Showing papers on "Energy conversion efficiency published in 2015"
TL;DR: Green et al. as mentioned in this paper presented consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules, and guidelines for inclusion of results into these tables are outlined and new entries since July 2014 are reviewed.
Abstract: Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells and modules are presented. Guidelines for inclusion of results into these tables are outlined and new entries since July 2014 are reviewed. URI: http://onlinelibrary.wiley.com/doi/10.1002/pip.2573/pdf [1] Authors: GREEN Martin A. EMERY Keith HISHIKAWA Y. WARTA W. DUNLOP Ewan Publication Year: 2015 Type: Articles in Journals
2,511 citations
TL;DR: A comprehensive review of the four modes, their theoretical modelling, and the applications of TENGs for harvesting energy from human motion, walking, vibration, mechanical triggering, rotating tire, wind, flowing water and more as well as self-powered sensors is provided in this article.
Abstract: Ever since the first report of the triboelectric nanogenerator (TENG) in January 2012, its output area power density has reached 500 W m−2, and an instantaneous conversion efficiency of ∼70% and a total energy conversion efficiency of up to 85% have been demonstrated. We provide a comprehensive review of the four modes, their theoretical modelling, and the applications of TENGs for harvesting energy from human motion, walking, vibration, mechanical triggering, rotating tire, wind, flowing water and more as well as self-powered sensors.
1,602 citations
TL;DR: The homologous 2D halide perovskites define a promising class of stable and efficient light-absorbing materials for solid-state photovoltaics and other applications.
Abstract: We report on the fabrication and properties of the semiconducting 2D (CH3(CH2)3NH3)2(CH3NH3)n–1PbnI3n+1 (n = 1, 2, 3, and 4) perovskite thin films. The band gaps of the series decrease with increasing n values, from 2.24 eV (CH3(CH2)3NH3)2PbI4 (n = 1) to 1.52 eV CH3NH3PbI3 (n = ∞). The compounds exhibit strong light absorption in the visible region, accompanied by strong photoluminescence at room temperature, rendering them promising light absorbers for photovoltaic applications. Moreover, we find that thin films of the semi-2D perovskites display an ultrahigh surface coverage as a result of the unusual film self-assembly that orients the [PbnI3n+1]− layers perpendicular to the substrates. We have successfully implemented this 2D perovskite family in solid-state solar cells, and obtained an initial power conversion efficiency of 4.02%, featuring an open-circuit voltage (Voc) of 929 mV and a short-circuit current density (Jsc) of 9.42 mA/cm2 from the n = 3 compound. This result is even more encouraging con...
1,589 citations
TL;DR: In this paper, an inverted MAPbI3 planar hybrid solar cells with 18.1% average power conversion efficiency was fabricated by depositing dense pinhole-free MAPBI3 perovskite on a PEDOT:PSS/ITO substrate via a single-step spin-coating of solubility controlled MAPI3 solution.
Abstract: Hysteresis-less inverted ITO/PEDOT:PSS/CH3NH3PbI3 (MAPbI3)/PCBM/Au planar hybrid solar cells with 18.1% average power conversion efficiency irrespective of the scan rate were fabricated by depositing dense pinhole-free MAPbI3 perovskite on a PEDOT:PSS/ITO substrate via a single-step spin-coating of solubility controlled MAPbI3 solution. The conductivities of PEDOT:PSS, PCBM, poly(triaryl amine) (PTAA):tert-butylpyrridne (tBP) + Li-bis(trifluoromethanesulfonyl)imide (Li–TFSI), MAPbI3, and TiO2 were 0.014, 0.016, 0.034, 0.015, and 0.00006 mS cm−1, respectively. The average PL lifetimes (τav) of the inverted and normal cell were 1.277 and 1.94 ns, respectively. The diffusion coefficient (Dn) and charge carrier lifetime (τn) for the inverted MAPbI3 planar hybrid solar cells were increased by 1.14-fold and 1.1-fold, respectively, compared with the conventional FTO/TiO2/MAPbI3/PTAA:tBP + Li–TFSI/Au planar hybrid cells. Hence, the inverted MAPbI3 planar hybrid solar cells exhibited better power conversion efficiency and stability than the conventional MAPbI3 cells because (i) the electron extraction from MAPbI3 to the electron conductor was improved because the electron conductivity of PCBM is higher than that of TiO2; (ii) the EQE value was increased by the better charge injection/separation efficiency between MAPbI3 and PCBM, and by the higher charge collection efficiency than the conventional cell; (iii) the fill factor is improved by the increased Dn and τn; and (iv) the air and humidity stability is improved by the absence of corrosive additives in the device architecture and the hydrophobicity of the PCBM top layer. The reduced current density–voltage (J–V) hysteresis with respect to the scan rate and scan direction in the inverted planar hybrid solar cells could be attributed to a more balanced electron flux (Je) and hole flux (Jh), and a reduced number of surface traps.
1,056 citations
TL;DR: A single-junction polymer solar cell with an efficiency of 10.1% is demonstrated by using deterministic aperiodic nanostructures for broadband light harvesting with optimum charge extraction through self-enhanced absorption due to collective effects, including pattern-induced anti-reflection and light scattering.
Abstract: A single-junction polymer solar cell with an efficiency of 10.1% is demonstrated by using deterministic aperiodic nanostructures for broadband light harvesting with optimum charge extraction. The performance enhancement is ascribed to the self-enhanced absorption due to collective effects, including pattern-induced anti-reflection and light scattering, as well as surface plasmonic resonance, together with a minimized recombination probability.
1,002 citations
TL;DR: The results demonstrate that a fine and balanced modification/design of chemical structure can make significant performance differences and that the performance of solution-processed small-molecule-based solar cells can be comparable to or even surpass that of their polymer counterparts.
Abstract: A series of acceptor-donor-acceptor simple oligomer-like small molecules based on oligothiophenes, namely, DRCN4T-DRCN9T, were designed and synthesized. Their optical, electrical, and thermal properties and photovoltaic performances were systematically investigated. Except for DRCN4T, excellent performances were obtained for DRCN5T-DRCN9T. The devices based on DRCN5T, DRCN7T, and DRCN9T with axisymmetric chemical structures exhibit much higher short-circuit current densities than those based on DRCN6T and DRCN8T with centrosymmetric chemical structures, which is attributed to their well-developed fibrillar network with a feature size less than 20 nm. The devices based on DRCN5T/PC71BM showed a notable certified power conversion efficiency (PCE) of 10.10% under AM 1.5G irradiation (100 mW cm(-2)) using a simple solution spin-coating fabrication process. This is the highest PCE for single-junction small-molecule-based organic photovoltaics (OPVs) reported to date. DRCN5T is a rather simpler molecule compared with all of the other high-performance molecules in OPVs to date, and this might highlight its advantage in the future possible commercialization of OPVs. These results demonstrate that a fine and balanced modification/design of chemical structure can make significant performance differences and that the performance of solution-processed small-molecule-based solar cells can be comparable to or even surpass that of their polymer counterparts.
766 citations
TL;DR: In this article, a solution-processed small-molecule solar cells with almost 100% internal quantum efficiency and a power conversion efficiency of 9% were reported, making use of a donor molecule called DRCN7T and use PC71BM as an acceptor.
Abstract: Solution-processed small-molecule solar cells with almost 100% internal quantum efficiency and a power conversion efficiency of 9% are reported. The cells make use of a donor molecule called DRCN7T and use PC71BM as an acceptor.
764 citations
TL;DR: A new copolymer PM6 based on fluorothienyl-substituted benzodithiophene is synthesized and characterized, and the inverted polymer solar cells based on PM6 exhibit excellent performance and power conversion efficiency.
Abstract: A new copolymer PM6 based on fluorothienyl-substituted benzodithiophene is synthesized and characterized. The inverted polymer solar cells based on PM6 exhibit excellent performance with Voc of 0.98 V and power conversion efficiency (PCE) of 9.2% for a thin-film thickness of 75 nm. Furthermore, the single-junction semitransparent device shows a high PCE of 5.7%.
758 citations
TL;DR: In this article, a flexible perovskite solar cell exhibiting 12.2% power conversion efficiency (PCE) while using a low-temperature technology for the fabrication of a compact charge collection layer is presented.
Abstract: Perovskite solar cells are promising candidates for realizing an efficient, flexible, and lightweight energy supply system for wearable electronic devices. For flexible perovskite solar cells, achieving high power conversion efficiency (PCE) while using a low-temperature technology for the fabrication of a compact charge collection layer is a critical issue. Herein, we report on a flexible perovskite solar cell exhibiting 12.2% PCE as a result of the employment of an annealing-free, 20 nm thick, amorphous, compact TiOx layer deposited by atomic layer deposition. The excellent performance of the cell was attributed to fast electron transport, verified by time-resolved photoluminescence and impedance studies. The PCE remained the same down to 0.4 sun illumination, as well as to a 45° tilt to incident light. Mechanical bending of the devices worsened device performance by only 7% when a bending radius of 1 mm was used. The devices maintained 95% of the initial PCE after 1000 bending cycles for a bending radius of 10 mm. Degradation of the device performance by the bending was the result of crack formation from the transparent conducting oxide layer, demonstrating the potential of the low-temperature-processed TiOx layer to achieve more efficient and bendable perovskite solar cells, which becomes closer to a practical wearable power source.
575 citations
546 citations
TL;DR: It is demonstrated that efficiencies above 22% can be reached, even in thick interdigitated back-contacted cells, where carrier transport is very sensitive to front surface passivation, meaning that the surface recombination issue has truly been solved and black silicon solar cells have real potential for industrial production.
Abstract: A power conversion efficiency of 22% is achieved in black silicon back-contacted solar cells through passivation of the nanostructured surface by a conformal alumina layer.
TL;DR: High efficiency and stable inverted PSCs (i-PSC) are presented by employing sol-gel processed simultaneously doped ZnO by Indium and fullerene derivative (BisNPC60-OH) film as cathode interlayer and PTB7-Th:PC71BM as the active layer.
Abstract: We present high efficiency and stable inverted PSCs (i-PSC) by employing sol-gel processed simultaneously doped ZnO by Indium and fullerene derivative (BisNPC60-OH) (denoted as InZnO-BisC60) film as cathode interlayer and PTB7-Th:PC71BM as the active layer (where PTB7-Th is a low bandgap polymer we proposed previously). This dual-doped ZnO, InZnO-BisC60, film shows dual and opposite gradient dopant concentration profiles, being rich in fullerene derivative at the cathode surface in contact with active layer and rich in In at the cathode surface in contact with the ITO surface. Such doping in ZnO not only gives improved surface conductivity by a factor of 270 (from 0.015 to 4.06 S cm−1) but also provides enhanced electron mobility by a factor of 132 (from 8.25*10−5 to 1.09*10−2 cm2 V−1 s−1). The resulting i-PSC exhibits the improved PCE 10.31% relative to that with ZnO without doping 8.25%. This PCE 10.31% is the best result among the reported values so far for single junction PSC.
TL;DR: This paper presents Functional Crystallization Center (FCC) results, which show the results of a successful crystallization experiment conducted at Kyung Hee University with real-time deposition of Na6(CO3)(SO4)2(SO3)2, which proved the ability of Na2SO4 to be converted to Na2CO3 by the FCC.
Abstract: J. H. Heo, D. H. Song, H. J. Han, Prof. S. H. Im Functional Crystallization Center (FCC) Department of Chemical Engineering Kyung Hee University 1732 Deogyeong-daero , Giheung-gu, Yongin-si , Gyeonggi-do 446-701 , Republic of Korea E-mail: imromy@khu.ac.kr S. Y. Kim, Prof. J. H. Kim Department of Physics Incheon National University 119 Academy-ro , Yeonsu-gu , Incheon 406-772 , Republic of Korea D. Kim, Dr. H. W. Shin, Prof. T. K. Ahn Department of Energy Science Sungkyunkwan University Seobu-ro 2066 , Jangan-gu , Suwon 440-746 , Republic of Korea C. Wolf, Prof. T.-W. Lee Department of Materials Science and Engineering Pohang University of Science and Technology (POSTECH) 77 Cheongam-Ro , Nam-Gu, Pohang , Gyungbuk 790-784, Republic of Korea
TL;DR: The optimized solar cells show remarkable external quantum efficiency, short circuit current, and power conversion efficiency up to 65%, 16.76 mA/cm(2), and 8.08%, respectively, which are the best values for BHJ solar cells with very low energy losses.
Abstract: We designed and synthesized the DPPEZnP-TEH molecule, with a porphyrin ring linked to two diketopyrrolopyrrole units by ethynylene bridges. The resulting material exhibits a very low energy band gap of 1.37 eV and a broad light absorption to 907 nm. An open-circuit voltage of 0.78 V was obtained in bulk heterojunction (BHJ) organic solar cells, showing a low energy loss of only 0.59 eV, which is the first report that small molecule solar cells show energy losses <0.6 eV. The optimized solar cells show remarkable external quantum efficiency, short circuit current, and power conversion efficiency up to 65%, 16.76 mA/cm2, and 8.08%, respectively, which are the best values for BHJ solar cells with very low energy losses. Additionally, the morphology of DPPEZnP-TEH neat and blend films with PC61BM was studied thoroughly by grazing incidence X-ray diffraction, resonant soft X-ray scattering, and transmission electron microscopy under different fabrication conditions.
TL;DR: A lead-free low bandgap organic-inorganic hybrid perovskite, formamidinium tin iodide, is utilized as a light absorbing layer in photovoltaics.
Abstract: A lead-free low bandgap organic–inorganic hybrid perovskite, formamidinium tin iodide, is utilized as a light absorbing layer in photovoltaics. This material has a bandgap of 1.41 eV which allows light harvesting from the near infrared region, making high photocurrents achievable. A power conversion efficiency of 2.10% was accomplished upon incorporating SnF2.
TL;DR: Two identical bulk heterojunctions are connected in series using novel interconnection layers combining pH-neutral conjugated polyelectrolytes and a thin film of ZnO nanoparticles by a solution process to achieve the best performing tandem cells.
Abstract: Rational materials design and interface engineering are both essential to realize a high performance for tandem cells. Two identical bulk heterojunctions are connected in series using novel interconnection layers combining pH-neutral conjugated polyelectrolytes and a thin film of ZnO nanoparticles by a solution process. The best performing tandem cells achieve a power conversion efficiency of 11.3%, with 25% enhancement in efficiency compared with single cells, which arises primarily from the increased light absorption.
TL;DR: In this paper, a liquid-metal-based triboelectric nanogenerator (LM-TENG) is developed for high power generation through conversion of mechanical energy, which allows a total contact between the metal and the dielectric.
Abstract: Harvesting ambient mechanical energy is a key technology for realizing self-powered electronics, which has tremendous applications in wireless sensing networks, implantable devices, portable electronics, etc. The currently reported triboelectric nanogenerator (TENG) mainly uses solid materials, so that the contact between the two layers cannot be 100% with considering the roughness of the surfaces, which greatly reduces the total charge density that can be transferred and thus the total energy conversion efficiency. In this work, a liquid-metal-based triboelectric nanogenerator (LM-TENG) is developed for high power generation through conversion of mechanical energy, which allows a total contact between the metal and the dielectric. Due to that the liquid–solid contact induces large contacting surface and its shape adaptive with the polymer thin films, the LM-TENG exhibits a high output charge density of 430 μC m−2, which is four to five times of that using a solid thin film electrode. And its power density reaches 6.7 W m−2 and 133 kW m−3. More importantly, the instantaneous energy conversion efficiency is demonstrated to be as high as 70.6%. This provides a new approach for improving the performance of the TENG for special applications. Furthermore, the liquid easily fluctuates, which makes the LM-TENG inherently suitable for vibration energy harvesting.
TL;DR: It is demonstrated that the improved performance results from synergistic effects of enlarged open circuit voltage, suppressed trap-assisted recombination, enhanced light absorption, increased hole extraction, efficient energy transfer and better morphology and suggest that ternary structure is a promising platform to boost the efficiency of OSCs.
Abstract: The integration of multiple materials with complementary absorptions into a single junction device is regarded as an efficient way to enhance the power conversion efficiency (PCE) of organic solar cells (OSCs). However, because of increased complexity with one more component, only limited high-performance ternary systems have been demonstrated previously. Here we report an efficient ternary blend OSC with a PCE of 9.2%. We show that the third component can reduce surface trap densities in the ternary blend. Detailed studies unravel that the improved performance results from synergistic effects of enlarged open circuit voltage, suppressed trap-assisted recombination, enhanced light absorption, increased hole extraction, efficient energy transfer and better morphology. The working mechanism and high device performance demonstrate new insights and design guidelines for high-performance ternary blend solar cells and suggest that ternary structure is a promising platform to boost the efficiency of OSCs.
TL;DR: A low-temperature process for efficient semi-transparent planar perovskite solar cells and a hybrid thermal evaporation–spin coating technique is developed to allow the introduction of PCBM in regular device configuration, which facilitates the growth of high-quality absorber, resulting in hysteresis-free devices.
Abstract: Semi-transparent perovskite solar cells are highly attractive for a wide range of applications, such as bifacial and tandem solar cells; however, the power conversion efficiency of semi-transparent devices still lags behind due to missing suitable transparent rear electrode or deposition process. Here we report a low-temperature process for efficient semi-transparent planar perovskite solar cells. A hybrid thermal evaporation-spin coating technique is developed to allow the introduction of PCBM in regular device configuration, which facilitates the growth of high-quality absorber, resulting in hysteresis-free devices. We employ high-mobility hydrogenated indium oxide as transparent rear electrode by room-temperature radio-frequency magnetron sputtering, yielding a semi-transparent solar cell with steady-state efficiency of 14.2% along with 72% average transmittance in the near-infrared region. With such semi-transparent devices, we show a substantial power enhancement when operating as bifacial solar cell, and in combination with low-bandgap copper indium gallium diselenide we further demonstrate 20.5% efficiency in four-terminal tandem configuration.
TL;DR: By controlling the polymer/polymer blend self-organization rate, all-polymer solar cells composed of a high-mobility, crystalline, naphthalene diimide-selenophene copolymer acceptor and a benzodithiophene-thieno[3,4-b]thiopheneCopolymer donor are achieved with a record 7.7% power conversion efficiency and a record short-circuit current density.
Abstract: By controlling the polymer/polymer blend self-organization rate, all-polymer solar cells composed of a high-mobility, crystalline, naphthalene diimide-selenophene copolymer acceptor and a benzodithiophene-thieno[3,4-b]thiophene copolymer donor are achieved with a record 7.7% power conversion efficiency and a record short-circuit current density (18.8 mA cm(-2)).
TL;DR: Solution-processed Cu2 O and CuO cells show significantly enhanced open circuit voltage Voc, short-circuit current Jsc, and power conversion efficiency compared with PEDOT cells, making Cu2O a promising material for further application in perovskite solar cells.
Abstract: Solution-processed Cu2 O and CuO are used as hole transport materials in perovskite solar cells. The cells show significantly enhanced open circuit voltage Voc, short-circuit current Jsc, and power conversion efficiency (PCE) compared with PEDOT cells. A PCE of 13.35% and good stability are achieved for Cu2O cells, making Cu2O a promising material for further application in perovskite solar cells.
TL;DR: In this paper, a non-conjugated small-molecule electrolyte was used as an interlayer to improve the performance of polysilicon solar cells with a power conversion efficiency of 10.02%.
Abstract: Small molecules improve the characteristics of polymer solar cells. Polymer solar cells have drawn a great deal of attention due to the attractiveness of their use in renewable energy sources that are potentially lightweight and low in cost. Recently, numerous significant research efforts have resulted in polymer solar cells with power conversion efficiencies in excess of 9% (ref. 1). Nevertheless, further improvements in performance are sought for commercial applications. Here, we report polymer solar cells with a power conversion efficiency of 10.02% that employ a non-conjugated small-molecule electrolyte as an interlayer. The material offers good contact for photogenerated charge carrier collection and allows optimum photon harvesting in the device. Furthermore, the enhanced performance is attributed to improved electron mobility, enhanced active-layer absorption and properly active-layer microstructures with optimal horizontal phase separation and vertical phase gradation. Our discovery opens a new avenue for single-junction devices by fully exploiting the potential of various material systems with efficiency over 10%.
TL;DR: The design, fabricate, and experimentally demonstrate an ultrathin, broadband half-wave plate in the near-infrared range using a plasmonic metasurface, enabling highly efficient and robust, background-free polarization conversion along with broadband operation.
Abstract: We design, fabricate, and experimentally demonstrate an ultrathin, broadband half-wave plate in the near-infrared range using a plasmonic metasurface. The simulated results show that the linear polarization conversion efficiency is over 97% with over 90% reflectance across an 800 nm bandwidth. Moreover, simulated and experimental results indicate that such broadband and high-efficiency performance is also sustained over a wide range of incident angles. To further obtain a background-free half-wave plate, we arrange such a plate as a periodic array of integrated supercells made of several plasmonic antennas with high linear polarization conversion efficiency, consequently achieving a reflection-phase gradient for the cross-polarized beam. In this design, the anomalous (cross-polarized) and the normal (copolarized) reflected beams become spatially separated, hence enabling highly efficient and robust, background-free polarization conversion along with broadband operation. Our results provide strategies for creating compact, integrated, and high-performance plasmonic circuits and devices.
Patent•
09 Jan 2015TL;DR: In this article, a light emitting device and a system providing white light with various color temperatures are provided, where a light-emitting element (LED) is operated by a driving bias and emits first light, and a phosphor layer is used to partially wavelength-converts first light and emits second light.
Abstract: In a light emitting device and system providing white light with various color temperatures are provided, a light emitting device includes a light emitting element (LED) that is operated by a driving bias and emits first light, and a phosphor layer including a phosphor that partially wavelength-converts first light and emits second light, thereby emitting white light using the first light and the second light, wherein the phosphor has a maximum conversion efficiency at a first level of the driving bias, and the LED has a maximum conversion efficiency at a second level of the driving bias, the first level being different from the first level.
TL;DR: An engineering dimensionless figure of merit (ZT)eng and an engineering power factor (PF)eng are defined as functions of the temperature difference between the cold and hot sides to predict reliably and accurately the practical conversion efficiency and output power, respectively, overcoming the reporting of unrealistic efficiency using average ZT values.
Abstract: The formula for maximum efficiency (ηmax) of heat conversion into electricity by a thermoelectric device in terms of the dimensionless figure of merit (ZT) has been widely used to assess the desirability of thermoelectric materials for devices. Unfortunately, the ηmax values vary greatly depending on how the average ZT values are used, raising questions about the applicability of ZT in the case of a large temperature difference between the hot and cold sides due to the neglect of the temperature dependences of the material properties that affect ZT. To avoid the complex numerical simulation that gives accurate efficiency, we have defined an engineering dimensionless figure of merit (ZT)eng and an engineering power factor (PF)eng as functions of the temperature difference between the cold and hot sides to predict reliably and accurately the practical conversion efficiency and output power, respectively, overcoming the reporting of unrealistic efficiency using average ZT values.
TL;DR: Low-temperature, solution-processable Cu-doped NiOX (Cu:NiOx ), prepared via combustion chemistry, is demonstrated as an excellent hole-transporting layer (HTL) for thin-film perovskite solar cells (PVSCs).
Abstract: Low-temperature, solution-processable Cu-doped NiOX (Cu:NiOx ), prepared via combustion chemistry, is demonstrated as an excellent hole-transporting layer (HTL) for thin-film perovskite solar cells (PVSCs). Its good crystallinity, conductivity, and hole-extraction properties enable the derived PVSC to have a high power conversion efficiency (PCE) of 17.74%. Its general applicability for various elecrode materials is also revealed.
TL;DR: In this paper, the conversion efficiency of CO2 to fuel on a ZnO/g-C3N4 composite photocatalyst under simulated sunlight irradiation was evaluated.
Abstract: The objective of this research was to prepare, characterize and evaluate the conversion efficiency of CO2 to fuel on a ZnO/g-C3N4 composite photocatalyst under simulated sunlight irradiation. The photocatalyst was synthesized by a simple impregnation method and was characterized by various techniques, including Brunauer–Emmett–Teller method (BET), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), and photoluminescence spectroscopy (PL). The characterizations indicate that ZnO and g-C3N4 were uniformly combined. The deposition of ZnO on g-C3N4 showed nearly no effect on its light-absorption performance. However, the interactions between the two components promoted the formation of a hetero-junction structure in the composite, inhibited the recombination of electron–hole pairs and, finally, enhanced the photocatalytic performance of ZnO/g-C3N4. The optimal ZnO/g-C3N4 photocatalyst showed a CO2 conversion rate of 45.6 μmol h−1 gcat−1, which was 4.9 and 6.4 times higher than those of g-C3N4 and P25, respectively. This work represents an important step toward artificial photocatalytic CO2 conversion to fuel using cost-efficient materials.
TL;DR: In this article, a solution-deposited polymer inverted double-and triple-junction solar cells were demonstrated, which achieved a power conversion efficiency of 10.39% and 11.83% respectively, with a bandgap ranging from 1.3 eV to 1.82 eV.
Abstract: High efficiency, solution-deposited polymer inverted double- and triple-junction solar cells are demonstrated. The devices are composed of three distinctive photosensitive materials in three distinct subcells, with minimal absorption spectral overlap, and with a bandgap ranging from 1.3 eV to 1.82 eV. A transparent hybrid inorganic organic mixture was introduced as an interconnecting layer to optically and physically connect the subcells. Accordingly, a power conversion efficiency of 10.39% was attained for the double-junction cell and a record high of 11.83% was obtained for the triple-junction cell.
TL;DR: The ability of a novel sequential inorganic ZnS/SiO2 double layer treatment onto the QD-sensitized photoanode for strongly inhibiting interfacial recombination processes in QDSCs while providing improved cell stability is demonstrated.
Abstract: At present, quantum-dot-sensitized solar cells (QDSCs) still exhibit moderate power conversion efficiency (with record efficiency of 6–7%), limited primarily by charge recombination. Therefore, suppressing recombination processes is a mandatory requirement to boost the performance of QDSCs. Herein, we demonstrate the ability of a novel sequential inorganic ZnS/SiO2 double layer treatment onto the QD-sensitized photoanode for strongly inhibiting interfacial recombination processes in QDSCs while providing improved cell stability. Theoretical modeling and impedance spectroscopy reveal that the combined ZnS/SiO2 treatment reduces interfacial recombination and increases charge collection efficiency when compared with conventional ZnS treatment alone. In line with those results, subpicosecond THz spectroscopy demonstrates that while QD to TiO2 electron-transfer rates and yields are insensitive to inorganic photoanode overcoating, back recombination at the oxide surface is strongly suppressed by subsequent inor...
TL;DR: In this article, an optical model based on the transfer-matrix formalism for analysis of perovskite-based planar heterojunction solar cells using experimentally determined complex refractive index data is presented.
Abstract: Metal-halide perovskite light-absorbers have risen to the forefront of photovoltaics research offering the potential to combine low-cost fabrication with high power-conversion efficiency. Much of the development has been driven by empirical optimisation strategies to fully exploit the favourable electronic properties of the absorber layer. To build on this progress, a full understanding of the device operation requires a thorough optical analysis of the device stack, providing a platform for maximising the power conversion efficiency through a precise determination of parasitic losses caused by coherence and absorption in the non-photoactive layers. Here we use an optical model based on the transfer-matrix formalism for analysis of perovskite-based planar heterojunction solar cells using experimentally determined complex refractive index data. We compare the modelled properties to experimentally determined data, and obtain good agreement, revealing that the internal quantum efficiency in the solar cells approaches 100%. The modelled and experimental dependence of the photocurrent on incidence angle exhibits only a weak variation, with very low reflectivity losses at all angles, highlighting the potential for useful power generation over a full daylight cycle.