Application In Photovoltaic Cells Research Articles

Polymer Based Functional Materials: A New Generation Photo‐active Candidate for Electrochemical Application

AbstractThis article reviews the successive development of photo‐assisted electrochemical performances using functionalized polymer materials. The photoelectrochemical technologies have already been well‐established as a major tool for generating renewable energy harvesting solar power. In this regard, the research on the generation of new photoactive polymer supported units has drawn remarkable attention to improve the power conversion output and build up low‐cost advanced devices. So, starting from fundamental working principle, we have tried to overview comprehensively the key features of most of these studies, which involve the tactical schemes behind the appropriate selection of different substituents to functionalize the polymer skeleton to achieve an optimal bandgap, challenges faced specially in the index of performance in post synthetic phase, the possible routes to overcome the hurdle, so that it can harvest photons matched with the solar spectrum and of course their relevance in the broad range of application window. Apart from photovoltaic solar cell application, the idea has been logically extended to cover highly selective photoelectrochemical sensing devices,where we have disclosed briefly the role of polymers in designing innovative biosensors, the trend of development along with specific illustrative examples, and some of their successful utilization in real time assay. The overall description is entirely focused on how these strategies have emerged from the background concepts and finally shaped to a viable and significant outcome.

Electric field and strain engineering tuning Rashba spin splitting in quasi-one-dimensional organic-inorganic hybrid perovskites (MV)AI3Cl2 (MV = methylviologen, A = Bi, Sb).

We systematically study the Rashba spin texture of lead-free quasi-one-dimensional organic-inorganic hybrid perovskites (OIHP), (MV)AI3Cl2 (MV = methylviologen, A = Bi, Sb) with first-principles calculations. The kx-ky plane Rashba spin splitting was found to depend on the composition of Bi (Sb) and I atoms at band edges. Importantly, increasing ferroelectric polarization and the stretch along the z-direction can effectively enhance the amplitude of the Rashba spin splitting. This work provides an avenue for electric field and strain-controlled spin splitting and highlights the potential of quasi-one-dimensional OIHP for further applications in spin field effect transistors and photovoltaic cells.

Spectroscopic study of D1–A–D2–A terpolymer films for optoelectronic applications

Several strategies have been considered in search of more efficient organic materials for charge transfer in photovoltaic devices. Among them, the integration of donor-acceptor (D-A) functional units on a conjugated copolymer has been widely applied. In this framework, we evaluated four terpolymers made up of donor moieties derived from 9,9-dioctylfluorene and 9-(heptadecan-9-yl)-9H-carbazole combined with 2,1,3-benzothiadiazole, the acceptor moiety, in different monomer ratios and polymerization routes (block and random microstructures). The preferred molecular orientation and charge transfer dynamics of the polymeric films were assessed by near edge X-ray absorption fine structure spectroscopy (NEXAFS) and resonant Auger electron spectroscopy (RAES) around the sulfur K-edge. Charge transfer times (τCT) were estimated by the Core-Hole Clock (CHC) method. Films with a high degree of organization were identified for the block terpolymer and random terpolymers with uneven amounts of donor units, showing a preferred orientation of the benzothiadiazole (BT) molecular plane parallel to the substrate surface. The values of τCT measured for all terpolymers were higher than those for typical polymers used in photovoltaic devices, which is not desirable for this type of optoelectronic application, but this may be correlated to the strong acceptor character of BT, the unit probed. To investigate the effect of film formation on the excited state behavior, steady-state and time-resolved photoluminescence measurements were also conducted. X-ray photoelectron spectroscopy (XPS) was employed to characterize the surface chemical composition of the terpolymer films. Based on the spectroscopic data the block copolymer appears to be the most suitable for the desired application.

DFT investigation of the electronic and optical properties of hexagonal MX2/ZrXO (M = W, Mo and X = S, Se) van der Waals heterostructures for photovoltaic solar cell application.

The van der Waals heterostructure of Janus materials with a TMD monolayer was used to create a two-dimensional class of nanomaterials for photovoltaic solar cell applications. It is one of the potential methods for enhancing the performance of photovoltaic systems. Two monolayers of different 2D materials, Janus (ZrXO) and TMDs (MX2), are stacked together to form the heterojunction. Based on density functional theory structural, electrical, and optical properties were investigated. The favorable stacking and stability of the MX2/ZrXO (M = W, Mo and X = S, Se) van der Waals heterostructures are confirmed through binding energies, phonon dispersion and ab initio molecular dynamics calculations. Standard excitonic peaks, which correspond to the bound valence-band hole and conduction-band electron, as well as excitonic peaks involving the mid-gap charges, can be seen in the system's computed absorption spectrum. MX2/ZrXO van der Waals heterostructures are excellent photovoltaic candidates with a maximum achived power conversion efficiency of above 22%. Furthermore, we discovered that the heterostructure materials have a high absorption efficiency which is good for the intended photovoltaic solar cell application.

Optimization design of uncertain parameters for improving the stability of photovoltaic system

The uncertainty of photovoltaic module material parameters have a great impact on the overall output performance of photovoltaic cells. Ignoring the uncertainty of these parameters results in low reliability in photovoltaic cell applications. In this study, the deterministic and robust optimization design of photovoltaic cells was demonstrated by considering the randomness of the actual working environment of photovoltaic cells and the interval uncertainty of material properties of photovoltaic components, and by using the theoretical efficiency of photovoltaic cells as constraint. The corresponding parameter values were obtained after optimization, and the optimization results are analyzed with Monte Carlo simulations. Making parameters after deterministic optimization obey the normal distribution, and the parameter value obtained after optimization is the mean value, then compared with the robust optimization. It can be concluded that compared with the traditional deterministic design, the mean value of the constraint conditions after robust optimization is far removed from the upper limit, the standard deviation is smaller, and the failure probability is far less than that after setting variables through deterministic optimization. Based on these findings, the influence of the uncertain factors can be reduced, the output is more reliable, and the performance optimization of photovoltaic cells can be provided guidance.

Fluorination of single-walled carbon nanotubes and their application in organic photovoltaic cells as an electron acceptor

Fluorination of single-walled carbon nanotubes and their application in organic photovoltaic cells as an electron acceptor

Organic Thin Films Deposited by Matrix-Assisted Pulsed Laser Evaporation (MAPLE) for Photovoltaic Cell Applications: A Review

Human society’s demand for energy has increased faster in the last few decades due to the world’s population growth and economy development. Solar power can be a part of a sustainable solution to this world’s energy need, taking into account that the cost of the renewable energy recently dropped owed to the remarkable progress achieved in the solar panels field. Thus, this inexhaustible source of energy can produce cheap and clean energy with a beneficial impact on the climate change. The considerable potential of the organic photovoltaic (OPV) cells was recently emphasized, with efficiencies exceeding 18% being achieved for OPV devices with various architectures. The challenges regarding the improvement in the OPV performance consist of the selection of the adequate raw organic compounds and manufacturing techniques, both strongly influencing the electrical parameters of the fabricated OPV devices. At the laboratory level, the solution-based techniques are used in the preparation of the active films based on polymers, while the vacuum evaporation is usually involved in the deposition of small molecule organic compounds. The major breakthrough in the OPV field was the implementation of the bulk heterojunction concept but the deposition of mixed films from the same solvent is not always possible. Therefore, this review provides a survey on the development attained in the deposition of organic layers based on small molecules compounds, oligomers and polymers using matrix-assisted pulsed laser evaporation (MAPLE)-based deposition techniques (MAPLE, RIR-MAPLE and emulsion-based RIR-MAPLE). An overview of the influence of various experimental parameters involved in these laser deposition methods on the properties of the fabricated layers is given in order to identify, in the forthcoming years, new strategies for enhancing the OPV cells performance.

On an iridescent film of carbon nitride grown on an aluminum sheet and composed of overlapped oak-leaf shaped nanoparticles

An iridescent carbon nitrogen film g-C3N4 was formed by chemical vapor deposition (CVD) on an aluminum sheet starting from melamine cyanurate as a precursor at a temperature of 600 °C. The film was easily detached and thoroughly characterized using various techniques, including X-ray powder diffraction, UV − Vis and infrared spectroscopies, and field emission scanning microscopy. The material exhibited a particular layered microstructure consisting of stacks of nano-/micro-sized oak-leaf-shaped particles. The UV − Vis spectrum exhibited two defined bands corresponding to localized electrons; however, the apparent direct bandgap was 3.1 eV, similar to that of bulk g-C3N4. The IR spectrum was similar to that of bulk material, with differences in band intensities of the bending zone of tri-s-triazine units, in the range of 900 − 800 cm−1. The 2 D unfolding of the material with the formation of a thin layer composed of oak-leaf-like particles led to structural iridescent colors. For this reason, applications in optoelectronics and photovoltaic cells based on thin films prepared by the reported synthesis route may be envisaged, taking advantage of the properties of structural colors.

Work Function Extraction of Transparent Conducting Indium Oxide Films Used As Gate Electrode for MOSFET

Indium Oxide (In2O3) has received a great deal of attention recently as a transparent conducting oxide (TCO) semiconductor that finds applications in photovoltaic solar cells, transparent windows [1] and flat panel displays due to its high electrical conductivity and good optical transparency in the visible region [2]. It is critical to understand the work function (WF) of a material since it is an important characteristic which has an impact on the device performance.In this work, WF of In2O3 has been estimated by fabricating n-Metal Oxide Semiconductor Field Effect Transistor (NMOSFET). Fabrication of two MOSFET devices has been carried out using four-level mask. The source and drain contacts for both the devices have been prepared by using Aluminum metal. The gate contact for one of the MOSFET devices was prepared using Aluminum metal and transparent conducting In2O3 is used as the gate contact for the second MOSFET. Aluminum deposition was carried out using thermal evaporation technique. A 2-inch copper-backed indium target is used to deposit thin films of In2O3 by RF magnetron sputtering and varying the oxygen gas flow. The substrate temperature is held constant at room temperature. Electrical characterization is performed on the fabricated MOSFETs which is further used in extracting the WF of In2O3 thin films. Timo Jäger, Yaroslav E. Romanyuk, Shiro Nishiwaki, Benjamin Bissig, Fabian Pianezzi, Peter Fuchs, Christina Gretener, Max Döbeli, and Ayodhya N. Tiwari , "Hydrogenated indium oxide window layers for high-efficiency Cu(In,Ga)Se2 solar cells" , Journal of Applied Physics 117, 205301 (2015)Min-Suk Lee, Won Chel Choi, Eun Kyu Kim, Chun Keun Kim, Suk-Ki Min, Characterization of the oxidized indium thin films with thermal oxidation, Thin Solid Films, Volume 279, Issues 1–2, 1996, Pages 1-3, ISSN 0040-6090.

Prospect of single and coupled heterojunction solar cells based on n-MoS2 and n-WS2

A novel structure is proposed for single heterojunction solar cells based on n-type molybdenum disulfide (MoS2) and tungsten disulfide (WS2) deposited on p-type silicon substrate using thermal chemical vapor deposition. Moreover, the coupled heterostructures namely MoS2/WS2 and WS2/MoS2 are prepared by the same method. The main aim of this study is to evaluate the photovoltaic characteristics of the proposed heterojunction solar cells. For this purpose, various characterization techniques namely X-ray diffraction, field emission scanning electron microscopy, diffuse reflectance and Raman spectroscopies are employed. XRD patterns confirm MoS2 and WS2 layers form in hexagonal structures. Furthermore, DRS and Raman spectroscopy confirm the formation of few layers of MoS2, WS2, MoS2/WS2 and WS2/MoS2 heterostructures. The greatest power conversion efficiency (PCE) is obtained for the proposed solar cell fabricated based on MoS2 on p-type Si as single junction. This approach has suitable scientific input for application in photovoltaic cells and optoelectronic devices.

Loss mechanisms in CZTS and CZTSe Kesterite thin-film solar cells: Understanding the complexity of defect density

Kesterite materials Cu2ZnSn(SxSe1−x)4, Cu2ZnSnS4 and Cu2ZnSnSe4 have received considerable attention as absorber layers for photovoltaic cell applications. But they exhibit efficiencies lower than 12%. In this work, different possible loss mechanisms that affect the solar cell performance are analysed. Numerical investigation is made on the influence of different loss mechanisms such as radiative recombination, presence of traps and defect densities on the performance of the device. A comparative between results on solar cells based on Cu2ZnSnS4 and Cu2ZnSnSe4 absorber layers is presented. The recombination mechanisms are found to play a vital role in degrading the performance of the solar cell. Additionally, trap centers and density of defect states are distributed to the absorber layer. It is observed that efficiency of the solar cell is severely affected and degraded by 10 % in the presence of defect states.

Large bulk photovoltaic effect and second-harmonic generation in few-layer pentagonal semiconductors PdS2 and PdSe2

Recently, atomically thin PdSe2 semiconductors with rare pentagonal Se–Pd–Se monolayers were synthesized and were also found to possess superior properties such as ultrahigh air stability, tunable band gap and high carrier mobility, thus offering a new family of two-dimensional (2D) materials for exploration of 2D semiconductor physics and for applications in advanced opto-electronic and nonlinear photonic devices. In this work, we systematically study the nonlinear optical (NLO) responses [namely, bulk photovoltaic effect (BPVE), second-harmonic generation (SHG) and linear electric-optic (LEO) effect] of noncentrosymmetric bilayer (BL) and four-layer PdS2 and PdSe2 by applying the first-principles density functional theory with the generalized gradient approximation plus scissors-correction. First of all, we find that these few-layer PdX 2 (X = S and Se) exhibit prominent BPVE. In particular, the calculated shift current conductivity is in the order of 130 μA V−2, being very high compared to known BPVE materials. Similarly, their injection current susceptibilities are in the order of 100 × 108 A V−2 s−1, again being large. Secondly, the calculated SHG coefficients (χ (2)) of these materials are also large, being one order higher than that of the best-known few-layer group 6B transition metal dichalcogenides. For example, the maximum magnitude of χ (2) can reach 1.4 × 103 pm V−1 for BL PdSe2 at 1.9 eV and 1.2 × 103 pm V−1 at 3.1 eV for BL PdS2. Thirdly we find significant LEO coefficients for these structures in the low photon energy. All these indicate that 2D PdX 2 semiconductors will find promising NLO applications in light signal modulators, frequency converters, electro-optical switches and photovoltaic solar cells. Fourthly, we find that the large BPVE and SHG of the few-layer PdX 2 structures are due to strong intralayer directional covalent bonding and also 2D quantum confinement. Finally, we also discuss the prominent features of these NLO spectra of these materials in terms of their electronic structure and optical dielectric functions.

Single‐Junction Organic Photovoltaic Cell with 19% Efficiency

Improving power conversion efficiency (PCE) is important for broadening the applications of organic photovoltaic (OPV) cells. Here, a maximum PCE of 19.0% (certified value of 18.7%) is achieved in single-junction OPV cells by combining material design with a ternary blending strategy. An active layer comprising a new wide-bandgap polymer donor named PBQx-TF and a new low-bandgap non-fullerene acceptor (NFA) named eC9-2Cl is rationally designed. With optimized light utilization, the resulting binary cell exhibits a good PCE of 17.7%. An NFA F-BTA3 is then added to the active layer as a third component to simultaneously improve the photovoltaic parameters. The improved light unitization, cascaded energy level alignment, and enhanced intermolecular packing result in open-circuit voltage of 0.879V, short-circuit current density of 26.7mA cm-2 , and fill factor of 0.809. This study demonstrates that further improvement of PCEs of high-performance OPV cells requires fine tuning of the electronic structures and morphologies of the active layers.

Room-Temperature Halide Perovskite Field-Effect Transistors by Ion Transport Mitigation.

Solution-processed halide perovskites have emerged as excellent optoelectronic materials for applications in photovoltaic solar cells and light-emitting diodes. However, the presence of mobile ions in the material hinders the development of perovskite field-effect transistors (FETs) due to screening of the gate potential in the nearby perovskite channel, and the resulting impediment to achieving gate modulation of an electronic current at room temperature. Here, room-temperature operation is demonstrated in cesium lead tribromide (CsPbBr3 ) perovskite-based FETs using an auxiliary ferroelectric gate of poly(vinylidenefluoride-co-trifluoroethylene) [P(VDF-TrFE)], to electrostatically fixate the mobile ions. The large interfacial polarization of the ferroelectric gate attracts the mobile ions away from the main nonferroelectric gate interface, thereby enabling modulation of the electronic current through the channel by the main gate. This strategy allows for realization of the p-type CsPbBr3 channel and revealing the thermally activated nature of the hole charge transport. The proposed strategy is generic and can be applied for regulating ions in a variety of ionic-electronic mixed semiconductors.

Tuning Bandgaps of Mixed Halide and Oxide Perovskites CsSnX3 (X=Cl, I), and SrBO3 (B=Rh, Ti)

Perovskites have recently attracted interest in the field of solar energy due to their excellent photovoltaic properties. We herein present a new approach to the composition of lead free perovskites via mixing of halide and oxide perovskites that share the cubic ABX3 structure. Using first-principles calculations through Density Functional Theory, we systematically investigated the atomic and electronic structures of mixed perovskite compounds composed of four cubic ABX3 perovskites. Our result shows that the B and X atoms play important roles in their band structure. On the other hand, their valence bands contributed by O-2p, Rh-4p, and Ti-3p orbitals, and their electronic properties were determined by Rh-O and Ti-O bonds. With new understandings of the electronic properties of cubic halide or oxide perovskites, we lastly combined the cubic perovskites in various configurations to improve stability and tune the bandgap to values desirable for photovoltaic cell applications. Our investigations suggest that the mixed perovskite compound Cs2Sn2Cl3I3Sr2TiRhO6 produced a bandgap of 1.2 eV, which falls into the ideal range of 1.0 to 1.7 eV, indicating high photo-conversion efficiency and showing promise towards solar energy applications.

Optical properties of PVC composite modified during light exposure to give high absorption enhancement

Modified poly(vinyl chloride) (PVC) films have been synthesized with a simple superficial deposition by using solvent tetrahydrofuran (THF). These modified films were prepared by a casting method over a glass substrate. Different types of the amino group with a suitable aromatic aldehyde as an organic compound, which were reacted to prepare different PVC composite films. These films have been analyzed by UV-Visible spectra. The percentage of PVC was (0.25 g) with (0.05 g) amino group and aromatic aldehyde combinedly, then dissolved with (8 ml) of tetrahydrofuran (THF) at room temperature (300 K). The optical properties as absorption coefficient, reflectance, transmittance, skin depth, energy gap, refractive index, extinction coefficient, and urbach energy were studied. The transmittance value of the pure PVC film was 1.0 then declined gradually after dispersion with the compounds to the lowest value at 0.1, the reflectance also decreased. The energy gap for direct allowed decreased from (5.1 to 2.9 eV), and indirect transition decreased also from (5.0 to 2.8 eV), this behavior indicate that the modified films become work as semi-crystalline compounds toward the light. In tailoring, the optical properties, and urbach energy have been increased after mixed with PVC polymer. The scattering energy (Ed) and the effective single oscillator (Eo), were decreased. In a similar manner the dielectric constant high frequency (ε∞) and effective mass (Nm*), of dielectric constants were increased for PVC modified films. The PVC modified films are appropriate for anti-reflected coating while being good suitable in high refractive lenses and photovoltaic cells applications.

Construction of Novel Polyoxometalate/Perylenediimide Hybrid Heterostructures for Enhanced Photocatalytic Oxidation of Mustard Gas Simulants

Developing and designing novel materials for effective sulfur mustard detoxification are of great importance given their threat to human health. Crystalline donor–acceptor (D–A) hybrid heterostructures as an emerging class of materials are composed of semiconducting organic and inorganic components with enhanced charge-separated properties and thus promising applications in photocatalysis and photovoltaic cells. Herein, we demonstrated that the combination of three perylene diimide derivatives (PDIs) as electron-deficient acceptors with polyoxometalate (POM) anion [SiW12O40]4– as electron-rich donors resulted in three crystalline D–A hybrid heterostructures, namely, (Me4-PDI)2·SiW12O40 (1), (Me4-Br2-PDI)1.5·(HSiW12O40) (2), and (Me4-Cl4-PDI)2·SiW12O40 (3). Due to the considerable electrostatically assisted noncovalent interactions (lone pair−π, π–π, anion−π, and hydrogen-bonding interactions) between electron donors and acceptors, POMs, and PDIs, these hybrids displayed a significant enhancement in the photochemical stability and selective photocatalytic oxidation of the sulfur mustard simulant, 2-chloroethyl ethyl sulfide (CEES).

New series of BODIPY dyes: Synthesis, characterization and applications in photovoltaic cells and light-emitting diodes

We report on the straightforward synthesis, characterization and photovoltaic and light-emission applications of two series of BODIPY molecules with aryloxy or alkoxy groups bonded to the boron centre. The crystal structures of two of these new dyes are also presented. The BODIPYs have absorption features similar to those of the analogous boron-fluorinated BODIPYs used as starting materials. However, the fluorescence properties vary significantly with the nature of the aryloxy/alkoxy group. The photovoltaic performance in bulk heterojunction solar cells of the newly synthesized compounds does not, however, outperform that of the parent boron-fluorinated BODIPYs. The maximum power conversion efficiency was obtained with two non-fluorescent BODIPYs, reaching 0.9%, compared with 2.79% obtained for the cells based on the corresponding boron-fluorinated precursor. The fluorine replacement by aryloxy/alkoxy groups had instead a positive effect on the light-emitting properties of the compounds of one of the series, leading to higher maximum luminance (114 cd/m2) and efficiency (0.057 cd/A), compared to devices based on the corresponding boron-fluorinated dye (35 cd/m2 and 0.015 cd/A, respectively).

Formation and Characterization of Ge1–x–ySixSny/Ge Heterojunction Structures for Photovoltaic Cell Application

Group-IV alloy semiconductor materials are much attractive for photovoltaic application, as those realizes multijunction photovoltaic with multi-heterostructure like group-III-V compound semiconductors [1]. In addition, group-IV alloy materials are expected to be familiar to Si integrated electronics. Ge1–x–ySixSny is one of candidate materials suitable for multijunction photovoltaic, since ternary alloy semiconductor provides energy band design independent on the lattice constant. The energy band gap of Ge1–x–ySixSny can be controlled from 0.66 eV to 1.0 eV with the epitaxial layer whose lattice is matching to Ge substrate.We previously reported the epitaxial growth of Ge1–x–ySixSny layers and also investigated the crystalline and electronic properties of them [2, 3]. However, the junction properties of Ge1–x–ySixSny/Ge heterostructure have not been well understood and it is necessary to clarify the crystalline and electronic properties of group-IV ternary alloy hetero junctions. In this study, we examined the crystal growth of pseudomorphic epitaxial layers of Ge1–x–ySixSny ternary alloy on Ge(001) substrates to form heterojunction structure for photovoltaic application. We also investigated the electronic and optoelectronic properties of these Ge1–x–ySixSny/n-Ge heterojunction diodes.Substrate used was n-type Ge(001) wafer. After chemical cleaning of substrate, a 200 nm-thick undoped Ge1–x–ySixSny layer was grown at 150–350 °C on substrate using molecular beam epitaxy system in ultrahigh vacuum chamber. Ge and Sn were deposited using Knudsen cells and Si was done using electron gun evaporation. Then, we prepared a mesa-shaped structure with wet etching. A 300 nm-thick SiO2 layer was deposited with coating of spin-on-glass and annealing at 450 °C. Finally, an Al electrode was prepared on contact holes to form heterojunction diode structure.We confirmed the crystalline structure of epitaxial layers with X-ray diffraction reciprocal space mapping. A Ge1–x–ySixSny layer with a high Sn content of 12% can be prepared with lattice matching epitaxy on Ge at a low temperature below 250 °C. It is also found that the small misfit between Ge1–x–ySixSny and Ge effectively impacts on the high crystalline quality and high thermal stability of substitutional Sn atoms in Ge matrix.Absorption spectroscopy and current-voltage characteristics of undoped Ge1–x–ySixSny/n-Ge heterojunction diodes were also performed. We observed good rectifying property of the diodes meaning that the majority carrier of these undoped Ge1–x–ySixSny ternary alloy layers is hole unintentionally generated due to defects. We also found the extension of the energy band gap of Ge1–x–ySixSny layer with Si and Sn contents. Photovoltaic property of Ge1–x–ySixSny/Ge heterojunction diodes were also measured. We can see the increasing of the open circuit voltage, Voc from 0.08 to 0.12 V for undoped Ge/n-Ge to undoped Ge0.54Si0.36Sn0.10/Ge heterojunction photovoltaic cell structure, which indicates the enhancement of Voc with increasing the energy bandgap of epitaxial layer. We also achieved the improvement of Voc by 0.14 V with 500 °C-annealing in hydrogen (H2) ambient, which suggests the annihilation or termination of point defect in the heterojunction structure.In conclusions, heterojunction structure with Ge1–x–ySixSny ternary alloy semiconductor layer provides the energy band engineering for photovoltaic applications. Understanding and controlling the defect properties in epitaxial growth and heterojunction formation should be key factors for the enhancement of performance of group-IV multijunction photovoltaic.

A new all-inorganic vacancy-ordered double perovskite Cs2CrI6 for high-performance photovoltaic cells and alpha-particle detection in space environment

Although MAPbI3 photovoltaics have gained increasing interest for space application, its low stability and radiation resistance is insurmountable. Here, we unexpectedly find a new vacancy-ordered double perovskite Cs2CrI6 to realize high-performance space solar cells and α-particle detectors through an innovative multi-scale simulation strategy based on the first-principle calculations coupling with drift-diffusion model and Monte Carlo method. Compared to the MAPbI3, Cs2CrI6 possesses more excellent stability and optical absorption, suitable band gap (1.08 eV), higher mobility (∼103 cm2/V) and lower capture cross-section. These lead to the ultra-high power conversion efficiency (PCE) for single-junction solar cells (22.4%) and monolithic all-perovskite tandem solar cells (26.6%), and excellent α-particle detectors with ultra-high charge collection efficiency (CCE = 99.3%) and mobility-lifetime product (μτh = 4.99 × 10−3 cm2V−1), which are superior to those of corresponding MAPbI3 devices. Meanwhile, the 90% of initial PCE can be remained even under the 5 × 1013 p. cm−2 fluence proton beam and several orders higher than traditional space solar cell. Moreover, the proton irradiation resistance of Cs2CrI6 α-particle detection can reach up to 1016 p. cm−2. The excellent device performance and irradiation resistance of Cs2CrI6 devices indicate the great potential application in photovoltaic cells, α-particle detectors and even their space applications.