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Converting non‐visual light into photocurrent while maintaining high visual transparency is vital for semitransparent organic solar cells (ST‐OSCs) application, yet often challenging over insufficient invisible light‐harvesting. Herein, spectrally selective optical manipulation for ST‐OSCs with high visual light transparency and full‐spectral non‐visual light reflection is proposed by matching the optical admittance of ultrathin Ag films using ZnS and MgF2. The reflection of optically enhanced ST‐OSCs at the spectral region beyond the human eye's response spectrum is improved and the transmission in the visual region is simultaneously enhanced. By further integrating an anti‐reflective structure, the optimal structure boosts the average visible transmittance and power conversion efficiency of ST‐OSCs to 44.3% and 12.6%, respectively, yielding a record light utilization efficiency of 5.6%. Corresponding flexible ST‐OSCs with high mechanical stability implies that this work provides a facile and universal strategy for ST‐OSCs aiming at building integrated photovoltaics. [ABSTRACT FROM AUTHOR]

Heating is a knotty factor contributing to device degradation of flexible organic solar cells (FOSCs), and thermal regulation plays a crucial role in the realization of long operational lifetime. Herein, a passive cooling strategy for stable FOSCs is proposed by boosting the optical‐thermal radiative transfer to reduce the insufficient thermal dissipation and the elevated temperature caused by irradiation‐induced heating, while retaining their flexibility and portability. A spectrally selective coupling structure consisting of subwavelength hemisphere pattern and distributed Bragg reflector is integrated into FOSCs to collectively enhance out‐coupling of infrared radiation and limit near‐infrared absorption‐induced heat generation, leading to a reduced heat power intensity of 292.5 W cm−2 and the decreased working temperature by 9.6 °C under outdoor sunlight irradiation. The D18:Y6:PC71BM‐based FOSCs achieve a power conversion efficiency of over 17% with a prolonged T80 lifetime as long as one year under real outdoor working conditions. These results represent a new opportunity for enhancing the operational stability of FOSCs. [ABSTRACT FROM AUTHOR]

Semitransparent organic solar cells (STOSCs) hold great promise for applications ranging from building‐integrated photovoltaics to portable electronic devices, yet often challenging over the realization of color tunability. The structural colors generated by microcavity, subwavelength grating, or photonic crystals are highly dependent on the viewing angle, which limits the application of STOSCs in real scenarios. Herein, the spectrally selective substrates consisting of silica spheres‐based amorphous photonic crystals (APCs) are proposed to unify the optical spectra of STOSCs at different viewing angles. By optimizing the periodicity of APCs, STOSCs exhibit viewing‐angle‐independent reflection with colors varying from blue to pink. The synergetic interplay between the reflection of APCs and the absorption of active layer results in the Janus optical effect that the transmitted light is fixed at blue regardless of the reflected color. The STOSCs on flexible plastic retain the stable color even at bending state. These results pave the way for the potential application of colorful solar photovoltaic glass curtains. [ABSTRACT FROM AUTHOR]

The vibration characteristics of a rigid-flexible coupling spacecraft with double-direction hinged solar arrays are studied. The Kirchhoff plate theory is adopted to derive the governing equations. The Chebyshev polynomials are introduced as admissible functions to construct the dynamic model of each solar panel. The Lagrange multiplier method is employed to describe the continuity conditions of the flexible hinges. The Rayleigh-Ritz method is used to obtain the natural frequencies and rigid-flexible coupling global mode shapes. The validity of the present method is verified by comparing with the ANSYS results. Then, detailed studies are carried out to illustrate the effects of the inertia moment of the central rigid body, hinges stiffness, and aspect ratio of solar panels on the natural frequencies and mode shapes of the spacecraft. The results demonstrate that there exist a series of frequency veering and mode shift phenomena due to the variation of inertia moment, hinges stiffness, and aspect ratio. The inertia moment of the central rigid body plays a significant role in the attitude motion of the central rigid body. Finally, the mode localization factor is introduced to compare the mode localization degrees of three types of spacecraft. Results reveal that the longer the length of chord-wise direction solar panels, the more severe mode localization degree. • The dynamical model of rigid-flexible coupling spacecraft with double-direction hinged solar arrays is established. • Improved continuity conditions for the flexible hinges are proposed. • Effect of inertia moment of central rigid body is revealed. • The mode localization, frequency veering, and mode shift phenomena are discovered. [ABSTRACT FROM AUTHOR]

Plasmonic metal electrodes with subwavelength nanostructures are promising for enhancing light harvesting in photovoltaics. However, the nonradiative damping of surface plasmon polaritons (SPPs) during coupling with sunlight results in the conversion of the excited hot‐electrons to heat, which limits the absorption of light and generation of photocurrent. Herein, an energy recycling strategy driven by hot‐electron emission for recycling the SPP energy trapped in the plasmonic electrodes is proposed. A transparent silver‐based plasmonic metal electrode (A‐PME) with a periodic hexagonal nanopore array is constructed, which is combined with a luminescent organic emitter for radiative recombination of the injected hot‐electrons. Owing to the suppressed SPP energy loss via broadband hot‐electron emission, the A‐PME achieves an optimized optical transmission with an average transmittance of over 80% from 380 to 1200 nm. Moreover, the indium‐tin‐oxide‐free organic solar cells yield an enhanced light harvesting with a power conversion efficiency of 16.1%. [ABSTRACT FROM AUTHOR]

Using narrow bandgap nonfullerene acceptors (NFAs) can broaden the absorption spectrum of organic solar cells (OSCs) to the near‐infrared region. However, the simultaneously decreased extinction coefficient of the active layer at the blue region results in inevitable light escaping and energy loss. Herein, a blazed grating‐based device configuration consisting of a patterned rear electrode is employed to compensate for the low absorption of nonfullerene OSCs. Experimental results reveal that the normal incidence light, especially blue light, that bounces off the patterned rear electrode is concentrated in a large tilted angle and subsequently trapped in waveguide mode. Along with the excitation of surface plasmon polariton, the structured nonfullerene OSCs using a new‐designed PM6:M36 active layer obtain the broadband absorption enhancement with 1.5 times increase at the blue region. The optimized device achieves an 8.95% increase in photocurrent and a champion power conversion efficiency of approaching 18%, which is the highest reported value among all the devices based on A‐D‐A type NFAs. [ABSTRACT FROM AUTHOR]

All‐inorganic CsPbI2Br perovskite has attracted great attention as an absorber for perovskite solar cells (PSCs) due to its excellent thermal and light resistance. However, its device performance is restricted by the large energy level offset between CsPbI2Br and the most commonly used hole‐transporting layer (HTL). Herein, multicarbazolyl‐substituted benzonitrile (4t‐5CzBn) is inserted into the interface between CsPbI2Br and HTL to form a uniform stepped (0.24 eV) interfacial energy level structure, which reduces the energy loss and boosts the hole extraction of CsPbI2Br PSCs. The incorporation of 4t‐5CzBn induces the increase in open‐circuit voltage and fill factor from 1.256 V and 74.5% to 1.335 V and 82.3%, respectively. The optimized device achieves a power conversion efficiency of 17.34%, which is among the highest reported values of CsPbI2Br PSCs. Besides the energy level tuning effect, the tert‐butyl groups in 4t‐5CzBn improve the moisture‐resistance of CsPbI2Br PSCs. The unencapsulated device maintains over 75% of its initial efficiency after 700 h storage in air. These results demonstrate that the rational tuned energy level step benefits the performance improvement of CsPbI2Br PSCs. [ABSTRACT FROM AUTHOR]

Perovskite light‐emitting diodes (PeLEDs) are emerging candidates for the applications of solution‐processed full‐color displays. However, the device performance of deep‐blue PeLED still lags far behind that of their red and green counterparts, which is largely limited by low external quantum efficiency (EQE) and poor operational stability. Here, a facile and reliable crystallization strategy for perovskite grains is proposed, with improved deep‐blue emission through rational interfacial engineering. By modifying the substrate with potassium cation (K+) as the supplier of heterogeneous nucleation seeds, the interfacial K+‐guided grain growth is realized for well‐packed perovskite assemblies with high surface coverage and the controlled crystal orientation, leading to the enhanced radiative recombination and hole‐transport capabilities. Synergistical boost in device performance is achieved for deep‐blue PeLEDs emitting at 469 nm with a peak EQE of 4.14%, a maximum luminance of 451 cd m–2, and spectrally stable color coordinates of (0.125, 0.076) that matches well with the National Television System Committee (NTSC) standard blue. [ABSTRACT FROM AUTHOR]

Flexible organic solar cells (OSCs) are very promising for use in portable power supply devices due to the advantages of low‐cost, light‐weight, and flexibility. However, the efficiencies of flexible OSCs are limited by the flexible transparent electrodes owing to their nonoptimal electrical, optical, and mechanical properties. To address these challenges, leaf‐like biomimetic electrodes are proposed to achieve an efficient light capture and glossy surface for a high‐efficiency flexible OSC. To mimic the internal anatomy of the leaf, the conformable electrode stack consists of a flexible polyimide substrate, light‐scattering polystyrene spheres, zinc oxide protecting layer, and electrically conductive silver nanowires to obtain a high transmittance, low sheet resistance, and low surface roughness. A record‐high power conversion efficiency of 16.1% is realized by a flexible OSC with the biomimetic electrode design, comparable to those rigid devices on glass. Moreover, the flexible OSC on this biomimetic electrode exhibits a robust bendability against flexural strain, retaining 85% of the initial efficiency after 5000 bending cycles at a radius of curvature as small as 1.0 mm. [ABSTRACT FROM AUTHOR]

Light management holds great promise of realizing high-performance perovskite solar cells by improving the sunlight absorption with lower recombination current and thus higher power conversion efficiency (PCE). Here, a convenient and scalable light trapping scheme is demonstrated by incorporating bioinspired moth-eye nanostructures into the metal back electrode via soft imprinting technique to enhance the light harvesting in organic-inorganic lead halide perovskite solar cells. Compared to the flat reference cell with a methylammonium lead halide perovskite (CH3NH3PbI3− x) absorber, 14.3% of short-circuit current improvement is achieved for the patterned devices with moth-eye nanostructures, yielding an increased PCE up to 16.31% without sacrificing the open-circuit voltage and fill factor. The experimental and theoretical characterizations verify that the cell performance enhancement is mainly ascribed by the broadband polarization-insensitive light scattering and surface plasmonic effects due to the patterned metal back electrode. It is noteworthy that this light trapping strategy is fully compatible with solution-processed perovskite solar cells and opens up many opportunities toward the future photovoltaic applications. [ABSTRACT FROM AUTHOR]x) absorber, 14.3% of short-circuit current improvement is achieved for the patterned devices with moth-eye nanostructures, yielding an increased PCE up to 16.31% without sacrificing the open-circuit voltage and fill factor. The experimental and theoretical characterizations verify that the cell performance enhancement is mainly ascribed by the broadband polarization-insensitive light scattering and surface plasmonic effects due to the patterned metal back electrode. It is noteworthy that this light trapping strategy is fully compatible with solution-processed perovskite solar cells and opens up many opportunities toward the future photovoltaic applications. [ABSTRACT FROM AUTHOR]

An inverted organic solar cell (OSC) device structure by incorporating pixelated speckle image holography carrier fringes (SIHFs) for efficient superimposed light harvesting is demonstrated. The proposed SIHF based OSCs yield an 18.2% increase in power conversion efficiency (PCE) compared to that of the flat control devices. Moreover, compared to the common two-dimensional (2D) periodic grating patterned OSCs, SIHF based devices achieve 7.8% higher short-circuit current (JSC) and 10.0% higher PCE. This observable improvement in PCE of SIHF based OSCs is mainly ascribed to the geometric effect due to the unique chaotic carrier fringes of SIHFs. [ABSTRACT FROM AUTHOR]

Metal halide perovskites, a class of crystalline semiconductors with unique optical and electronic properties, are emerging as potential solutions for low-cost photovoltaics and photonic sources in fields of solar cells, sensors, light-emitting diodes and lasers. Regardless of significant progress on device efficiency with the control over perovskite structures and film morphologies, unveiling the interface energetics and band alignment of these perovskite systems is indispensable for the performance optimization in the optoelectronic applications by grasping the photon harvest and charge transport processes. Herein we review the recent advances in the energetics of metal halide perovskite interfaces. The electronic properties of perovskite materials are addressed in terms of halide substitution, thermal annealing and substrate effects as well as trap states. The energy level alignments of interfaces between perovskite films and charge transport layers are then discussed, which is correlated to the photovoltaic properties in perovskite solar cells. [ABSTRACT FROM AUTHOR]

This study investigates the free vibration characteristics of a double-direction (D-D) solar array structure connected with flexible hinges. We propose the more accurate continuity conditions in the theoretical model. The Kirchhoff plate theory is adopted to derive the energy equations of the structure. The Chebyshev polynomials are introduced as admissible functions to construct the dynamic model of each solar panel. The Lagrange multiplier method is employed to describe the continuity conditions of the flexible hinges. The natural frequencies and corresponding global mode shapes of the structure are calculated using the Rayleigh–Ritz method. Furthermore, a comparison with the results obtained from ANSYS is performed to confirm the validity of the present method. Finally, investigations are carried out to illustrate the effect of the structural parameters on the natural frequency and mode shape of the structure. A comparison study shows that the present continuity conditions can significantly improve the accuracy of the results. Different from the single direction solar panels structures, there exist coupling effect between x - and y -direction solar panels in D-D solar array structures. Moreover, unique frequency stability phenomenon and coplanar phenomenon of solar panels are discovered in D-D solar array structures. In addition, the results of frequency curves, mode shapes, and modal assurance criterion (MAC) values reveal that the variation of the hinge torsional stiffness and the solar panel aspect ratio induce a series of frequency veering and mode shift phenomena. Particularly, the mechanism of these phenomena is explored. The present theoretical study can significantly improve the calculation efficiency, and is convenient to analyze the parameter influence law, which outperforms the finite element analysis. • The dynamical model of thin plate system joined by hinges in double directions is established. • A more accurate continuity condition is proposed. • Frequency veering and mode shape shift phenomena are discovered in this structure. • The mechanism of frequency veering and mode shape shift phenomena is explored. [ABSTRACT FROM AUTHOR]

In the pursuit of developing highly efficient polymer solar cells, it is indispensable to experimentally determine the molecular electronic and geometrical structures of distributed donor/acceptor bulk heterojunctions for understanding the processes inside the cell. In this article, substrate effect on interface energetics and film morphology of the poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)]:[6,6]-phenyl-C70 butyric acid methyl ester (PCDTBT:PC70BM) blends with various blending ratios on various conductive substrates is clarified based on the characterization of photoelectron spectroscopy and atomic force microscope, where the PCDTBT:PC70BM blend film serves as an important model system due to efficient charge generation and transport with low recombination. The energetics of the PCDTBT:PC70BM blend film is demonstrated to be highly dependent on the substrate work function, showing the transition from vacuum level alignment to Fermi level pinning with the variation of PC70BM ratio in the blend film. The resulting morphology is in good agreement with the observed formation of a PCDTBT-rich layer at the top of the PCDTBT:PC70BM blend film irrespective of the variation of the PC70BM blending ratio and annealing temperature. The results show the possibility of tuning the interfacial electronic structures by utilizing the substrate effects and potential applications on performance enhancement in polymer solar cells. [ABSTRACT FROM AUTHOR]

We constructed a concept of the full-organic carrier collection layer (CCL) used for polymer solar cells. The CCL is composed of dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile as hole collection layer (HCL) and chlorine-free solvents (formic acid (FA)) processed 4,7-Diphenyl-1,10-phenanthroline (Bphen) as electron collection layer, exhibiting good solubility, and environmental protection. The FA based device shows ideal power conversion efficiency (3.75%), which is higher than that of control device (3.6%). Besides, the HCL shows a different mechanism in hole extraction by functioning as a charge recombination zone for electrons injected from anode and holes extracted from the donor materials. [ABSTRACT FROM AUTHOR]

Advanced light manipulation is extremely attractive for applications in organic optoelectronics to enhance light harvesting efficiency. A novel method of fabricating high-efficiency organic solar cells (OSCs) is proposed using biomimetic moth eye nanostructures in a quasi-periodic gradient shape active layer and an antireflective coating. A 24.3% increase in photocurrent is realized without sacrificing dark electrical properties, yielding a 22.2% enhancement in power conversion efficiency to a record of 7.86% for OSCs with a poly(3-hexylthiophene-2,5-diyl):indene-C60 bis-adduct (P3HT:ICBA) active layer. The experimental and theoretical characterizations verify that the substantial improvement of OSCs is mainly ascribed to the self-enhanced absorption resulting from the broadband polarization-insensitive light trapping in biomimetic nanostructured active layer, the reduction in reflectance by the antireflective coating, and surface plasmonic effect excited by corrugated metallic electrode. It is noteworthy that the pathway described here is promising for opening up opportunities to realize high-performance OSCs towards the future photovoltaic applications. [ABSTRACT FROM AUTHOR]

Highlights: [•] An efficient inverted polymer solar cell is demonstrated. [•] The electron collection layer consists of a small molecular layer of Cs2CO3:Alq3. [•] Efficient electron extraction is achieved due to favorable energy level alignment. [•] The Cs2CO3:Alq3 layer can act as an optical spacer to modulate the incident light. [ABSTRACT FROM AUTHOR]

A three-layer process and apparatus have been developed for electrorefining of silicon for solar cell application. The anode is solidified from a hypereutectic solution of copper and MG silicon. At the temperature of operation (1223 K (950 °C)), elements that have an electronegativity greater than that of silicon will remain at the anode ( e.g., Cu, B, P, etc.) and then the Cu-Si phase can be used under certain conditions as a filter for purifying silicon with an electrorefining process. According to the stable liquid electrode reactive surface, high current density is possible during electrorefining and such advantages obviously improve the rate of deposition, which is a key point to reach commercial development. Deposited silicon particles are found embedded in electrolyte. Furthermore, with increasing operation time and current density, recombination of silicon particles is revealed and yields silicon balls with a diameter of 2 cm. The analysis of the anode feed and refined silicon shows a remarkable reduction of B and P concentrations, from 12.7 to 2.4 ppmw and 98.6 to 4.3 ppmw, respectively. Besides, particular mention should be made of efficient removal of impurities such as Fe, Mn, and Ti, which are present in significant quantities in the anode feed. [ABSTRACT FROM AUTHOR]

Hot carriers in hybrid perovskite have been proven to have eminent properties with long carrier cooling time and long carrier migration distance. The invention of the internally photoemitted hot carrier (IPHC) solar cell recently makes it possible to utilize the hot electrons in CH 3 NH 3 PbI 3 perovskite and capture their excess energies under steady state illumination. How to further improve the efficiency of IPHC cells is challenging and crucial to demonstrate their effectiveness. In this work, sodium iodide (NaI) is added into the CH 3 NH 3 PbI 3 precursor solution for inducing a P-type doping and downshifting its Fermi level. The lowered energy barrier at the interface of Au/doped CH 3 NH 3 PbI 3 promotes the hot electron extraction, thereby enhancing the power conversion efficiency of IPHC devices. The FTO/TiO 2 /Au/Na+-doped MAPbI 3 construction with considerable photocurrent would be an alternative approach for light-to-electricity conversion. Image 1 • A novel IPHC device has been adopted to collect hot electrons under steady-state sunlight illumination. • The location of the perovskite active layer is on the utmost outside of the collection structure of Au/TiO 2 /FTO. • The performance of this newly developed hot electron collection device is enhanced by P-type doping the perovskite layer. • P-type doping is the effective way to boost the hot electron internal photoemission. [ABSTRACT FROM AUTHOR]

Inorganic mixed‐halide CsPbX3‐based perovskite solar cells (PeSCs) are emerging as one of the most promising types of PeSCs on account of their thermostability compared to organic–inorganic hybrid counterparts. However, dissatisfactory device performance and high processing temperature impede their development for viable applications. Herein, a facile route is presented for tuning the energy levels and electrical properties of sol–gel‐derived ZnO electron transport material (ETM) via the doping of a classical alkali metal carbonate Cs2CO3. Compared to bare ZnO, Cs2CO3‐doped ZnO possesses more favorable interface energetics in contact with the CsPbI2Br perovskite layer, which can reduce the ohmic loss to a negligible level. The optimized PeSCs achieve an improved open‐circuit voltage of 1.28 V, together with an increase in fill factor and short‐circuit current. The optimized power conversion efficiencies of 16.42% and 14.82% are realized on rigid glass substrate and flexible plastic substrate, respectively. A high thermostability can be simultaneously obtained via defect passivation at the Cs2CO3‐doped ZnO/CsPbI2Br interface, and 81% of the initial efficiency is retained after aging for 200 h at 85 °C. [ABSTRACT FROM AUTHOR]

Flexible perovskite solar cells (PeSCs) possess the extraordinary potential in the applications of portable power sources and wearable electronics because of their superiorities in ease fabrication and efficient power conversion. These features are reinforced when a transparent conductive electrode with good flexibility is achieved. A unique electrode based on Ag periodic mesh (APM) perforated with hexagonal close‐packed nanoholes is proposed, showing a square resistance of ≈19.0 Ω sq−1 and optical transmittance of 66.0% in the whole visible region. PeSCs made on the optimal APM electrode with a rigid glass substrate achieve over twofold of photocurrent as compared to the counterpart on flat Ag film, resulting in a maximum power conversion efficiency of 17.06%. Experimental and theoretical characterizations indicate that the performance enhancement is mainly ascribed to the surface plasmon‐assisted extraordinary transmission enhancement and the scattering of incident light. Furthermore, the APM electrode enables PeSCs that are not only efficient but also highly flexible against bending deformation. Flexible PeSCs on plastic remain 90% of their initial efficiency after 1500 bending cycles with a bending radius of 3.0 mm. It is anticipated that the APM electrode with unique light coupling abilities provides a facile design route to achieving efficient and flexible PeSCs. [ABSTRACT FROM AUTHOR]

In article number 1801292, Yan‐Qing Li, Jian‐Xin Tang and co‐workers demonstrate a facile and solution‐processed light manipulation scheme consisting of ZnO colloidal spheres and nanoparticles for achieving highly efficient organic solar cells. The enhanced device performance benefits from the concentrated electromagnetic field in the absorber with the coupling of anti‐reflection effect, light scattering effect and localized surface plasmon resonance. [ABSTRACT FROM AUTHOR]

Light manipulation strategy plays a critical role in increasing the light harvesting of organic solar cells (OSCs). However, the incorporation of light manipulation structures in OSCs is usually hindered by complex lithography‐based techniques. Herein, a facile and solution‐processed structured ZnO film is proposed, consisting of ZnO colloidal spheres (CS) embedded in ZnO nanoparticles for broadband light scattering and antireflection in OSCs. By combining monodisperse ZnO CS (m‐ZnO) as an electron collection layer and polydisperse ZnO CS (p‐ZnO) as an antireflection layer, single‐junction OSCs yield a substantial increase in photocurrent and power conversion efficiency by 14.63% compared to the reference cell with a flat structure. The experimental and theoretical characterizations ascribe the performance enhancement to the enhanced absorption due to a synergetic interplay of p‐ZnO‐induced antireflection and surface plasmonic scattering excited by corrugated metal electrode. It is anticipated that this light manipulation method represents a facile yet cost‐effective route to achieving high‐efficiency OSCs for commercially viable photovoltaic applications. A facile, solution‐processed light manipulation scheme consisting of ZnO colloidal spheres and nanoparticles is proposed for achieving high‐efficiency organic solar cells. The light harvesting enhancement by 14.63% is obtained by a synergetic interplay of broadband light scattering, surface plasmonic resonance, and the antireflective effect due to the structured ZnO films. [ABSTRACT FROM AUTHOR]

An effective light trapping scheme in perovskite solar cells is achieved by incorporating bio‐inspired moth‐eye nanostructures into metal back electrode to improve the sunlight absorption. The enhanced light harvesting is ascribed by the collective effects of broadband polarization‐insensitive light scattering and surface plasmonic excitation. This is reported by Yan‐Qing Li, Chun‐Sing Lee, Jian‐Xin Tang, and co‐workers in article number 1700492. [ABSTRACT FROM AUTHOR]

In this work the degradation effects of the GaInAs (1.0 eV) and GaInAs (0.7 eV) sub-cells for IMM4J solar cells are investigated after 1-MeV electron irradiation by using spectral response and photoluminescence (PL) signal amplitude analysis, as well as electrical property measurements. The results show that, compared with the electrical properties of traditional single junction (SJ) GaAs (1.41 eV) solar cell, the electrical properties (such as , , and of the newly sub-cells degrade similarly as a function of , where represents the electron fluence. It is found that the degradation of is much more than that of in the irradiated GaInAs (0.7 eV) cells due to the additional intrinsic layer, leading to more serious damage to the space charge region. However, of the three types of SJ cells with the gap widths of 0.7, 1.0, and 1.4 eV, the electric properties of the GaInAs (1.0 eV) cell decrease largest under each irradiation fluence. Analysis on the spectral response indicates that the of the GaInAs (1.0 eV) cell also shows the most severe damage. The PL amplitude measurements qualitatively confirm that the degradation of the effective minority carrier life-time ( in the SJ GaInAs cells is more drastic than that of SJ GaAs cells during the irradiation. Thus, the output current of GaInAs sub-cell should be controlled in the irradiated IMM4J cells. [ABSTRACT FROM AUTHOR]

Enhanced performance of polymer solar cells is reported by incorporating a solution-processed luminescent down-shifting (LDS) sensitizer, which is composed of a C545T fluorescent molecule doped tris(8-quinolinolato) aluminum (C545T:Alq3). An optimized LDS sensitizer can result in ∼15% enhancement in power conversion efficiency than the reference device with pristine Alq3. The performance enhancement is associated with the increase in photocurrent induced by LDS sensitizer, which is capable of absorbing short-wavelength solar spectrum and re-emitting long-wavelength light, which is complementary with the absorption spectrum of the active layer. This method provides a facile approach for high-performance polymer solar cell designs. [ABSTRACT FROM AUTHOR]

Efficient inverted polymer solar cell is reported upon by integrating with a small molecular 1,3,5-tri(phenyl-2-benzimi-dazolyl)-benzene (TPBi) electron extraction layer (EEL) at low processing temperature with thermal-evaporation and solution-process, resulting in the power conversion efficiencies of 3.70% and 3.47%, respectively. The potential of TPBi as an efficient EEL is associated with its suitable electronic energy level for electron extraction and hole blocking from the active layer to the indium tin oxide cathode. [ABSTRACT FROM AUTHOR]

• Lateral charge collection range of silver nanowires are clarified via microscopic photocurrent images. • Doping LiTFSI in ZnO improves carrier mobility and energy level alignment with AgNWs. • Flexible organic solar cells achieve an efficiency of 18.0%. Although the transparency and sheet resistance of silver nanowire (AgNW) electrodes are comparable to those of rigid indium-tin-oxide electrodes, flexible organic solar cells (FOSCs) are still less efficient than their rigid counterparts. Herein, by recording the microscopic photocurrent images of AgNW-based FOSCs in operation, it has been revealed that the limited lateral charge collection range of AgNW leads to inevitable electrical energy loss. The regulation of carrier mobility and energy level of adjacent ZnO electron transport layer increases the effective collection range of AgNWs by 1.8 times and uniform the electrical potential distribution in FOSCs. The D18:Y6:PC 71 BM-based FOSCs achieve a power conversion efficiency of approaching 18%. Moreover, the performance drop of large-area FOSCs is significantly reduced due to the improved charge collection on large area scale. This work provides an intuitive insight into the electrical energy loss mechanism of AgNW electrodes and demonstrates an electric field regulation strategy in FOSCs. [ABSTRACT FROM AUTHOR]

Abstract While metal halide hybrid perovskite solar cells (PeSCs) are remarkably efficient, the rapid and undesirable degradation limit their practical applications for renewable energy sources. Herein, the evolution of perovskite decomposition under white light illumination has been investigated under the ultrahigh vacuum conditions, which can effectively rule out the influence of other factors such as oxygen or moisture. The chemical composition, electronic structure, surface morphology, and crystal structure of CH 3 NH 3 PbI 3 perovskite films have been systematically characterized by X-ray and ultraviolet photoelectron spectroscopies (XPS and UPS), scanning electron microscopy, and X-ray diffraction techniques. The surface roughening with cracks and defects occurs in CH 3 NH 3 PbI 3 perovskite films after a short-time white-light illumination in ultrahigh vacuum. In situ compositional analysis reveals the decomposition of the perovskite films with the appearance of metallic Pb feature, which is accompanied with the energy level shift towards higher binding energy during the illumination process. However, the decomposition rate is decreased and becomes saturated after exposed to light illumination for 24 h. These findings provide a direct evidence that CH 3 NH 3 PbI 3 perovskite is photosensitive, and a light-induced degradation mechanism is proposed. Graphical abstract Image 1 Highlights • The perovskite decomposition under white light illumination is explored under ultrahigh vacuum conditions. • In-situ compositional analysis reveals the perovskite decomposition with the appearance of metallic Pb. • A light-induced degradation mechanism is proposed. [ABSTRACT FROM AUTHOR]

We constructed an effective electron extraction layer (EEL) used for polymer solar cells by integrating one new kind of organic material of 4,4′-(1,4-phenylene) bis(2-phenyl-6-p-tolylnicotinonitrile) (p-PPtNT) and cesium carbonate (Cs 2 CO 3 ) used as a compound EEL (CEEL). The CEEL based device exhibits an ideal PCE of 4.15%, corresponding to an enhancement 220% in contrast to that of control device without EEL, which is also comparable to that of ZnO based device. Our analyses indicated that the remarkably improved PCE for CEEL based device is mainly ascribed to the Ohmic contact and the negligible electron extraction barrier at cathode/active layer by inserting CEEL. [ABSTRACT FROM AUTHOR]

Cathode buffer layer (CBL) is one of the key issues influencing the performance of organic solar cells. In this article, a nanocomposite of zinc oxide nanoparticles (ZnO) together with a conjugated polymer, poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene) -alt -2,7-(9,9-dioctyl)-fluorene] (PFN) was developed, and used as the CBL for solution processed inverted organic solar cells (OSC). In comparison with the bare ZnO, PFN or ZnO/PFN stacked layer, the ZnO:PFN nanocomposite CBL employing device showed superior device performance, in particular significantly improved fill factor. Optimized power conversion efficiency (PCE) of P3HT:PC 61 BM and PTB7:PC 61 BM device using ZnO:PFN composite CBLs reached to 3.56% and 7.17%, respectively. Influences of the mixing ratio and the layer thickness of the ZnO:PFN nanocomposite CBL on solar cell performance were carefully studied, and results indicated that ZnO:PFN CBL showed a wide tolerance of blend ratio and layer thickness. In particular, no obvious thickness dependent-device performance was found, even when the CBL layer thickness was higher than 125 nm, providing a good printing processibility of the nanocomposite. Photoelectron spectroscopy, photoluminescence, as well as electric conductivity of the ZnO:PFN films were studied, and the results were compared with that of the other three reference CBLs. Results demonstrated that the interaction between ZnO and PFN decreases the work function of the blended film, leading to a more favorable energy level alignment for electron injection at the interface. Analysis on the dark J – V curves of the solar cells revealed that device using ZnO:PFN CBL had the best diode characteristics including lowest reverse saturated current density ( J 0 ), ideal factor ( n ), and series resistance ( R s ), and highest shunt resistance ( R sh ). Such an improvement was ascribed to the defect passivation by the conjugated polymer, which led to an improved charge carrier selectivity of the CBL and consequently enhanced the FF of the solar cells. In addition, long-term stability of organic solar cells was also improved by using ZnO:PFN nanocomposite as the CBL. The current work provides a valuable guideline for the development of high performance cathode buffer layer material for printable organic solar cells. [ABSTRACT FROM AUTHOR]

Highlights: [•] Efficient polymer solar cell is demonstrated with a nanostructured scattering rear electrode. [•] Enhanced light harvesting is realized through efficient backscattering-induced light trapping. [•] An enhanced power conversion efficiency of 7.21% is obtained. [ABSTRACT FROM AUTHOR]

Enhanced performance of polymer solar cells is reported by incorporating a solution-processed luminescent down-shifting (LDS) sensitizer, which is composed of a C545T fluorescent molecule doped tris(8-quinolinolato) aluminum (C545T:Alq3). An optimized LDS sensitizer can result in ~15% enhancement in power conversion efficiency than the reference device with pristine Alq3. The performance enhancement is associated with the increase in photocurrent induced by LDS sensitizer, which is capable of absorbing short-wavelength solar spectrum and re-emitting long-wavelength light, which is complementary with the absorption spectrum of the active layer. This method provides a facile approach for high-performance polymer solar cell designs. [ABSTRACT FROM AUTHOR]

Abstract: An efficient inverted polymer solar cell is enabled by incorporating an n-type doped wide-gap organic electron transporting layer (ETL) between the indium tin oxide cathode and the photoactive layer for electron extraction. The ETL is formed by a thermal-deposited cesium carbonate-doped 4,7-diphenyl-1,10-phenanthroline (Cs2CO3:BPhen) layer. The cell response parameters critically depended on the doping concentration and film thickness of the Cs2CO3:BPhen ETL. Inverted polymer solar cell with an optimized Cs2CO3:BPhen ETL exhibits a power conversion efficiency of 4.12% as compared to 1.34% for the device with a pristine BPhen ETL. The enhanced performance in the inverted device is associated with the favorable energy level alignment between Cs2CO3:BPhen and the electron-acceptor material, as well as increased conductivity in the doped organic ETL for electron extraction. The method reported here provides a facile approach to optimize the performance of inverted polymer solar cells in terms of easy control of film morphology, chemical composition, conductivity at low processing temperature, as well as compatibility with fabrication on flexible substrates. [Copyright &y& Elsevier]

Abstract: An efficient inverted polymer solar cell (PSC) is reported by employing an atomic layer deposited (ALD) cadmium sulfide (CdS) film between the indium tin oxide (ITO) cathode and the photoactive layer as the electron collection layer (ECL), on which a active layer is composed of a blended poly(3-hexylthiophene) and [6,6]-phenyl C61 butyric acid methyl ester (P3HT:PCBM) bulk heterojunction. As determined by photoelectron spectroscopy, the sulfur vacancy induces an n-type semiconducting property in the ALD-grown CdS films, and suitable energy level alignment at the ITO/CdS/PCBM interface is favorable to electron extraction through CdS to the ITO electrode. With the optimized CdS film thickness, the power conversion efficiency increases to 3.33%, with short-circuit current of 8.94mA/cm2, open-circuit voltage of 0.61V, and fill factor of 61.1% under AM1.5G 100mW/cm2 irradiation. [Copyright &y& Elsevier]