Despite the fact that antimony triselenide (Sb2Se3) thin‐film solar cells have undergone rapid development in recent years, the large open‐circuit voltage (VOC) deficit still remains as the biggest ...bottleneck, as even the world‐record device suffers from a large VOC deficit of 0.59 V. Here, an effective interface engineering approach is reported where the Sb2Se3/CdS heterojunction (HTJ) is subjected to a post‐annealing treatment using a rapid thermal process. It is found that nonradiative recombination near the Sb2Se3/CdS HTJ, including interface recombination and space charge region recombination, is greatly suppressed after the HTJ annealing treatment. Ultimately, a substrate Sb2Se3/CdS thin‐film solar cell with a competitive power conversion efficiency of 8.64% and a record VOC of 0.52 V is successfully fabricated. The device exhibits a much mitigated VOC deficit of 0.49 V, which is lower than that of any other reported efficient antimony chalcogenide solar cell.
A heterojunction post‐annealing treatment is utilized to suppress the nonradiative recombination for a highly competitive power conversion efficiency of 8.64% and a record open‐circuit voltage (VOC) of 520 mV in Sb2Se3 thin‐film solar cells. The VOC deficit of the device is lower than that of any other reported efficient antimony chalcogenide solar cells.
Inorganic films possess much higher thermoelectric performance than their organic counterparts, but their poor flexibilities limit their practical applications. Here, Sb2Te3/Tex hybrid thin films ...with high thermoelectric performance and flexibility, fabricated via a novel directional thermal diffusion reaction growth method are reported. The directional thermal diffusion enables rationally tuning the Te content in Sb2Te3, which optimizes the carrier density and leads to a significantly enhanced power factor of >20 µW cm–1 K–2, confirmed by both first‐principles calculations and experiments; while dense boundaries between Te and Sb2Te3 nanophases, contribute to the low thermal conductivity of ≈0.86 W m–1 K–1, both induce a high ZT of ≈1 in (Sb2Te3)(Te)1.5 at 453 K, ranking as the top value among the reported flexible films. Besides, thin films also exhibit extraordinary flexibility. A rationally designed flexible device composed of (Sb2Te3)(Te)1.5 thin films as p‐type legs and Bi2Te3 thin films as n‐type legs shows a high power density of >280 µW cm–2 at a temperature difference of 20 K, indicating a great potential for sustainably charging low‐power electronics.
A high ZT of ≈1 at 453 K is achieved in an inorganic Sb2Te3/Te hybrid thin film via a novel directional thermal diffusion reaction growth method with extraordinary flexibility, and the rationally designed flexible device shows a high power density by a low‐temperature difference.
High relative contact electrical resistance and poor flexibility in inorganic thin‐film thermoelectric devices significantly limit their practical applications. To overcome this challenge, a one‐step ...thermal diffusion method to fabricate assembly‐free inorganic thin‐film thermoelectric devices is developed, where the in situ grown electrode delivers an excellent leg‐electrode contact, leading to high output power and flexibility in the prepared p‐type Sb2Te3/n‐type Bi2Te3 thin‐film device, which is composed of 8 pairs of p‐n junctions. Such a device shows a very low relative contact electrical resistance of 7.5% and a high power density of 1.42 mW cm–2 under a temperature difference of 60 K. Less than 10% change of the whole electrical resistance before and after bending test indicates the robust bending resistance and stability of the device. This study indicates that the novel assembly‐free one‐step thermal diffusion method can effectively enhance the leg‐electrode contact, the device thermoelectric performance, bending resistance, and stability, which can inspire the development of thin‐film thermoelectric devices.
In this study, highly flexible inorganic thin‐films device through one‐step thermal diffusion synthesis process is successfully prepared. It secures good contact between the electrodes and the thermoelectric legs through in situ growth of the electrode, together with the highly crystallized Sb2Te3 and Bi2Te3 thermoelectric legs, contributing to ultralow relative contact resistance and high thermoelectric device performance.
Antimony selenide (Sb2Se3) is regarded as one of the key alternative absorber materials for conventional thin film solar cells due to its excellent optical and electrical properties. Here, we ...proposed a Sb2Se3 thin film solar cell fabricated using a two-step process magnetron sputtering followed by a post-selenization treatment, which enabled us to optimize the best quality of both the Sb2Se3 thin film and the Sb2Se3/CdS heterojunction interface. By tuning the selenization parameters, a Sb2Se3 thin film solar cell with high efficiency of 6.06% was achieved, the highest reported power conversion efficiency of sputtered Sb2Se3 planar heterojunction solar cells. Moreover, our device presented an outstanding open circuit voltage (VOC) of 494 mV which is superior to those reported Sb2Se3 solar cells. State and density of defects showed that proper selenization temperature could effectively passivate deep defects for the films and thus improve the device performance.
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•A promising sputtered and post-selenized Sb2Se3 thin film was present.•Orientation, morphology, composition and defect passivation was depending on the post-selenized temperature.•Highest PCE of 6.06% for sputtered Sb2Se3 planar heterojunction solar cells achieved.
Flexible Bi2Te3‐based thermoelectric devices can function as power generators for powering wearable electronics or chip‐sensors for internet‐of‐things. However, the unsatisfied performance of n‐type ...Bi2Te3 flexible thin films significantly limits their wide application. In this study, a novel thermal diffusion method is employed to fabricate n‐type Te‐embedded Bi2Te3 flexible thin films on flexible polyimide substrates, where Te embeddings can be achieved by tuning the thermal diffusion temperature and correspondingly result in an energy filtering effect at the Bi2Te3/Te interfaces. The energy filtering effect can lead to a high Seebeck coefficient ≈160 µV K−1 as well as high carrier mobility of ≈200 cm2 V−1 s−1 at room‐temperature. Consequently, an ultrahigh room‐temperature power factor of 14.65 µW cm−1 K−2 can be observed in the Te‐embedded Bi2Te3 flexible thin films prepared at the diffusion temperature of 623 K. A thermoelectric sensor is also assembled through integrating the n‐type Bi2Te3 flexible thin films with p‐type Sb2Te3 counterparts, which can fast reflect finger‐touch status and demonstrate the applicability of as‐prepared Te‐embedded Bi2Te3 flexible thin films. This study indicates that the thermal diffusion method is an effective way to fabricate high‐performance and applicable flexible Te‐embedded Bi2Te3‐based thin films.
In this study, flexible n‐type Bi2Te3‐based thin‐films are successfully prepared through facile thermal diffusion method and further induce Te/Bi2Te3 heterojunctions and energy filtering effect at the Te/Bi2Te3 interfaces to optimize the thermoelectric performance through tuning the diffusion temperature.
A unique strain‐mediated lattice rotation strategy is introduced via nanocompositing to upsurge the optimized limits in the composition‐to‐structural pathway on rationally engineering the efficient ...thermoelectric material. In this study, a special lattice rotation via strain engineering is realized to optimize the desired electronic and chemical environment for enhancing thermoelectric properties in n‐type Bi2S2Se. This approach results in a unique transport phenomenon to assist high‐energy electrons in transferring through the optimized transport channels, and appropriate structure disparity to significantly localize phonons. As a result, Sb over Cl doping in Bi2S2Se gently reduces Eg and introduces defect states in bandgap with shifting down the Fermi level, thus causing increase in carrier concentration, which contributes to a higher power factor of ≈7.18 µW cm−1 K−2 (at T = 773 K). Besides, a lower thermal conductivity of ≈0.49 W m−1 K−1 is driven through lattice strain and defect engineering. Consequently, an ultra‐high ZTmax = 1.13 (at T = 773 K) and a high ZTave = 0.54 (323 K‐773 K) are realized. This study not only leads to an extraordinary thermoelectric performance but also reveals a unique paradigm for electron transportation and phonon localization via lattice strain engineering.
A unique strain‐mediated lattice rotation strategy is introduced via nanocompositing to upsurge the optimized limits in the composition‐to‐structural pathway on rationally engineering the efficient thermoelectric material. The obtained ultra‐high ZTmax (=1.13 at T = 773 K) successfully demonstrates the effectiveness of doping‐induced structural variation and lattice rotation strategy, unlocking new prospects to develop atomistic lattice engineering in thermoelectric materials.
An easy method of preparing well-crystallized Sb2Se3 films and nanorods through magnetron sputtering was proposed, and their growth mechanism was examined. The microstructure, morphology, ...composition, and optical and electrical properties of the Sb2Se3 films depended strongly on the substrate temperature (Tsub). Sb2Se3 films prepared at > 250°C contained the orthorhombic phase without Sb2O3 phase owing to the high-purity vacuum environment. Well-crystallized Sb2Se3 films deposited at Tsub = 325°C showed compact grains with a bandgap of 1.23eV and a high absorption coefficient of 105cm−1 in the visible region. Photoelectrochemical measurements showed that Sb2Se3 films were p-type semiconductors with excellent photoresponse. A clear photovoltaic effect with a power conversion efficiency (PCE) of 3.35% was measured for the first time by using the sputtering Sb2Se3 films as absorbers in a photovoltaic solar cell. At Tsub = 375°C, highly uniform films with monodispersed Sb2Se3 nanorods were obtained. The preferential orientation of the Sb2Se3 crystals by self-organization was promoted by increasing Tsub. By using the Sb2Se3 nanorods as absorbers in a solar cell, good photoresponse and a PCE of 2.15% were achieved.
•Thermally induced mechanism of Sb2Se3 film and nano-rod prepared by sputtering.•Tsub is the key for Sb2Se3 films and an efficient self-organization for nano-rods.•High crystalline Sb2Se3 film prepared at 325°C, 3.35% PCE in solar cell achieved.
Owing to the earth-abundancy, eco-friendliness and high thermoelectric performance, CoSb3 skutterudites have been employed in thermoelectric devices with a high energy conversion efficiency. However, ...the thermoelectric performance of CoSb3-based thin films is still relatively low within the medium temperature range. In this work, we report a record high ZT of ~0.65 at 623 K in the n-type Ag/In co-doped CoSb3 thin films, fabricated by a facile magnetron sputtering technique. Extensive characterizations and computational results indicate both Ag and In as fillers prefer to occupy the interstitial sites in the CoSb3 lattice. A 0.2% Ag doping induces impurity states in the band structure of CoSb3, boosts the density-of-states near the Fermi level and enhances the absolute Seebeck coefficient up to ~198 μV K−1. Simultaneously, a 4.2% In doping further tunes the bandgap, increases the electrical conductivity up to ~75 S cm−1, and contributes to an optimized power factor of ~2.94 μW cm−1 K−2 at 623 K. In addition, these interstitial dopants accompanying with dense grain boundaries contribute an ultra-low thermal conductivity of ~0.28 W m−1 K−1 at 623 K, leading to a high ZT in the film system. This work demonstrates that rational band engineering and structural manipulations can achieve high performance in n-type CoSb3-based thin films, which possess full potential for applying to miniature thermoelectric devices.
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•A record high ZT of ~0.65 at 623 K is achieved in the n-type CoSb3 thin films.•Both Ag and In prefer to occupy the interstitial sites in the CoSb3 lattice.•Ag induces impurity states in the band structure, and In further tunes the bandgap.•Interstitial dopants with dense grain boundaries contribute ultra-low thermal conductivities.•Strengthened mechanical properties were realized by Ag/In co-doping.
Hybrid two-dimensional (2D) halide perovskites has been widely studied due to its potential application for high performance perovskite solar cells. Understanding the relationship between ...microstructural and opto-electronic properties is very important for fabricating high-performance 2D perovskite solar cell. In this work, the effect of solvent annealing on grain growth was investigated to enhance the efficiency of photovoltaic devices with 2D perovskite films based on (BA)
(MA)
Pb
I
prepared by single-source thermal evaporation. Results show that solvent annealing with the introduction of solvent vapor can effectively enhance the crystallization of the (BA)
(MA)
Pb
I
thin films and produce denser, larger-crystal grains. The thin films also display a favorable band gap of 1.896 eV, which benefits for increasing the charge-diffusion lengths. The solvent-annealed (BA)
(MA)
Pb
I
thin-film solar cell prepared by single-source thermal evaporation shows an efficiency range of 2.54-4.67%. Thus, the proposed method can be used to prepare efficient large-area 2D perovskite solar cells.
Computational, thin-film deposition, and characterization approaches have been used to investigate the all-inorganic lead-free CsBi3I10 as a candidate to act as a thin-film photovoltaic absorber. In ...this paper, CsBi3I10 was firstly predicted with a layer crystal structure of stable hexagonal phase-like Cs3Bi2I9 and then prepared by one-step coating also showing the high purity hexagonal phase and crystallinity, very consistent with the theoretical calculation. After solvent annealing, a high absorption coefficient of approximately 105 cm–1 in visible light and a suitable optical band gap of 1.78 eV were obtained for the CsBi3I10 thin film. The solar cell based on the CsBi3I10 perovskite thin film exhibited a high power conversion efficiency of 1.05%, good reproducibility, hysteresis-free behavior, and long-term stability. These results indicate that the performance of all-inorganic Pb-free perovskite solar cells can be further improved.
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