMMA composite and single SbSI micro rod (SMR) were extensively investigated. These harvesters incorporate both mechanical and optical sources, thereby providing broad opportunities for the expansion of piezoelectronic material systems.
Efficient and Stable Antimony Selenoiodide Solar Cells
Advanced Science, 2021
Although antimony selenoiodide (SbSeI) exhibits a suitable bandgap as well as interesting physicochemical properties, it has not been applied to solar cells. Here the fabrication of SbSeI solar cells is reported for the first time using multiple spin-coating cycles of SbI 3 solutions on Sb 2 Se 3 thin layer, which is formed by thermal decomposition after depositing a single-source precursor solution. The performance exhibits a short-circuit current density of 14.8 mA cm −2 , an open-circuit voltage of 473.0 mV, and a fill factor of 58.7%, yielding a power conversion efficiency (PCE) of 4.1% under standard air mass 1.5 global (AM 1.5 G, 100 mW cm −2). The cells retain ≈90.0% of the initial PCE even after illuminating under AM 1.5G (100 mW cm −2) for 2321 min. Here, a new approach is provided for combining selenide and iodide as anions, to fabricate highly efficient, highly stable, green, and low-cost solar cells. Small effective mass, large dielectric constant, high band dispersion level, and valence band maximum with antibonding states are desirable properties for highly efficient and defect-tolerant light harvesters. [1] Most of the aforementioned properties exist in materials containing metal cations with ns 2 valence electron configuration, [2] owing to their high bandwidth conduction band and high Born effective charge derived from large spin-orbit effects as well as their soft Polaris ability. Popular light harvesters including halides or chalcogenides of Pb 2+ , [3] Sn 2+ , [4] Ge 2+ , [5] Sb 3+ , [6] and Bi 3+[7] contain metal cations with the ns 2 valence electron configuration. However, most of them are affected by one or several issues, such as low efficiency, low stability, toxicity, and high cost. Hence, efficient, stable, green, and low-cost light-harvesters must be developed. As important material exhibiting the ns 2 electronic configuration, metal chalcohalides have received extensive attention owing to their interesting physical and chemical properties. [8] Because of the distinct bonding preferences of chalcogenide and halide atoms, to form stable sites in compounds, the competition among atoms might yield unique structures and properties. [9] Additionally, a wide bandgap range can be obtained in these materials because halide and chalcogenide coexist as anions; hence,
Advanced Energy Materials, 2013
Hybrid solar cells based upon organic-inorganic semiconductor heterojunctions are currently the subject of signifi cant interest as they incorporate the attractive properties of both organic and inorganic materials, including the ability to tune both the electronic and structural properties over a wide range using solution-based fabrication methods. A confi guration of particular promise is the hybrid inorganic nanocrystalpoly mer bulk heterojunction solar cell. A typical device consists of a photoactive layer composed of a blend of inorganic nanoparticles and a semiconducting polymer, which is sandwiched between two charge-collecting electrodes. The operation of such a system is based upon a photoinduced charge separation reaction at the inorganic-organic semiconductor heterojunction, followed by charge carrier transport and collection at the device electrodes. To date, a variety of inorganic semiconductors have been used in solution processed polymer solar cells including metal oxides, sulfi des and selenides. Metal chalcogenide nanocrystals are especially attractive for use in photovoltaic device applications as they offer the potential to extend the light harvesting capability of the device into the near infrared region of the solar spectrum. For example, impressive solar-light to electrical power conversion effi ciencies have been recently reported for photovoltaic devices based upon CdSe:PCPDTBT ( > 3%) [ 5 , 8 ] and CdS:P3HT nanocomposite fi lms (4.1%). Key challenges to the design of high-performance hybrid solar cells are (i) the development of new fabrication routes for hybrid thin fi lms that enable the achievement of high yields of charge separation whilst maintaining good electrical connectivity between the inorganic nanocrystals in the photoactive layer and (ii) the development of alternative inorganic electron acceptors that exhibit light harvesting properties superior to the typically used cadmium-based materials. To address challenge (i), we have recently reported a new approach to the fabrication of hybrid metal sulfi de-polymer solar cell photoactive layers, which is based upon the in-situ thermal decomposition of a single source metal xanthate precursor in a polymer fi lm. The use of metal xanthate (or metal o-alkyl dithiocarbonate) precursors for the in-situ growth of metal sulfi de nanocrystals in polymer fi lms is of particular interest due to their high solubility, low decomposition temperature and the volatility of the side products generated upon thermal decomposition. As such, we have implemented this design strategy in the fabrication of CdS:P3HT and CuInS 2 :polymer nanocomposite fi lms and demonstrated effi cient charge photogeneration at the donor-acceptor heterojunction. Furthermore, the integration of such photoactive layers into solar cell architectures yielded impressive power conversion effi ciencies approaching 3% under AM1.5 simulated solar illumination. In this paper, we extend our previous work and report on a bulk heterojunction hybrid solar cell composed of antimony sulfi de (Sb 2 S 3 ) nanocrystals and a semiconducting polymer poly-3-hexylthiophene (P3HT). Sb 2 S 3 is an attractive material for use in photo voltaic devices due to its narrow band-gap (1.7 eV) and high absorption coeffi cient ( ∼ 1.8 × 10 5 cm − 1 at 450 nm). Consequently, Sb 2 S 3 has been recently employed as a lightharvesting material in extremely thin absorber (ETA) and solidstate nanocrystal-sensitized solar cells. Herein, we present the fi rst example of a solution processed polymer/Sb 2 S 3 blend solar cell, in which Sb 2 S 3 acts as both a light absorber and an electron-transporting material. Specifi cally, we report the fabrication of an Sb 2 S 3 :P3HT fi lm utilizing an antimony triethyldithiocarbonate (antimony ethyl xanthate) precursor complex that decomposes into the metal sulfi de at relatively low temperatures ( ∼ 160 ° C). A combination of steady state and timeresolved optical spectroscopy, transmission electron microscopy and Raman techniques are used to characterize the nanomorphology and photo-induced interfacial charge transfer in the Sb 2 S 3 :P3HT nanocomposite fi lms. Transient absorption spectroscopy measurements provide evidence for charge separation at the Sb 2 S 3 :polymer heterojunction. In particular, we show that charge separation and current generation in the device results primarily from Sb 2 S 3 light absorption followed by hole-transfer from the inorganic semiconductor to the organic hole transporting material. We discuss the implications of our fi ndings for the design of hybrid inorganic-organic solar cells. shows the chemical structure of the antimony ethyl xanthate (Sb(S 2 COEt) 3 ) complex employed in this study. Sb 2 S 3 :P3HT fi lms were prepared by spin coating a blend composed of varying volume ratios of polymer (25 mg/mL in chlorobenzene) and precursor (400 mg/mL in chlorobenzene) solutions. The resultant fi lms were thermally annealed at 160 ° C to decompose the precursor and to generate the Sb 2 S 3 nanocrystals in the polymer fi lm. a shows the steadystate UV-Vis absorption characteristics for fi lms comprising P3HT and Sb(S 2 COEt) 3 (50:50 volume ratio) before and after thermal annealing at 160 ° C. The un-annealed fi lm exhibits the Adv.
Bulk Heteroj unction Organic-Inorganic Photovoltaic Cell Based on Doped Silicon Nanowires
CRC Press eBooks, 2019
Heterojunction photovoltaic devices were fabricated using single crystal silicon nanowires and the organic semiconductor regioregular poly-(3-hexyl thiophene) (RR-P3HT). N-type nanowires were first grown on an nþ silicon substrate by the vapor-liquid-solid (VLS) method. Devices were then fabricated by filling the gap between the nanowires and a transparent indium tin oxide (ITO) glass electrode with a polymer. For initial devices the gap was filled with P3HT deposited from chlorobenzene solution. Device performance indicates that both silicon and P3HT act as absorbers for photovoltaic response, but that photocurrents were very low due to high series resistance in the cell. A second type of device was fabricated by depositing a thin layer of P3HT on the grown nanowires by dip coating from a dilute solution, and then filling the voids between nanowires and the transparent electrode with the conductive polymer poly-[3,4-(ethylenedioxy)thiophene]: poly-(styrene sulfonate) (PEDOT:PSS). The relatively high mobility of this organic conductor results in much higher photocurrents in photovoltaic cells, but results in a dip in the spectral response of the cells in the blue-green region due to light absorption in the conducting polymer. These materials show promise for efficient low-cost photovoltaic devices, but the cell geometry and materials interfaces will need to be optimized to reach their potential.
A comprehensive review of the application of chalcogenide nanoparticles in polymer solar cells
Nanoscale, 2014
In this review the use of solution-processed chalcogenide quantum dots (CdS, CdSe, PbS, etc.) in hybrid organic-inorganic solar cells is explored. Such devices are known as potential candidates for low-cost and efficient solar energy conversion, and compose the so-called third generation solar cells. The incorporation of oxides and metal nanoparticles has also been successfully achieved in this new class of photovoltaic devices; however, we choose to explore here chalcogenide quantum dots in light of their particularly attractive optical and electronic properties. We address herein a comprehensive review of the historical background and state-of-the-art comprising the incorporation of such nanoparticles in polymer matrices. Later strategies for surface chemistry manipulation, in situ synthesis of nanoparticles, use of continuous 3D nanoparticles network (aerogels) and ternary systems are also reviewed.
Nanotechnology, 2012
We report chemical-vapor-deposition (CVD) synthesis of high-density lead sulfide (PbS) nanowire arrays and nano pine trees directly on Ti thin films, and the fabrication of photovoltaic devices based upon the PbS nanowires. The as-grown nanowire arrays are largely vertically aligned to the substrates and are uniformly distributed over a relatively large area. Field effect transistors incorporating single PbS nanowires show p-type conduction and high mobilities. These catalytic metal thin films also serve as photocarrier collection electrodes and greatly facilitate device integration. For the first time, we have fabricated Schottky junction photovoltaic devices incorporating PbS nanowires, which demonstrate the capability of converting near-infrared light to electricity. The PbS nanowire devices are stable in air and their external quantum efficiency shows no significant decrease over a period of 3 months in air. We have also compared the photocurrent direction and quantum efficiencies of photovoltaic devices made with different metal electrodes, and the results are explained by band bending at the Schottky junction. Our research shows that PbS nanowires are promising building blocks for collecting near-infrared solar energy.
Nanowire-based dye-sensitized solar cells
Applied Physics Letters, 2005
We describe the design and performance of a ZnO nanowire-based dye-sensitized solar cell. ZnO nanowires with a branched structure were employed as the wide-band-gap semiconductor to construct dye-sensitized solar cells which exhibit energy conversion efficiencies of 0.5% with internal quantum efficiencies of 70%. The nanowires provide a direct conduction path for electrons between the point of photogeneration and the conducting substrate and may offer improved electron transport compared to films of sintered nanoparticles. The devices have light harvesting efficiencies under 10%, indicating that current densities and efficiencies can be improved by an order of magnitude by increasing the nanowire surface area.
Solution-processable bismuth iodide nanosheets as hole transport layers for organic solar cells
Solar Energy Materials and Solar Cells, 2014
In this paper we demonstrate the use of low-temperature-solution-processable bismuth iodide (BiI 3) nanosheets as hole transport layers in organic photovoltaics with an active layer comprising poly(3hexylthiophene) (P3HT) mixed with a fullerene derivative. The performance of the resulting devices was comparable with that of corresponding conventionally used systems incorporating polyethylenedioxythiophene:polystyrenesulfonate (PEDOT:PSS). UV-vis spectroscopy revealed that the transparency of a BiI 3 layer in the visible (4620 nm) and near-infrared range is greater than that of a PEDOT:PSS layer. X-ray photoemission spectroscopy of a BiI 3 film revealed signals at 158.8, 164, 618.6, and 630 eVcharacteristic of Bi 4f 7/2 , Bi 4f 5/2 , I 3d 5/2 , and I 3d 3/2 , respectively-that indicated a stoichiometric BiI 3 film. Wet milling of BiI 3 crystals resulted in the formation of nanosheets, the presence of which we confirmed using scanning electron microscopy. The resultant power conversion efficiency of the device was approximately 3.5%, with an open-circuit voltage of 0.56 V, a short-circuit current density of 10.4 mA cm-2 , and a fill factor of 60.1% under AM1.5G irradiation (100 mW cm À 2).
J. Mater. Chem. A, 2015
We demonstrate the preparation of functional 'extremely thin absorber' solar cells consisting of massively parallel arrays of nanocylindrical, coaxial n-TiO 2 /i-Sb 2 S 3 /p-CuSCN junctions. Anodic alumina is used as an inert template that provides ordered pores of 80 nm diameter and 1-50 mm length. Atomic layer deposition (ALD) then coats pores of up to 20 mm with thin layers of the electron conductor and the intrinsic light absorber. The crystallization of the initially amorphous Sb 2 S 3 upon annealing is strongly promoted by an underlying crystalline TiO 2 layer. After the remaining pore volume is filled with the hole conductor by solution evaporation, the resulting coaxial p-i-n junctions display stable diode and photodiode electrical characteristics. A recombination timescale of 40 ms is extracted from impedance spectroscopy in open circuit conditions, whereas transient absorption spectroscopy indicates that holes are extracted from Sb 2 S 3 with a lifetime of 1 ns.