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Antimony sulfide-selenide, Sb2(SxSe1−x)3 (0 < x < 1), with a tunable bandgap combining the advantages of antimony sulfide (Sb2S3) and antimony selenide (Sb2Se3), shows great potential as a promising light-absorbing material in low-cost, low-toxic, and high-stability thin-film solar cells. In this work, high-quality Sb2(SxSe1−x)3 thin films were successfully prepared by pulsed laser deposition (PLD) using the Sb2(SxSe1−x)3 compound targets for the first time and realized tunable bandgaps by simply changing the S/(Se + S) ratios of compound targets. The effects of substrate temperature and S/(S + Se) ratio on the structural, morphological, and optical properties of films were investigated separately. It was discovered that 500 °C was the optimum substrate temperature to grow high-crystallinity, good-morphology, and low-defects Sb2(SxSe1−x)3 thin films, and the film with S/(S + Se) ratio of 0.2 showed optimal properties. Optical characterization demonstrated all Sb2(SxSe1−x)3 thin films owned high absorption coefficients above 105 cm−1 at the visible light region and suitable bandgaps near the ideal value of the Shockley–Queisser limit. The results of energy dispersive spectrometer showed that all films were poor in Sb and rich in (S + Se), which was a favorable condition for them as light absorbers. The activation energy obtained from the electrical measurement revealed that the conductivity of Sb2(SxSe1−x)3 thin films was mainly contributed by the intrinsic thermal excitation at 350–500 K. Our research offered a simple and reliable technology to prepare Sb2(SxSe1−x)3 thin films with adjustable bandgaps and favorable properties, which is expected to promote the development and application of this semiconducting material in thin-film solar cells. [ABSTRACT FROM AUTHOR]

The effect of post annealing in CdCl2 was investigated to elucidate the correlation between the evolution of the microstructure of CdTe thin films with the annealing time and the performance of CdS/CdTe thin-film solar cells made by in situ pulsed laser deposition (PLD). It has been found that the crystallinity of the annealed film is improved considerably as the CdTe polycrystalline grains evolved into grain clusters with a dendrite structure. While longer annealing time allows larger grain size, the increased film surface roughness outweighs the benefit of the improved crystallinity, resulting in increased structural disorders, such as pinholes. In fact, the concentration of the pinholes was found to increases monotonically with annealing time when it exceeds the optimal value, resulting in degradation of device performance and yield especially when pinholes appeared near the CdS/CdTe interface. This result illustrates the importance of controlling the microstructure of CdTe film and its interface with CdS to high-performance CdTe/CdS thin-film solar cells. [ABSTRACT FROM AUTHOR]

An in situ thermal annealing process (iTAP) has been introduced before the common ex situ cadmium chloride (CdCl2) annealing to improve crystal quality and morphology of the CdTe thin films after pulsed laser deposition of CdS/CdTe heterostructures. A strong correlation between the two annealing processes was observed, leading to a profound effect on the performance of CdS/CdTe thin film solar cells. Atomic force microscopy and Raman spectroscopy show that the iTAP in the optimal processing window produces considerable CdTe grain growth and improves the CdTe crystallinity, which results in significantly improved optoelectronic properties and quantum efficiency of the CdS/CdTe solar cells. A power conversion efficiency of up to 7.0% has been obtained on thin film CdS/CdTe solar cells of absorber thickness as small as 0.75 μm processed with the optimal iTAP at 450°C for 10–20 min. This result illustrates the importance of controlling microstructures of CdTe thin films and iTAP provides a viable approach to achieve such a control. [ABSTRACT FROM AUTHOR]

A combinatorial pulsed laser deposition system was developed by integrating a computer controlled scanning sample stage in order to rapidly screen processing conditions relevant to CdTe/CdS thin-film solar cells. Using this system, the thickness of the CdTe absorber layer is varied across a single sample from 1.5 μm to 0.75 μm. The effects of thickness on CdTe grain morphology, crystal orientation, and cell efficiency were investigated with respect to different postprocessing conditions. It is shown that the thinner CdTe layer of 0.75 μm obtained the best power conversion efficiency up to 5.3%. The results of this work shows the importance that CdTe grain size/morphology relative to CdTe thickness has on device performance and quantitatively exhibits what those values should be to obtain efficient thin-film CdTe/CdS solar cells fabricated with pulsed laser deposition. Further development of this combinatorial approach could enable high-throughput exploration and optimization of CdTe/CdS solar cells. [ABSTRACT FROM AUTHOR]

Aluminum antimony (AlSb) is a promising photovoltaic material with a band gap of about 1.62 eV. However, AlSb is highly deliquescent and not stable, which has brought great difficulties to the applications. Based on the above situation, there are two purposes for preparing our Zn-doped AlSb (AlSb:Zn) thin films: One is to make P-type AlSb and the other is to find a way to suppress the deliquescence of AlSb. The AlSb:Zn thin films were prepared on glass substrates at different substrate temperatures by using the pulsed laser deposition (PLD) method. The structural, surface morphological, optical, and electrical properties of AlSb:Zn films were investigated. The crystallization of AlSb:Zn thin films was enhanced and the electrical resistivity decreased as the substrate temperature increased. The scanning electron microscopy (SEM) images indicated that the grain sizes became bigger as the substrate temperatures increased. The Raman vibration mode AlSb:Zn films were located at ~107 and ~142 cm−1 and the intensity of Raman peaks was stronger at higher substrate temperatures. In the experiment, a reduced band gap (1.4 eV) of the AlSb:Zn thin film was observed compared to the undoped AlSb films, which were more suitable for thin-film solar cells. Zn doping could reduce the deliquescent speed of AlSb thin films. The fabricated heterojunction device showed the good rectification behavior, which indicated the PN junction formation. The obvious photovoltaic effect has been observed in an FTO/ZnS/AlSb:Zn/Au device. [ABSTRACT FROM AUTHOR]

Sb 2 Se 3 is a promising absorber for thin film solar cells due to its nontoxicity, low cost, earth abundance and excellent photovoltaic properties. However, few reports focus on Sb 2 Se 3 thin films prepared by pulsed laser deposition (PLD). Here we successfully deposited Sb 2 Se 3 thin films at different substrate temperatures by PLD. Structural, morphological, compositional, optical and electrical properties of Sb 2 Se 3 thin films were characterized. Results show that Sb 2 Se 3 thin films exhibit orthorhombic phase with good crystallinity and higher substrate temperature can distinctly improve crystal quality. Optical band gap is about 1.30 eV, 1.20 eV, 1.18 eV and 1.16 eV for Sb 2 Se 3 thin films deposited at 370 °C, 390 °C, 410 °C and 430 °C, respectively. In addition, the atomic ratio of selenium to antimony is 3/2, entirely consistent with the stoichiometry ratio of Sb 2 Se 3. Image 1 • Sb 2 Se 3 thin films were prepared on glass at different substrate temperatures by KrF PLD. • The atomic ratio of selenium to antimony was 3/2, entirely consistent with the stoichiometry ratio of Sb 2 Se 3. • Optical band gap was estimated to be 1.30 eV, 1.20 eV, 1.18 eV and 1.16 eV for Sb 2 Se 3 thin films deposited at 370 °C, 390 °C, 410 °C and 430 °C respectively. • High substrate temperature improved crystal quality. [ABSTRACT FROM AUTHOR]

Sb 2 Se 3 , an emerging promising binary compound semiconductor, was prepared at different substrate temperatures by pulsed laser deposition for thin film solar cells for the first time. In this work, CdS and Sb 2 Se 3 films were subsequently deposited by pulsed laser deposition to simplify the process. Film properties and device performance, closely related to the substrate temperature, were characterized by thermal gravimetric analysis, X-ray diffraction, UV–Vis–NIR spectrophotometer, scanning electron microscope, light and dark current density-voltage, external quantum efficiency and capacitance-voltage, respectively. Results indicate that Sb 2 Se 3 solar cells film deposited at 500 °C is better, with a better efficiency of 3.58%. Furthermore, SnO 2 high resistive layer was introduced into Sb 2 Se 3 solar cell to improve the junction quality, leading to a champion device efficiency of 4.41%. Image 1 • CdS/Sb 2 Se 3 bilayer was deposited by pulsed laser deposition for the first time. • Effects of substrate temperature on film properties and device performance were studied. • Sb 2 Se 3 film deposited at 500 °C is more suitable for Sb 2 Se 3 solar cells. • Champion efficiency of 4.41% was achieved due to the insertion of SnO 2 layer. [ABSTRACT FROM AUTHOR]

Sb 2 Se 3 , a very promising absorber layer for thin film solar cells, has attracted more and more attention because of its special structural and optical properties. In this work, pulsed laser deposition (PLD), a simple and effective technique, was used to deposit CdS/Sb 2 Se 3 solar cells for the first time. Results show that the grain size is 200–250 nm, the bandgap is calculated to be 1.21 eV and Sb 2 Se 3 thin film with thickness of 400 nm is more suitable for solar cells. To reduce reflection loss, lattice mismatch and shunt pathways, SnO 2 high resistive layer was introduced into Sb 2 Se 3 solar cells. Due to the introduction of SnO 2 , overall performance, especially J sc , was improved and champion device was achieved with efficiency of 4.77%. Image 1 • Sb 2 Se 3 solar cells were deposited by pulsed laser deposition for the first time. • PLD-Sb 2 Se 3 thin film has a bandgap of 1.21 eV and grain size is 200–250 nm. • PLD-Sb 2 Se 3 with thickness of 400 nm is more suitable for solar cells. • The introduction of SnO 2 improves device performance, especially J sc. [ABSTRACT FROM AUTHOR]

A low electric resistive and stable ohmic back contact are crucial to the commercial application of CdTe solar cells. In this study the Sb 2 Te 3 thin film is employed as a buffer layer in the back contact of CdTe solar cells. The Sb 2 Te 3 thin films are deposited at different substrate temperature by pulsed laser deposition and then characterized to investigate the thin film properties, firstly. Hall measurements shows the Sb 2 Te 3 thin film presents strong p-type semiconductor features with high Hall mobility and carrier concentration. CdTe solar cells with Sb 2 Te 3 buffer layer in different layer thickness and deposition temperature are fabricated to obtain the optimal experiment conditions for device performance. The dark J-V curve of CdTe solar cell with Sb 2 Te 3 buffer layer exhibits a typical diode curve without roll-over phenomenon. An insertion of Sb 2 Te 3 buffer layer eliminates the Schottky barrier resulting in remarkable enhancement of open circuit voltage, short-circuit current and fill factor. Besides, the external quantum efficiency gets improvement in almost all of the absorber wavelength compared to the cells with Au-only contact. [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]

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]

AlSb films which are a promising absorber layer for thin film solar cells were grown on glass substrate at different substrate temperature ranging from room temperature to 400 °C on glass substrates using aluminum-antimony alloying target by pulsed laser deposition (PLD) technique. Structural, optical and electrical properties of AlSb thin films were studied by X-ray diffraction (XRD), ultraviolet–visible spectrophotometer and a home-made four-probe-contact high temperature system respectively. XRD pattern shows that AlSb film is amorphous at room temperature, but when substrate temperature is higher than 100 °C, AlSb films present cubic phase structure with the preferential orientation of (111) plane. And intensity of diffraction peaks of AlSb film prepared at substrate temperature of 200 °C are stronger than that of other substrate temperature. The electrical measurement results show that conductivity activation energy of AlSb film is 0.25 eV and 0.28 eV. The indirect optical band gap is about 1.63 eV, which is very close to its theoretical value of 1.62 eV. The results of energy dispersive spectrometer (EDS) indicated the ratio of Al to Sb of AlSb films is about 1:1. [ABSTRACT FROM AUTHOR]

Aluminum antimony (AlSb) is a potential absorber for solar cells. In present work, we fabricated AlSb thin films by using pulsed laser deposition method, and investigated the influence of substrate temperature on the structural, electrical and optical properties of AlSb thin films. The results suggested that the AlSb thin films were crystal when the substrate temperature was higher than 300 °C. The average grain size of AlSb films increased and the electrical resistivity decreased with the increase of substrate temperature. At the optimized temperature of 400 °C, the optical band gap of AlSb thin film was 1.82eV. The simulated device performance of ZnS/AlSb ultra-thin solar cells showed that the power conversion efficiency was 18.01% and the quantum efficiency values were higher than 55% in the visible range. [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]