Solar Energy Materials Research Articles

Molecular topological indices-based analysis of thermodynamic properties of graphitic carbon nitride

Graphitic carbon nitride $$({\text {g-C}}_{3}{\text {N}}_{4})$$ has become a new interdisciplinary research hot spot due to its metal-free and visible-light-responsive nature along with alluring electronic band structure and high physicochemical stability. This fascinating semiconductor conjugated polymer is considered a feasible material for harvesting clean and inexhaustible solar energy in the field of environmental remediation and energy applications. Chemical graph theory plays an important role in modeling and designing the chemical structure of complex compounds. The molecular topological indices are the numerical invariants of a molecular graph and are very useful for predicting the reactivity of respective compound. In this paper, we studied the chemical graph of crystalline graphitic carbon nitride, i.e., $$({\text {g-C}}_{3}{\text {N}}_{4})$$ , via degree-based topological indices such as general Randic index, atom bond connectivity index, geometric arithmetic index and Zagreb-type indices. Curve fitting between the calculated thermodynamic properties and topological indices was done together with the numerical and graphical representation of computed results. This mathematical framework of graphitic carbon nitride based on topological indices presents a comprehensive picture of potentially valuable thermodynamic properties such as entropy and enthalpy which could be useful in structural modification of $$({\text {g-C}}_{3}{\text {N}}_{4})$$ for specific application.

Formation of Intermediate SiO2 nano-Layer As Effective Passivation at Si/TiO2 Interface By Zone Heating Recrystallization Toward Perovskite/Silicon Tandem Solar Cell

A monolithic perovskite/c-Si tandem solar cell has attracted a lot of attention in the field of photovoltaic for its high theoretical energy conversion efficiency and cost-effectiveness. For this technology to reach its potential, optimization and compromised for both perovskite top cell and silicon bottom cell has to be investigated.In a single-junction perovskite solar cell, the hybrid organic-inorganic perovskite light-absorbing layer is sandwiched with electron and hole transporting layers (ETL and HTL). For optimal carrier extraction, the bandgap of the transporting layers has to match the perovskite material such that electron can be selectively transported to the ETL while only hole moves through HTL. In the majority of perovskite solar cells, titanium dioxide (TiO2) is used as ETL, for its high bandgap alignment, ease of fabrication, and low cost. For this reason, a tandem solar cell with c-Si/ETL(TiO2)/Perovskite/HTL structure has the potential to be highly efficient and low in cost [1].In a single-junction c-Si solar cell, surface passivation of silicon using large bandgap materials such as Al2O3, SiO2 or SiNx is widely known to reduce the velocity of carrier recombination and thus increase the carrier lifetime at silicon surface. This approach, however, is not applicable in tandem solar cells with c-Si/ETL/Perovskite/HTL structure, as the utilization of large bandgap materials in between c-Si and ETL causes bandgap misalignment and prevents interlayer exchange of carriers between perovskite and silicon cells. For this reason, a new approach that accommodates both interlayer exchange of carriers and passivate silicon surface effectively is required.In most of Si-Oxides (Al2O3, TiO2, ZnO, etc.) interface, the existence of SiOx layer is unavoidable and widely known due to high reactivity of silicon surface under oxidizing atmosphere [2]. Furthermore, while the improvement of perovskite solar cell efficiency by controlling spray pyrolysis of TiO2 and the thermal annealing procedure has been reported [3], prolonged exposure to heat during TiO2 fabrication might negatively affect the performance of silicon bottom cell, and thus requires further studies. Due to the high surface passivation effect of thermally grown SiO2 layer, we hypothesized that a proper crystallization of SiOx layer might be able to increase the lifetime of carrier at Si/TiO2 interface and mitigate the surface passivation problem in tandem solar cells with c-Si/ETL/Perovskite/HTL structure.Zone Heating Recrystallization (ZHR) is a process developed by our research group in which the surface of samples was selectively heated by the scanning of highly focus line lamp heater with elliptical mirror. Previously, we reported the utilization of ZHR to obtain smooth seed layers for thin-film silicon solar cell applications [4, 5] among other functionalities. The use of high-intensity lamp heater in ZHR process combines with high transparency of TiO2 layer makes ZHR a suitable process to selectively treat the Si/TiO2 interface and test our hypothesis on SiOx crystallization.With the introduction of ZHR, the minority carrier lifetime of Si/TiO2 interface was increased from less than 5 µs to more than 250 µs. Different scanning rates of lamp heater in ZHR process lead to different carrier lifetime, with higher scanning rates lead to higher carrier lifetime. To explain this phenomenon, cross-sectional TEM images of Si/TiO2 treated with different scanning rate was taken and analyzed. Here, we found that samples treated with higher scanning rates of ZHR have thinner SiOx layer and higher carrier lifetime. The relationship between SiOx thickness and carrier lifetime might be explained with the interface trap density of SiOx layer in which thinner layer shows lower interface trap density. This leads to lower carrier recombination velocity and therefore higher carrier lifetime at Si/TiO2 interface.References Mailoa J. P. et al., A 2-terminal perovskite/silicon multijunction solar cell enabled by a silicon tunnel junction. Appl. Phys. Lett. 106, 121105 (2015).Black L. E. et al., Explorative studies of novel silicon surface passivation materials: Considerations and lessons learned. Solar Energy Materials and Solar Cells 188, 182- 189 (2018).Nukunudompanich M., Ihara M. et al., Dominant effect of the grain size of the MAPbI3 perovskite controlled by the surface roughness of TiO2 on the performance of perovskite solar cell. CrysEngComm 22, 2718-2727 (2020).Ihara M. et al., Fabrication of silicon thin films with defects below detection limit of electron spin resonance for solar cells by high-speed zone-melting crystallization of amorphous silicon. Appl. Phys. Lett. 79, 3809 (2001).Lukianov A., Ihara M. et al., Formation of the seed layers for layer-transfer process silicon solar cells by zone-heating recrystallization of porous silicon structures. Appl. Phys. Lett. 108, 213904 (2016). Figure 1

Types of Transformational Leadership at PT. Permata Sinergi Madani

This type of leadership has many forms according to the character of the leadership and the way of coordination in achieving work goals. PT. Permata Sinergi Madani is a retail company that sells special materials for solar energy. It has a leadership type characterized by a transformational leadership type. The purpose of this study is to describe the type of leadership of PT. Permata Sinergi Madani in terms of Ideal Influence, Inspirational Motivation, Intellectual Stimulation and Individual Consideration. The research method used is descriptive qualitative methodology with data collection techniques using participant observation. To determine the validity of the data, this study used triangulation of sources. The results of the analysis show that the type of transformational leadership in the aspect of ideal influence is that the leader influences others to move or carry out his vision, with good coordination or cooperation between the leader and his subordinates. Aspects of insporational motivation, leaders motivate only by demanding employees to obtain high profits. Intellectual stimulation aspect, provides an overview to employees in increasing the profit from the products sold through briefing activities. Aspects of individual consideration, leaders consider the relationship with employees to provide suggestions or input for the achievement of company profits. Conclusion The type of transformational leadership is more depicting the activities of the leader which are oriented towards work results that have a greater influence on employee performance.

Defects and Their Passivation in Hybrid Halide Perovskites toward Solar Cell Applications

The rise of hybrid metal–halide perovskites as potential solar energy materials has revolutionized research on next‐generation solar cells. According to recent studies, the rationale behind such success is the rich defect physics of materials. Studies on the origin of different types of prevailing defects, their formation, and mechanism of defect passivation have hence become decisive avenues. Herein, the possible origins of defects and different defect analysis techniques in hybrid halide perovskites are discussed. While initiating the discussion with the archetypal methylammonium lead halide, perovskites beyond the conventional ABX3 structure are included. In this direction, some major advancements to date on defect formation in the bulk of hybrid halide perovskites, at the grains and grain boundaries, are summarized. Numerous effective methods to passivate the defects and the adverse effect of defects on device efficiency are further highlighted. Hence, the prospect of defect engineering in perovskite materials is pointed toward improving the power conversion efficiency and long‐term stability of perovskite solar cells (PSCs). The discussion rightfully addresses that the in‐depth exploration of defect engineering is anticipated to have a gigantic impact toward the achievement of predicted efficiency in metal–halide PSCs.

Properties of Selenium Colloidal Solution Obtained via Laser Ablation and a Subsequent Method for Producing Highly Dispersed CuInSe2

Various methods of synthesis of CuInSe2 remain relevant because it is one of the most effective materials for solar energy. An effective method for the preparation of the CuInSe2 nanodispersed selenium precursor for microwave synthesis is considered. Colloidal selenium solutions were obtained using laser ablation in various liquid media: water, ethanol, triethylene glycol, polyethylene glycol–400 (PEG-400), and a 1% solution of PEG-1500 in PEG-400. The optical properties of the obtained colloidal selenium solutions were studied. Electron microscopy of selenium particles was conducted. Trends of ablation rate change and physicochemical properties of dispersed selenium particles in the variety of liquid media listed above are discussed. The possibility of synthesizing CuInSe2 using the obtained precursor was verified.

Electronic properties of the Sn1\u2212xPbxO alloy and band alignment of the SnO/PbO system: a DFT study

Tin monoxide (SnO) has attracted attention due to its p-type character and capability of ambipolar conductivity when properly doped, properties that are beneficial for the realization of complementary oxide thin film transistors technology, transparent flexible circuits and optoelectronic applications in general. However, its small fundamental band gap (0.7 eV) limits its applications as a solar energy material, therefore tuning its electronic properties is necessary for optimal performance. In this work, we use density functional theory (DFT) calculations to examine the electronic properties of the Sn1−xPbxO ternary oxide system. Alloying with Pb by element substitution increases the band gap of SnO without inducing defect states in the band gap retaining the anti-bonding character of the valence band maximum which is beneficial for p-type conductivity. We also examine the properties of the SnO/PbO heterojunction system in terms of band alignment and the effect of the most common intrinsic defects. A broken gap band alignment for the SnO/PbO heterojunction is calculated, which can be attractive for energy conversion in solar cells, photocatalysis and hydrogen generation.

Liquid Thermo-Responsive Smart Window Derived from Hydrogel

Summary Buildings account for 40% of global energy consumption, while windows are the least energy-efficient part of buildings. Conventional smart windows only regulate solar transmission. For the first time, we developed high thermal energy storage thermo-responsive smart window (HTEST smart window) by trapping the hydrogel-derived liquid within glasses. The excellent thermo-responsive optical property (90% of luminous transmittance and 68.1% solar modulation) together with outstanding specific heat capacity of liquid gives the HTEST smart window excellent energy conservation performance. Simulations suggested that HTEST window can cut off 44.6% heating, ventilation, and air-conditioning (HVAC) energy consumption compared with the normal glass in Singapore. In outdoor demonstrations, the HTEST smart window showed promising energy-saving performance in summer daytime. Compared with conventional energy-saving glasses, which need expensive equipment, the thermo-responsive liquid-trapped structure offers a disruptive strategy of easy fabrication, good uniformity, and scalability, together with soundproof functionality that opens an avenue for energy-saving buildings and greenhouses.

Materials for Solar Energy

Energy is very important to all, without Energy we can’t do any work. There are different forms of Energy sources such as Renewable and Non-Renewable sources. But nonrenewable energy resources are depleting now because of high usage, and their demand also increases day by day due to the low supply of nonrenewable energy its cost increases, then now renewable energy sources are used. Renewable sources are wind, solar, hydro, tidal, etc. This solar energy is commonly used now a day. In this paper, we focused on different types of materials for solar energy and their efficiency.

Structural limiting factors of mixed-valent tin oxides in photoelectrochemical application: A comparative exploration

Abstract Photoelectrocatalytic (PEC) materials for harvesting solar energy can be discovered from existing photocatalytic semiconductors. Nonetheless, mixed valence tin oxides, a group of widely reported visible light active photocatalysts, can hardly be developed into efficient PEC photoelectrodes. To overcome this difficulty by clarifying its origin, two typical mixed valence tin oxides, Sn2+:SnO2 microrods and porous Sn3O4 particles were deliberately prepared as the models. Sn2+:SnO2 microrods of less porosity exhibited a photocurrent over ten times higher than Sn3O4 particles. Photo-electrochemical impedance spectroscopy revealed this was due to their charge kinetics difference, specifically the internal transport/transfer responding to the morphology. Moreover, hydroxyl residuals from synthesis were found to be very inhibitive for the PEC efficiency as well, which was in coherence with our TGA and Raman spectroscopic study. These finding experimentally proved the necessity of reconsidering the surface area, crystallinity, and defects when developing photocatalysts into efficient PEC structures.

Materials for Solar Energy

Energy is very important to all, without Energy we can’t do any work. There are different forms of Energy sources such as Renewable and Non-Renewable sources. But nonrenewable energy resources are depleting now because of high usage, and their demand also increases day by day due to the low supply of nonrenewable energy its cost increases, then now renewable energy sources are used. Renewable sources are wind, solar, hydro, tidal, etc. This solar energy is commonly used now a day. In this paper, we focused on different types of materials for solar energy and their efficiency.

IR thermographic camera as useful and smart tool to analyse defects in organic solar cells

The main goal of this paper was to show that organic layers prepared for organic solar cells construction can be partially characterized by IR thermographic camera to detect dysfunctionalities of the active layer. Moreover, we used IR thermographic camera to check thermal and electrical behaviour of created simple solar cells to reduce time and cost in global production of solar cells. As model system organic compounds such as PTB7 polymer and small molecule PC71BM as commercial components and newly synthesized imine PV-BLJ-SC11 there were used, to construct simple devices. Full Text: PDF ReferencesK. D. G. I. Jayawardena, L. J. Rozanski, C. A. Mills, M. J. Beliatis, N. A. Nismy, S. R. P. Silva, "Inorganics-in-Organics’: recent developments and outlook for 4G polymer solar cells", Nanoscale, 2013, 5, 8411-8427. CrossRef Y. Lin, X. Zhan, "Oligomer Molecules for Efficient Organic Photovoltaics", Accounts of Chemical Research, 2016, 49, 175-183. CrossRef R. Steim, S. A. Choulis, P. Schilinsky, U. Lemmer, C. J. Brabec, "Formation and impact of hot spots on the performance of organic photovoltaic cells", Applied Physics Letters, 2009, 94, 043304. CrossRef J. Hepp, F. Machui, H. J. Egelhaaf, C. J. Brabec, A. Vetter, "Automatized analysis of IR‐images of photovoltaic modules and its use for quality control of solar cells", Energy Science and Engineering. 2016, 4, 363-371. CrossRef H. Hoppe, J. Bachmann, B. Muhsin, K. H. Drüe, I. Riedel, G. Gobsch, C. Buerhop-Lutz, C. J. Brabec, V. Dyakonov, "Quality control of polymer solar modules by lock-in thermography", Journal of Applied Physics, 2010, 107, 014505. CrossRef J. Bachmann, C. Buerhop-Lutz, C. Deibel, I. Riedel, H. Hoppe, C. J. Brabec, V. Dyakonov, "Organic solar cells characterized by dark lock-in thermography", Solar Energy Materials and Solar Cells, 2010, 94, 642-647. CrossRef A. Różycka, K. A. Bogdanowicz, N. Górska, J. Rysz, M. Marzec, A. Iwan, R. Pich, A. Januszko, "Influence of TiO2 Nanoparticles on Liquid Crystalline, Structural and Electrochemical Properties of (8Z)-N-(4-((Z)-(4-pentylphenylimino)methyl)benzylidene)-4-pentylbenzenamine", Materials, 2019, 12, 1097. CrossRef M. L. Petrus, R. K. M. Bouwer, U. Lafont, S. Athanasopoulos, N. C. Greenham, T. J. Dingemans, "Small-molecule azomethines: organic photovoltaics via Schiff base condensation chemistry", Journal of Materials Chemistry A, 2014, 2, 9474-9477. CrossRef K. A. Bogdanowicz, A. Iwan, "Symmetrical Imines with Trirphenylamine Core and the Method of Obtaining Thereof.", March 11th 2019, patent application P.429044. DirectLink K. P. Korona, T. Korona, D. Rutkowska-Zbik, S. Grankowska-Ciechanowicz, A. Iwan, M. Kamińska, "Polyazomethine as a component of solar cells-theoretical and optical study", Journal of Physics and Chemistry of Solids, 2015, 86, 186-193. CrossRef

Photovoltaic Greenhouse Load Control Based on Phase Change Thermal Storage Method

Aiming at the problem of unstable grid connection of photovoltaic power source, an in-situ consumption strategy was proposed, and a photovoltaic energy and phase change energy storage method was proposed to provide energy for greenhouse loading. Design an agricultural greenhouse power supply system with complementary solar energy and phase change thermal storage materials, including constant temperature control center, detection circuit, input circuit and display circuit. It could be seen through software programming and simulation analysis that phase change and photovoltaic combined energy supply could to meet the load demand of agricultural greenhouses, it provided a reference for the local consumption of photovoltaic energy.

Direct Z-Scheme Heterojunction of Semicoherent FAPbBr3/Bi2WO6 Interface for Photoredox Reaction with Large Driving Force.

Metal halide perovskites with direct band gap and strong light absorption are promising materials for harvesting solar energy; however, their relatively narrow band gap limits their redox ability when used as a photocatalyst. Adding a second semiconductor component with the appropriate band structure offsets can generate a Z-scheme photocatalytic system, taking full advantage of the perovskite's intrinsic properties. In this work, we develop a direct Z-scheme photocatalyst based on formamidinium lead bromide and bismuth tungstate (FAPbBr3/Bi2WO6) with strong redox ability for artificial solar-to-chemical energy conversion. With desirable band offsets and strong joint redox potential, the dual photocatalyst is shown to form a semicoherent heterointerface. Ultrafast transient infrared absorption studies employing selective excitation reveal synergetic photocarrier dynamics and demonstrate Z-scheme charge transfer mechanisms. Under simulated solar irradiation, a large driving force photoredox reaction (∼2.57 eV) of CO2 reduction coupled with benzyl alcohol oxidation to benzaldehyde is achieved on the Z-scheme FAPbBr3/Bi2WO6 photocatalyst, harnessing the full synergetic potential of the combined system.

The application of asymmetric transmission in daytime radiative cooling cannot increase the cooling power

Recently, the asymmetric transmission has been employed to enhance the cooling power of daytime radiative cooler [Wong et al., Solar Energy Materials and Solar Cells 2018, 186: 330–339]. we argue here that the radiative cooling power cannot be improved by integrating the radiative cooler with an asymmetric electromagnetic transmission device. The reason is that the equivalence between the absorption and emission of the whole structure cannot be broken by adding the asymmetric transmission device. The theoretical analyses are provided to tackle this problem. The scattering matrix method is used to prove that the asymmetric transmission can be realized in reciprocal materials only when there is mode-to-mode conversion. However, the ray tracing method did not take the mode-to-mode conversion into account in Wong's paper, thus the absorption and emission of the whole structure could not be accurately calculated. We believe this work can prevent researchers from advancing in the improper way.

An experimental study of a nearly perfect absorber made from a natural hyperbolic material for harvesting solar energy

In this paper, the absorptance of a broadband nearly perfect absorber, consisting of a metal surface covered by a rough Bi2Te3 layer, was measured and the optical properties of such a sample are calculated by using the finite-difference time-domain (FDTD) method. The results show that the measured absorptance of a designed sample with a roughness of 794 nm is larger than 0.94 in the wavelength range of 380–1800 nm, which can also be validated and explained by the calculated results. However, the absorptance of the absorber is affected by the morphology of the Bi2Te3 layer, including the roughness and the bottom width of the Bi2Te3 nanostructures. It is shown that the calculated absorptance of the absorber increases with the increasing roughness of the Bi2Te3 layer made of sharp nanostructures (with increasing cross section in the direction of incident light) if the bottom width of the Bi2Te3 nanostructures is fixed. However, the absorptance of the absorber decreases with the increase of the bottom width of Bi2Te3 nanostructures for absorbers with the same roughness. The underlying mechanisms for perfect absorbers are owing to the slow-light effect and gradient index effect, which require tall nanostructures with suitable bottom width for the total absorption of electromagnetic (EM) waves in the solar wavelength range. Furthermore, different samples were fabricated by using an electrochemical reaction method, and the measured absorption properties of these samples are shown in good agreement with calculated results.

Special Issue: “Advanced Thin Film Materials for Photovoltaic Applications”

Photovoltaic (PV) technology is rapidly entering the energy market, providing clean energy for sustainable development in society, reducing air pollution. In order to accelerate the use of PV solar energy, both an improvement in conversion efficiency and reduction in manufacturing cost should be carried out continuously in the future. This can be achieved by the use of advanced thin film materials produced by low-cost growth techniques in novel device architectures. This effort intends to provide the latest research results on thin film photovoltaic solar energy materials in one place. This Special Issue presents the growth and characterisation of several PV solar energy materials using low-cost techniques to utilise in new device structures after optimisation. This will therefore provide specialists in the field with useful references and new insights into the subject. It is hoped that this common platform will serve as a stepping-stone for further development of this highly important field.

Comment on “towards high-efficiency industrial p-type mono-like Si PERC solar cells” [solar energy materials & solar cells volume 204, January 2020, 110202

We show that the data of external quantum efficiency (EQE) reported in the paper in title are measured at illuminated metal front contacts and the data of external reflectance (R) reported in the same paper are measured at not illuminated metal front contacts. Such inconsistency prevents the simulation programs Quokka 2 and PC1D from fitting the reported EQE-data by using the R-data reported in the paper in title. The reported EQE-data can be fitted by using an effective reflectance including the reflectance of metal front contacts. The need of determining curves of effective reflectance can be avoided by providing EQE- and R-curves that are consistent with each other.

Accelerated Development of Refractory Nanocomposite Solar Absorbers using Bayesian Optimization

ABSTRACTMachine learning-based approach is desired for accelerating materials design, development and discovery in combination with high-throughput experiments and simulation. In this work, we propose to apply a Bayesian optimization method to design ultrathin multilayer tungsten-silicon carbide (W-SiC) nanocomposite absorber for high-temperature solar power generation. Based on a semi-analytical scattering matrix method, the design of spectrally selective absorber is optimized over a variety of layer thicknesses to maximize the overall solar absorptance. Our nanofabrication and experimental characterization results demonstrate the capability of the proposed approach for accelerated development of refractory light-absorbing materials. Comparison with other global optimization methods, such as random search, simulated annealing and particle swarm optimization, shows that the Bayesian optimization method can expedite the design of multilayer nanocomposite absorbers and significantly reduce the development cost. This work sheds light on the discovery of novel materials for solar energy and sustainability applications.

Probing Nonequilibrium Dynamics of Photoexcited Polarons on a Metal-Oxide Surface with Atomic Precision.

Understanding the nonequilibrium dynamics of photoexcited polarons at the atomic scale is of great importance for improving the performance of photocatalytic and solar-energy materials. Using a pulsed-laser-combined scanning tunneling microscopy and spectroscopy, here we succeeded in resolving the relaxation dynamics of single polarons bound to oxygen vacancies on the surface of a prototypical photocatalyst, rutile TiO_{2}(110). The visible-light excitation of the defect-derived polarons depletes the polaron states and leads to delocalized free electrons in the conduction band, which is further corroborated by abinitio calculations. We found that the trapping time of polarons becomes considerably shorter when the polaron is bound to two surface oxygen vacancies than that to one. In contrast, the lifetime of photogenerated free electrons is insensitive to the atomic-scale distribution of the defects but correlated with the averaged defect density within a nanometer-sized area. Those results shed new light on the photocatalytically active sites at the metal-oxide surface.

Feature issue introduction: Optical Devices and Materials for Solar Energy and Solid-state Lighting (PVLED) 2019.

This special feature issue of Optics Express highlights contributions from authors who presented their latest research in the Optical Devices and Materials for Solar Energy and Solid-state Lighting (PVLED) topical meeting of the OSA Advanced Photonics Congress, held in Burlingame, California, from 29 July - August 1, 2019. This feature issue is comprised of nine contributed papers, expanding upon their respective conference proceedings to cover timely research topics applying optics and photonics to solar energy and solid-state lighting.