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Flexible thin-film solar cells are important for their advantages in many aspects, and aluminum antimonide (AlSb) can be used as an absorbent layer in thin-film solar cells. However, its deliquescence limits its practical use. In this work, AlSb films were prepared by radio frequency (RF) magnetron sputtering on stainless steel flexible substrates. A flexible conformal coating membrane using acrylic resin was deposited on the AlSb films and its deliquescence prevention effect was verified. It was found that after conformal coating treatment, the deliquescence of the AlSb film was effectively stopped. The bare AlSb films and the Ni/AlSb/acrylic resin/Ni multilayer films were exposed to ambient air at the same time under the same conditions for lengths of time ranging from 1 min to 60 days. After 60 days, the bare AlSb film experienced significant deliquescence, such that the film was completely destroyed. However, the Ni/AlSb/acrylic resin/Ni multilayer films did not exhibit deliquescence. [ABSTRACT FROM AUTHOR]

Sb 2 S 3 has a unique one-dimensional structure-composed (Sb 4 S 6) n ribbons leads to strong anisotropic carrier transport characteristic: carrier transport along the (Sb 4 S 6) n ribbon is more efficient than other ribbons. Therefore, it's crucial to control the direction of grain growth along the (hk1) orientation. In this work, the close space sublimation method was utilized to fabricate Sb 2 S 3 thin films with a systematic al regulation of substrate temperature. The results demonstrate that optimized Sb 2 S 3 thin film presented preferred orientation at the direction of (hk1). The champion device based on Au and Ni electrodes achieved a power conversion efficiency (PCE) of 3.06% and 1.69%, respectively. Schematic diagram of the close space sublimation system. [Display omitted] • The (hk1)-oriented Sb 2 S 3 thin films were prepared by close space sublimation method. • Study of the effect of different substrate temperatures on the structure and morphology of Sb 2 S 3 thin films. • Solar cells with structure of FTO/TiO 2 /CdS/Sb 2 S 3 /Ni were fabricated. • Ni was firstly used as the electrode for Sb 2 S 3 solar cells. [ABSTRACT FROM AUTHOR]

AlSb is a new type of optoelectronic material with wide potential application prospects, but the applications of AlSb thin films for solar cells were few reported before, owing to the intrinsic drawbacks of deliquescence for AlSb. In this work, four types of AlSb/Sb stacks were fabricated by using pulsed laser deposition: (1) AlSb/Sb (5 nm), (2) AlSb/Sb (10 nm), (3) AlSb/Sb (15 nm) and (4) the in situ annealed AlSb film covered with Sb film which thickness is 15 nm. The experimental results indicate that the thicker the Sb layer deposited on the surface of the AlSb film is, the lower the degree of deliquescence will be. XRD measurements showed that the AlSb/Sb stacks were not deliquesced completely after exposed to air for 48 h. The EDS spectrum suggested that the percentage of oxygen atoms in the annealed AlSb film covered with Sb (15 nm) was smaller than the unannealed. The SEM morphology analysis revealed the deliquescence of AlSb film: the local film deliquesced to form sand inclusions first, after then the gradual increased of the sand inclusions lead to all deliquescence of the crystalline AlSb. [ABSTRACT FROM AUTHOR]

Copper doping in polycrystalline CdTe thin films and optimal band alignment at the CdTe/back-contact interface are critical for obtaining high performance devices. A CuCl 2 solution treatment was used in this work to enhance the p-doping of CdTe. The carrier density of CdTe was increased from 4.72 × 10 13 to 1.11 × 10 14 cm −3 and the open circuit voltage of the device was obviously improved more than ~50 mV from 728 to 783 mV. In order to further improve device performance, Te/Cu bilayer using rapid thermal processing was implemented to reduce barrier at the back contact. The short time-high temperature process efficiently activated the Te/Cu bilayer back contact and precisely controlled the Cu diffusion. The proper dose of Cu diffusion can further increase the p-doping of CdTe (~2.22 × 10 14 cm −3 ), resulting in the apparent increase in response from the CdS spectral region. The chemical reaction occurred between Te and Cu after rapid thermal processing treatments causing the formation of the Cu x Te phases, which can form a barrier in the conduction band to reflect electrons and reduce recombination at the back contact. With the increase of the temperature, the open circuit voltage of the device increased. However, the device with excessive Cu contacted at higher temperature showed the reduction in response in the long-wavelength region and decrease in fill factor due to the formation of much more Cu-related recombination states. Finally, open circuit voltage of > 820 mV, and fill factor of > 72% for CdTe solar cells with an area of 0.24 cm 2 were achieved. [ABSTRACT FROM AUTHOR]

The study of CdS/CdTe solar cells has become popular in the photovoltaic field, in which the highest efficiency achieved is more than 20%. However, the CdTe thin film as the absorbing layer doesn’t perform very well in the long wavelength photon absorption regime. Here, a new single offset superlattice was designed to be the composite absorbing layer, which is based on a super lattice-structure of CdTe/ZnTe using cycle growth. Different cycles are to applied to the solar cells to characterize properties with respect to the super lattice. The crystallinity and transmission spectrum as well as the cross sectional morphology of the ZnTe/CdTe composite layers with different cycles are also characterized in this work. X-ray diffraction analysis showed that there is a strong (111) preferred orientation of CdTe growth. The solar cells based on the structure of FTO/CdS/CdTe/ZnTe:Cu/(ZnTe|CdTe) n /ZnTe:Cu/Au are fabricated which exhibited a desired spectral response in the range of 550–800 nm and still possess slight spectral response in the range of 850–900 nm. The photoelectric conversion efficiency of the cell of this structure is 12.8%, with a short-circuit current density of 25.59 mA/cm 2 and fill factor of 66.8%, significantly improving these properties compared with a cell without the composite layer. This structure can improve the spectral response of the solar cell when integrated with other leading technologies. [ABSTRACT FROM AUTHOR]

Incorporating Se element into Cadmium telluride (CdTe)-based superstrate configuration solar cells have advanced impressively. However, molybdenum (Mo)/CdTe/CdSe substrate configuration devices remain relatively unexplored, and Mo foil oxidation behavior during the fabrication process is kept in the dark. This work investigates a fresh CdTe/CdSe substrate configuration solar cell using Mo substrates. Mo/CdTe/CdSe/ZnO/AZO/ITO solar cells have been fabricated, CdTe absorber layer was obtained by closed space sublimation (CSS) under ∼2000 pa pressure in varying Ar/O 2 flu ratio. The champion device had an efficiency of 3.87% with unintentional Cu-doping and back contact. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-Ray spectroscopy (EDS) were applied to study the properties of CdTe films. Before CdTe deposition, molybdenum oxide (MoO x) was generated while heating the Mo substrate in an oxygen-containing environment. This buffer layer plays a pivotal role in blocking non-Ohmic back contact analyzed by current-voltage-temperature (J-V-T) measurements. Molybdenum oxidation states were extensively studied to build the relationship with a solar cell device. Our findings indicated that different oxygen partial pressure had less relevance with the CdTe surface chemical environment but was incredibly relevant for Mo metal foil oxidation states. [ABSTRACT FROM AUTHOR]

CuSbSe 2 has been a potential absorber layer for thin film solar cells by reason of its attractive photovoltaic properties and environmentally friendly constituent elements. In this work, high-quality CuSbSe 2 thin film was prepared by pulsed laser deposition (PLD) and further in-situ annealing. Structural, morphological, compositional and optical properties of the unannealed and annealed films were characterized and compared separately. The results proved the existence of CuSbSe 2 , Sb 2 Se 3 and Cu 3 SbSe 3 in the unannealed film. With the rising of deposition temperature, the content of Sb 2 Se 3 increased significantly. Moreover, in-situ annealing at 350 °C can effectively reduce the Sb 2 Se 3 and Cu 3 SbSe 3 in the film. The atomic ratio of Cu:Sb:Se in the annealed film is estimated to be 25.45:26.29:48.27, basically consistent with the stoichiometry ratio of CuSbSe 2. Both annealed and unannealed CuSbSe 2 films revealed a high absorption coefficient greater than 104 cm−1. The optical band gap of the annealed film was about 1.15eV, which meets the requirements for the absorber layer of solar cells. •High-quality CuSbSe 2 thin film was successfully prepared by pulsed laser deposition •The effect of deposition temperature on CuSbSe 2 thin film prepared by pulsed laser deposition was explored •In-situ annealing was applied to reduce impurities and promote the formation of CuSbSe 2 •It would be helpful for the applications of CuSbSe 2 in solar cells in the future. [ABSTRACT FROM AUTHOR]

Ohmic back contact is one of the keys to fabricate high efficient CdTe solar cells, as it can improve fill factor FF and open-circuit voltage V oc. In this work, antimony-containing reduced graphene oxide (RGO) was prepared and used as a back contact for CdTe thin film solar cells, in which antimony is an effective dopant for CdTe and RGO acts as a hole transport layer and diffusion barrier of antimony in the solar cells. Post deposition annealing was performed to activate the back contact layer and passivate the interface defect states. Electrical performance and apparent quantum efficiency characterization were performed to investigate device performance of CdTe solar cells with antimony-containing RGO back contacts. The results indicate that, the introduction of extrinsic doping near the CdTe back surface serves to reduce the back contact depletion width and enhance the built-in potential to enable the tunnelling of majority carrier holes through the barrier, and the RGO is beneficial for the formation of Ohmic back contact on CdTe. [ABSTRACT FROM AUTHOR]

As an important functional film, tin dioxide (SnO 2) was widely used in the communities of gas sensors as well as solar cells. SnO 2 (110) and (100) surfaces were thought to be stable, and both could be easily obtained by common preparation method. The characteristics of SnO 2 surface were critical to the performance of devices when it was applied in solar cells, and the SnO 2 (100) surface had not been understood explicitly. A series of SnO 2 (100) surface models with different terminal atoms were built in this work and calculated by density functional theory (DFT) with GGA + U. SnO 2 (100) surfaces with different terminal atoms exhibited distinctly different surface states. Basically, these surface states mainly originated from the terminal atoms, and they extended to the tenth monoatomic layer. SnO 2 (100) surface terminated with single monolayer of O atoms was the structure with the least surface states. The real surface of SnO 2 was thought to be consisting of O terminal atoms mostly. The charge neutral level of SnO 2 (100) surface was thought to be 2.94 eV above the valence band. Image 1 • SnO 2 (100) with different terminal atoms was investigated systematically by first-principle calculations. • Surface states were origin from the ten monolayers of surface and showed different characters with different terminal atoms. • The real surface of SnO 2 (100) was mainly terminated with O, and surface states mainly from structure terminated with Sn. [ABSTRACT FROM AUTHOR]