Properties For Solar Cell Applications Research Articles

First principle study of X2GaAgCl6 (X = Cs, Rb) double perovskites: structural, mechanical, vibrational, electronic, optical, SLME, thermoelectric, and thermodynamic properties for solar cell applications.

The structural, mechanical, vibrational, electronic, optical, SLME, thermoelectric, and thermodynamic properties of X2GaAgCl6 (X = Cs, Rb), a double perovskite material, were computed by employing Density Functional Theory (DFT). CASTEP and Quantum ESPRESSO were used to perform first-principles calculations. X2GaAgCl6 possesses a cubic structure with the space-group symmetry Fm-3m. The lattice parameters of Cs2GaAgCl6 and Rb2GaAgCl6 were optimized using the energy-volume curves, resulting in values of 7.357Å and 7.365Å, respectively. The population analysis confirmed the charge transfer among transition metals and halogen atoms. The stability of crystal X2GaAgCl6 (X = Cs, Rb) is effectively demonstrated by analyzing phonon dispersion curves with no negative frequencies. The band structure calculations indicated the semiconducting nature of compounds with energy gaps of 0.96eV and 0.88eV for Cs2GaAgCl6 and Rb2GaAgCl6, respectively. The optical characteristics results confirm that the examined materials are suitable for devices working, primarily in the electromagnetic spectrum's visible region. SLME results showed that Cs2GaAgCl6 has 30% and Rb2GaAgCl6 has 27% efficiency, respectively, suggesting their use in photovoltaics. The thermoelectric properties of X2GaAgCl6 (X = Cs, Rb) were calculated by using the BoltzTraP code in the temperature range of 300 to 800K. The quasi-harmonic Debye model was applied to calculate the thermodynamic characteristics.

Perovskite solar cells with ferroelectricity

AbstractHalide perovskites show excellent optoelectronic properties for solar cell application. Notably, perovskite crystalline structures have been widely reported to deliver superior ferroelectric properties. As a result, the integration of the ferroelectric process with the photon‐to‐electron energy conversion process becomes feasible to generate interesting photo‐physical properties and further boost the device performance of perovskite solar cells (PSCs), which have started to attract more and more attention in recent years. Here, we have reviewed the recent progress in PSCs with ferroelectricity (FE‐PSCs), by classifying them into three regimes according to the degree of phase segregation, for example, the layer‐structured ferroelectric/halide perovskite composite, micro phase‐separated ferroelectric/halide perovskite composite, and the intrinsic ferroelectric halide perovskite composite. The different composite structures enable a large range of interesting optoelectronic properties and the specific structure significantly enhances the device performance of PSCs. The most prominent contribution of ferroelectricity is that it can provide an extra electrical field to drive charge generation, transport, and collection. Further, key challenges and opportunities of the integration of ferroelectricity with photovoltaics are discussed. We hope our work can draw intensive attention in this field to accelerate the establishment of the basic theories in ferroelectricity and the commercialization of PSCs.

Investigation of optical and dispersion parameters poly vinyl alcohol doped Safranin O dye (PVA/SO) thin film

Optical characteristics of polyvinyl alcohol/Safranin O dye (PVA/SO) thin films prepared by casting technique have been examined. Compositions and crystalline features of PVA/SO thin films are investigated with X-Ray Diffraction analyses. Ultraviolet–Visible spectroscopy has been utilized to measure the absorption and transmission optical properties of the thin films through the wavelength range 300-900 nm. Two regions can be recognized in absorption coefficient related to the direct band gaps, which are about 3.93 eV of the fundamental energy gap and 2.11eV of the onset gap. The theoretical WempleDiDomenico model has been performed to quantify the static refractive index n and the dispersion energy in addition to the oscillation energy (Eo). The results reveal that the data of the refractive index dispersion in this model obeyed the single oscillator, which is used to deduce the dispersion and the high frequency dielectric constant. In the examined wavelength range, it has been investigated the complex dielectric constant of PVA/SO dye thin films. The ratio of the carrier concentration to the effective mass has been estimated. Oscillation energy values have been examined in this study by describing the expression Eo ≈ Eg and checking the Wemple-DiDomenico model. PVA/SO thin films have interesting physical properties for solar cell applications.

First-principles calculations to investigate structural, electronic, and optical properties of AgWO4 and PdWO4 tungstate materials for optoelectronic applications

The optoelectronic devices play a crucial role in our daily lives by seamlessly integrating optics and electronics, enabling technologies like smartphones, solar cells, and optical communication. Solar cells have been very vital in terms of providing sustainable and clean energy. Conventional Perovskite-based solar cells possess limitations like stability and toxicity. Recently, ABO4-type materials have gained attention in optoelectronic devices due to their structural stability and suitable optoelectronic properties for solar cell applications. The structural, electronic, and optical properties of AgWO4 and PdWO4 have been explored using the first principal simulations in line with density functional theory (DFT) using WIEN2K simulation software. The Perdew-Burke-Ernzerhof Generalized-Gradient-Approximation (PBE-GGA) is acclimated to optimize the geometry of both materials under consideration. Trans-Balha modified Becke-Johnson approximation (TB-mBJ) approximation is implemented to study materials' optoelectronic properties. Structural analysis revealed the stable structure of AgWO4 and PdWO4 in the monoclinic phase with increasing lattice parameters and decreased unit cell volume upon replacement of Ag with Pd cation on the A site. Both materials ' negative values of ground state energies indicate the stability of both compounds. Upon analysis of the band structure of AgWO4 and PdWO4, it is found that both materials possess a band gap of 1.34eV and 0.73eV,respectively, signifying that both materials under consideration are semiconductors, with a potential for a controlled flow of electrical charges, coming up with promising various optoelectronic applications. Optical characteristics were explored and examined in depth in the framework of hypothetical dielectric constant. It has been discovered that the dielectric function has a broad span of energy integrity when it comes to its dielectric function. Materials with narrow bandgaps and excellent UV light absorption were found suitable for optoelectronic and solar cell applications.

Electrophoretic Deposition of Fluorine–Nitrogen Graphene Quantum Dots with Highly Luminescent Upconversion Properties for Solar Cell Applications

Nitrogen–fluorine codoped graphene quantum dots (N, F-GQDs) were synthesized through a one-pot hydrothermal method using glucose and ammonium fluoride (AF). The composition of nitrogen and fluorine with GQDs by AF was optimized to approach the highest light absorption edge in UV–visible spectroscopy and receive upconversion properties in photoluminescence (PL) analysis. Maximum absorption edge of the optimized N, F-GQDs was observed at 580 nm. Transmission electron microscopy analysis revealed the formation of the nanoparticles with an average size of 18 ± 0.9 nm. Raman analysis approved the formation of GQDs with graphitic carbon atom structures. X-ray photoelectron spectroscopy analysis indicated doping of F and N in the GQD structure and photoluminescence analysis revealed excitation-dependent emissions with upconversion properties for the best sample of the N,F GQD synthesized with an AF concentration of 0.07 gmol/dm3 in the primary synthesis solution. For the fabrication of solar cells, a uniform and stable layer of N, F-GQDs was deposited on the TiO2/FTO electrode, as the photoanode, by an additive-free electrophoretic deposition (EPD) method, confirmed by field-emission scanning electron microscopy analysis. Photovoltaic properties of the fabricated solar cells were studied under a simulated solar irradiation of AM 1.5 G. It was revealed that an appropriate ratio of N,F doped in GQDs in addition to the EPD layer formation highly improved the solar cell efficiency. The best cell with N, F-GQD0.07/TiO2/ FTO photoanode (size of 1 × 1 × 0.2 cm3) improved the efficiency, open circuit voltage, and short circuit current density, from 0.07 to 0.51, 370 to 699 mV, and 0.3 to 1.2 mA/cm2, respectively, compared to the cell fabricated by the blank TiO2/FTO photoanode.

Study of physico-chemical properties of Cu2NiSnS4 thin films

This study reports the synthesis of quaternary copper nickel tin sulfide (Cu2NiSnS4) thin films using two different strategies and their physico-chemical properties. The first strategy includes co-evaporation of copper–nickel-tin–sulfur (CNTS) followed by sulfurization and the second strategy includes co-evaporation of copper–nickel–tin (CNT) followed by sulfurization. The X-ray diffraction (XRD) study reveals that the film prepared by both strategies has a polycrystalline Kesterite structure. The scanning electron microscope (SEM) analysis shows densely covered CNTS all over the substrate. The optical analysis of both CNTS films exhibits absorption of visible wavelength in an optimal range. The CNTS thin film synthesized using thermal evaporation technique followed by sulfurization has the potential to exhibit better photovoltaic properties for solar cell applications.

Understanding Grain Growth Mechanism in Vacuum Evaporated CdTe Thin Films by Different Halide Treatments: An Evolution of Ion Size Impact on Physical Properties for Solar Cell Applications

ABSTRACT In the present study, detailed investigation on postdeposition halides treatment using CdCl2, CdI2, MgF2, MgCl2 and MgI2 is undertaken over thermally evaporated CdTe films. As-deposited films are subjected to halide treatment and subsequent annealing at 385°C. Halide activation induced grain growth mechanism is presented along with anions and cations roles on change in films properties and formation of different complexes. XRD patterns of all CdTe thin films exhibited polycrystalline nature with preferential cubic phased (310) plane except for CdI2 treated films where preferred reflection is appeared corresponding to (220) plane. Grain growth is observed with treatment employing amicable estimation tools. All films have a conspicuous ohmic character owing to linear I–V plots. Optical study reveals that CdCl2 treated CdTe films have higher absorbance and optical energy band-gap is measured out in the range 1.42–1.53 eV with halide treatment. Surface topography and PL study revealed to variations in surface roughness and photoluminescence peaks intensity with halide treatments. Film growth and treatment are validated by EDS analysis and FESEM images demonstrated explicit grain growth. Findings warrant amazing role of halide activation on film properties and CdCl2 is found a suitable surface treatment agent to CdTe films in order to develop better devices.

Constructing of Cu2ZnSnS4 thin films with enhanced optical properties for solar cell application

Thin films of Cu2ZnSnS4 (CZTS) were created utilizing the thermal evaporation method. For the (CZTS) nanoparticles, thermogravimetric analysis (TGA) was initially carried out. According to TGA analysis, different annealing temperatures (400, 450, 475, and 500 °C) were used to anneal the (CZTS) thin films. Investigations were done into how different annealing temperatures affected the structural, morphological, and optical characteristics of the CZTS films. The development of a thin CZTS crystal with a high-quality crystal structure has been demonstrated by XRD patterns and Raman spectra. Using Debye-Scherrer's equation, the crystallite size for CZTS thin films was determined to be between 8 and 69.9 nm. As the annealing temperature rises, crystallite size increases. Using a double-beam computer-controlled spectrophotometer with a 400–2500 nm wavelength range, the optical characteristics were examined. While the reflectance was discovered to increase with an increase in annealing temperature, the transmittance was found to decrease. Calculating the extinction coefficient and refractive index was done using Kramers-Kronig relations. Using Tauc's relation, the optical energy gap was estimated, and it was discovered that it shrank as annealing temperature was raised. The (CZTS) thin film that was annealed at 500 °C had the highest power conversion efficiency (PCE).

Two-Dimensional Lead-Free Double Perovskite with Superior Stability and Optoelectronic Properties for Solar Cell Application

Two-Dimensional Lead-Free Double Perovskite with Superior Stability and Optoelectronic Properties for Solar Cell Application

Sb2S3microbars prepared via the solvothermal method: Precursor sulfur source's effect on structural and optical properties for solar cell applications

In this study, antimony sulfide Sb2S3microbarswere successfully fabricated via the solvothermal method using different sulfur sources at 180oC for 14 h. The effects of different sulfur sources including natrium thiosulfate, thiourea, sulfur, and l-cystine on the structural, compositional, and optical properties of the Sb2S3 microbars were inspected using XRD, TEM, XPS, FE-SEM, EDX, UV–vis spectra and Raman scattering. The XRD and Raman spectral studies indicated theSb2S3 microbars’ high purity, crystalline nature, single phase, and orthorhombic structure of in the preferred (1 3 0) orientation. The TEM images showed the formation of well-defined Sb2S3microbars and confirmed the crystallinity. The EDX investigation indicated that the Sb/S atomic ratio was close to2:3, revealing the nearly stoichiometric nature of the Sb2S3 structure. The XPS analysis demonstrated the elemental composition and chemical states. The microbars had absorption coefficients over 104 cm−1and energy gaps between 1.53 and 1.81 eV depending on the precursor sulfur used. The Sb2S3 thin film-based microbars were smooth, compact, and free from holes and cracks with grain sizes of more than 1.5 μm. The highest power conversion efficiency of 3.63% was achieved in the Mo/Sb2S3/CdS/ITO/Ag solar cell structure, with open-circuit voltage Voc = 465 mV, short-circuit current density Jsc = 12.83 mA/cm2, and a fill factor FF = 60.9%when thiourea was used as the sulfur source.

Electrical Characterization of II-VI Thin Films for Solar Cells Application

Cds and CdTe both are effective absorber semiconductors for thin-film solar cells. It is a naturally n-type material, which has a direct bandgap value of 2.42 eV at room temperature It has great importance in light detectors in this work, CdS thin films (TF) were synthesized on glass substrates by RF Magnetron sputtering technique in an inert gas atmosphere. The electrical properties of CdS were characterized by the Van Der Pauw method. The films showed p-type conductivity, while the films deposited at different annealed times exhibited n-type conductivity. The resistivity of the CdTe films decrease as the conductivity increased. As the source rate was increased, the hole concentration in the as-grown p-type CdTe films increased. It was also reported annealing process affects the electrical properties. Al doping CdS the value of resistivity becomes minimum as the resistivity becomes maximum although mobility has maximum value after an increase in Al doping the mobility value. As a result, the CdS/CdTe thin-film showed enhanced electrical properties for solar cell applications.

Role of metal and anions in organo-metal halide perovskites CH3NH3MX3 (M: Cu, Zn, Ga, Ge, Sn, Pb; X: Cl, Br, I) on structural and optoelectronic properties for photovoltaic applications.

Methylammonium metal halide perovskites have recently been explored for new uses due to their unique and exciting optoelectronic properties. Their exceptional electronic properties have often been attributed to the overlap between the metal cation s and halogen p states. In this study, density functional theory calculations have been carried out based on the orthorhombic phase of the organometal trihalide perovskite CH3NH3MX3 (M: Cu, Zn, Ga, Ge, Sn, Pb; X: Cl, Br, I) to systematically investigate the effects of the metal cation and halogen anion on the structural, electronic, and optical properties for solar cell applications. The calculated lattice parameters agree well with previously obtained experimental and theoretical results. All of these perovskites are direct band gap compounds at the G symmetry point, except CH3NH3GaX3. The band gap increases from iodide to chloride and also with the metal cation size, from Ge to Pb or Cu to Zn. Furthermore, metal halide perovskites show blue shifts in their optical absorption spectra with an increase in metal cation size. Among the studied examples, CH3NH3GaBr3 and CH3NH3CuCl3 absorb a wide range of light, from UV to the visible region, and possess very unusual high dielectric constants and refractive indices. Our calculations reveal that CH3NH3SnI3, CH3NH3GeI3, and CH3NH3ZnI3 are favorable candidates for lead-free photovoltaic applications.

Solution-processed CIGS thin film solar cell by controlled selenization process

Cu(In,Ga)Se2 (CIGS) is a prevalent material with superior thermo-chemical stability and excellent optoelectronic properties for solar cell applications. In thin film form, CIGS could be a potentially economicalandbuilding integrated photovoltaicadaptable substitute to Silicon solar cells, solving humanity's extensive energy demands. To be economically sustainable, CIGS thin film processing must be abridged and affordable. We explored a low-cost, simplified wet chemical nano-ink method to make the CIGS thin film absorber layer comprising precursor thin film preparation by spraying CIGS nano-ink and subsequent post-treatment using Selenium vapor under Nitrogen atmosphere at a temperature of 550 °C. The spray-casted nanocrystalline layers were selenized at a low pressure of 1 Torr or 1 atm Nitrogen utilizing elemental pallets of Selenium as a source of Se vapor. The impact of Selenization pressure on the structure, morphology, composition, and electronic conductivity of selenized CIGS thin films absorber is investigated in this study, as well as the device performance associated with the processing parameters.

Tuning Dielectric Transitions in Two-Dimensional Organic-Inorganic Hybrid Lead Halide Perovskites.

Organic-inorganic hybrid metal halide perovskites possessing unique two-dimensional (2D)-layered structures have been demonstrated with excellent molecular tunability and stability, especially the promising semiconductor properties for solar cell applications. In this work, three 2D lead halide organic-inorganic hybrid perovskites (IAA)2PbX4 (IAA = isoamylammonium cation and X = Cl, Br, and I) were synthesized by employing a solution processing method and demonstrate distinct tuning solid-state phase transitions coupled with dielectric responses, as well as light absorption properties. Among the title perovskites, the phase transition temperature decreases gradually, and their band gap also indicates a narrowing trend. The results are mainly derived from slight changes in the crystal structure by halogen regulation. These findings might provide an effective crystal engineering strategy for exploring high-performance functional perovskite materials.

Comprehensive study of physical properties of cadmium telluride thin films: effect of post-deposition high annealing temperature

Thin films of cadmium telluride (CdTe) with a thickness of 550 nm were prepared using the thermal evaporation method. The resulting films were annealed in air atmosphere at 200 °C, 300 °C, 400 °C and 500 °C. The annealed films were subjected to x-ray diffraction (XRD), micro-Raman spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), ultraviolet-visible spectroscopy and transverse current–voltage (I–V) test analyses to investigate the structural, surface morphological, optical and electrical properties of films, respectively. The XRD patterns reveal the zinc blende structure of the pristine and treated film with the preferred (111) orientation. In addition, the crystallite size increases with the rise in annealing temperature. The Raman spectra reveal a redshift with annealing as well as the formation of Te precipitates in CdTe films. The SEM images show the uniformity and homogeneity of the as-prepared films. The AFM studies show an increase in the surface roughness of the annealed films. The optical energy band gap is found to decrease with the annealing temperature. The I–V measurement indicates the ohmic behavior of CdTe films. The experimental results indicate that the annealed CdTe thin films at 400 °C have optimized physical properties for solar cell applications as an absorber layer.

Heterostructure AZO/WSeTe/W(S/Se)2 as an Efficient Single Junction Solar Cell with Ultrathin Janus WSeTe Buffer Layer

Transition metal dichalcogenides based materials exhibit promising optoelectronic properties for solar cell application. We considered the heterostructure single junction solar cell with bulk W(S/S...

Una ruta nueva para la síntesis de películas delgadas de Sn3Sb2S6 por depósito químico

In this work, SnS-Sb2S3 stack films were formed by sequential chemical deposition, and then they were annealed in a nitrogen atmosphere to synthesize Sn3Sb2S6 thin films successfully. The structural and optical properties were studied by X-ray diffraction and transmittance and reflectance. All the samples show a high absorption coefficient of > 105 cm-1 in the visible region. Their optical bandgap and refractive index are between 1.6-1.8 eV and 3.00-2.71, respectively, which decrease with the increase of film thickness. The electrical conductivity is in the range of 10-8 to 10-7 Ω−1 cm−1. The light-generated current density (JL) is presented as a function of Sn3Sb2S6 film thickness when exposed to air mass 1.5 global (AM1.5G) and solar radiation intensity of 1000 W/m2. In short, Sn3Sb2S6 thin films obtained via the proposed new route exhibit appropriate properties for solar cell applications.

Designing highly stable yet efficient solar cells based on a new triple-cation quasi-2D/3D hybrid perovskites family

In a nutshell, this study outlines the efficacy of mixed dimensional (2D/3D) hybrid perovskites by developing a new class of triple-cation quasi-2D perovskites having (S0.97S′0.03)2[Cs0.05(FA0.97MA0.03)0.95]n-1Pbn(I0.07Br0.03)3n+1 general composition, in which a mixture of ý5-ammonium valeric acid ýiodideý‏ (S) and ‏tetra-n-octylammonium ýbromide (S′) was employed ýas a spacer.ý The effect of the 2D and 3D structures molar ratios (i.e., C=2D/2D+3D) in the range of 0-100 % on photovoltaic performance of the deposited photoanodes was systemically studied. Drawing a comparison between such compounds and an analogous triple-cation 3D counterpart (i.e., Cs0.05(FA0.83MA0.17)0.95Pb(I0.83Br0.17)3) as a reference (i.e., C=0) showed that the C=10 film containing 10 % 2D and 90 % 3D perovskites had optimal properties for solar cell applications. The pronounced (0 k 0) peak series at low angles and the blue shift of the 3D perovskites peaks observed in X-ray diffraction set forth that quasi-2D perovskites were formed in the layers. The C=10 film having the bandgap of around 1.62 eV exhibited the optimal photon ýabsorption, light harvesting, and crystallinity compared to all the deposited layers, ensuring ýadequate photocurrent. CuInS2 nanoparticles were employed as a novel hole-transporting material to assemble solar cells. The C=10 cell also indicated the highest power conversion efficiency (i.e., 12.33 %), recombination resistance (i.e., 1650.23 Ω), and electron lifetime (20.73 μs) as well as the lowest series resistance of 10.23 Ω amongst all the 2D/3D films, demonstrated by electrochemical impedance spectroscopy (EIS). Although the efficiency of this cell was not yet sufficient to compete with that of the C=0 (i.e., 12.87 %), it could retain 80 % of its own performance over 2500 h in ambient conditions without encapsulation, endowing more stability than its 3D counterpart which sustained 64 % of the initial efficiency. Therefore, developing triple-cation 2D/3D perovskites is a facile, straightforward strategy for fabricating stable, efficient solar cells.

Formation of metastable cubic phase in SnS thin films fabricated by thermal evaporation

Metastable cubic SnS phase (π-SnS) is an emerging material having attractive properties for solar cell applications. In this study, we have investigated the thermal evaporation process of SnS with substrate temperatures of 250–350°C, and have observed the formation of π-SnS together with the stable orthorhombic phase (α-SnS) for the first time by using only SnS as a starting material. X-ray diffraction analysis shows that a single-phase α-SnS film is obtained at 350°C, and the fraction of π-SnS increases with decreasing the substrate temperature to 250°C. The grain shape of the SnS film grown at 250°C observed by scanning electron microscopy was more isotropic than 350°C, consistent with the cubic lattice of π-SnS. Electrical characterization by Hall measurement reveals the existence of the maximum point of carrier density as a function of substrate temperature, which is understood by the competition between the increases of crystal defects and the fraction of wider-gap π-SnS than α-SnS with decreasing substrate temperature. The formation of π-SnS brings about lowering of absorption coefficients below the absorption edge of π-SnS, which are analyzed from transmittance and reflectance spectra. The reason of π-SnS formation is discussed by comparing the conditions of film deposition with previous reports.

First-Principles Study of Ion Diffusions in CH3NH3PbI3 and (NH2)2CHPbI3 for Perovskite Solar Cells

Perovskite solar cells (PSCs), which photo-absorbing layer consists of organometal halide perovskites, have gotten much attention because of their rapidly increasing power conversion efficiencies (3.8% in 2009, but nowadays over 22% cell has appeared). [1, 2] Especially, lead halide perovskites such as CH3NH3PbI3 (MAPbI3) and (NH2)2CHPbI3 (FAPbI3) show remarkable properties for solar cell applications, e.g. high optical absorption coefficients and long diffusion lengths of both charge carriers. However, the current−voltage (J−V) curve of PSCs often depends on voltage sweep rates and sweep directions, [3, 4] which make the evaluation of conversion efficiency difficult. Recently, the rate-dependent J−V hysteresis, which is due to a slow process continued about seconds, was attributed to ionic diffusions in MAPbI3. [5] In this study, we calculated activation barriers of ion diffusions in tetragonal MAPbI3 and trigonal FAPbI3 by first-principles calculations. The vacancy migrations of I− anions in both perovskites show low barriers of 0.3 to 0.45 eV, which values indicate that MAPbI3 and FAPbI3 are ion conductors. Furthermore, MA+ and FA+ cations have rather low barriers c.a. 0.6 eV. The results strongly suggest that the not only anions but also molecular cations can migrate in the perovskites when a bias voltage is applied. Based on the dilute diffusion theory, we can expect that small vacancy concentrations suppress these ion conductions. In addition, we suggest that replacement of MA molecule with larger one is also able to reduce MA migrations and to prevent the degradation of PSC photo absorbers. [6] [1] A. Kojima, K. Teshima, Y. Shirai, and T. Miyasaka, J. Am. Chem. Soc., 131, 6050 (2009). [2] Best Research-Cell Efficiencies, National Renewable Energy Laboratory. http://www.nrel.gov/ncpv/images/efficiency_chart.jpg [3] A. Dualeh, T. Moehl, N. Tétreault, J. Teuscher, P. Gao, M. K. Nazeeruddin, M. Grätzel, ACS Nano, 8, 362 (2014). [4] H. J. Snaith, A. Abate, J. M. Ball, G. E. Eperon, T. Leijtens, N. K. Noel, S. D. Stranks, J. T.-W. Wang, K. Wojciechowski, W. Zhang, J. Phys. Chem. Lett., 5, 1511 (2014). [5] W. Tress, N. Marinova, T. Moehl, S. M. Zakeeruddin, M. K. Nazeeruddin, M. Grätzel, Energy Environ. Sci., 8, 995 (2015). [6] J. Haruyama, K. Sodeyama, L. Han, and Y. Tateyama, J. Am. Chem. Soc., 137, 10048 (2015).