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The surface morphologies, crystallinities, and excitonic characteristics of MAxCs1−xPb(IxBr1−x)3 thin films deposited on top of the P3CT‐Na/ITO/glass substrates are investigated by using the atomic‐force microscopic images, absorbance spectra, grazing incidence X‐ray diffraction patterns, photoluminescence (PL) spectra, and Raman scattering spectra. The P3CT‐Na‐based perovskite solar cell shows a stable and efficient maximum power density curve due to the formation of a graded MA0.83Cs0.17Pb(I0.83Br0.17)3 alloy thin film which is confirmed by using the surface‐sensitive PL and Raman scattering spectra. The highest power conversion efficiency (PCE) of the P3CT‐Na‐based MA0.83Cs0.17Pb(I0.83Br0.17)3 solar cells is 15.93% mainly due to the high fill factor of 79.4%. Besides, the PCE of the nonencapsulated solar cell slowly decreases to a moderate value (10.48%) within 157 days under an uncontrolled environment (55–60 relative humidity%) at room temperatures (22–25 °C). [ABSTRACT FROM AUTHOR]

Atomic-force microscopic images, x-ray diffraction patterns, Urbach energies and photoluminescence quenching experiments show that the interfacial contact quality between the hydrophobic [6,6]-phenyl-C61-buttric acid methyl ester (PCBM) thin film and hydrophilic CH3NH3PbI3 (MAPbI3) thin film can be effectively improved by using a binary antisolvent mixture (toluene:dichloromethane or chlorobenzene:dichloromethane) in the anti-solvent mixture-mediated nucleation process, which increases the averaged power conversion efficiency of the resultant PEDOT:PSS (P3CT-Na) thin film based MAPbI3 solar cells from 13.18% (18.52%) to 13.80% (19.55%). Beside, the use of 10% dichloromethane (DCM) in the binary antisolvent mixture results in a nano-textured MAPbI3 thin film with multicrystalline micrometer-sized grains and thereby increasing the short-circuit current density and fill factor (FF) of the resultant solar cells. It is noted that a remarkable FF of 80.33% is achieved, which can be used to explain the stable photovoltaic performance without additional encapsulations. [ABSTRACT FROM AUTHOR]

The averaged power conversion efficiency of polyelectrolytes (P3CT-Na) based MAPbI3 solar cells can be increased from 14.94% to 17.46% with a wetting method before the spin-coating process of MAPbI3 precursor solutions. The effects of the wetting process on the surface, structural, optical and excitonic properties of MAPbI3 thin films are investigated by using the atomic-force microscopic images, x-ray diffraction patterns, transmittance spectra, photoluminescence spectra and Raman scattering spectra. The experimental results show that the wetting process of MAPbI3 precursor solution on top of the P3CT-Na/ITO/glass substrate can be used to manipulate the molecular packing structure of the P3CT-Na thin film, which determines the formation of MAPbI3 thin films. [ABSTRACT FROM AUTHOR]

Dimethylformamide/dimethyl sulfoxide solvent mixtures were used as the CH3NH3PbI3 (MAPbI3) precursor solvent in a one-step spin coating method to fabricate smooth and hydrophilic crystalline MAPbI3 thin films on top of hydrophobic carbon-60 (C60) thin film for highly efficient photovoltaics. The structural, optical, and excitonic characteristics of the resultant MAPbI3 thin films were analyzed using X-ray diffraction (XRD), atomic-force microscopy, absorbance spectroscopy, photoluminescence (PL) spectrometry, and nanosecond time-resolved PL. There was a trade-off between the crystallinity and surface roughness of the MAPbI3 thin films, which strongly influenced the device performance of MAPbI3-based photovoltaics. The high power conversion efficiency (PCE) of 17.55% was achieved by improving the wettability of MAPbI3 precursor solutions on top of the C60 thin films. In addition, it was predicted that the fill factor and PCE could be further improved by increasing the crystallinity of the MAPbI3 thin film while keeping it smooth. [ABSTRACT FROM AUTHOR]

This study aims to discuss the sheet resistance of ultrathin indium tin oxide (ITO) transparent conductive films during the postannealing treatment. The thickness of the ultrathin ITO films is 20 nm. They are prepared on B270 glass substrates at room temperature by a direct-current pulsed magnetron sputtering system. Ultrathin ITO films with high sheet resistance are commonly used for touch panel applications. As the annealing temperature is increased, the structure of the ultrathin ITO film changes from amorphous to polycrystalline. The crystalline of ultrathin ITO films becomes stronger with an increase of annealing temperature, which further leads to the effect of enhanced Hall mobility. A postannealing treatment in an atmosphere can enhance the optical transmittance owing to the filling of oxygen vacancies, but the sheet resistance rises sharply. However, a higher annealing temperature, above 250°C, results in a decrease in the sheet resistance of ultrathin ITO films, because more Sn ions become an effective dopant. An optimum sheet resistance of 336 Ω/sqr was obtained for ultrathin ITO films at 400°C with an average optical transmittance of 86.8% for touch sensor applications. [ABSTRACT FROM AUTHOR]

An approximate growth model was employed to predict the time required to grow a graphene film by chemical vapor deposition (CVD). Monolayer graphene films were synthesized on Cu foil at various hydrogen flow rates from 10 to 50 sccm. The sheet resistance of the graphene film was 310Ω/□ and the optical transmittance was 97.7%. The Raman intensity ratio of the G-peak to the 2D peak of the graphene film was as high as ~4 when the hydrogen flow rate was 30 sccm. The fitting curve obtained by the deviation equation of growth model closely matches the data. We believe that under the same conditions and with the same setup, the presented growth model can help manufacturers and academics to predict graphene growth time more accurately. [ABSTRACT FROM AUTHOR]

Abstract: Mixed alloy Cu–In–Ga precursors were deposited from Cu–Ga alloy and Indium targets by the DC magnetron co-sputtering method. There were four crystallization phases, In, CuIn2, Cu11In9 and Cu3Ga, identified in the precursor after deposition. A large grain-size CIGS film was achieved by controlling the annealing period for selenization and utilizing a two-stage selenization process for secondary crystallization during rapid thermal annealing process. As the annealing temperature increased, the phase transitions moved toward the Cu-rich inter-metallic phases. In addition, the phase transition, stoichiometric ratio and surface-morphology were modified by Ar-ion plasma etching process of the precursors. The results show that after the ion etching process, the precursors can be transferred into a single Cu11In9 crystallization phase and the number of crevices increased due to the soft texture of indium on the surface of the precursors. Finally, CIGS films with good crystalline properties were achieved after a suitable selenization process of only 1-stage. [Copyright &y& Elsevier]

This paper describes a method for fabricating silicon heterojunction thin film solar cells with an ITO/p-type a-Si : H/n-type cSi structure by radiofrequency magnetron sputtering. A short-circuit current density and efficiency of 28.80 mA/cm² and 8.67% were achieved. Novel nanopatterned silicon wafers for use in cells are presented. Improved heterojunction cells are formed on a nanopatterned silicon substrate that is prepared with a self-assembled monolayer of SiO2 nanospheres with a diameter of 550 nm used as an etching mask. The efficiency of the nanopattern silicon substrate heterojunction cells was 31.49% greater than that of heterojunction cells on a flat silicon wafer. [ABSTRACT FROM AUTHOR]

Ta2O5 films are prepared by e-beam evaporation with varied deposition temperatures, annealing temperatures, and annealing times. The effects of temperature on the optical properties, chemical composition, structure, and laserinduced damage threshold (LIDT) are systematically investigated. The results show that the increase of deposition temperature decreases the film transmittance slightly, yet annealing below 923 K is beneficial for the transmittance. The XRD analysis reveals that the film is in the amorphous phase when annealed below 873 K and in the hexagonal phase when annealed at 1073 K. While an interesting near-crystalline phase is found when annealed at 923 K. The LIDT increases with the deposition temperature increasing, whereas it increases firstly and then decreases as the annealing temperature increases. In addition, the increase of the annealing time from 4 h to 12 h is favourable to improving the LIDT, which is mainly due to the improvement of the O/Ta ratio. The highest LIDT film is obtained when annealed at 923 K, owing to the lowest density of defect. [ABSTRACT FROM AUTHOR]

The absorption coefficient at 1.4 eV is divided by the value at 0.9 eV to obtain the factor used to judge the quality of µc-Si:H. PV device performance can be predicted by multiplying Voc with Isc when using this layer as an intrinsic layer. The results show a good relationship between the quality factor and the product of open-circuit voltage and short-circuit current. However, the final efficiency is influenced by the identities of the interface in the multilayer structure. [ABSTRACT FROM AUTHOR]

High-quality single-crystal-like Ge (004) thin films have been epitaxially grown using radio-frequency magnetron sputtering on Si (001) substrates successfully. The crystalline quality of the Ge films can be obviously improved by applying a positive bias on the substrate holder. X-ray diffraction measurements show that the single-crystal-like Ge film has a narrow full width at half maximum of 0.26°. The perpendicular lattice constant ( a Ge ⊥ ) and in-plane lattice constant ( a Ge ∥ ) are 0.5671 and 0.564 nm. The Raman shift full width at half maximum shows that the defects in the film are obviously reduced. Transmission electron microscopy diffraction patterns also show that the Ge (004) film has good crystalline quality. The results can be applied as Ge buffer layers on Si substrates for the fabrication of high-efficiency III–V solar cells and photodetectors. [ABSTRACT FROM AUTHOR]

A modified rule was applied to design a grating optical low-pass spatial filter (GOLF) with a thin-film phase grating. This filter differed from the crystal type of optical low-pass spatial filter (OLPF). The fabrication method of the thin-film phase GOLF was also different from the conventional lithographic process. A new fabrication method utilizing a metal mesh mask and a thin-film coating process was applied to make the GOLF. The process had the advantages of being simple and cheap, and would thus be good for mass-production. The modulation transfer function (MTF) of the device was measured and the results agree well with the theoretical calculations. Finally, the GOLF was installed on a digital camera which was used to capture images of the circular zone plane (CZP), to show the Moiré pattern suppression ability. [ABSTRACT FROM AUTHOR]

The corresponding description of this figure should be "As shown in Fig.2, the full width at half maximum (FWHM) of the Tl-1223(006) reflection peak is only 0.58 , which shows that the film possesses a good crystalline structure", instead of "As shown in Fig.2, the FWHM of the Tl-1223(003) reflection peak is only 0.58 , which shows that the film possesses a good crystalline structure". 36(2019)057401] Jian Xing( ) 1, Li-Tian Wang( ) 1, Xiao-Xin Gao( ) 1, Xue-Lian Liang( ) 1, Kai-Yong He( ) 1, Ting Xue( ) 1, Sheng-Hui Zhao( ) 1, Jin-Li Zhang( ) 1, Ming He( ) 1,2, Xin-Jie Zhao( ) 1,3, Shao-Lin Yan( ) 1, Pei Wang( ) 4, and Lu Ji( ) 1,3* 1 College of Electronic Information and Optical Engineering, Nankai University, Tianjin 300350, China 2 Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology, Tianjin 300350, China 3 Key Laboratory of Photoelectronic Thin Film Devices and Technology of Tianjin, Tianjin 300350, China 4 Beijing Institute of Radio Measurement, Beijing 100854, China (Received 26 October 2020; accepted 18 December 2020; published online 27 January 2021) DOI: 10.1088/0256-307X/38/2/029901 1 4 1 6 1 8 2 0 0. 0 1. 5 3. 0 4. 5 6. 0 I n t e n s i t y (1 0 4 c p s) w (d e g) F W H M = 0. 5 8 O Fig. In Fig.2 of the article, [1] the figure caption should be"Rockingcurveofthe(006)peakoftheTl-1223thin film" instead of "Rocking curve of the (003) peak of the Tl-1223 thin film". [Extracted from the article]

TlBa2Ca2Cu3O9 (Tl-1223) films have promising applications due to their high critical temperature and strong magnetic flux pinning. Nevertheless, the preparation of pure phase Tl-1223 film is still a challenge. We successfully fabricate Tl-1223 thin films on LaAlO3 (001) substrates using dc magnetic sputtering and a post annealing two-step method in argon atmosphere. The crystallization temperature of Tl-1223 films in argon is reduced by 100°C compared to that in oxygen. This greatly reduces the volatilization of Tl and improves the surface morphology of films. The lower annealing temperature can effectively improve the repeatability of the Tl-1223 film preparation. In addition, pure Tl-1223 phase can be obtained in a broad temperature zone, from 790°C to 830°C. In our study, the films show homogenous and dense surface morphology using the presented method. The best critical temperature of Tl-1223 films is characterized to be 110 K, and the critical current Jc (77 K, 0 T) is up to 2.13 × 106 A/cm2. [ABSTRACT FROM AUTHOR]

A novel technique was proposed to fabricate a three-dimensional photonic crystal by self-assembling microspheres and the autocloning technology. The autocloning thin-film layers were superimposed on the prepared two-dimensional structural substrates using self-assembled microspheres. The thin-film process allows the three-dimensional periodic structure to be easily modified in the thickness dimension to structure as needed. We analyzed the etching effect using the unified process model according to the surface movement and surface velocity of the film to achieve the surface profile of the SiO2adjusting layer. Finally, 17 layers of Ta2O5SiO2multilayers were stacked on the SiO2adjusting layer successfully. [ABSTRACT FROM AUTHOR]

Comprehensive studies were carried out to explore the roles of phenyl-C 61 -butyric acid methyl ester (PCBM) thin films in inverted-type CH 3 NH 3 PbI 3 (MAPbI 3 ) based photovoltaics, including the surface morphologies, transmittance spectra, photoluminescence spectra, X-ray diffraction (XRD) patterns, Raman scattering spectra and thin-film residual stress analysis. The reduction in the photoluminescence line width indicates that the crystallinity of the MAPbI 3 thin film can be increased by covering it with the PCBM thin film. The XRD patterns and Raman scattering spectra show a reduction in the compressive stress of MAPbI 3 thin film when covered by the PCBM thin film. In addition, it is noted that the residual stress at the contact interface between the hydrophilic MAPbI 3 and the hydrophobic PCBM can be ignored as confirmed by the results obtained with a home-made Twyman-Green interferometer. Consequently, the superior optoelectronic properties of the perovskite materials, as well as the use of a multifunctional fullerene-based thin film as the capping layer allow for the high-efficiency perovskite photovoltaics. [ABSTRACT FROM AUTHOR]

A series of nonpolar antisolvents (chlorobenzene, bromobenzene, iodobenzene and toluene) were used to assist in the formation of smooth and crystalline CH 3 NH 3 PbI 3 thin films by a one-step spin-coating method. The structural, optical and excitonic characteristics of the resultant CH 3 NH 3 PI 3 thin films were analyzed using an atomic-force microscope, X-ray diffractometer, absorbance spectrum, photoluminescence (PL) spectrum, time-resolved PL and temperature-dependent PL. The properties of the CH 3 NH 3 PbI 3 thin films are dependent on the relative polarity and boiling point of the nonpolar antisolvents used in the washing treatment process. The interplay between nucleation (relative polarity) and crystal growth (boiling point) during the formation of CH 3 NH 3 PbI 3 thin films influences the short-circuit current density (J SC ) and power conversion efficiency (PCE) of the corresponding solar cells. The experimental results demonstrate that iodobenzene can be substituted for toluene as a more efficient antisolvent in the washing treatment process during the fabrication of CH 3 NH 3 PbI 3 thin films. In addition, it is predicted that the J SC and PCE can be further improved by increasing the crystallinity of the CH 3 NH 3 PbI 3 thin film. [ABSTRACT FROM AUTHOR]

A comprehensive study was carried out to understand the influence of organic cations on high-performance CH 3 NH 3 PbI 3 based photovoltaics. Scanning electron microscope, X-ray diffractometer, Hall measurement, absorbance spectrum, photoluminescence (PL) spectrum and nanosecond time-resolved PL measurements were used to explore the structural, electrical, optical and excitonic characteristics of CH 3 NH 3 PbI 3 thin films fabricated under different thermal annealing temperatures from 60 °C to 140 °C. The decrease in the open-circuit voltage ( V OC ) with an increase in the thermal annealing temperature can be explained as due to the reduced work function of the CH 3 NH 3 PbI 3 thin film. The short-circuit current density ( J SC ) of the CH 3 NH 3 PbI 3 based photovoltaics is dependent on the efficiencies of light absorption and carrier collection, which results in an optimized J SC when the thermal annealing temperature is 120 °C. The atomistic interaction between the organic cations and Pb–I framework strongly influences the absorbance of CH 3 NH 3 PbI 3 thin films, as confirmed by the libration of CH 3 NH 3 cations shown by Raman scattering spectroscopy. In addition, the experimental results indicate that the power conversion efficiency can be further improved when the absorption strength of the CH 3 NH 3 PbI 3 thin film and the energy-level alignment of each photovoltaic layer are simultaneously fulfilled. [ABSTRACT FROM AUTHOR]

The open-circuit voltage of CH 3 NH 3 PbI 3 based photovoltaics was enhanced from 0.77 V to 0.9 V, which resulted in an improvement of the average power conversion efficiency from 5.63% to 11.74% achieved by tuning the work function of the poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole transport layer. The higher work function of the PEDOT:PSS (1:20 wt%) thin film, as compared to the PEDOT:PSS (1:6 wt%) and PEDOT:PSS (1:2.5 wt%) thin films, was observed using photoelectron spectrometer. The carrier density of PEDOT was obtained by analyzing the transmittance spectrum of PEDOT:PSS/glass with the transfer matrix method. The Drude model can be used to explain the increased work function of the PEDOT:PSS thin film obtained by decreasing the ratio of PEDOT to PSS. The increased carrier density of the PEDOT in PEDOT:PSS thin films originated from conformational changes in the PEDOT chains as confirmed by Raman scattering spectroscopy. [ABSTRACT FROM AUTHOR]

Transmittance spectra, atomic-force microscopic images, energy-dispersive X-ray spectra and droplet contact angle images show that a facile wet etching process can be used to manipulate the thickness, surface roughness, surface chemical composition and surface wettability of the indium-tin oxide (ITO) thin films, which influences the molecular packing structure of the P3CT-Na thin films and thereby dominating the crystal quality of the CH 3 NH 3 PbI 3 (MAPbI 3) thin films. The power conversion efficiency (PCE) of the P3CT-Na based MAPbI 3 solar cells can be improved from 17.02% to 19.35% by increasing the Sn/In concentration ratio of the ITO thin films from 0.36 to 0.47 with a facile wet etching process at a constant temperature of 40 °C. It is noted that the PCE of the optimal solar cell decreases slowly toward a stable PCE of 16% for more than 60 days under moderate environment conditions (55 ± 10 RH%). • Surface properties of the ITO/glass substrates can be varied by the wet etching process. • The contact quality at the P3CT-Na/ITO interface can be improved. • The contact quality at the MAPbI3/P3CT-Na interface can be improved. • After 60 days, the PCE slowly decreased from 19.35% to 16.03%. [ABSTRACT FROM AUTHOR]

—The structural, optical and excitonic characteristics of urea doped CH 3 NH 3 PbI 3 (MAPbI 3) multi-crystalline thin films were investigated by using the X-ray diffraction patterns, atomic-force microscopic images, absorbance spectra, photoluminescence (PL) spectra and Raman scattering spectra. The surface-sensitive Raman scattering spectra show that the urea small molecules are mainly distributed in the top region of the MAPbI 3 thin films and thereby effectively passivating the electron-poor defects (interfacial MA cations) of MAPbI 3 thin films. Besides, the thermal annealing temperature and the concentration of urea additive both strongly influence the formation of MAPbI 3 thin films, which dominates the photovoltaic performance. The use of 5-wt% urea can increase the open-circuit voltage (V OC) and short-circuit current density (J SC) of the MAPbI 3 solar cells from 0.88 V to 19.75 mA/cm2 to 0.94 V and 22.97 mA/cm2, respectively. In addition, the reduced current hysteresis in the J-V curves of the MAPbI 3 solar cells can be explained as due to the effective defect passivation in the top region of the MAPbI 3 thin film by the oxygen-donors of the urea small molecules. Image 1 • The optoelectronic properties of urea-doped MAPbI 3 thin films are investigated. • The 5-wt% urea-doped MAPbI 3 thin film has the disk-like shaped grains. • The urea small molecules are mainly distributed in the top region of MAPbI3 thin films. • The V OC and J SC of MAPbI3 solar cells are simultaneously increased by using the urea additive. [ABSTRACT FROM AUTHOR]