Semitransparent Thin Film Research Articles

Radial Junctions on Laser-Cutting Tinplate Enable Semitransparent Thin-Film BIPVs with Low Reflection and Designable Transmission

Radial Junctions on Laser-Cutting Tinplate Enable Semitransparent Thin-Film BIPVs with Low Reflection and Designable Transmission

Determination of the thickness and optical properties by reflectance method

In this study, we propose a method based on the reflection spectrum envelope to calculate the thickness and optical constants of a semi-transparent thin film deposited on a glass substrate. To validate this method, we compare these optical constants with those obtained from the transmission spectrum in two different thickness cases: one involving a film with a thickness of 700 nm and the other with a thin film of 80 nm. Comparative results of the methods, including well-established approaches such as Swanepoel, Chambouleyron, Sellmeier, Lorentz and Forouhi–Bloomer reveal notable accuracy with RMS errors of 0.21, 0.22, 0.31, 0.36 and 0.38% respectively. In contrast, the “Cauchy” method shows lower precision with a higher RMS error at 0.71%. The method proposed in this study, applied to a film with a thickness of 700 nm, demonstrates the lowest RMS error at 0.17%.

Effect of annealing on the stoichiometry and plasmonic properties of PLD nanostructured semi-transparent copper thin film using BEMA

Effect of annealing on the stoichiometry and plasmonic properties of PLD nanostructured semi-transparent copper thin film using BEMA

Review on Implementation of Dye-sensitised Solar Cells (DSSC)

Abstract: Solar cells give better power conversion efficiency (PCE) compared to conventional solar cells made of Silicon in terms of low materials and manufacturing costs. Materials required for the manufacturing of DSSCs such as titanium oxide are inexpensive, abundant and environmentally friendly. DSSC materials are contamination resistant and processable at room temperature, a roll-to-roll process can be used to print DSSCs in a mass production facility. DSSCs have been found to perform better under low light conditions and so they are a great choice for indoor applications, especially in powering of low powered objects such as IoT devices. A lot of work has also been done to make coloured and semi-transparent thin film DSSCs to use indoors and in window modules and enhance their aesthetic values. This review is a report about some selected works done in manufacturing of DSSCs, especially the transparent cells and their integration in buildings, both outdoors and indoor [1].

Precise spectrophotometric method for semitransparent metallic thin-film index determination using interference enhancement

A precise spectrophotometric method to determine the refractive index of a semitransparent metallic thin film is presented. This method relies on interference enhancement of the measured spectra, employing an opaque substrate with a dielectric spacer layer beneath the absorbing layer of interest to create interference fringes.The resulting spectral oscillations of the stack are highly sensitive to the properties of the top absorbing layer, allowing precise determination of the refractive index via fitting. The performance of this method is verified using simulations in comparison to the typical method of depositing the absorbing thin film directly onto a transparent substrate. An experimental demonstration is made for titanium thin films over the visible range (370-835 nm). The refractive index of these films is extracted from experimental data using a combination of the Modified Drude and Forouhi-Bloomer models. This method showed high repeatability and precision, and is verified for Ti films between 6-70 nm thickness.

Numerical study of semi-transparent thin film heterojunction p-CuO/nZnO/AZO/ITO solar cells device model using SCAPS-1D

In the current time, transparent and semitransparent solar cells in photovoltaic industry have drawn important attention owing to their potential use as solar windows, and energy harvesting devices for building, vehicle integration and flexible electronics. In this work, a semitransparent thin film heterojunction solar cells device structure of p-CuO/nZnO/AZO/ITO was numerically modeled using SCAPS-1D software tools. The cell’s performance was investigated in terms of the different material layer properties, such as the thickness and carrier concentration or doping level. The simulation results of copper based semi-transparent thin film solar cell (TFSC) as the bottom cell model indicates that the highest efficiency was achieved at 8.9116 %, with the thickness and carrier concentration of n-ZnO material layer set at 20 nm, and 5.0 x 1018 cm-3 respectively, whereas the thickness of CuO absorber layer was fixed at 110 nm. Finally, the overall results show that CuO based absorber layer exhibits potential as photoactive material particularly for semitransparent thin film solar cells applications.

Flexible Organic Photovoltaics with Colorful Semi-Transparent Metal/Dielectric/Metal Top Electrode

Organic solar cells (OSCs) have the advantages of a semi-transparent thin film, and of changing colors through controlling optical energy bandgap of organic semiconducting materials. In addition, the flexible OSCs can also be fabricated to be applied in multiple applications such as film-type or foldable solar cells. Here, we have fabricated flexible semi-transparent organic solar cells (STOSCs) with high transparency accompanying highly vivid red, green, and blue colors. To gain high transparency of STOSCs, we employed Fabry-Pérot etalon-type electrodes. An antimony oxide (Sb2O3) cavity layer was introduced between two thin silver layers. By adjusting the thickness of Sb2O3 from 45 nm to 100 nm, vivid colors of red, green, and blue semi-transparent top electrodes were achieved. Besides, selecting well-matched photoactive layers for each color, a less drop of short-circuit current density (Jsc) has been observed. Finally, we obtained high maximum transmittance of 22.52%, 30.10%, and 22.13%, with a power conversion efficiency of 9.16%, 9.85%, and 12.64% for red, green, and blue STOSCs, respectively. Likewise, a power conversion efficiency of 5.75% was achieved with a green-colored large area sub-module.

Bending Sensors Based on Thin Films of Semitransparent Bithiophene-Fulleropyrrolidine Bisadducts.

A novel bithiophene-fulleropyrrolidine bisadducts system (bis-Th2PC60 ) was synthesized and electropolymerized by chronoamperometry onto flexible ITO/PET substrates. The resulting semitransparent thin film was characterized by XPS, FT-IR, cyclic voltammetry and optical techniques, confirming the good outcome of the electropolymerization process. AFM investigations permitted to highlight an inherent disordered granular morphology, in which the grain-to-grain separation depends upon the application of bending. The electrical resistance of the thin film was characterized as a function of bending (in the range 0°-90°), showing promising responsivity to low bending angles (10°-30°). The ΔR/R0 variations turn out to be 8 %,16 % and 20 % for bending angles equal to 10°, 20° and 30°, respectively. This study represents a first step towards the understanding of piezoresistive properties in electropolymerized fullerenes-based thin films, opening up applications as bending sensor.

Performance Analysis of an integrated Semi-Transparent Thin Film PV Vacuum Insulated Glazing

Performance Analysis of an integrated Semi-Transparent Thin Film PV Vacuum Insulated Glazing

Semitransparent Sb2S3 thin film solar cells by ultrasonic spray pyrolysis for use in solar windows.

The integration of photovoltaic (PV) solar energy in zero-energy buildings requires durable and efficient solar windows composed of lightweight and semitransparent thin film solar cells. Inorganic materials with a high optical absorption coefficient, such as Sb2S3 (>105 cm−1 at 450 nm), offer semitransparency, appreciable efficiency, and long-term durability at low cost. Oxide-free throughout the Sb2S3 layer thickness, as confirmed by combined studies of energy dispersive X-ray spectroscopy and synchrotron soft X-ray emission spectroscopy, semitransparent Sb2S3 thin films can be rapidly grown in air by the area-scalable ultrasonic spray pyrolysis method. Integrated into a ITO/TiO2/Sb2S3/P3HT/Au solar cell, a power conversion efficiency (PCE) of 5.5% at air mass 1.5 global (AM1.5G) is achieved, which is a record among spray-deposited Sb2S3 solar cells. An average visible transparency (AVT) of 26% of the back-contact-less ITO/TiO2/Sb2S3 solar cell stack in the wavelength range of 380–740 nm is attained by tuning the Sb2S3 absorber thickness to 100 nm. In scale-up from mm2 to cm2 areas, the Sb2S3 hybrid solar cells show a decrease in efficiency of only 3.2% for an 88 mm2 Sb2S3 solar cell, which retains 70% relative efficiency after one year of non-encapsulated storage. A cell with a PCE of 3.9% at 1 sun shows a PCE of 7.4% at 0.1 sun, attesting to the applicability of these solar cells for light harvesting under cloud cover.

Effect of Ag-doping on the structural, optical, electrical and photovoltaic properties of thermally evaporated Cadmium Selenide thin films

To study the capability of the CdSe thin films to use as an absorber layer in semi-transparent thin film solar cells, the structural, optical, electrical and photovoltaic properties of thermally evaporated CdSe thin films (thickness 300 nm) as a function of silver-doping were investigated. A novel and facile method was used to Ag-doping of the samples. Some aqueous solution of silver nitrate (with various concentration) was spin coated onto the surface of CdSe thin films followed by air-annealing to diffuse silver dopants into the layers. The field emission scanning electron microscope (FE-SEM) images showed that the surface of CdSe thin films was improved with our doping method. X-ray diffraction (XRD) analysis revealed the hexagonal structure of the samples. The crystallite size, micro-strain and dislocation density of CdSe thin films were evaluated using XRD patterns. The transmittance spectra in the wavelength range of 400–2500 nm were measured and then used to study other optical parameters. The optical energy band gap was decreased with Ag-doping from 1.96 eV to 1.67 eV. The electrical conductivity of FTO/CdSe:Ag/Al Schottky junction devices was improved by Ag-doping, and the photovoltaic efficiency was increased by Ag-doping form 1.53% for the undoped sample to 2.78% for the sample with the highest doping concentration. Obtained results show that Ag-doped CdSe thin films are a promising candidate to use as an absorber layer in semi-transparent solar cells and colorful photovoltaic windows.

P/i interfacial engineering in semi-transparent silicon thin film solar cells for fabrication at a low temperature of 150 °C

In this study, we aimed to develop semitransparent solar cells (STSCs) using hydrogenated amorphous silicon (a-Si:H) at a low temperature of 150 °C to support the fabrication of flexible solar modules, applicable in building-integrated photovoltaics (BIPV). To compensate for the presumable loss of device performance at such a low processing temperature, careful control of the p/i interface is proposed. We fabricated buffer layers with hydrogen (H2)/silane (SiH4) gas flow ratios (R) ranging from 4 to 16 (R4–R16) to investigate their characteristics and incorporate them at the p/i interface by considering energy band matching. By employing this buffer, the power conversion efficiency (PCE) of a STSC was improved from 4.83% to 5.57% which is the best record in a-Si:H STSCs processed at a low temperature of 150 °C. This p/i interfacial buffer can support the realization of flexible a-Si:H-based BIPV systems using plastic- or polymer-based substrates.

Analysis of the daylight performance of window integrated photovoltaics systems

Integrating photovoltaics into windows provides the possibility of including an additional function of energy production to a conventional building fenestration component. There is no doubt that electrical power can be generated on-site. However, the effect of PV windows on the indoor luminous environment of the space served by them has not been comprehensively researched. This paper investigated the daylight performance of integrating four types of photovoltaics (semi-transparent thin film Cadmium telluride (CdTe) solar cells with 10% and 50% transparency, crystalline silicon solar cells with and without crossed compound parabolic concentrators (CCPC)) to a window of a typical south-facing office under different Window-to-Wall Ratios (WWRs). Annual useful daylight illuminance (UDI), daylight uniformity ratio (UR) and daylight glare probability (DGP) have been analysed based on dynamic simulation using RADIANCE. The simulation results show that windows integrated with crystalline silicon cells and CCPC optics have the potential to provide best daylight availability when compared with standard double glazed windows and other tested PV window prototypes, if it is applied to rooms with large WWRs (e.g. 60% or 75% WWR) at high latitudes (e.g. city of Harbin). Its application also improves the uniformity of daylight spatial distribution and eliminates the risk of glare. Semi-transparent CdTe PV window with 10% transparency can also improve the percentage of working hours that fall into UDI 500–2000lux range, however, it will result in the most sharp illuminance contrasts within the room. Applying all of these tested PV windows can effectively reduce the possibility of glare.

Solar ray collection rate fluctuation analysis with Monte Carlo Ray Tracing method for space solar power satellite

According to the ideal optical design, the spherical concentrator made by the semi-transparent and semi-reflecting thin film is used in SSPS-OMEGA system. To obtain the continuous power, the PV array should rotate around the spherical concentrator to point the sun when SSPS-OMEGA rotate around the earth on GEO. However, considering the in-orbit assembly, the concentrator is assembled by many planar elements to be approximate to the ideal spherical concentrator. The solar ray collection rate fluctuates in certain scope because the original solar ray path is changed. In addition, planar element is deformed easily by the rotating PV array, which also lead to the fluctuation because the position of the planar element is changed. In this paper, the spherical concentrator is divided into many planar elements by using equal latitude and longitude method. It is studied that the relationship between the number of division layers and the collection rate fluctuation by using Monte Carlo Ray Tracing method. The simulation results indicate that with increasing dividing layers, the collection rate increases and the fluctuation amplitude decreases, which ranges 80.72–83.70% (2.98%) of 24-layers concentrator, ranges 88.45–89.91% (1.47%) of 48-layers concentrator, and ranges 92.46–93.80% (1.33%) of 72-layers concentrator. To solve the deformation of the concentrator, the flexible multibody dynamics model of SSPS-OMEGA is established. Combing the deformation and Monte Carlo Ray Tracing method, it is studied that the relationship between the deformation of the concentrator and the collection rate. The simulation results indicate that the stiffness of 72-layers concentrator is better than 24-layers concentrator and 48-layers concentrator, and the reduction of the collection rate of 72-layers concentrator, which is 0.4%, is less than 24-layers concentrator (1.57%) and 48-layers concentrator (0.81%).

A Semitransparent Nitride Photoanode Responsive up to λ=600 nm Based on a Carbon Nanotube Thin Film Electrode

AbstractThe development of semitransparent photoanodes is required for the construction of tandem photoelectrochemical (PEC) water splitting cells incorporating photocathodes. However, the poor stability of transparent conductive oxides at high temperatures hampers the growth of non‐oxide photoanodes with intense visible light absorption. In this work, semitransparent Ta3N5 thin film photoanodes were prepared on quartz glass substrates coated with carbon nanotubes (CNTs) by sputtering and thermal nitridation. This process makes use of the high thermal and chemical stability as well as the tunable conductivity and transmittance of CNT substrates. The photoanodic current produced by these Ta3N5 photoanodes at negative potentials is also enhanced by surface modification with Mg species. Conductive semitransparent CNT substrates such as these will assist in the development of new tandem PEC cells for water splitting.

Transparent Thin Film Solid-State Lithium Ion Batteries.

Transparent electrochemical energy storage devices have attracted extensive attention for the power supply of next-generation transparent electronics. In this paper, semitransparent thin film batteries (TFBs) with a grid-structured design have been fabricated on glass substrates using specific photolithography and etching processes to achieve LiCoO2/LiPON/Si structures below human eye resolution. UV-vis transmittances up to 60% have been measured for the obtained TFBs. A discharge capacity as high as 0.15 mAh has been recorded upon galvanostatic cycling at the C/2 rate within 4.2-3 V voltage range for the highest transmittances. The capacity variation trend exhibits an initial phase of a gradual decrease with an average capacity loss of 0.15% per cycle and thereafter a second phase with almost stable capacity. Particular attention has been given to the effects of architecture parameters on the TFB optical and electrochemical properties. To the best of our knowledge, this work is the first demonstration of transparent, all inorganic, thin film lithium ion batteries. While reported studies are limited to battery structures involving liquid or polymer materials, our devices will contribute to improve form factor freedom, extend operating ranges, enhance long-term stability, and will be relevant to the integration into various optoelectronic devices.

A facile method to prepare transparent and stretchable epidermal thin film heaters

A stretchable and semi-transparent epidermal thin film heater (TFH) has been fabricated by using silver nanowire (Ag NW) networks as a Joule heat generator and polydimethylsiloxane (PDMS) as a stretchable and transparent matrix. The device is a conductive layer of interconnected Ag NWs sandwiched with two layers of PDMS. The output power and transparency of the device were rationally tuned by adjusting the Ag NW amount. Our results show that the device transparency at 600 nm decreases from 70% to 46% when we tuned the sheet resistance of Ag NW layer from 30.0 Ω/□ to 5.4 Ω/□. The TFH shows a favorable stretchability, and it can almost completely recover when we applied a strain up to 200% or after a fatigue test of 1000 cycles, 50% in strain. The ultimate temperature in air reached up to 81 °C when we applied an electric field of 1.0 V/cm. Its epidermal heating performance was simulated by warming a piece of pork, and it can make the subcutaneous temperature increase 12 °C. A model to evaluate the heating performance of TFHs with thermal capacity per-unit area, device resistance and energy conversion efficiency was also proposed, which will fatally determine their heating rate and ultimate temperature.

Performance evaluation of semi-transparent CdTe thin film PV window applying on commercial buildings in Hong Kong

The energy performances of c-Si PV windows and a-Si PV windows have been investigated comprehensively worldwide. However, CdTe thin film PV windows which are supposed to achieve better performance due to its higher efficiency are rarely studied. This study evaluated the energy performance of semi-transparent CdTe thin film PV window applying on commercial buildings. The results show that CdTe PV windows have large energy saving potential in Hong Kong, and the annual energy generation of per unit CdTe PV windows is 52.3kWh/m2. Compared to the common window and a-Si PV window, the saving in net energy consumption is 19.6% and 15.3%, respectively.

Simultaneous measurement of thermal conductivity and diffusivity of an undoped Al0.33Ga0.67As thin film epitaxially grown on a heavily Zn doped GaAs using spectrally-resolved modulated photothermal infrared radiometry

In this paper, we propose a method for measuring thermal and infrared properties of infrared transparent and semi-transparent thin film. We have investigated an undoped Al0.33Ga0.67As thin film epitaxially grown on a heavily Zn doped GaAs substrate using spectrally-resolved modulated photothermal infrared radiometry (SR-PTR). We perform supplementary measurements in order to determine values of layer thickness and infrared absorption coefficient and estimate successively values of the thermal conductivity and diffusivity of the Al0.33Ga0.67As thin layer, using the SR-PTR method. The obtained values of the thermal conductivity and diffusivity of the Al0.33Ga0.67As thin layer demonstrate that PTR method can be used for the thermal characterization of infrared transparent layers deposited on a highly infrared absorbing substrate. Supplementary Fourier Transform Infrared (FTIR) Spectroscopy measurements yield information only about the thickness of the Al0.33Ga0.67As layer. The results demonstrate that the SR-PTR method is a very good method for characterizing the thermal, geometrical and infrared properties of infrared-transparent thin film samples. However, some of the layer properties should be known a priori. It is worth emphasizing that the spectrally resolved measurements increase the reliability in estimating parameters of the thin layer by introducing additional channels of information. Finally, we conclude that the SR-PTR method combines features of infrared spectroscopic and calorimetric methods.

Highly flexible and semi-transparent Ag–Cu alloy electrodes for high performance flexible thin film heaters

We investigated the properties of thermally evaporated Ag–Cu films for application as flexible and semi-transparent electrodes for semi-transparent flexible thin film heaters (TFHs) and heat shielding films (HSFs).