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Photovoltaic devices are expected to display peak performance if fabricated with perfect single crystals. Since surfaces break the periodicity of a single crystal, there are regions of defects, which give rise to states inside the forbidden energy gap. In polycrystalline thin films, the main structural defect is the grain boundary. The presence of grain boundaries affects the optical absorption, carrier mobility and lifetime of the semiconductor. This review focuses on grain boundary passivation in thin film photovoltaic devices based on copper chalcogenides. Achieving enhanced performance in copper chalcogenide thin film Photovoltaic devices requires effective grain boundary passivation. This approach aims to mitigate the adverse effects of grain boundaries on the optoelectronic properties of the material, leading to improved efficiency and stability in Photovoltaic devices. The abstract discusses recent developments, methodologies and outcomes related to grain boundary passivation strategies, shedding light on their significance in advancing the performance of copper chalcogenide thin film Photovoltaic devices. The exploration of grain boundary passivation in this context contributes valuable insights to the ongoing efforts in optimizing the performance of thin film Photovoltaic technologies.

Metal chalcogenide copper sulfide nanoparticles exhibit a broad spectrum of applications, encompassing solar cells, photovoltaics, optical devices, ionic materials and more. In this investigation, CuS nanoparticles were synthesized through a facile co-precipitation method. The synthesis involved employing copper sulfate and thiourea as precursors for Cu and S, respectively. Quantitative analysis, confirming the presence of Cu–S and S–S bonds, was conducted through Raman spectroscopy. X-ray diffraction (XRD) was employed to ascertain the structural phases. The semiconducting behavior of the synthesized CuS nanoparticles was studied through UV–Vis spectroscopy, correlating optical absorption and energy bandgap. The comprehensive findings suggest that the prepared CuS nanoparticles hold promise for advancements in photovoltaic technology and optical devices.

With the help of the SCAPS simulation program, this study investigates the possible buffer layer in copper zinc tin sulfide (CZTS)/zinc oxide (ZnO) thin-film solar cells. The tin sulfide (SnS${}_2)$ and cadmium sulfide (CdS) are taken into consideration. Based on electronic band structure analysis, SnS₂ exhibits a more favorable alignment of the conduction band than CZTS, which minimizes the barrier to energy transfer. SnS₂ buffer layer showed enhanced carrier generation because of its higher absorption coefficient. Quantum efficiency plots highlighted SnS₂’s superior performance in the 400–800nm range, where CZTS strongly absorbs. The ${\mathrm{\text{SnS}}}_2$ buffer layer solar cell exhibited a larger J–V curve area, driven by a higher short-circuit current density ($J_{\mathrm{\text{sc}}}$.) of 24.27mA/cm² compared to 23.69mA/cm² for CdS, achieving an impressive 15.71% efficiency versus 15.35% for CdS. Because of improved band alignment, enhanced charge generation and higher quantum efficiency, ${\mathrm{\text{SnS}}}_2$ is proving to be a promising buffer layer for high-efficiency CZTS solar cells.

Halide perovskite materials such as FAPbI3 are of great interest for photovoltaic applications and could replace silicon cells if problems of chemical instability, strain and crystal defects are solved. In this paper we present a preliminary modeling study of lattice relaxation in epitaxial FAPbI₃ on MAPbCl_xBr_3-x (001).

Recent trends of photovoltaics account for the conversion efficiency limit making them more cost effective. To achieve this we have to leave the golden era of silicon cell and make a path towards III–V compound semiconductor groups to take advantages like bandgap engineering by alloying these compounds. In this work we have used a low bandgap GaSb material and designed a single junction (SJ) cell with a conversion efficiency of 32.98%. SILVACO ATLAS TCAD simulator has been used to simulate the proposed model using both Ray Tracing and Transfer Matrix Method (under 1 sun and 1000 sun of AM1.5G spectrum). A detailed analyses of photogeneration rate, spectral response, potential developed, external quantum efficiency (EQE), internal quantum efficiency (IQE), short-circuit current density (J${}_{\mathrm{\text{SC}}}$), open-circuit voltage (V${}_{\mathrm{\text{OC}}}$), fill factor (FF) and conversion efficiency ($\eta$) are discussed. The obtained results are compared with previously reported SJ solar cell reports.

In this work, spatially resolved characterization methods are used to identify loss mechanisms for common $p$-type silicon solar cell architectures, including multicrystalline aluminum back surface field (Al-BSF), monocrystalline Al-BSF, monocrystalline passivated emitter and rear cells (PERC), and bifacial monocrystalline PERC. The characterization methods used in this work include suns-$V_{\mathrm{\text{OC}}}$, photoluminescence imaging, and spatially resolved external quantum efficiency and reflectance measurements. The optical and recombination losses are driven by the material properties, cell processing conditions, and device architecture. These losses are quantified and categorized in terms of underlying mechanisms (e.g., front reflectance, escape reflectance, front recombination, and parasitic optical absorption and recombination in the bulk and rear). The ability to create images of these loss parameters can be used to gain more insight into the materials and manufacturing processes used to produce solar cells, and examples are given in this work to illustrate how these images can help reveal the origin of defects.

There is intensive research by the community to improve materials for renewable energy applications such as hydrogen production, photovoltaics and light-emitting diodes. Titanium dioxide (TiO₂) is an important material where we can improve its fundamental properties, through doping aiming to form more efficient devices. Here, we use electronic structure calculations based on density function theory (DFT) to explore the effect of dopants, such as boron (B), germanium (Ge), molybdenum (Mo), and tungsten (W), on the structural and electronic properties of TiO₂. We investigated both the interstitial and the oxygen substitutional positions, and for the minimized energy optimized structures, we used hybrid DFT calculations to predict the electronic properties through the density of states, which proved costly but not as much to outweigh their advantage in accuracy. For most cases considered, the dopants reduce the theoretical bandgap of TiO₂, while gap states form. The variation of the bandgap ranges from a very small increase of 0.04eV to a significant decrease of 0.8eV, while the exact “position” of new gap states differs for each type of dopant and for its “spot” in the crystalline structure. It is proposed that these states and the change of the bandgap contribute to the significant changes in the optical and electronic properties of TiO₂ and can be beneficial to the photovoltaic and photocatalytic applications of TiO₂ and its implementation for hydrogen production.

We present and discuss a mathematical model for the operation of bilayer organic photovoltaic devices. Our model couples drift–diffusion–recombination equations for the charge carriers (specifically, electrons and holes) with a reaction–diffusion equation for the excitons/polaron pairs and Poisson's equation for the self-consistent electrostatic potential. The material difference (i.e. the HOMO/LUMO gap) of the two organic substrates forming the bilayer device is included as a work-function potential. Firstly, we perform an asymptotic analysis of the scaled one-dimensional stationary state system: (i) with focus on the dynamics on the interface and (ii) with the goal of simplifying the bulk dynamics away from the interface. Secondly, we present a two-dimensional hybrid discontinuous Galerkin finite element numerical scheme which is very well suited to resolve: (i) the material changes, (ii) the resulting strong variation over the interface, and (iii) the necessary upwinding in the discretization of drift–diffusion equations. Finally, we compare the numerical results with the approximating asymptotics.

Renewed interest has brought significant attention to tune coherently the electronic and optical properties of hybrid organic–inorganic perovskites (HOIPs) in recent years. Tailoring the intimate structure–property relationship is a primary target toward the advancement of light-harvesting technologies. These constructive progresses are expected to promote staggering endeavors within the solar cells community that needs to be revisited. Several considerations and strategies are introduced mainly to illustrate the importance of structural stability, interfacial alignment, and photo-generated carriers extraction across the perovskite heterostructures. Here, we review recent strides of such vast compelling diversity in order to shed some light on the interplay of the interfacial chemistry, photophysics, and light-emitting properties of HOIPs via molecular engineering or doping approach. In addition, we outline several fundamental knowledge processes across the role of charge transfer, charge carrier extraction, passivation agent, bandgap, and emission tunability at two-dimensional (2D) level of HOIPs/molecule heterointerfaces. An extensive range of the relevant work is illustrated to embrace new research directions for employing organic molecules as targeted active layer in perovskite-based devices. Ultimately, we address important insights related to the physical phenomena at the active molecules/perovskites interfaces that deserve careful considerations. This review specifically outlines a comprehensive overview of surface-based interactions that fundamentally challenges the delicate balance between organic materials and perovskites, which promotes bright future of desired practical applications.

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Lead-based nanocrystals (NCs) are promising materials for high-efficiency solar cells since they are able to generate multiexcitons with high efficiency. One complication of utilizing these NCs is the insulating ligands capping their surfaces. In this paper, we have successfully developed and characterized a phosphonate-functionalized poly-3-hexylthiophene (POP3HT-50) and used it in the direct synthesis of PbS NCs within the polymeric host matrix without extraneous ligands. Devices made of POP3HT-50/PbS nanocomposites show an order of magnitude improvement in η when compared to that reported for a P3HT/PbS device (η = 0.011% versus 0.001%). The improved performance is consistent with better electronic contact between PbS NCs and POP3HT-50.

Photoconductive and photovoltaic properties of film composites based on poly-$N$-epoxypropylcarbazole doped with a derivative of nickel dithiolene are investigated. These composites possess a hole-type photoconductivity. The internal photoeffect is attributed to the photogeneration of charge carriers from the metal complex and the hole transport through the donor fragments of the polymer matrix.

The triphenylamine (TPA), thiophene and pyrimidine are being used as efficient advanced functional semiconductor materials. In the present study, some new TPA donor–π–acceptor derivatives were designed where TPA moiety acts as donor, thiophene-pyrimidine π-bridge and acetic/cyanoacetic acid as acceptor. The ground-state geometries were optimized at B3LYP/6-31G** level of theory. The excitation energies and oscillator strengths were computed at TD-CAM-B3LYP/6-31G** (polarizable continuum model (PCM), in methanol) level of theory. The electronic, photophysical and charge transport properties were calculated wherever possible the computed values were compared with the available experimental as well as computational data. The electron injection (ΔG^inject), relative electron injection , electron coupling constants (∣V_RP∣) and light harvesting efficiencies (LHE) have been calculated and compared with referenced compounds. The energies of the lowest unoccupied molecular orbitals (E_LUMOs), diagonal bandgaps and energy level offsets were studied to shed light on the electron transport behavior. The effect of anchoring groups (acetic acid and cyanoacetic acid) was studied on the properties of interests in the dye and dye@Ti₆O₁₂. It was observed that after interaction of dye with the TiO₂ cluster intra-molecular charge transport enhanced from HOMO of the dye to LUMO of the semiconductor cluster. The cyanoacetic acid anchoring group leads the superior LHE, ΔG^inject and ∣V_RP∣ which might improve the solar cell performance.

The preparation and spectroscopic properties of a series of metallocorroles with polar head groups CHO and CH=C(CN)(COOH) are reported, as well as the X-ray crystal structure of 5,10,15-tris(pentafluorophenyl)corrolatoaluminium(III)bispyridine (triclinic space group (P-1) with unit cell parameters: a = 9.426(1) Å; b = 13.202(1) Å; c = 19.936(1) Å; α = 74.19(1)°; β = 78.47(1)°; γ = 75.75(1)°; V = 2289.57(8) ų). Amphiphilic aluminium(III) and gallium(III) corroles exhibit electronic absorption (Soret peaks between 410 and 448 nm; Q-bands between 584 and 638 nm) and fluorescence (band maxima between 634 and 706 nm) at lower energies than their hydrophobic analogs.

The importance and complexity of energy and electron transfer reactions in biological and artificial light energy conversion systems have prompted the preparation and photophysical study of donor-acceptor (D-A) molecular models. This article aims to highlight the efforts of Portuguese and Spanish research groups on the design, synthesis and photophysical study of molecular and supramolecular donor-acceptor systems based on phthalocyanines, subphthalocyanines and porphyrins.

A series of core-modified porphyrins with different meso aryl groups (R₁), anchoring groups (R₂), and core atoms (X) were studied as light-harvesting sensitizers for dye-sensitized solar cells (DSSCs). DSSCs were fabricated using these porphyrins as well as TiO₂ nanoparticles with a particle diameter of around 25 nm. A dense layer of TiO₂ was deposited as an interfacial layer on fluorine-doped tin dioxide (FTO) substrates. A TiO₂ nanocrystalline film was then deposited on the dense layer by spin coating. The comparison of DSSC performance from different core-modified porphyrins was studied. The UV-vis absorption spectroscopy of porphyrin films attached on TiO₂ and porphyrin solutions were also measured. The results indicated that both anchoring and meso aryl groups impacted on cell performance. The cell efficiency was correlated to the absorption of porphyrin films attached on TiO₂ at the Soret band.

This review summarizes recent advances in the use of porphyrins, phthalocyanines, and related compounds as components of solar cells, including organic molecular solar cells, polymer cells, anddye-sensitized solar cells. The recent report of a porphyrin dye that achieves 11% power conversion efficiency in a dye-sensitized solar cell indicates that these classes of compounds can be as efficient as the more commonly used ruthenium bipyridyl derivatives.

A saddle-distorted porphyrin bearing a carboxyl group as a hydrogen-bonding site on a meso-phenyl group was synthesized and characterized. A supramolecular structure with intermolecular hydrogen bonding was revealed by X-ray diffraction analysis. The effects of the peripheral carboxyl group on the physicochemical properties of the porphyrin as well as on self-assembly were investigated by spectroscopic measurements in solutions. The redox properties of the porphyrin and its Zn(II) complex were also studied by electrochemical measurements and their application to dye-sensitized solar cells was examined.

We designed and synthesized anthryl-disubstituted magnesium tetraethynylporphyrin([{5,15-bis(anthracen-9′-yl)ethynyl}-10,20-bis{(triisopropylsilyl)ethynyl}porphyrinato] magnesium(II)), and applied it as an electron donor to solution-processed bulk heterojunction small molecule organic solar cells. The compound was characterized by single crystal X-ray crystallography as well as UV-vis light absorption spectrum showing the absorption maximum and onset at 700 and 740 nm, respectively. Organic solar cells using this compound and [6,6]-phenyl-C61-butyric acid methyl ester (PC₆₁BM) as electron donor and acceptor, respectively, showed power conversion efficiency of 1.31% at the donor and acceptor ratio of 1:3. The use of pyridine as a coordinating additive increased power conversion efficiency to 1.61%, which was the best among tested additives, THF, pyradine, dioxane, and 1,8-diiodooctane.

We synthesized a diporphyrin compound [4,7-bis[5-[arylethynyl]-10,20-bis{(triisopropylsilyl)ethynyl}porphyrin-15-yl]]-2,1,3-benzothiadiazole dimagnesium(II)], in which two porphyrin units were linked using a benzodiathiazole unit as an electron-withdrawing moiety. These diporphyrins have low-lying HOMO and LUMO levels with long-wavelength light absorption property. Power conversion efficiency of the organic solar cell using this diporphyrin and mix-PCBM (a 85:15 mixture of [6,6]-phenyl-C₆₁-butyric acid methyl ester (PC₆₁BM) and [6,6]-phenyl-C₇₁-butyric acid methyl ester (PC₇₁BM) was 2.75% with short-circuit current density of 8.79 mA/cm², open-circuit voltage of 0.80 V, and fill factor of 0.39. Photocurrent conversion in the near infrared region was demonstrated by the incident photon-to-current efficiency spectrum.