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This study investigated the integration of perovskite solar cells (PSCs) on stainless steel (SS) substrates for application in building-integrated photovoltaics (BIPV). Using advanced atomic force microscopy measurements, we confirmed that enhanced substrate roughness increased the reflectance along an interface. Consequently, a remarkable final efficiency of 11.9% was achieved. Notably, PSCs, known for their exceptional efficiency of 26.1%, can overcome the inherent efficiency limitations of SS-based thin-film solar cells. In this study, a PSC with an efficiency of 14% was fabricated on a flexible SS substrate. This study is a significant step towards advancing sustainable energy solutions for BIPV applications. The global shift towards renewable energy sources has catalyzed intensive research and development efforts, rendering the exploration of alternative materials and manufacturing processes a priority. The success of PSCs on SS substrates underscores their promise to achieve a balance between efficiency and versatility in BIPV solutions. Moreover, our findings reveal that controlling the substrate surface characteristics can significantly enhance the performance of PSCs, offering a pathway toward greater energy efficiency and sustainability in the construction industry. [ABSTRACT FROM AUTHOR]

Abstract In recent days few-layered or ultrathin molybdenum disulfide (MoS 2) one of the transition metal dichalcogenides (TMDs) is gaining serious attention for photovoltaics. TMD materials are able to absorb up to 5–10% of incident sunlight in less than 1 nm thickness to achieve an order of magnitude higher solar light absorption. Metal organic chemical vapor deposition (MOCVD) was employed to obtain atomic layered MoS 2 on SiO 2 /Si substrate which subsequently transferred on InP substrate using a simple transfer protocol. We realized photovoltaic operation in atomically few-layered MoS 2 by forming a type II heterojunction with low dopped p-InP, instead of widely used p-Si. The built-in electric field arised due to interface between n-MoS 2 and p-InP heterojunction is beneficial for the photogenerated carrier generation and separation. The solar cell device could achieve a power conversion efficiency of 0.11% with 1.87 mA/cm2 current density, first attempt of TMD based solar cell on InP substrate, demonstrating a promising solar cell performance. The obtained results pave the way for the integration of TMD materials with the InP substrate to obtain efficient solar cells. Highlights • n-MoS 2 /p-InP Heterojunction solar cell. • Atomic layered MoS 2 nanosheets. • MOCVD synthesis of MoS 2 nanosheets. • Use of p-InP substrate than conventional p-Si. • Power conversion efficiency of 0.11%. [ABSTRACT FROM AUTHOR]

Boron-doped hydrogenated silicon carbide alloys containing silicon nanocrystallites (p-nc-SiC:H) were prepared using a plasmaenhanced chemical vapor deposition system with a mixture of CH4, SiH4, B2H6 and H2 gases. The influence of hydrogen dilution on the material properties of the p-nc-SiC:H films was investigated, and their roles as window layers in hydrogenated nanocrystalline silicon (nc-Si:H) solar cells were examined. By increasing the RH (H2/SiH4) ratio from 90 to 220, the SiC bond density in the p-nc-SiC:H films increased from 5.20 × 1019 to 7.07 × 1019/cm³, resulting in a significant increase of the bandgap from 2.09 to 2.23 eV in comparison with the bandgap of 1.95 eV for p-nc-Si:H films. For the films deposited at a high RH ratio, the Si nanocrystallites with a size of 3-15nm were formed in the amorphous SiC:H matrix. The Si nanocrystallites played an important role in the enhancement of vertical charge transport in the p-nc-SiC:H films, which was verified by conductive atomic force microscopy measurements.When the p-nc-SiC:H films deposited at RH = 220 were applied in the nc-Si:H solar cells, a high conversion efficiency of 8.26% (Voc=0.53V, Jsc = 23.98mA/cm² and FF = 0.65) was obtained compared to 6.36% (Voc=0.44V, Jsc = 21.90 mA/cm² and FF = 0.66) of the solar cells with reference p-nc-Si:H films. Further enhancement in the cell performance was achieved using p-nc-SiC:H bilayers consisting of highly doped upper layers and low-level doped bottom layers, which led to the increased conversion efficiency of 9.03%. [ABSTRACT FROM AUTHOR]

CuInSe2 nanoparticles (NPs) were successfully synthesized by a simple Se-redox method. All the precursor materials (copper chloride, indium chloride and selenium) were mixed in a solvent (oleylamine) together, and the mixtures were reacted at 240°C. The CuInSe2 NPs, acquired by a centrifugation and washing process, have tetragonal crystal structure and the atomic elemental ratio (Cu:In:Se) of nearly 1:1:2. The size of the CuInSe2 NPs ranges from 4 nm to 80 nm, and the size could be easily controlled by adjusting the reaction time. Using this simple but novel method, we demonstrate the production of CuInSe2 NPs of stoichiometric ratio with size controllability suitable for mass-production. [ABSTRACT FROM PUBLISHER]

Abstract: We have investigated the change in photocurrent density (J SC) of dye-sensitized solar cell (DSSC) before and after covering an aperture mask on the cell, especially its dependence on solar absorption range in dye. Four different dyes having absorption threshold at 460nm (P5), 520nm (TA-St-CA), 680nm (N719) and 820nm (N749) are tested. J SC of the DSSC without mask decreases after mask, where the decreasing rate (△J SC = J SC (no mask) −J SC (with mask)/J SC (no mask)) becomes larger when dye absorption threshold decreases. △J SC at the given TiO2 film thickness of 10μm is determined to be about 20%, 15% and 13% for P5, TA-St-CA and N719–N749, respectively, which is reduced to 14% (TA-St-CA), 11.3% (N719) and 10.5% (N749) after increasing the thickness to 20μm, except for P5 dye remaining unchanged. According to the analysis based on IPCE and photon flux data, the over photocurrents observed for the unmasked dye-sensitized solar cells and their dependence on dye absorption range are found to be attributed to diffuse light leaving the dye-adsorbed TiO2 active area. [Copyright &y& Elsevier]

The potential-induced degradation (PID) mechanism in Cu(In,Ga)(Se,S)2 (CIGS) thin-film solar cells, which are alternative energy sources with a high efficiency (>23%) and upscaling possibilities, remains unclear. Therefore, the cause of PID in CIGS solar cells was investigated in this study at the cell level. First, an appropriate PID experiment structure at the cell level was determined. Subsequently, PID and recovery tests were conducted to confirm the PID phenomenon. Light current–voltage (I–V), dark I–V, and external quantum efficiency (EQE) analyses were conducted to determine changes in the cell characteristics. In addition, capacitance–voltage (C–V) measurements were carried out to determine the doping concentration and width of the space charge region (SCR). Based on the results, the causes of PID and recovery of CIGS solar cells were explored, and it was found that PID occurs due to changes in the bulk doping concentration and built-in potential at the junction. Furthermore, by distinguishing the effects of temperature and voltage, it was found that PID phenomena occurred when potential difference was involved. [ABSTRACT FROM AUTHOR]

Abstract: As an effective method of increasing its total conversion efficiency, the protective layer of solar cells was patterned with a nano-sized moth-eye structure. This pattern with its special shape and size serves as an anti-reflective layer. To form a pattern on the PVC film, the hot-embossing method was used. Moreover, a polyvinyl chloride (PVC) film patterned on both sides was also fabricated to improve the performance of anti-reflection functionality. A solar cell with a patterned PVC film as a protective layer exhibited higher quantum efficiency and total conversion efficiency than a solar cell with a bare PVC film as a protective layer. [Copyright &y& Elsevier]

Abstract Passivation quality of poly-Si contacts with different phosphorus doping concentration were investigated in this study. Intrinsic poly-Si layers were deposited by LPCVD on a tunnel oxide surface, followed by n + poly-Si doping and hydrogenation. For lightly doped poly-Si contacts with phosphorus concentration of 2.1 × 10 19 cm − 3 , higher temperatures and longer times increased iV OC achieving maximum value of 734 mV, as poly-Si grain size increases from 13 nm to 40 nm. However, for heavily doped poly-Si contacts with phosphorus concentration of 1.1 × 10 20 cm − 3 , iV OC decreased from 731 mV to 696 mV as annealing time increased from 10 to 60 min because Auger recombination rate increased from 9.3 fA / cm 2 to 21.6 fA / cm 2 as phosphorus in-diffusion occurs. The contact resistance of poly-Si contacts was also investigated to achieve a high fill factor. Finally, a poly-Si/SiO x /c-Si passivated contact solar cell using a poly-Si contact on the back and boron diffused emitter on the front was fabricated. As a result, high efficiency of 21.1% solar cell was achieved with V OC of 665 mV, J SC of 40.6 mA/cm2, and fill factor of 78.3%. Highlights • Passivation quality of poly-Si passivated contacts is controlled by annealing temperature, time and doping concentration. • Passivation quality is improved by grain size growth. • Phosphorus in-diffusion decreases passivation quality because of increased Auger recombination. • High-quality poly-Si passivated contact with i V O C of 734 mV was achieved by large grain size and low in-diffusion. • Cell efficiency of 21.1% was achieved using improved poly-Si passivated contact. [ABSTRACT FROM AUTHOR]

Passivated contact in advanced high-efficiency silicon solar cells based on the full back surface field (BSF) is reported here in based on the application of a tunnel oxide layer that is less than 2 nm thick. The open-circuit voltage ( V oc ) was significantly improved via interface passivation due to insertion of the tunnel oxide layer. During oxide layer growth, a transition region, such as a sub-oxide, was observed at a depth of about 0.75 nm in the growth interface between the silicon oxide layer and silicon substrate. The properties of the less than 2 nm thick tunnel oxide layer were primarily affected by the characteristics of the transition region. The passivation characteristics of tunnel oxide layer should depend on the physical properties of the oxide. The interface trap density D it is an important parameter in passivation and is influenced by the stoichiometry of the oxide which in turn strongly affected by the fabrication and the post annealing conditions. During heat treatment of a-Si:H thin films (for the purpose of crystallization to form doped layers), thin film blistering occurs due to hydrogen effusion on flat substrate surfaces. To minimize this behavior, we seek to control the surface morphology and annealing profile. Also, the passivation quality of passivataed contact structure declined for the sample annealed above 900 °C. This decline was attributed not only to local disruption of the tunnel oxide layer, but also to phosphorus diffusion. The resistivity of the tunnel oxide layer declined precipitously for the sample annealed above 900 °C. On the basis of these, implied V oc over 740 mV was achieved in n-type Si wafer through the control of the oxide stoichiometry via optimizing the annealing conditions. [ABSTRACT FROM AUTHOR]

The temperature variation of solar cells due to white bias light irradiation during the spectral responsivity measurement and its effect on the spectral responsivity measurement result were investigated for various types of solar cells, such as crystalline silicon (c-Si), Cu(In,Ga)Se 2 (CIGS), and dye-sensitized solar cells (DSSCs). For the investigation, a spectral responsivity measurement system, which can employ the well-known sample temperature control methods (such as the “temperature controlled sample stage” method and the “forced air cooling” method) has been used. Hence, the availability of these sample temperature control methods has also been tested. Through the investigation, it was found that the actual temperature of the solar cells located under the AM1.5G-approximated white bias light can be increased significantly during the spectral responsivity measurement, depending on the sample temperature control methods applied. In addition, it was also found that the increase of sample temperature can lead to a significant error in the measured spectral responsivity, depending on the types of solar cells being measured. In addition, a simple analytic model based on the classical heat transfer theory was developed to understand the temperature variation of the solar cells under the spectral responsivity measurement environment. [ABSTRACT FROM AUTHOR]

Abstract: Nanocrystalline silicon (nc-Si:H) thin-film n-i-p solar cells were constructed on flexible stainless steel substrates by plasma-enhanced chemical vapor deposition. Influence of the n-type seed-layer on the microstructural evolution of the subsequent intrinsic nc-Si:H absorbers and the resultant performance of nc-Si:H solar cells was investigated. The crystalline volume fraction of the seed-layer can be effectively controlled by varying the hydrogen (H2) to silane (SiH4) gas flow ratio. Defect-dense amorphous regions were observed at the initial growth stage of the i-layers deposited on low crystalline volume fraction n-type seed-layers. Increasing the reduced the amorphous region at the n/i interface of the i nc-Si:H layers, evidenced by Raman scattering and transmission electron microscopy (TEM) measurements. Elimination of the defect-rich amorphous region within the i-layer by depositing the nc-Si:H solar cells on highly crystalline seed-layer caused significant improvements in the short circuit current density (J sc) and fill factor (FF). This is mainly due to the enhancement of long-wavelength light response and extraction efficiency of photo-carrier charges. The nc-Si:H solar cells prepared on a highly crystalline seed-layer exhibited a 65.6% higher conversion efficiency than those on the n-type amorphous layers . [Copyright &y& Elsevier]

Abstract: Intrinsic hydrogenated amorphous silicon films incorporated with oxygen (i a-Si(H,O):H) were prepared using a plasma-enhanced chemical vapor deposition system with a carbon dioxide (CO2), silane (SiH4) and hydrogen (H2) gas mixture. The influence of oxygen incorporation on the chemical structure and on the optoelectronic properties of the deposited films was investigated. The performance of the solar cells that use these films as absorber layers was also evaluated. For the films incorporated with oxygen, local bonding configurations were identified in which H and O alloy atoms were bonded to the same Si site. With the incorporation of oxygen, the bandgap (E opt) of the a-Si(H,O):H films increased significantly to 1.82 eV, while that of the pure hydrogenated amorphous (a-Si:H) films was 1.73 eV. The optoelectronic properties of the oxygen-incorporated films degraded due to the newly created dangling bonds that arose from an increased structural disorder. Increasing the hydrogen dilution in the plasma effectively reduced the defect density in the a-Si(H,O):H films, resulting in an improved photosensitivity. The solar cells that used wide-bandgap a-Si(H,O):H films as absorber layers exhibited a 26.3% higher open circuit voltage (V oc) than those that used pure a-Si:H films, mainly because of the increased E opt of the films and the reduced defect density that was due to a high hydrogen dilution. [Copyright &y& Elsevier]

Abstract: Quantitative estimation of the specific contact resistivity and energy barrier at the interface between transparent conducting oxide (TCO) and hydrogenated p-type amorphous silicon carbide (a-Si1−xCx:H(p)) was carried out by inserting an interfacial buffer layer of hydrogenated p-type microcrystalline silicon (μc-Si:H(p)) or hydrogenated p-type amorphous silicon (a-Si:H(p)). In addition, superstrate configuration p–i–n hydrogenated amorphous silicon (a-Si:H) solar cells were fabricated by plasma enhanced chemical vapor deposition to investigate the effect of the inserted buffer layer on the solar cell device. Ultraviolet photoelectron spectroscopy was employed to measure the work functions of the TCO and a-Si1−xCx:H(p) layers and to allow direct calculations of the energy barriers at the interfaces. Especially interface structures were compared with/without a buffer which is either highly doped μc-Si:H(p) layer or low doped a-Si:H(p) layer, to improve the contact properties of aluminum-doped zinc oxide and a-Si1−xCx:H(p). Out of the two buffers, the superior contact properties of μc-Si:H(p) buffer could be expected due to its higher conductivity and slightly lower specific contact resistivity. However, the overall solar cell conversion efficiencies were almost the same for both of the buffered structures and the resultant similar efficiencies were attributed to the difference between the fill factors of the solar cells. The effects of the energy barrier heights of the two buffered structures and their influence on solar cell device performances were intensively investigated and discussed with comparisons. [Copyright &y& Elsevier]

Abstract: The relationship between aluminum fire-through and the properties of a-SiNx:H thin films was investigated to aid their use as dielectric layers in rear side and front passivation layers in crystalline solar cells. Aluminum fire-through was shown to depend on the refractive index and the deposition rate of the films. Refractive index, density and deposition rate increased with increasing SiH4/NH3 ratio, while the etching rate decreased. Aluminum fire-through occurred in a sample of refractive index 2.0 during fast deposition but not when the deposition rate was slow. Aluminum fire-through occurred during extended firing, despite it not occurring during normal firing by RTP. The results of this work demonstrate that refractive index was the major determinant of aluminum fire-through, and that the aluminum and the a-SiNx:H thin film reacted immediately at the beginning of firing at a rate determined by the deposition rate. [Copyright &y& Elsevier]

Abstract: This study examined the effects of Ga content in the CIGS absorber layer on the properties of the corresponding thin films and solar cells fabricated using a co-evaporation technique. The grain size of CIGS films decreased with increasing Ga content presumably because Ga diffusion during the 2nd stage of the co-evaporation process is more difficult than In diffusion. The main XRD peaks showed a noticeable shift to higher diffraction angles with increasing Ga content, which was attributed to Ga atoms substituting for In atoms in the chalcopyrite structure. Band gap energy and the net carrier concentration of CIGS films increased with Ga/(In+Ga) ratios. Regarding the solar cell parameters, the short circuit current density (J SC) decreased linearly with Ga/(In+Ga) ratios due to the lack of absorption in the long-wavelength portion of the spectrum, while the open circuit voltage (V OC) increase with those. However, V OC values at high Ga/(In+Ga) regions (>0.35) was far below than those extrapolated from the low Ga contents regions, finally resulting in an optimum Ga/(In+Ga) ratio of 0.28 where the solar cell showed the highest efficiency of 15.56% with V OC, J SC and FF of 0.625V, 35.03 mAcm−2 and 0.71, respectively. [Copyright &y& Elsevier]

Abstract: The effect of different surface morphologies obtained by anisotropic etching on the light trapping and short circuit current of single crystalline silicon solar cells was investigated. The anisotropic texturing of a (100) silicon surface was performed using potassium hydroxide (KOH) solution and/or tetramethylammonium hydroxide (TMAH) solution including isopropyl alcohol (IPA) additive or tertiary butyl alcohol (TBA) additive. Texturing in TMAH solution formed smaller pyramids on the textured surface compared with texturing in KOH solution. Although the textured samples showed similar reflectances (except in the case of the TBA additive), they showed different short circuit currents. Texturing in KOH/TMAH solution led to a 9.6% increase in short circuit current compared with texturing in KOH/IPA solution, a typical etchant in commercial processes. Based on these results, the reflectivity has no simple proportionality relationship to the short circuit current, and the short circuit current of silicon solar cells should be the criterion used in evaluating texturing effects on reducing reflectance and forming a sound junction with high collection efficiency. [Copyright &y& Elsevier]